Cancer Treatment: The Critical Factors
In order to derive the greatest potential benefit from any cancer treatment regimen, both patients and physicians must respect and adapt to the complex and multidimensional nature of each individual's unique cancer. Sadly, the mainstream medical establishment treats the majority of cancer cases with a "one size fits all" strategy that may deprive many patients of a greater chance of successful treatment.
Implementing strategies to address each of the ten critical factors of cancer treatment identified in this Life Extension protocol provides an evidenced based approach that will:
In this protocol, Life Extension will discuss the following ten critical steps that may increase the likelihood of a successful outcome in the treatment of many cancers:
Of critical importance to treatment-naïve patients is implementing as many of these ten critical steps as can safely be done concurrently with conventional therapy. In newly diagnosed patients who have not yet been treated, the objective is to eradicate the primary tumor and metastatic cells with a multi-pronged "first strike therapy" so that residual tumor cells are not given an opportunity to evolve survival mechanisms that make them resistant to further treatments.
Step One: Evaluating the Molecular Biology of the Tumor Cell Population
Throughout this protocol, you will see terminology relating to the molecular aspects of the cancer cell. When we use the term molecular, we are referring to specific characteristics of cancer cells such as:
These individual variations—the unique biology of the cancer cell—help explain why a particular therapy may be highly effective for some cancer patients but fail others.
People typically think of their disease based on the organ it affects (eg, lung cancer or colon cancer). The problem with that rationale is not all cancers are the same, even if they affect the same organ. With the advent of advanced molecular diagnostic profiling, the specific strengths and vulnerabilities of each patient's cancer can be identified in order to design an individually tailored treatment program.
It is critically important to obtain a description of the type of cells that populate your tumor. Not only does this assist the oncologist in recommending the most effective conventional therapy, but it also helps determine what adjuvant nutritional and/or off-label drug therapies to consider. The human eye can serve to provide the most basic information about a cancer cell through the microscopic examination of the cell's general characteristics. Taking this one step further is evaluation by an immunohistochemistry test. This test detects markers of diagnostic value, on and within the cell surface, through the application of colored dye or stains. In order to perform this and other tests, it is necessary for a sample of your tumor to be sent to a specialized laboratory.
Caris Life Sciences provides a comprehensive range of customized analyses to help cancer specialists correctly identify difficult-to-diagnose tumors, establish prognosis in many cancers (including breast, prostate, and colon), and determine optimal treatment. By providing this information, Caris Life Sciences starts treatment on the right course and helps avoid unnecessary and potentially ineffective therapies. Caris Life Sciences performs more specialized analyses for cancer than any other laboratory in the world.
When a person has cancer, the physician confronts a chain of pressing questions: What type of cancer is it? Where did it originate? Which treatments are most likely to be effective? Caris Life Sciences can help clinicians with answers to many of these questions.
As far as diagnosis is concerned, many cancers defy classification by visual examination. In fact, the diagnosis of "metastatic cancer of unknown primary site" accounts for 2 – 6% of cancer diagnoses (Tan 2011). In a majority of these difficult cases, Caris Life Sciences' medical expertise and advanced technologies lead to an accurate diagnosis.
Visual examination of tumors provides very little information about their growth rate or the type of treatment to which they will respond. Caris Life Sciences' prognostic expertise can accurately evaluate the aggressiveness of the cancer and predict the effects of therapy.
Cancers have traditionally been treated as follows: if one therapy proves ineffective, then try another until a successful therapy is found or all options are exhausted. Caris Life Sciences helps eliminate the need for this trial-and-error method by providing individualized information to help determine the optimal therapy before initiating treatment. This can save the patient time, money, and most importantly, it may provide a better opportunity for "first strike" eradication.
Caris Life Sciences provides highly sensitive patient monitoring for the follow-up care of many cancers. For example, Caris Life Sciences can determine whether certain types of lymphomas have recurred before they can be detected by any other method. The earlier tumor recurrence is detected, the greater the likelihood of therapeutic success.
Typically, within 48 hours after receiving a specimen, Caris Life Sciences returns the stained slides along with a thorough and detailed case report to a physician. Your oncologist can also consult with a member of the Caris Life Sciences staff by phone.
How to Implement Step One
Make certain your surgeon sends a specimen of your tumor to Caris Life Sciences for immunohistochemistry testing. Be sure to follow the instructions that Caris Life Sciences provides for proper shipping of the surgical specimen. You may have to pay out of pocket for this test because not all insurance plans reimburse for it. Please note that this test may not be of benefit to all cancer patients. While it provides a basis for improved treatment, not all cancers are effectively treated with current therapies.
Step Two: Determine Sensitivity or Resistance to Chemotherapy
When a person is prescribed a treatment for their cancer, they might assume that the treatment was chosen based on the uniqueness of their cancer. For instance, when a woman with early-stage breast cancer is told that her chemotherapy treatment regimen will consist of the drugs Adriamycin®, Cytoxan®, and Taxol® (ACT), she might think this treatment was individually tailored for her cancer. In actuality, ACT is a standard chemotherapy protocol given to breast cancer patients. This "one size fits all" approach to breast cancer treatment would work well if superior results were obtained from this routine practice. Sadly, this has not been the case.
The "one size fits all" approach to prescribing chemotherapy has failed to improve survival for the vast majority of women with breast cancer. In a shocking study of women with breast cancer over the age of 50 who had cancer present in their lymph nodes, standard chemotherapy regimens were shown to increase 10 year survival by only 3% (Lancet 1998; Clarke MJ 2008). Other studies have determined that standard chemotherapy does not improve survival in women with estrogen-receptor positive breast cancer (Gelber 1996; International Breast Cancer Study Group 2002).
A critical flaw of the "one size fits all" approach rests in treating all breast cancers as if they are one in the same. Although traditional oncology does make distinctions in a few obvious qualities, such as size of the cancer, lymph node status, and estrogen receptor status, we now know there can be substantial individual differences in cancer cell genetics among those with "similar" breast cancers. These differences can dramatically influence the response to treatment. A powerful illustration of the lack of appreciation for individual differences in cancer treatment was clearly revealed in a landmark study published in the New England Journal of Medicine in 2007. Researchers compared women with lymph node positive breast cancer who received ACT chemotherapy to those who did not receive chemotherapy (Hayes 2007). Their HER2 status was also determined—which refers to a genetic characteristic of the cancer. The researchers discovered that the group of women who were HER2 negative and estrogen receptor positive did not benefit at all from taking Taxol®. The ramifications of this study are immense,asa large percentage of women with breast cancer fall into this category. In recognition of the failure of Taxol® to benefit this large group of women with breast cancer, oncologist Anne Moore, M.D., Professor of Clinical Medicine at the Weill Medical College of Cornell University in New York stated, "The days of 'one size fits all' therapy for patients with breast cancer are coming to an end" (Moore 2007).
Breast cancer is not the only type of cancer in which resistance to chemotherapy my impair treatment; in fact, all cancers may display interindividual variability in chemosensitivity. For example, assessing expression of a chemoresistance protein (IGFBP2) in leukemia patients helped identify those who were likely to respond to standard chemotherapy, and those who were not (Kuhnl 2011).
If chemotherapy is being considered, it is crucial to ascertain which chemotherapy drugs will have the highest probability of being effective against your particular cancer. A company called Rational Therapeutics, Inc. performs chemo-sensitivity testing on your living cancer cells to determine how your cancer cells respond when exposed to various drugs in the laboratory.
Rational Therapeutics, Inc., was founded in 1993 by Dr. Robert Nagourney, a prominent hematologist and oncologist. Rational Therapeutics pioneers cancer therapies that are specifically tailored for each individual patient, and is a leader in individualized cancer strategies. With no financial ties to outside healthcare organizations, recommendations are made without financial bias.
Rational Therapeutics develops and provides cancer therapy recommendations that have been designed scientifically for each patient. Following the collection of living cancer cells obtained at the time of biopsy or surgery, Rational Therapeutics performs an Ex-Vivo Analysis of Programmed Cell Death (EVA-PCD) functional profile on your tumor sample to measure drug activity (sensitivity and resistance). Ex-vivo analyses means that your living tumor cells are maintained outside of your body for the purpose of determining which drug or drug combination most effectively induces cell death in the laboratory. Each patient is highly individualized with regard to his or her sensitivity to chemotherapy drugs. Your responsiveness to chemotherapy is as unique as your fingerprints. Therefore, this test will help to determine which drug(s) will be most effective for you. Rational Therapeutics will then make a treatment recommendation based on these findings.
Rational Therapeutics provides custom-tailored, assay-directed therapy based on your tumor response in the laboratory. This eliminates much of the guess work prior to your undergoing the potentially toxic side effects of chemotherapy regimens that could prove to be of little value against your cancer.
Contact information for Rational Therapeutics:
Rational Therapeutics, Inc.
How to Implement Step Two
Contact Rational Therapeutics so that your surgeon can follow the precise instructions required to send a living specimen of your tumor for chemo- sensitivity testing. It is important that your surgeon carefully coordinate with Rational Therapeutics in order to ensure your cells arrive in a viable condition. You may have to pay for this test yourself because your insurance may not reimburse for it. Please note that this test may not be of benefit to all cancer patients. While it provides a basis for improved treatment, not all cancers are effectively treated with current therapies.
Step Three: Circulating Tumor Cell Testing
Circulating Tumor Cell (CTC) testing involves the detection of cancer cells in the bloodstream. These circulating tumor cells are the "seeds" that break away from the primary site of cancer and spread to other parts of the body. Understanding circulating tumor cells is critically important since it is the spread of cancer to other parts of the body—and not the primary cancer—that is very often responsible for the death of a person with cancer.
Historically, medical science has been focused on the primary tumor, basing treatment decisions on the specific genetic characteristics of the primary cancer cells—which assumes that the metastatic cancer cells are genetically identical to the primary tumor. This assumption might be ill-advised, as research has demonstrated that metastatic cancer cells can be genetically dissimilar from the primary tumor as they become more highly differentiated.
In an illuminating study conducted with metastatic breast cancer patients, researchers compared the genetic composition of the cancer cells that had formed distant metastasis to the genetic composition of the corresponding cancer cells in the primary breast tumor. The findings were alarming—in 31% of the comparisons, the genetic composition of the metastatic cancer cells differed almost completely from that of the primary breast tumors (Kuukasjärvi et al. 1997). Amazingly, further analysis revealed that none of the pairs of primary breast tumors with its corresponding metastatic cancer were identical. Based on these findings, the authors remarked that "because metastatic cells often have a completely different genetic composition, their phenotype [biological behavior], including aggressiveness and therapy responsiveness, may also vary substantially from that seen in the primary tumors," leading to their conclusion that "the resulting heterogeneity [genetic variability] of metastatic breast cancer may underlie its poor responsiveness to therapy..." To further support the evidence that metastatic cancer cells can vary genetically from the primary tumor, two additional studies with breast cancer patients have demonstrated that CTC can be HER2 positive while the primary breast tumor can be HER2 negative (Meng et al. 2004; Wülfing et al. 2006).
This research suggests that directing treatment towards the cancer cells of the primary tumor can, in some cases, be "barking up the wrong tree". Treatments designed to attack the primary tumor could fail to destroy the circulating tumor cells. For this reason, focusing on the metastatic cancer cells could potentially lead to better results. Circulating Tumor Cell (CTC) testing provides us with the means with which we can now focus our attention on these potential metastatic cancer cells.
CTC testing has been shown to improve prognostic accuracy. German scientists studied 35 women with non-metastatic breast cancer who had their levels of CTC measured before they had received any treatment for their cancer (Wülfing 2006). 17 tested positive for CTC, while 18 tested negative for CTC. The group that tested negative for CTC had a median overall survival of 125 months. The group with 5 or more CTC present in their blood sample had a median overall survival of only 61 months – less than half as long. In a related study, researchers at the University of Texas M. D. Anderson Cancer Center measured CTC in 151 women with metastatic breast cancer (Cristofanilli et al. 2007). These patients were also evaluated for other prognostic cancer markers, such as hormone receptor status, CA 27.29, and HER2 status. Those who had 5 or more CTC per blood sample had a median overall survival of 13 ½ months. The median overall survival for those with less than 5 CTC per blood sample was over 29 months. The researchers also discovered that the presence of 5 or more CTC in a blood sample had the highest predictive value compared to all other tumor markers. The researchers went on to state that "circulating tumor cells have superior and independent prognostic value…"
Furthermore, recent research indicates that CTC evaluation can be used to predict prognosis for men with prostate cancer. Researchers at Thomas Jefferson University compared the levels of CTC in 37 men with metastatic prostate cancer (Moreno et al. 2005). Their findings were remarkable—for the men with 5 or more CTC per blood sample, the median overall survival was only 8.4 months. For those men with fewer than 5 CTC the median overall survival was 48 months. Yet another study measured CTC in 55 men with a rising PSA after surgery for prostate cancer (Tombal et al. 2003). A rising PSA after surgery is strongly predictive of prostate cancer recurrence (Pound et al. 1999). Radiation therapy was administered to 15 patients. 60% of those who were CTC positive had progression of their disease during radiation therapy, while there were no diseaseprogressions in the CTC negative group. Additional studies have confirmed these results (Halabi et al. 2003; Danila et al. 2007).
One of the most exciting potential uses of CTC technology is to allow doctors to evaluate treatment effectiveness during the early phase of therapy. With regard to chemotherapy, doctors have often had to wait at least a few months before they can assess the effectiveness of treatment. This inability to evaluate a treatment’s efficacy during the early phase of therapy can have disastrous consequences for the person with cancer. Those three months of waiting to know if the treatment is working can make the difference between altering therapy to reflect the lack of response, or continuing with an ineffective treatment and allowing the cancer to progress. This waiting may become a thing of the past, as recent studies have demonstrated that CTC testing can reliably predict the response to treatment during the early phase of therapy. In an important study (Hayes et al. 2006), 163 women with metastatic breast cancer were tested for CTC at four different times during the course of treatment. The first measurement of CTC was taken approximately 4 weeks after treatment had begun. At the first measurement the researchers discovered that those patients with less than 5 CTC per sample had a median overall survival of greater than 18.5 months. Those with 5 or more CTC per sample had a median overall survival of only 7 months. Additionally, 66% of those with 5 or more CTC per sample had died after one year, compared to only 19% of those who had less than 5 CTC per sample. Thus, as early as 4 weeks into therapy CTC testing determined which patients were not responding and whose cancer would continue to progress with ineffective treatment. The authors of this study concluded that "detection of elevated CTC at any time during therapy is an accurate indication of subsequent rapid disease progression and mortality for metastatic breast cancer patients."
In a study published in the Journal of Clinical Oncology in 2008, 430 patients with metastatic colon cancer had CTC testing before and 3-5 weeks after the initiation of treatment with chemotherapy (Cohen et al. 2008). For patients who initially started with 3 or more CTC detected in their blood sample, if they converted to less than 3 CTC then the median survival was 11.0 months. However, if they continued to have 3 or more CTC on follow-up testing then the median survival was only 3.7 months. For patients whose cancers were deemed to be nonprogressing by imaging studies, median survival was 18.8 months if they had less than 3 CTC on follow-up testing, whereas those with 3 or more CTC on follow-up testing had a median survival of only 7.1 months. The authors concluded that "the number of CTCs before and during treatment is an independent predictor of…overall survival in patients with metastatic colorectal cancer. CTCs provide prognostic information in addition to that of imaging studies."
CTC testing can also predict the likelihood of recurrence after initial cancer treatment. In 2006, scientists in Spain measured the presence of CTC in 84 high-risk breast cancer patients after they received initial chemotherapy (Quintela-Fandino et al. 2006). The researchers found dramatic differences in the relapse rates between those who tested positive for CTC, as compared to those that did not have any CTC detected in their blood samples. The group testing positive for CTC had a 269% increased risk of relapse, and a 300% increased risk of death, compared to the group testing negative for CTC. Further analysis showed a striking 53 month difference in the time to relapse between the groups. In a related study, German scientists in 2008 studied 25 women with breast cancer that had not metastasized (Pachmann et al. 2008). They measured CTC levels before and after the patients received chemotherapy. The results showed that relapse occurred in only 9% of patients whose CTC levels indicated a decline, no change, or minor increase when compared to baseline CTC levels. There was a substantially higher relapse rate of 40% in the group with a CTC increase at the end of therapy.
Given that CTC can be the seeds that eventually form metastatic disease, then CTC analysis provides medical science with an excellent opportunity to examine the genetic features of these cancer cells before metastasis occurs, when treatment is far more likely to be successful. In addition to detecting the presence and quantity of CTC in the bloodstream, recent advances in technology now allows the examination of CTC for a large number of tumor cell markers and genetic expressions. The information obtained from this analysis can provide vital insight as to which chemotherapy drugs are best suited to exploit the genetic weaknesses of the CTC, as well as which chemotherapy agents are likely to be powerless against the genetic strengths of the CTC.
Let’s illustrate the benefits of CTC analysis of tumor markers and genetic expressions with a few examples. Chemotherapy drugs can exert their therapeutic effects by inhibiting essential enzymes within the cancer cell. The over expression of these enzymes—called drug targets—can enhance the tumor destructive effects of these drugs. Adriamycin (Doxorubicin) is a prime example of this mechanism of action. The main drug target for Adriamycin is topoisomerase 2. Studies have demonstrated that those patients with cancers expressing higher levels of topoisomerase 2 can benefit from treatment with Adriamycin (Di Leo et al. 2002). Conversely, those patients with cancers that produce smaller amounts of topoisomerase 2 are less likely to respond to Adriamycin. Cancer cells also have the ability to produce enzymes that convert chemotherapy drugs into less potent forms, which weakens the anti-tumor activity of these drugs. 5-FU is commonly used in the treatment of breast and colon cancer. DPD is an enzyme that degrades 5-FU to an inactive metabolite. Cancer cells expressing higher levels of DPD can be resistant to 5-FU. One study of colorectal cancer patients treated with 5-FU revealed that those with high DPD levels had significantly shorter overall survival compared to patients with low DPD expression (Ciaparrone et al. 2006).
As an added benefit, genetic analysis of CTC can inform us as to which natural supplements might be best indicated. For instance, NF-kB promotes the growth of cancer. Curcumin is an inhibitor of NF-kb (Siwak et al. 2005). So, a person whose cancer is expressing high levels of NF-kB might consider including curcumin as part of their supplement program.
Some cancers are able to produce GSTpi, which confers resistance to multiple chemotherapy drugs. Ellagic acid—from pomegranate—inhibits GSTpi (Hayeshi et al. 2007). Supplementation with Ellagic acid may be wise if CTC analysis demonstrates over production of GSTpi.
How to Implement Step Three
To test for the presence and quantity of CTC in your blood, speak with your physician regarding the Veridex CellSearch® CTC test. You may also order quantitative CTC tests for breast, colon, and prostate cancer from Life Extension at 800-226-2370, or on the web at www.lef.org.
Note: Qualitative CTC testing is most feasible with any kind of carcinoma (e.g. lung, colon, breast, ovary, cervix, prostate, stomach, gastric, esophagus, liver...), mesothelioma or melanoma.
It is also possible to test for synovial sarcoma. However, other types of sarcoma (e.g. liposarcoma, leiomyosarcoma, chondrosarcoma...) gave lower success rates for isolation of tumor cells (<50%).
Testing of tumors of the central nervous system (e.g. glioblastoma) is limited, because in the majority of cases it is not successful to isolate CTCs, since these tumors rarely shed tumor cells into the bloodstream.
For a molecular analysis of your CTC, contact the International Strategic Cancer Alliance at 610-628-3419 to arrange for a blood specimen to be obtained and shipped for testing. Note: this test is qualitative and will not provide the number of CTC present in your blood. You may have to pay out of pocket for this test because not all insurance plans reimburse for it. Please note that this molecular analysis test of circulating tumor cells may not be of benefit to all cancer patients. While it provides a basis for improved treatment, not all cancers are effectively treated with currently available therapies.
Step Four: Inhibiting the Cyclooxygenase Enzymes (COX-1 & COX-2)
Inflammation plays a pivotal role in the formation and progression of cancer. There are many inflammatory pathways in the body. The cyclooxygenase (COX-2) enzyme is a particular inflammatory pathway that has been the focus of research in the realm of oncology. Initially, scientists believed COX-2 was merely an inducible response to inflammation. It is now speculated that COX-2 performs biological functions in the body, particularly in the brain and kidneys as well as the immune system. COX-2 becomes troublesome when upregulated (sometimes 10- to 80-fold) by pro-inflammatory stimuli (interleukin-1, growth factors, tumor necrosis factor, and endotoxins). When over-expressed, COX-2 participates in various pathways that could promote cancer (i.e. angiogenesis), cell proliferation, and the production of inflammatory prostaglandins (Sears 1995; Newmark 2000; Chakraborti AK 2010).
A growing body of research has documented the relationship between COX-2 and cancer:
Life Extension recognizes the value of COX-2 inhibitors in cancer treatment. Some progressive oncologists include COX-2 inhibitors in their anticancer protocols, but the numbers are still relatively few. TGhe risks associated with traditional NSAIDs include gastrointestinal perforation, ulceration and bleeding, and less frequently, renal and liver damage, but the benefits of for certain cancer patients may outweigh these risks.
A number of natural COX-2 inhibitors are discussed in the protocol entitled Cancer Adjuvant Therapy.
Like COX-2, the COX-1 enzyme also catalyzes (mediates) the conversion of certain fatty acids into inflammatory end products in some cell types. Cancer cells are sometimes genetically altered in such a way that causes them to express higher levels of COX-1; this has been observed in several types of cancer including ovarian, colon, and head and neck cancers (Erovic 2008; Khunnarong 2008; Wu 2009). Moreover, selectively inhibiting COX-1 with experimental compounds has demonstrated a marked reduction in viability of colon cancer cells and ovarian cancer cells (Wu 2009; Li 2009).
Experimental studies on breast cancer cells revealed that simultaneous inhibition of both COX-1 and COX-2 might exert a synergistic effect to combat cancer cell growth (McFadden 2006). The authors of this study concluded that "The significant and additive effects exhibited by the combination of COX-1 and -2 inhibitors and their effects on cell cycle suggest that these agents could become an effective treatment modality for carcinoma of the breast."
Aspirin is an NSAID, but its actions are unique in that it selectively inhibits COX-1 activity while modulating the expression of COX-2 (Wu 2003). The net result of this dualistic action is diminished production of harmful metabolites via COX-1 and a reduction in total COX-2 activity. Since both COX-1 and COX-2 are drivers of inflammatory cancer cell growth, aspirin is an important yet underappreciated anticancer drug.
At the forefront of the growing field of research into aspirin’s role as a cancer fighter is Professor Peter Rothwell of Oxford University. Having specialized primarily in cardiovascular medical research, he and his colleagues had at their disposal a trove of information compiled from eight massive studies examining the effect of aspirin therapy on cardiovascular health.
Among the most compelling of their findings:
The data correlating aspirin therapy with colon cancer prevention proved particularly compelling. Rothwell’s team saw a 24% reduction in the risk of developing colon cancer over a 20-year period in patients who took aspirin daily and a 35% reduction in the risk of dying from colon cancer. The most potent preventive benefit was observed in cancers of the upper colon (the ascending and transverse colon) (Rothwell 2010).
Separate observational studies have suggested a preventive effect for cancers of the esophagus, stomach, lung, breast, and ovaries (Sjodahl 2001; Corley 2003; Bosetti 2009). A 2010 study revealed that men taking regular aspirin supplements attained a 10% reduction in prostate cancer risk compared to men who took no aspirin (Dhillon 2010). Another study showed a risk reduction of 24% in long-term users (greater than 5 years), and 29% in daily aspirin users (Salinas 2010).
How to Implement Step Four
Note: The use of Lodine and Celebrex® has been associated with an increased risk of heart attack and stroke. The anti-cancer benefits of these drugs have to be weighed against these increased cardiovascular risks. Using aspirin in combination with a COX-2 inhibitor may increase the risk for bleeding, but also reduce cardiovascular risks; speak with your physician before combining aspirin with a COX-2 inhibitor.
Step Five: Suppressing Ras Oncogene Expression
The family of proteins known as Ras plays a central role in the regulation of cell growth. It fulfills this fundamental role by integrating the regulatory signals that govern the cell cycle and proliferation.
Defects in the Ras-Raf pathway can result in cancerous growth. Mutant Ras genes were among the first oncogenes identified for their ability to transform cells into a cancerous phenotype (i.e. a cell observably altered because of distorted gene expression). Mutations in one of three genes (H, N, or K-Ras) encoding Ras proteins are associated with upregulated cell proliferation and are found in an estimated 30-40% of all human cancers. The highest incidences of Ras mutations are found in cancers of the pancreas (80%), colon (50%), thyroid (50%), lung (40%), liver (30%), melanoma (30%), and myeloid leukemia (30%) (Duursma 2003; Minamoto 2000; Vachtenheim 1997; Bartram 1988; Bos 1989; Minamoto 2000; Hsieh JS 2005; Däbritz J 2009).
The differences between oncogenes and normal genes can be slight. The mutant protein that an oncogene ultimately creates may differ from the healthy version by only a single amino acid, but this subtle variation can radically alter the protein's functionality.
The Ras-Raf pathway is used by human cells to transmit signals from the cell surface to the nucleus. Such signals direct cells to divide, differentiate, or even undergo programmed cell death (apoptosis).
A Ras gene usually behaves as a relay switch within the signal pathway that instructs the cell to divide. In response to stimuli transmitted to the cell from outside, cell-signaling pathways are activated. In the absence of stimulus, the Ras protein remains in the "off" position. A mutated Rasprotein gene behaves like a switch stuck on the "on" position, continuously misinforming the cell, instructing it to divide when the cycle should be turned off (Gibbs et al. 1996; Oliff et al. 1996). Researchers have known for some time that injecting anti-Ras antibodies, specific for amino acid 12, cause a reversal of excessive proliferation and a transient alteration of the mutated cell to one of a normal appearance (Feramisco et al. 1985). Recently, scientists have taken advantage of the high frequency at which K-ras is mutated in several types of cancer by developing vaccines that trigger the immune system to attack cells harboring this mutant protein. For example, a 2011 study found that patients with resected pancreatic cancer were much more likely to be alive 10 years post vaccination (20%) than those who did not receive the vaccine (0%) (Weden 2011).
To establish new methods for diagnosing pancreatic cancer, K-Ras mutations were examined in the pancreatic juice of pancreatic cancer patients. Pancreatic juice was positive for K-Ras in 87.8% (36/41) of patients (Lu 2001). When combined with p53 mutations in the stool and CA 19-9 (a blood marker for pancreatic cancer), it may be possible to identify the disease much earlier than by conventional diagnostic methods (Wu X 2006).
Greater understanding regarding the activity of mutant Ras genes opens exciting avenues of treatment. Researchers found that precursor Ras genes must undergo several biochemical modifications to become mature, active versions. After such maturation, the Ras proteins attach to the inner surface of the cells outer membrane where they can interact with other cellular proteins and stimulate cell growth.
The events resulting in mature Ras genes take place in three steps, the most critical being the first—referred to as the farnesylation step. A specific enzyme, farnesyl-protein transferase (FPTase), speeds up the reaction. One strategy for blocking Ras protein activity has been to inhibit FPTase. Inhibitors of this enzyme block the maturation of Ras protein and reverse the cancerous transformation induced by mutant Ras genes (Oliff et al. 1996).
A number of natural substances impact the activity of Ras oncogenes. For example, limonene is a substance found in the essential oils of citrus products. Limonene has been shown to act as a farnesyl transferase inhibitor. Administering high doses of limonene to cancer-bearing animals blocks the farnesylation of Ras, thus inhibiting cell replication (Bland 2001; Asamoto et al. 2002). Curcumin inhibited the farnesylation of RAS, and caused cell death in breast cancer cells expressing RAS mutations (Kim et al. 2001; Chen et al. 1997).
Japanese researchers examined the effects of vitamin E on the presence of K-Ras mutations in mice with lung cancer. Prior to treatment with vitamin E, K-Ras mutations were present in 64% of the mice. After treatment with vitamin E, only 18% of the mice expressed K-Ras mutations (Yano et al. 1997). Vitamin E decreased levels of H-Ras proteins in cultured melanoma cells (Prasad et al. 1990). A study conducted at Mercy Hospital of Pittsburgh also showed that diallyl disulfide, a naturally occurring organosulfide from garlic, inhibits p21 H-Ras oncogenes, displaying a significant restraining effect on tumor growth (Singh et al. 2000).
Researchers at Rutgers University investigated the ability of different green and black tea polyphenols to inhibit H-Ras oncogenes. The Rutgers team found that all the major polyphenols contained in green and black tea except epicatechin showed strong inhibition of cell growth (Chung et al. 1999). Investigators at Texas A&M University also found that fish oil decreased colonic Ras membrane localization and reduced tumor formation in rats. In view of the central role of oncogenic Ras in the development of colon cancer, the finding that omega-3 fatty acids modulate Ras activation could explain why dietary fish oil protects against colon cancer (Collett et al. 2001).
Statins are a class of popular cholesterol-lowering drugs. Mevacor (lovastatin), Zocor (simvastatin), and Pravachol (pravastatin) are statin drugs shown to inhibit the activity of Ras oncogenes (Wang et al. 2000). Statin drugs block the HMG-COA) reductase enzyme, which depletes cells of farnesyl pyrophosphate. This results in a reduction of activated farnesylated Ras (Hohl et al. 1995).
Illustrative of the potential of statin therapy, patients with primary liver cancer were treated with either the chemotherapeutic drug 5-FU or a combination of 5-FU and 40 mg/day of pravastatin (Kawata S 2001). Median survival increased from 9 months, among patients treated with only 5-FU, to 18 months when using 5-FU combined with the statin drug pravastatin (Pravachol®). In 2008, German researchers studied the effects of pravastatin in patients with advanced liver cancer (Graf H 2008). 131 patients received chemoembolization alone, while 52 patients received chemoembolization plus pravastatin (20mg-40mg). During the observation period of up to 5 years, 23.7% of the patients treated with chemoembolization alone had survived, compared to a 36.5% survival for the chemoembolization and pravastatin group. Median survival was 12 months for the chemoembolization only group, while the pravastatin group had a median survival of 20.9 months.
Statin drugs are known to deplete coenzyme Q10 (CoQ10) levels, therefore those taking a statin drug should supplement with CoQ10. For a detailed explanation, please consult the Coenzyme Q10 section in the Cancer Adjuvant Therapy protocol.
Individuals with cancer should consider an immunohistochemistry test of their cancer tissue for mutated ras genes at Caris Life Sciences Laboratories (see Step One of this protocol), a recommendation the Life Extension first made in 1997. Life Extension strongly believes all cancer patients should undergo immunohistochemical testing to determine Ras status.