Is Cancer a Genetic Disease?

I recently had the opportunity to meet two charming young patients: One, a 32-year-old female with an extremely rare malignancy that arose in her kidney and the other a 33-year-old gentleman with widely metastatic sarcoma.

Both patients had obtained expert opinions from renowned cancer specialists and both had undergone aggressive multi-modality therapies including chemotherapy, radiation and surgery. Although they suffered significant toxicities, both of their diseases had progressed unabated. Each arrived at my laboratory seeking assistance for the selection of effective treatment.

With the profusion of genomic analyses available today at virtually every medical center, it came as no surprise that both patients had undergone genetic profiling. What struck me were the results. The young woman had “no measurable genetic aberrancies” from a panoply of 370 cancer-causing exomes, while the young man’s tumor revealed no somatic mutations and only two germ-line SNV’s (single nucleotide variants) from a 50 gene NextGen sequence, neither of which had any clinical or therapeutic significance.

What are we to make of these findings? By conventional wisdom, cancer is a genetic disease. Yet, neither of these patients carried detectable “driver” mutations. Are we to conclude that the tumors that invaded the cervical vertebra of the young woman, requiring an emergency spinal fusion, or the large mass in the lung of the young man are not “cancers”? It would seem that if we apply contemporary dogma, these patients do not have a cancer at all. But nothing could be further from the truth.

Cancer as a disease is not a genomic phenomenon. It is a phenotypic one. As such, it is extremely likely that these patients’ tumors are successfully exploiting normal genes in abnormal ways. The small interfering RNAs or methylations or acetylation or non-coding DNA’s that conspired to create these monstrous problems are too deeply encrypted to be easily deciphered by our DNA methodologies. These changes are effectively gumming up the works of the cancer cell’s biology without leaving a fingerprint.  

I have long recognized that cellular studies like the EVA-PCD platform provide the answers, through functional profiling, that genetic analyses can only hope to detect. The assay did identify drugs active in these patients’ tumor, which will offer meaningful benefit, despite the utter lack of genetic targets. Once again, we are educated by cellular biology in the absence of genomic insights. This leaves us with a question however – is cancer a genetic disease?

In Cancer Research: An Awakening?

In 2005, as the Iraq War reached a low point with casualties mounting and public support dwindling, Sunni tribesman in the Anbar Province arose to confront the enemy. Joining together as an ad hoc army these fighters turned the tide of the war and achieved victories in the face of what had appeared at the time, to be overwhelming odds.

I am reminded of this by an article in The Wall Street Journal by Peter Huber and Paul Howard of the Manhattan Institute that examined the bureaucracy of drug development. It raised the question: Are new cancer treatments failures or is the process by which they are approved a failure? They describe “exceptional responders” defined as patients who show unexpected benefits from drug treatments. Using molecular profiles, they opine, scientists will unravel the mysteries of these individuals and usher in an era of personalized medicine. Thus, rigid protocols that use drugs based upon tumor type e.g. lung vs. colon fail because they do not incorporate the features that make each patient unique – an awakening.

The example cited is from Memorial Sloan-Kettering where a patient with bladder cancer had an unexpected response to the drug Everolimus (approved for kidney cancer). Subsequent deep sequencing identified a genetic signature associated with sensitivity to this drug. While it is a nice story, I already knew it very well because it had been repeated many times before and would in the past have been dismissed as an “anecdote.” It is precisely because of its rarity that it has been repeated so many times.

The WSJ analysis strikes a familiar chord. For decades, we have decried the failure of rigid clinical trials that underestimate a patient’s unique biology yet cost millions, even billions of dollars, while denying worthy candidates new treatments under stultifying disease-specific designs.

We pioneered phenotypic (functional) analyses (the EVA-PCD platform) to examine whole cell models as we explored drug response profiles, novel combinations and new targets. It is regrettable that these WSJ authors, having raised such important issues, then stumble into the same tantalizing trap of molecular diagnostics, and call for bigger, better, faster genomic analyses.

Cancer patients need to receive treatments that work. They do not particularly care why or how they work, just that they work. These authors seem to perpetuate the myth that we must first understand why a patient responds before we can treat them. Nothing could be further from the truth.

Alexander Fleming knew little about bacterial cell wall physiology when he discovered penicillin in 1928, and William Withering knew nothing about the role of muscle enzymes in congestive heart failure when he discovered digoxin extracts in 1785. Would anyone argue that we should have waited decades, even centuries to apply manifestly effective therapies to patients because we did not have the “genes sequenced?’

We may be witness to an awakening in cancer drug development. It may be that a new understanding of individualized patient response will someday provide better outcomes, but platforms with the proven capacity to connect patients to available treatments should be promoted and applied today.

A New Use for One of the Oldest “New” Drugs

With the profusion of new targeted agents entering the clinical arena, a report from the American Society of Hematology bears consideration.

The trial known as the SORAML trial enrolled 276 patients with newly diagnosed acute myelogenous leukemia. The patients were between the ages of 18 and 60. All patients received a standard chemotherapy regimen. The patients were then randomized to receive Sorafenib or placebo. Patients on the Sorafenib arm then remained on a maintenance therapy for twelve months.

While the achievement of complete remission was almost identical between the two arms at 59% and 60%, the event free survival demonstrably favored the Sorafenib group at 20.5 months versus 9.2 months. At three years of follow-up 40% of the Sorafenib group were well with only 22% of the placebo group still in remission. This corresponds to a three-year relapse free survival of 38% for placebo and 56% for Sorafenib (P=0.017).

The results are of interest on several levels.
1.    Sorafenib a multitargeted tyrosine kinase inhibitor was approved in December 2005 for the treatment of renal cell carcinoma. This makes Sorafenib one of the first targeted agents to achieve FDA approval.

2.     Sorafenib has many modes of action and it is not entirely clear which of its functions were responsible for the superior survival in this AML study.

3.    Sorafenib’s approval reflects a rather convoluted and interesting history. When first developed the drug was designed to target the oncogene B-Raf. As a result the drug was introduced into early clinical trials for the treatment of advanced melanoma, a disease known to be associated with B-Raf mutation. As the drug proved ineffective, it appeared unlikely to gain FDA approval. That is, until it showed cross reactivity with VEGF pathway associated with tumor cell vascularity. A successful trial published in the New England Journal of Medicine then led to the approval.

Now, nine years later this old new drug has gained new life. This time in acute myelogenous leukemia.

The term “dirty drug” refers to agents that target many kinases at the same time. Sorafenib is an example of a “dirty drug.” However it is Sorafenib’s “dirty drug” quality that led first to its approval and most likely now leads to its application in AML. This reflects the fact that Sorafenib may be inhibiting B-Raf signaling associated with the common mutation in Ras upstream of B-Raf or it may reflect Flt3 a secondary activity associated with Sorafenib.

Indeed B-Raf and Flt3 may not be upregulated in every patient, but could serve a function of permissive activity granting an additional survival signal to the AML cells as they go through induction therapy. These subtleties of drug effect may escape genomic analysis as the true “target” may not be mutated, upregulated or amplified. No doubt the investigators in this study will conduct gene sequencing to determine whether there is a driver mutation associated with the advantage reported in this clinical study. What will be intriguing is to determine whether that advantage is an abnormal gene functioning within these cancerous cells or possibly a normal gene functioning abnormally in these cancer cells. More to come.

Systems Biology Comes of Age: Metastatic Lung Cancer in the Crosshairs

Cancer therapists have long sought mechanisms to match patients to available therapies. Current fashion revolves around DNA mutations, gene copy and rearrangements to select drugs. While every cancer patient may be as unique as their fingerprints, all of the fingerprints on file with the federal AFIS (automated fingerprint identification system) database don’t add up to a hill of genes (pun intended), if you can’t connect them to the criminal.

To continue the analogy, it doesn’t matter why the individual chose a life of crime, his upbringing, childhood traumas or personal tragedies. What matters is that you capture him in the flesh and incarcerate him (or her, to be politically correct).

The term we apply to the study of cancer, as a biological phenomenon is “systems biology.” This discipline strikes fear into the heart of molecular biologists, for it complicates their tidy algorithms and undermines the artificial linearity of their cancer pathways. We frequently allude to the catchphrase, genotype ≠ phenotype, yet it is the cancer phenotype that we must confront if we are to cure this disease.

Using a systems biology approach, we applied the ex-vivo analysis of programmed cell death (EVA-PCD®) to the study of previously untreated patients with non-small cell lung cancer. Tissue aggregates isolated from their surgical specimens were studied in their native state against drugs and signal transduction inhibitors. This methodology captures all of the interacting “systems,” as they respond to cytotoxic agents and growth factor withdrawal. The trial was powered to achieve a two-fold improvement in response.

At interim analysis, we had more than accomplished our goal. The results speak for themselves.

First: a two-fold improvement in clinical response – from the national average of 30 percent we achieved 64.5 percent (p – 0.00015).

Second: The median time to progression was improved from 6.4 to 8.5 months.

Third: And most importantly the median overall survival was improved from an average of 10 – 12 months to 21.3 months, a near doubling.

These results, from a prospective clinical trial in which previously untreated lung cancer patients were provided assay directed therapy, reflects the first real time application of systems biology to chemotherapeutics. The closest comparison for improved clinical outcome with chemotherapeutic drugs chosen from among all active agents by a molecular platform in a prospective clinical trial is . . .

Oh, that’s right there isn’t any.

The Good, the Bad and the Good

Two years ago, almost to the day, I met a charming gentleman who had been diagnosed the preceding month with metastatic non small cell lung cancer.

The work-up that confirmed his diagnosis also identified an EGFR mutation. This mutation enabled him to receive the targeted agent erlotinib (Tarceva®) as first line therapy and it provided immediate benefit. An incidental finding in his work-up was a meningioma (a benign brain tumor that often arises in the midline of the brain, in an area known as the falx).

Follow up MRI showed no growth of the meningioma. The patient remained on the same therapy for three months at which time his treating physician decided to consolidate him with chemotherapy. The patient’s tolerance could not have been worse: nausea, malaise, fatigue and a 30 pound weight loss. He requested that I assume his care. After careful consideration, I put him right back on what worked in the first place – erlotinib.

With the exception of a few minor toxicities the patient did beautifully. As we approached his restaging with PET/CT and MRI of the brain, scheduled for August 2012 (his two-year point), he presented to a university medical center with disturbing neurological symptoms. An MRI revealed the meningioma to be much larger than originally found two years earlier. Surgery was scheduled for the following day.

The patient and I discussed his situation by phone as he sat in his hospital room awaiting the surgery. If this were a meningioma, it could be removed. However, if this was related to his lung cancer, then there was an opportunity at hand to determine (using the EVA-PCD® platform) whether the cancer was still responsive to erlotinib or had developed mutations that might confer resistance (e.g., T790M). On the one hand, high dose pulse erlotinib can be effective for CNS disease, so long as resistance has not developed. On the other hand, newer classes of drugs that target T7090M might be required.

We needed tissue for testing, so we could create a functional profile of the tumor, and the surgery was 12 hours away. The patient wanted us to do the study. I wanted to do the study. The problem was that I needed to arrange to get tissue to the lab and time was running short.

With an admirable degree of sleuth work, we identified the surgical resident on duty that evening. We explained our need and he proceeded to explain in great detail that this would never happen. Above and beyond the protocols and standards by which he delivered care, he had 45 other patients to cover, as well as consults to conduct. I hung up disappointed that this opportunity would be missed.

The next morning as I finished hospital rounds I noticed a 6:40 a.m missed call on my cell phone. It was from the hospital where the patient was undergoing surgery. I then received a second call from the same number. It was the attending senior surgeon. He was about to scrub in for the scheduled surgery and offered to assist me in any way he could. He explained that they hoped and believed that this was a benign meningioma. If it was, he would remove it and there would be no need for our involvement. An hour later, communicating via speakerphone in the OR, the surgeon explained that this was indeed adenocarcinoma consistent with the patient’s lung cancer diagnosis. He promised to process the tissue carefully, and then provided his cell phone number so we could communicate. I felt a sense of great relief.

While I cannot say what our laboratory tests will find, the story is both educational and inspirational. The patient is an example of a breakthrough in medical science that provided him an excellent and durable response with comparatively little toxicity. That was the good.

The bad reflected the overworked resident’s insouciance. He was busy, it was late and it appeared that we had confused him with someone who cared. After all, there is no payback to perform above-and-beyond-the-call-of-duty medicine. That was sad, for we are now training physicians who are technicians and not healers. They play by the rules and never extend themselves. No one can ding them for doing their job and no one applauds them for doing more.

The really good news was the response of the attending physician. This individual whom I have never met, evidenced an admirable degree of patient advocacy, commitment and compassion. This patient’s good outcome mattered to him and if there was something that I could bring to the table to help this person in need, then he was all there.

We are at a crossroads in medicine. Will we sponsor the healers or promote the technicians? In our laboratory we do everything in our power to provide all the science that we can bring to bear for every patient. The one component that we cannot offer as a service is the art of medicine. That is up to each individual physician.

No One is More Interested in Curing Your Cancer Than You

A diagnosis of cancer thrusts a, heretofore, healthy individual into the strange and unfamiliar territory of medical oncology. Many of my patients describe this transition as “entering the cancer bubble.” Suddenly, you are on the inside and everyone on the outside is talking at you about what to do, where to go, whom to see, and what treatments to receive.

From the inside of the bubble however, all of this has a hollow ring as you ponder many options, few good and some, positively frightening. Unfortunately, few patients have the time to complete a MD, or PhD, between diagnosis and the initiation of treatment. Lacking the requisite expertise, they turn to the “authorities” for advice.

Depending on which “authority” one consults, the recommendations may be colored by prejudices and biases. Some physicians adhere strictly to the National Comprehensive Cancer Network guidelines. Others insist upon accrual to Cooperative Group and Phase II trials. University-based investigators will often recommend developmental studies. And some physicians will follow the path of least resistance, examining such issues as cost, chair time and reimbursement, before considering what treatment to deliver.

It is in this milieu, that patients find themselves adrift. Who exactly should you trust? What is their motivation? To put it crassly, when they recommend a specific treatment, what’s in it for them: Cooperative Group points (provided to the most active accruers), academic accolades (the currency of junior faculty), cost containment (the purview of the managed care physicians), or finally, profit margins? Yes, there are a small number of physicians whose choices reflect their own pecuniary interests.

The antidote to all this uncertainty lies within each patient; answers to vexing questions crying out to be heard. These answers reflect the biologic features of each individual’s tumor. What pathway, what repair mechanism, what survival signal drives your tumor? No one has a perfect answer, not the genomic investigators (despite their protestations to the contrary), nor the immunohistochemists, despite the significant appeal of the platform. And not the immunologist (despite brilliant progress in this field over recent years). The closest approximation to human tumor biology is, well, human tumor biology. Using cellular constructs, in the form of native state microspheroids, we can today approximate the response profiles of patients undergoing systemic therapies. Using systems approaches to complex questions, the multitude of factors that contribute to objective response can be examined and elucidated.

No test is perfect. No patient is guaranteed a good outcome. Yet, doubling the objective response rate, and as we and others have documented, improving the time to progression and overall survival can be achieved with available methodologies that apply functional profiling to individual tumors.

No one would walk away from an investment formula that doubled the value of their portfolio. Few would turn down the opportunity to enhance their real estate positions predicated on reliable information from a realtor. Yet everyday, physicians convince patients to walk away from available, published, established methods that can improve response rates, diminish toxicities and avoid futile care. In this environment it is critical for patients to take charge of their own cancer management. Patients must not be dissuaded from seeking the best possible outcomes. Physicians, no matter how well intentioned, are human. Their opinions can be colored by misconceptions and an incomplete understanding of the questions at hand. Laboratory analysis empowers patients to make smart decisions.

In the game of cancer we need all the help we can get. After all, no one is more interested in saving your life than you.

The Unfulfilled Promise of Genomic Analysis

In the March 8 issue of the New England Journal of Medicine, investigators from London, England, reported disturbing news regarding the predictive validity and clinical applicability of human tumor genomic analysis for the selection of chemotherapeutic agents.

As part of an ongoing clinical trial in patients with metastatic renal cell carcinoma (the E-PREDICT) these investigators had the opportunity to conduct biopsies upon metastatic lesions and then compare their genomic profiles with those of the primary tumors. Their findings are highly instructive, though not terribly unexpected. Using exon-capture they identified numerous mutations, insertions and deletions. Sanger sequencing was used to validate mutations. When they compared biopsy specimens taken from the kidney they found significant heterogeneity from one region to the next.

Similar degrees of heterogeneity were observed when they compared these primary lesions with the metastatic sites of spread. The investigators inferred a branched evolution where tumors evolved into clones, some spreading to distant sites, while others manifested different features within the primary tumor themselves. Interestingly, when primary sites were matched with metastases that arose from that site, there was greater consanguinity between the primary and met than between one primary site and another primary site in the same kidney. Another way of looking at this is that your grandchildren look more like you, than your neighbor.

Tracking additional mutations, these investigators found unexpected changes that involved histone methyltransferase, histone d-methyltransferase and the phosphatase and tensin homolog (PTEN). These findings were perhaps among the most interesting of the entire paper for they support the principal of phenotypic convergence, whereby similar genomic changes arise by Darwinian selection. This, despite the observed phenotypes arising from precursors with different genomic heritages. This fundamental observation suggests that cancers do not arise from genetic mutation, but instead select advantageous mutations for their survival and success.

The accompanying editorial by Dr. Dan Longo makes several points worth noting.  First he states that “DNA is not the whole story.” This should be familiar to those who follow my blogs, as I have said the same on many occasions.  In his discussion, Dr Longo then references Albert Einstein, who said “Things should be made as simple as possible, but not simpler.” Touché.

I appreciate and applaud Dr. Longo’s comments for they echo our sentiments completely. This article is only the most recent example of a growing litany of observations that call into question molecular biologist’s preternatural fixation on genomic analyses. Human biology is not simple and malignantly transformed cells more complex still. Investigators who insist upon using genomic platforms to force disorderly cells into artificially ordered sub-categories, have once again been forced to admit that these oversimplifications fail to provide the needed insights for the advancement of cancer therapeutics. Those laboratories and corporations that offer “high price” genomic analyses for the selection of chemotherapy drugs should read this and related articles carefully as these reports portend a troubling future for their current business model.

An Ounce of Prevention

Colorectal cancer is among the leading causes of cancer death in the United States. While most patients develop this disease over a period of decades, associated with an accumulation of genetic mutations (elegantly described by Burt Vogelstein, PhD at Johns Hopkins), a small percentage of patients have a genetic predisposition for this cancer. Among these are those people that carry the familial adenomatous polyp syndrome (FAPS) and those who carry mismatch repair mutations know as Lynch syndrome.

It is the latter group who are the subject of a report in the October issue of the English journal Lancet. In this study, known as the CAPP2 trial, patients with Lynch syndrome received either placebo or 600mg of aspirin per day (the equivalent of two tablets). The results reveal a statistically significant reduction of colon cancer that clearly favored the aspirin group.

To put this in perspective, this dramatic improvement in the highest risk population didn’t come about as the result of a new signal transduction inhibitor or a monoclonal antibody. Instead, it came from the simple administration of one of mankind’s earliest medicinal substances. I applaud these English investigators in conducting this study of 861 patients.

What is most laudatory is that the intervention, while highly effective, is so inexpensive. In an era of proprietary medications and the promotion of expensive new interventions, it is indeed refreshing to read the results of a well-conducted study using an intervention available to all.

Data generated more than two decades ago established the benefit of non-steroidal anti-inflammatory drugs like aspirin for the prevention of colorectal cancer. It is gratifying that this simple intervention has additional scientific support both for those with high-risk predisposition, as well as other patients at risk for this relatively common, yet potentially lethal, malignancy.

Cancer Research Becomes “Curiouser and Curiouser”

Following the Gina Kolata New York Times article on July 8, 2011, which described the failure of the Duke University gene profile program in lung cancer, a second New York Times article popped up on the radar screen.  “Cancer’s Secrets Come into Sharper Focus” by George Johnson, examined the growing complexity of cancer research.

This article explored the growing realization that human biology is not linear. Included were references to work that we have previously described in this blog, including the groundbreaking work of Pier Paolo Pandolfi. It also described the interaction between the human body and its microbial flora. We have long recognized that human health is, in part, associated with our interaction with microbes in our environment. The gastrointestinal tract has numerous species that are increasingly believed to contribute to our health. The growing field of probiotics, wherein people consume “healthy organisms,” has gone from quackery to community standard in less than a decade.

What is interesting over the past years is the growing recognition that many cancers are related to infections. Viral infections are known to be oncogenic, with the Epstein-Barr virus, HPV and other viruses now known to be causative of lymphomas, cervical, head and neck, and other cancers. The association between helicobacter and ulcers, gastric lymphoma, and esophageal malignancies are of interest both epidemiologically and therapeutically.

What is most interesting of all is the growing recognition that the cancer cell is but a small component of the cancer.

Here at Rational Therapeutics we recognized the interplay between cells, stroma, vascular elements, cytokines, macrophages, lymphocytes and other environmental factors. This lead to our focus on the human tumor primary culture microspheroid, which contains all of these elements. In our earlier work, we endeavored to isolate tumor cells from their benign constituents so as to study “pure” tumor cells. As time went on, however, we found that these disaggregated cells were artificially sensitized to the effects of chemotherapy and provided false positive results in vitro.

Early work by Beverly Teicher and Robert Kerbel that examined cells alone and in 3-dimensional structures, lead to the realization that cancer cells inhabit a microenvironment. Our lab now studies cancer response to drugs within this microenvironment, enabling us to provide clinically relevant predictions to our patients.

It is our capacity to study human tumor microenvironments that distinguishes us from other platforms in the field. And, it is this capacity that enables us to conduct discovery work on the most sophisticated classes of compounds that influence cell signaling at the level of notch, hedgehog and WNT, among other (Gonsalves, F, et al. (2011). An RNAi-based chemical genetic screen identifies three small-molecule inhibitors of WNT/wingless signaling pathway. PNAS vol. 108, no. 15, pp. 5954-5963).  With this clinically validated platform we are now positioned to streamline drug development and advance experimental therapeutics.