The need for more reliable biomarkers is especially urgent in the field of kidney cancer or renal cell carcinoma (RCC), said Eric A. Singer, MD, MA, MS, FACS a urologic oncologist and director of the kidney cancer program at the Rutgers Cancer Institute of New Jersey in New Brunswick. For example, renal masses can range from benign, to low grade, to high grade aggressive tumors with a high potential for metastasis. Additionally, there are multiple different kinds of kidney cancer. “They often have different genetic alterations that drive those tumors, so understanding which of those tumor types we’re dealing with is important,” he said. “I don’t think we’ll find a holy grail that gives us a grand unified biomarker for all kidney cancer disease states very soon. It’s more likely that we’ll use different sets of biomarkers for each of those disease states. But we’re looking to identify subsets of tumors to determine if we can detect important differences that can help inform treatment choices.” For example, he explains that a certain kind of aggressive kidney cancer has shown a remarkable response to immunotherapy, but hasn’t responded to targeted therapy.
Dr Singer said he hopes more research will lead to new treatments for rarer forms of RCC, because the single-agent immunotherapies and combination therapies that were approved during the past few years were for clear cell kidney cancer. “That means that for 1 in 4 patients who come to us, we don’t have FDA-approved treatments for their tumor type,” said Dr Singer, who is also an associate professor of surgery and radiology in the division of urology at Rutgers Robert Wood Johnson Medical School.
In addition to offering insight on which drug combination regimen to select, better biomarkers also may help oncologists develop treatment plans. “The larger question of biomarkers is for us to figure out the best treatment for a disease state. Maybe it’s a renal mass that we should schedule surgery to remove,” he said. “How long do we need to follow the patient after surgery? Which radiology test should we use? For example, it doesn’t make sense to give someone in their 50s a CT [computed tomography] scan every 6 months for 30 years.”
In addition to molecular and immunological markers, there are also serum, imaging, plasma metabolite-based, radiomic, and immunohistological biomarkers. Pathomics and radiomics data could also eventually be harnessed to help account for some of the measurement discrepancies seen across assays that analyze molecular-based biomarkers.
The good news is that the amount of research on biomarkers is exploding, prompting calls for more clinical trials to validate their reliability. “If you do a PubMed.gov search today and another in a month, there will be new papers on more discoveries. It’s an exciting time to be in our field,” said Dr Singer.
Rebuzzi SE, Perrone F, Bersanelli M, et al. Prognostic and predictive molecular biomarkers in metastatic renal cell carcinoma patients treated with immune checkpoint inhibitors: a systematic review Expert Rev Mol Diag. doi: 10.1080/14737159.2019.1680286