A major concern among clinicians when treating cancer patients is the ability of tumors to adapt and evade anti-cancer therapies. Researchers found that biopsies (small samples of tumor tissue), generally taken just before patients start cancer therapy, reveal important pathways of therapeutic resistance. Therefore, they propose using repeat biopsies routinely in the clinic to predict cancer’s response to therapy.
Normally, to follow treatment efficacy, clinicians analyze tumor size and volume by imaging tests such as computed tomography (CT) or magnetic resonance imaging (MRI) scans, and tumor metabolic activity by positron emission tomography (PET). Now, researchers suggest that biopsies can also be a valuable tool in monitoring cancer patients.
“We should be incorporating analysis of longitudinal tumor and blood samples into clinical trials, and ultimately we may even incorporate this into treatment with standard of care therapy,” Dr. Jennifer Wargo, MD, said in a press release.
Wargo led the study, titled “Analysis of Immune Signatures in Longitudinal Tumor Samples Yields Insight into Biomarkers of Response and Mechanisms of Resistance to Immune Checkpoint Blockade,” published in the journal Cancer Discovery.
Researchers had access to samples of 2,100 patients collected by the Adaptive Patient-Oriented Longitudinal Learning and Optimization (APOLLO) platform. These included high-quality biopsies and blood samples taken before, during, and at the end of treatment of patients with different types of cancer: melanoma, multiple myeloma, glioblastoma, lymphoma, lung, breast, colorectal, pancreas, ovarian cancers, sarcoma, and cancers caused by the human papilloma virus.
The research team used several approaches to study these biopsies at the molecular level, primarily the MD Anderson Moon Shots Cancer Genomics Laboratory platform to analyze the DNA and RNA, and the immunotherapy platform to address the immune response to the tumor.
With this revolutionary approach, researchers found early on-treatment biopsy alterations in gene expression and immune response, which can be used as markers of melanoma response to therapy.
“Cancers are exceptionally adaptive in the face of treatment pressure,” said Andrew Futreal, PhD, the study’s co-author, interim chair of Genomic Medicine, and co-leader of the Moon Shots Program. “We know a tumor after therapy is likely to be different than before, but we haven’t done a good job at tackling this from a research perspective until now.”
Biopsies are normally an invasive procedure. But in the future, less-invasive analyses of tumors before and after treatment could be performed with blood samples — so-called liquid biopsies. Researchers still need to provide more evidence before this type of assessment can be implemented.
“We have to build the evidence first, you can’t just go full bore into clinical implementation of this until we generate and analyze the data in the research setting,” Futreal said.