What Cancers Have in Common: Pushing the Boundaries of Science

A Point of View by Dr. Bao Lam, Clinical Director, Merck Research Laboratories

Dr. Bao Lam, like many Merck physicians, continues to see patients. This is his personal perspective.

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Historically, oncology practice or clinical trial design primarily focused on where the tumor first emerged, such as colon or rectum, lung, breast, and endometrium. This approach follows the logic of the scalpel: pinpointing the location of the tumor first enabled surgical plans.

However, there have been significant advances in our understanding of the role of cancer biomarkers in molecular and cellular mechanisms that can drive tumor growth. Biomarkers are biological molecules found in blood or tissues that can serve as signs to help better understand a condition or disease. Sometimes, the same biomarker can be found across many different types of cancer, regardless of where the tumor first developed.

The beauty in discovering these biomarkers is that they can be used to help inform clinical research. Looking for more links across cancers has the potential to speed up the process of getting targeted medicines to patients where separate trials would take years to conduct. Importantly, in some cases, these features can be assessed using simple laboratory tests that have long been available.

The goal here is to use deeper understanding of the tumor biology and the associated biomarkers to tackle tumor research in a more precise way that goes beyond looking only where a tumor arose. Instead, we are focused on uncovering how to attack a cancer based on how it behaves at the cellular level.

At Merck, efforts are underway to better understand microsatellite instability (MSI) or mismatch repair deficiency (dMMR). These biomarkers do show up across tumor types, regardless of the original location of the cancer. The presence of high levels of MSI (MSI-H) or dMMR signifies an underlying problem in a cell's ability to fix errors that occur when DNA replicates. Tumor cells determined to have MSI-H or dMMR harbor hundreds to thousands of mutations.

The ultimate proof of our efforts will be a new generation of cancer medicines: those that follow the logic of biology, not the logic of the scalpel.