Cancer patients have primarily been limited to one option for care — chemotherapy — which attacks almost any cell that replicates quickly. Recently, however, predictive biomarkers have opened the door to matching patients with targeted treatments based on their unique disease biology. As objective, quantifiable measures of biological processes, biomarkers can reveal details of a patient’s disease and its progression, as well as how they might respond to treatment.
Tumor mutation burden (TMB) is a measurement of the number of mutations carried by tumor cells and an emerging area of focus in biomarker research. By comparing DNA sequences from a patient’s healthy tissues and tumor cells, and using a number of complex algorithms, scientists can determine the number of acquired somatic mutations present in tumors but not in normal tissues. “It’s important because that’s a marker in the cancer itself. By measuring TMB, the cancer cell now has a unique fingerprint of natural and mutated proteins,” says Saurabh Saha, head of translational medicine at Bristol-Myers Squibb.