Immunoscore vs. Microsatellite instability as prognostic biomarkers in colorectal cancer: who wins?

Colorectal cancer (CRC) incidence rates decreased since 2001 due to improved screening tests and treatments (1,2). However, CRC still remains one of the main causes of cancer-related deaths world-wide (2). Thus, improved knowledge derived from ongoing research is required to achieve further improvements. Retrospective analyses of large CRC patient cohorts have identified specific patterns of immune activation in the tumor microenvironment which were associated with patients’ overall survival. The type, density, and location of immune cells intratumorally established the Immunoscore (IS). The IS combined with the expression of genes encoding T helper 1 (Th1) cytokines (IFNγ, IL2) and cytotoxic mediators (granzymes, granulysin) delineate the immune contexture (IC). Both, the IS and IC have been generally associated with favorable clinical outcome, supporting a major role of T-cell-mediated immunity to restrain tumor progression (3-6).