Abstract
Advanced colorectal cancer (CRC) continues to present with poor survival and treatment options remain limited. We have shown that increased activin A (activin) expression in the tumor microenvironment (TME) is associated with poor outcome in a cohort of stage III and IV CRC patients. Here, we hypothesized that activin promotes stage specific outcomes in CRC, enhancing metastasis and tolerance in late-stage CRC exclusively. We employed Digital Spatial Profiling (DSP) technology on a cohort of stage II and III CRC patient tissue samples obtained at the time of curative surgery to show that activin co-localization was associated with increased mitogenic signaling, proliferation, and immunosuppression in stage III, but not stage II, CRCs. Furthermore, we found strong linear correlations between markers of immunosuppression and signaling proteins in activin (+) areas, an effect that was not observed in activin (-) areas of tissue. Taken together these data suggest activin exerts pro-metastatic and immunosuppressive effects in stage III, but not stage II, CRC providing an attractive therapeutic target for advanced CRC.