Prognostic significance of tumor genotypes and CD8+ infiltrates in stage I-III colorectal cancer

Abstract We explored the clinical significance of tumor genotypes and immunophenotypes in non-metastatic colorectal cancer (CRC). In primary tumors (paraffin blocks) from 412 CRC patients treated with adjuvant chemotherapy, we examined pathogenic mutations (panel NGS; 347 informative); mismatch repair (MMR) immunophenotype (360 informative); and CD8+ lymphocyte density (high - low; 412 informative). The primary outcome measure was disease-free survival (DFS). We evaluated 1713 pathogenic mutations (median: 3 per tumor; range 0-49); 118/412 (28.6%) tumors exhibited high CD8+ density; and, 40/360 (11.1%) were MMR-deficient. Compared to MMR-proficient, MMR-deficient tumors exhibited higher CD8+ density (chi-square, p