Associations between potentially functional IL6 (rs2069837 and rs1800795) and STAT3 (rs744166 and rs4796793) SNPs and clinical outcomes [progression-free survival (PFS), overall survival, and tumor response rate] were evaluated in mCRC patients receiving first-line FOLFIRI plus bevacizumab in two randomized phase III trials: TRIBE (n = 223, training cohort) and FIRE-3 (n = 288, validation cohort).
We found that rs744166 in STAT3 was associated with colon cancer risk in two studies; however, the direction of the observation was reversed in TP53 mutant tumors possibly due to a nullification of the effect by mutant p53.