PIK3CA mutations and PTEN loss are negatively associated with survival in mCRCs patients treated with panitumumab or cetuximab...PTEN loss was similarly associated with shorter PFS (P = 0.0681) that reached statistical significance if this variable was combined with PIK3CA mutations (loss of PTEN and/or PIK3CA mutation; P = 0.0066; Fig. 1D–E)...PTEN loss of expression was significantly associated with worse OS (P = 0.0048), as was the combination of PTEN loss with PIK3CA mutations (P = 0.0161; Fig. 2D–E).

The biomarker distribution was as follows: BRAF mutant, 20 patients (11%); PIK3CA mutated/PTEN loss, 98 patients (58%); DP, 23 patients (12.7%). The clinical variables in the clinical score were progression status >0, left-sided tumor, and resectable liver metastasis as the only metastatic site....The addition of BRAF, PIK3CA/PTEN, and DP to a clinical score does not improve the discrimination of 12-month PFS.