CONTRADICTING EVIDENCE...2 of 10 with PIK3CA mutations, 1 of 9 with PTEN mutations, and 1 of 2 with CTNNB1 mutations responded to panitumumab.

...RECIST``metrics: Pathological complete response (pCR): no residual cancer cells;major response (pPR): 1% to 49% residual cancer cells remaining; minor response (pMR): 50% to 99% residual cancer cells remaining; no response (pNR): 100% residual cancer cells remaining`CR + PR + SD rate according to RECIST`analyzed for responders only`number of patients with adverse events and severity according to NCI CTC 3.0`histological findings according to CASH/SOS scores`scores according to EORTC QLQ-C30 scoring manual (Quality of life)`Determination of EGFR mutations (exons 18, 19, 20, 21) in tumor tissue; determination of PIK3CA mutations (exon 9, 20) in tumor tissue; determination of EGFR, ERCC1, TS, MTHFR, OPRT, DHFR and CDKN polymorphism from normal and tumor tissue; determination of ERCC1, PTEN and TS protein expression in tumor tissue; epigenetic candidates; further exploratory studies such as miRNA analysis as approved by the AIO review board...

...Mutations analysis on platelet-resorbed tumour RNA (with Real-time PCR) in Codon 12 of KRAS gene mutations`Mutations analysis on platelet-resorbed tumour RNA (with Real-time PCR) in Codon 61 of KRAS gene mutations`Mutations analysis on platelet-resorbed tumour RNA (with Real-time PCR) in exon 15 of BRAF gene mutations`Mutations analysis on platelet-resorbed tumour RNA (with Real-time PCR) in Codon 12 of NRAS gene mutations`Mutations analysis on platelet-resorbed tumour RNA (with Real-time PCR) in Codon 61 of NRAS gene mutations`Mutations analysis on platelet-resorbed tumour RNA (with Real-time PCR) in exon 20 of PIK3CA gene mutations...

PIK3CA mutations were significantly associated with clinical resistance to panitumumab or cetuximab; none of the mutated patients achieved objective response (P = 0.038).

PIK3CA mutations and PTEN loss are negatively associated with survival in mCRCs patients treated with panitumumab or cetuximab...Patients with KRAS mutations had a trend toward a decreased PFS (P = 0.0815; Fig. 1B). Shorter PFS was also detected in patients harboring at least a mutation of either KRAS or PIK3CA (P = 0.0032; Fig. 1C).