PIK3CA mutation (42.9% in resistant tumors vs none of the tumors having clinical benefits, p = 0.0196; Fisher exact test) was found associated with resistance, as opposed to TP53 (72.7% in clinical benefit tumor vs 64.3% in no clinical benefit tumors) and KRAS (27.3% in sensitive tumor vs 57.1% in resistant tumors). The gene discussed is PIK3CA; the disease is neoplasm.