Similarly, the univariate analysis also showed PIK3CA amplification was associated with a significantly increased risk of cancer-related death (OR = 2.57, 95% CI = 1.21-5.48; P < 0.05), and there was a positive association of PIK3CA mutations (OR = 5.05, 95% CI = 0.60-42.5) and PIK3CA amplification (OR = 1.92, 95% CI = 0.92-4.01) with tumor differentiation (see Additional file 1: Table S1). This evidence concerns the gene PIK3CA and cancer.