In a disease-specific subanalysis in colorectal and ovarian cancer we noticed a trend toward an association between exon 9 PIK3CA and KRAS mutations in colorectal cancer (20% in KRAS mutant vs. 6% in wtKRAS; p = 0.07) and a statistically significant association between exon 20 PIK3CA and KRAS mutations in ovarian cancer (75% in KRAS mutant vs. 5% in wtKRAS; p = 0.003). Here, PIK3CA is linked to ovarian carcinoma.