Carcinomas with mucinous differentiation, however, share genomic similarities across different cancer types, such as quieter copy-number alteration profiles in CRC-muc, BRCA-muc, LUAD-muc and STAD-muc, a lower frequency of p53 pathway alterations in CRC-muc and LUAD-muc and a lower frequency of PIK3CA pathway alterations in BRCA-muc and STAD-muc. This evidence concerns the gene PIK3CA and cancer.