Whole genome sequencing studies showed that: (a) no mutations in genes significantly mutated in breast cancer, including TP53, PIK3CA, GATA3, and MAP3K1 were detected; (b) copy number alterations that have been reported in micropapillary carcinomas, such as recurrent gains of 1q, 6p, 8q, and 10q, recurrent losses in 16q, 11q, and 13q, as well as a recurrent 8p12–8p 11.2 amplification encompassing FGFR1 were detected [231]. This evidence concerns the gene PIK3CA and breast cancer.