It has been reported that BT474 and MDA-MB-361 are Her2 high-expressing, and BT20 and MDA-MB-231 are Her2 low-expressing cancer cells, and that BT20, MDA-MB-361, and BT474 have mutations in PIK3CA, and only MDA-MB-231 has KRAS mutation among these cell lines [27, 28]. This evidence concerns the gene PIK3CA and cancer.