PIK3R1 and cancer: Pathway and network analysis also identified a set of interesting genes, including PIK3R1, SOCS2 and BMP7. Philp et al. [33] reported the presence of somatic mutations in PIK3R1, the gene for the p85α regulatory subunit of phosphatidylinositol 3-kinase (PI3K), in primary human colon and ovarian tumors and cancer cell lines, resulting in the constitutive activation of PI3K.