[9] PIK3CA mutations are present in over one-third of breast cancers, with enrichment in the luminal and in human epidermal growth factor receptor 2-positive subtypes (HER2 +).

[10] While substantial preclinical data show an association with robust activation of the pathway and resistance to common therapies, clinical data do not indicate that such mutations are associated with high levels of pathway activation or with a poor prognosis.

[18][19] PIK3CA-associated segmental overgrowth includes brain disorders such as macrocephaly-capillary malformation (MCAP) and hemimegalencephaly.

It is also associated with congenital, lipomatous overgrowth of vascular malformations, epidermal nevi and skeletal/spinal anomalies (CLOVES syndrome) and fibroadipose hyperplasia (FH).

[21][22] In September 2017 Copanlisib, inhibiting predominantly p110α and p110δ, got FDA approval for the treatment of adult patients with relapsed follicular lymphoma (FL) who have received at least two prior systemic therapies.