All patients enrolled in the study had a baseline blood sample collection for analysis of circulating nucleic acid for mutations in PIK3CA. Only three of the 37 patients enrolled were found to have PIK3CA gene mutations: two patients with breast cancer who went on to receive treatment had an H1047L mutation in exon 9 and an E545K mutation, and the third patient had a less predominant M1043I mutation but withdrew prior to documentation of progression of disease. The gene discussed is PIK3CA; the disease is breast cancer.