Three out of 4 patients in PR had documented PTEN mutations (3 out of 5 patients with PTEN mutations enrolled on study achieved PR; Supplementary Table S2); 2 of these patients (2/4) had concomitant alterations in the PI3K pathway, that is, these patients had documented lesions in PTEN and STK11 (patient with breast cancer), PTEN and TSC2 (patient with leiomyosarcoma), respectively. The gene discussed is PTEN; the disease is breast carcinoma.