As others previously reported based on analysis of breast cancer cell lines [6], we found an association between PI3KCA mutational status amongst cells in the NCI-60 tumor cell line collection and sensitivity to GDC-0941 (P = 0.044; Figs. S1B and S1C), whereas there is no association between loss of PTEN protein and response to GDC-0941 (P = 0.31; Figs. S1B and S1C). The gene discussed is PTEN; the disease is breast cancer.