PTEN and breast cancer: We tested the MLN0128 sensitivity of 16 cell lines; the panel was enriched for breast cancer cell lines but consisted of cell lines with varying genomic alterations including mutations in PIK3CA and PTEN. These cell lines were selected as they represented cell lines with a range of sensitivities to rapamycin based on our previous study of a larger 43 cell line screen for rapamycin sensitivity (Supplementary Table S1) [3].