ALB and breast carcinoma: Albumin can support the proliferation of some macropinocytic cells in low glutamine or when non-essential amino acids are limiting4,10, but was not sufficient to support breast cancer cell proliferation in media generally deficient in amino acids, in both amino acids and glucose, or in cells exposed to 5-FU (Fig. 1c and Supplementary Figs. 3f and 7c, d).