Since the colony formation of MCT2-expressing breast cancer cells was enhanced when co-culturing with MGDAs in the medium containing 1 mM pyruvate as shown in Figs 1 and 3, simply supplementing with higher amounts of pyruvate did not further promote colony formation (Supplementary Fig. 3C), pyruvate was less likely playing a key role in promoting colony formation of breast cancer cells mediated by MGDAs in an MCT2-dependent manner. Here, SLC16A7 is linked to breast cancer.