APC and neoplasm: Here, we demonstrate a direct relationship between loss of a key tumor suppressor gene, APC, and dysregulation of MPC1. Our finding that mpc1 expression is downregulated in embryos harboring a genetic mutation (apcmcr) or knocked down expression (apc mo) of apc is reflected in human tumors as well, where we not only discovered a significant downregulation of MPC1 expression in colon adenocarcinomas with APC deletions, but also samples possessing mutations in both APC and several pyruvate metabolism enzymes (Figure 1, Figure 6, Figure 6—figure supplement 1).