TSC2 and kidney neoplasm: As a model of mTORC1 hyperactivity, we first examined B7-H3 expression in three TSC2-deficient cell lines: 621-101 cells, derived from a benign renal angiomyolipoma with a TSC2 mutation (G1832A or R611Q) and TSC2 loss of heterozygosity (LOH) at chromosome 16, 105K cells, derived from a renal tumor that developed in a Tsc2+/− mouse, and Tsc2 KO mouse embryonic fibroblasts, generated from Rosa26Cre-ERT2/Tsc2flox/flox mice.