TSC1 and bladder transitional cell carcinoma: Consistent with our mechanistic observations, RMC-6272 drove deeper tumor regression in 4 weeks of treatment, and significantly delayed tumor regrowth upon treatment cessation, compared with rapamycin, both at translatable doses, in a human TSC1-null BLCA patient-derived xenograft (PDX) model (n = 8 per group; Figure 4, A and B).