BMPR1A and neoplasm: To further determine whether conversion between the basal and luminal-like subtypes requires Hh-mediated BMP signaling, whose activity is necessary for the suppression of tumor growth (Figure 3), we established transplant models in which BBN-induced tumor organoids transduced to express shRNA targeting Bmpr1a were orthotopically injected into the mouse bladder (Figure 5A and Figure 5—figure supplement 1A).