SMAD4 and neoplasm: These findings show that the well-documented prostate tumor formation in Pten/Smad4 KO mice29 is severely impaired by concomitant deletion of Kmt9α. Using TUNEL assays, we did not detect increased cell death in prostates of Pten/Smad4/Kmt9α KO compared to Pten/Smad4 KO mice, indicating that Kmt9α deletion suppresses tumor growth independently of cell death induction (Supplementary Fig. 11b, c).