TGFBR1 and prostate carcinoma: In our quest to unravel possible downstream regulators of Snail1, we silenced the expression of Snail1 by siRNA and found that TβRI expression decreased in the absence of Snail1, suggesting that Snail1 regulates TβRI expression (Figure 1, Supplementary Figure 1) and that treatment of prostate cancer cells with TGFβ stimulated formation of Snail1 and TβRI-ICD complexes in the nucleus of these cancer cells (Figure 2, Supplementary Figures 2 and 4).