CD34 and neoplasm: Importantly, rescue of Tgfbr2 abolished Elmo1 mRNA expression in YFP+mCherry+ cells isolated from tumors generated from Tgfbr2 cKO CD34+ SCC cells infected with full-length Tgfbr2 compared to YFP+mCherry-CD34+ cells isolated from the same tumor (Figure 6H), confirming that the RAC-activating GEF Elmo1 is a novel target of TGFβ repression.