MERTK and neoplasm: In addition, stable knockdown of Axl also downregulates TGFBR3 in PC3 cells, which is required for induction of tumor cell dormancy by TGF-β2 and also essential for TGF-β2 presentation to the Type I and Type II receptpors6, whereas Mer or Tyro3 knockdown does not alter TGFBR3 expression (Fig. S7).