MERTK and neoplasm: Interestingly, WT and Axl-/- MDSCs were found in both the primary tumor as well as the tumor-draining lymph node (TDLN), but Mertk-/- and Tyro3-/- MDSCs were predominantly in the primary tumor and not in the TDLN, suggesting that the loss of MERTK or TYRO3 attenuates MDSC migration.