INPP4B and cancer: Notably, an emerging role for Inositol polyphosphate 4-phosphatase type II (INPP4B), a PtdIns phosphatase that dephosphorylates PtdIns(3,4)P2 to form PtdIns(3)P, in lysosome homeostasis has been reported in diverse cancer settings (28, 29).