Thus, given the disparities in PIP5K1C protein levels between WX8-sensitive and resistant cells, the dependence of nonmalignant cells on PIP5K1C to maintain PtdIns(4,5)P2, cancers that would respond to treatment with PIKFYVE inhibitors could be identified clinically as cancers with low levels of PIP5K1C. The gene discussed is PIKFYVE; the disease is cancer.