We examined the functional consequences of silencing PIP5K1α on growth of DU145 cells by using tumor-spheroid formation assays. The number of tumor-spheroids derived from siPIP5K1α cells was significantly reduced, i.e. a 29% decrease relative to siRNA controls (siRNA control cells mean = 1,003, 95% CI: 653-1,351; siPIP5K1α cells mean = 731, difference = 272, 95% CI: 531-931, p = 0.0025, Figure 2E). The gene discussed is PIP5K1A; the disease is neoplasm.