To explore the function of HSD17B4 in cancer cells, we knocked down endogenous HSD17B4 by shRNA or overexpressed exogenous Flag-HSD17B4 in PCa cells (Figure 2A and Supplementary Figure 2A) and detected a significant difference in the proliferating velocity and colony formation (Figure 2B–2C and Supplementary Figure 2B). The gene discussed is HSD17B4; the disease is posterior cortical atrophy.