Furthermore, knockdown of PURPL significantly decreased proliferation of HepG2 (P = 0.02, 72 h) and Sk-hep-1 cells (P = 0.006, 48 h; P = 0.02, 72 h) (Fig. 2c + d), suggesting that PURPL could function as a potential pro-survival gene in liver cancer. The gene discussed is PURPL; the disease is liver cancer.