Following studies have shown that POU3F3 participate in many types of cancers, such as breast cancer [12], nasopharyngeal carcinoma [13] and prostate carcinoma [14] mainly by regulating cancer cell behaviors through regulating cancer-related genes, such as caspase 9, TGF-β1 and rho-associated protein kinase 1 [12–14]. The gene discussed is CASP9; the disease is breast cancer.