For instance, activated STAT1 appears to exert pro-apoptotic and anti-proliferative effect as STAT1-null mice lead to higher risk of tumor development than controls (11, 12), these results indicate that STAT1 has the tumor-suppressing properties like TP53 and could be an antagonist for STAT3 and STAT5 activation. The gene discussed is STAT5B; the disease is neoplasm.