The majority of the pituitary tumors also showed no expression of β-catenin; a weak β-catenin staining was observed only in 2 of 16 (12.5%) ACTH-secreting, 1 of 18 (5.5%) GH-secreting, and 1 of 18 (5.5%) non-secreting pituitary tumors. The gene discussed is POMC; the disease is pituitary tumor.