GPC2 expression was significantly upregulated in 12 early-stage cancers compared with normal tissues.GPC2 displayed high diagnostic value (AUC > 0.90) for 6 cancer types, moderate diagnostic value (AUC > 0.70) in 16 cancer types, and low diagnostic value (AUC > 0.50) in 7 cancer types. The gene discussed is GPC2; the disease is cancer.