上部尿路上皮腫瘍47例(すべて腎・尿管全摘出術兼膀胱部分切除術施行.30例は腎盂の移行上皮癌, 17例に尿管の移行上皮癌)を対象にAvidin-Biotin-Peroxidase Complex (ABC)法を用いてABH-AgとT-Agを検索し, その抗原性の変化と病理組織学的異型度, 深達度および予後(5年生存率)との関係について検討した.ABH-Agでは抗原性の消退と異型度との間に有意の相関(p<0.05)があったが, 深達度および予後との間には有意の相関はなかった.一方, T-Agでは抗原性の消退と異型度, 深達度ならびに予後との間に有意の相関(p<0.01)があった.以上より, 上部尿路移行上皮癌におけるABH-AgおよびT-Agの検索は, その癌のmalignant potentialを知る上で有益であり, 予後予知因子としてはT-Agはより有用性が高いと考えられたABH-isoantigen (ABH-Ag) and Thomsen-Friedenreich antigen (T-Ag) were investigated by the Avidin-Biotin-Peroxidase Complex (ABC) method on 47 patients with epithelial tumor of the upper urinary tract (all patients underwent nephroureterectomy including the cuff of the bladder; 30 patients were diagnosed as transitional cell carcinoma of renal pelvis and 17 ureteral organs). The correlations between ABC expression for ABH-Ag and T-Ag with histological grade, stage and prognosis (5 year survival rate) were studied. A correlation was observed between grade (p less than 0.05) and deletion of the antigenicity of ABH-Ag, but no correlation was evident with stage and prognosis. A high correlation was evident, however, between grade (p less than 0.01), stage (p less than 0.01) and prognosis (p less than 0.01) and deletion of the antigenicity of T-Ag. The analysis of ABC expression for ABH-Ag and T-Ag may therefore be valuable for predicting the malignant potential in transitional cell carcinoma of the upper urinary tract. T-Ag determination in particular may provide a useful prognostic probe should it find clinical application