CAG repeats in the androgen receptor gene are shorter in patients with pulmonary, esophageal or bladder carcinoma and longer in women with uterine leiomyoma

Preferential occurrence of pulmonary, esophageal and bladder carcinomas in males indicate a possible involvement of androgen receptor (AR)-mediated functions. We evaluated the roles of the CAG repeat polymorphism in AR exon 1 in development of these lesions. The exon 1 of AR gene was amplified in samples from 198 male patients with lung carcinoma, 183 with esophageal carcinoma, 95 with bladder carcinoma and 94 males with appendicitis, as a reference group. Mean numbers of the CAG repeat in these 3 cancer groups were determined to be 20.2, 20.0 and 20.0, respectively, all being significantly smaller than that of the reference group (21.1; P<0.05). Samples from 118 female patients with lung carcinoma and 154 females with appendicitis, as a reference group, were examined, with the mean CAG repeat number significantly smaller (19.8) than that of the female reference group (20.7; P<0.01). Samples from 108 patients with uterine leiomyoma were also examined, and their CAG repeat numbers were found to be markedly expanded (23.4; P<0.01). The patients with multiple leiomyomas tend to carry a longer CAG repeat structure, with the mean CAG repeat number longer in the multicentric multiple cases (24.1) compared to that of the unicentric, multinodular cases (22.2) and those with solitary lesions (23.1; P<0.01). These results indicate that a shorter CAG repeat structure may predispose individuals to a higher risk to some male-predominant neoplasms including pulmonary, esophageal and bladder carcinomas and a longer one confers women greater susceptibility to leiomyoma development in the uterus.