We have reported that a novel
tumor-associated
antigen (Ag), 22-1-1, was expressed in
cancer cells derived mainly from the uterus and ovary [K. Sonoda et al.,
Cancer (Phila.), 77: 1501-1509, 1996]. The 22-1-1 Ag existed not only in
adenocarcinomas but also in
squamous cell carcinomas in the uterine cervix. Here, a relationship between
tumor progression and invasion and 22-1-1 Ag expression was investigated in
squamous cell neoplasms of the uterine cervix using immunohistochemical staining. The 22-1-1 Ag was not detected in normal uterine cervix (0 of 10 total cases) and dysplasias (0 of 47 total cases). However, 20% of
carcinoma in situ (4 of 20 total cases) and 16.7% of microinvasive
carcinomas (2 of 12 total cases) stained positively for 22-1-1 Ag. Moreover, areas depicting microinvasion on histology in
uterine cancers (stage Ia) were more strongly stained than
carcinoma in situ lesions. 22-1-1 Ag expression was found to be more frequent in invasive
squamous cell carcinomas (82.6%; 57 of 69 total cases). The 22-1-1 Ag existed both in the cytoplasm and on the membrane of
cancer cells. These findings suggest that 22-1-1 Ag expression might be related to
tumor cell progression and invasion in the uterine cervical squamous cell epithelium.