Tumor‐Antigen (TA‐4) of Squamous Cell Carcinomaits Tissue Distribution and its Relationship to Serum TA‐4 Concentrations

Tissue concentrations of the tumor‐antigen (TA‐4) in squamous cell carcinoma were determined in several malignant and non‐malignant tissues utilizing a radioimmunoassay method, and the relationship between tissue TA‐4 concentrations and serum TA‐4 concentrations was investigated in patients with cervical squamous cell carcinoma. Squamous cell carcinoma tissue contained 1,080.5 + 208.7 μ u/mg of TA‐4 activities, which was significantly greater than those in normal squamous epitheliums of the uterine cervix (219.1 + 21.7 μ u/mg), vagina (280.1 + 26.6 μ u/mg) and vulva (264, 324 μ u/mg). Neither adenocarcinomas of the uterine cervix, endometrium and ovary nor normal columnar epithelium, stroma and endometrium of the uterus showed TA‐4 activities. There was no direct correlation between tumor TA‐4 contents and serum TA‐4 concentrations, suggesting that circulating TA‐4 levels were not solely attributable to the antigen content of the tumor but also to other factors.