alpha-Lactalbumin levels in human mammary tumors, sera, and mammary cell culture lines.

Antiserum to purified human alpha-lactalbumin was produced in rabbits and used to develop a radioimmunoassay capable of detecting 0.1 ng of alpha-lactalbumin per ml of sample. Human breast diseases were analyzed for alpha-lactalbumin levels. A high percentage of breast carcinomas contained varying levels of alpha-lactalbumin. Lymph node metastases from primary carcinomas that synthesized alpha-lactalbumin also contained it. Analysis of serum from breast cancer patients indicated that approximately 25 percent had measurable levels of alpha-lactalbumin before surgery, but no alpha-lactalbumin was found in postsurgery sera. alpha-Lactalbumin was not detected in the urine of early lactational women, although it was present in the sera. Human cell culture lines derived from pleural effusions of mammary carcinomas contained little, if any, alpha-lactalbumin. Other human cell lines derived from mammary carcinomas and grown as solid tumors in athymic mice did not contain measurable levels of alpha-lactalbumin.