Casein was measured in the sera of breast cancer patients, in breast cancers and in breast cancer cells in long term tissue culture using a sensitive and specific radioimmunoassay. Level % breast cancer sera showed control values. Eight of 47 (17%) of the tumor samples tested were positive for casein, the highest level representing 0.003% of the soluble protein. When 7 human breast cancer cell lines were assayed for casein, the results were uniformly negative even under conditions of stimulation by lactogenic hormones (placental lactogen, insulin, dexamethasone, estradiol, progesterone). In addition, direct immunoprecipitation of labeled cellular protein supported the negative result of the radioimmunoassay. Thus it appears that casein production is normally activated only in the fully developed lactating breast stimulated by a number of hormones. Therefore one might not expect casein production under conditions of malignant growth.
|Number of pages||6|
|State||Published - Nov 12 1977|
ASJC Scopus subject areas
- Cancer Research