CLONING OF A NOVEL PROTEIN OVEREXPRESSED IN HUMAN MAMMARY-CARCINOMA

A novel M(r) 150,000 protein (p150), which was found to he preferentia lly expressed in virally and oncogene transformed mouse cells, was par tially purified, and the cDNA mas cloned. p150 is the largest member o f a putative protein family, the molecular function of which is as yet unknown. Its pattern of expression correlates well not only with tran sformation hut also with the dedifferentiated state of several mouse c ell lines and cells. Furthermore, human breast carcinoma specimens and normal tissue from the same breast were screened for the presence of tile p150 antigen. In all carcinoma samples, Western blotting revealed higher p150 expression levels than that in control tissue from the sa me patient, Immunohistochemical analyses of the same specimens display ed specific staining of the carcinoma cells.