Cloning of a novel protein overexpressed in human mammary carcinoma

A novel Mr 150,000 protein (p150), which was found to be preferentially expressed in virally and oncogene transformed mouse cells, was partially purified, and the cDNA was cloned. p150 is the largest member of a putative protein family, the molecular function of which is as yet unknown. Its pattern of expression correlates well not only with transformation but also with the dedifferentiated state of several mouse cell lines and cells. Furthermore, human breast carcinoma specimens and normal tissue from the same breast were screened for the presence of the p150 antigen. In all carcinoma samples, Western blotting revealed higher p150 expression levels than that in control tissue from the same patient. Immunohistochemical analyses of the same specimens displayed specific staining of the carcinoma cells.