ISOLATION OF A CDNA FOR THE HUMAN HOMOLOG OF MAT-1 ONCOGENE AND ITS EXPRESSION IN HUMAN BREAST-CANCER CELLS

Overexpression of mouse MAT-1 oncogene is associated with carcinogensi s of mouse mammary epithelial cells. A human cDNA (hMAT) homologous to MAT-1 was isolated from normal human breast tissue. The hMAT cDNA is 1312 bp long and produces a 8.5 kDa peptide in vitro. The hMAT probe h ybridized with 2.5 kb RNA in normal human breast epithelial cells from reduction mammoplasty specimens and in human breast cancer cell lines . The extent of hMAT gene expression in human breast cancer cell line was variable, with BT-20, T47-D, and MDA-MB-231 showing about a 10-fol d overexpression compared to primary normal human breast epithelial ce lls, MCF-7, and ZR-75-1.