DETECTION OF HOXA1 EXPRESSION IN HUMAN BREAST-CANCER

Homeodomain-containing proteins are transcription factors that regulat e the coordinated expression of multiple genes involved in development , differentiation and malignant transformation. To better understand t he role played by these proteins in breast cancer cells, we demonstrat e, using semi-quantitative RT-PCR experiments, that progestin induces HOXA1 mRNAs in MCF7 cells. This is the first evidence of regulation of a HOX gene by steroids. Moreover, we detected HOXA1 expression in a v ariety of human breast cancer lesions, suggesting that HOXA1 may be re quired for the establishment of breast cancer cells phenotype. We prop ose that HOXA1 gene could be one of the orchestrators that regulate br east epithelial cell differentiation and that alteration of HOXA1 expr ession could play a role in breast cancer progression. (C) 1996 Academ ic Press, Inc.