HAG-2, THE HUMAN HOMOLOG OF THE XENOPUS-LAEVIS CEMENT GLAND GENE XAG-2, IS COEXPRESSED WITH ESTROGEN-RECEPTOR IN BREAST-CANCER CELL-LINES

hAG-2, the human homologue of the Xenopus laevis cement gland gene Xen opus Anterior Gradient-2 (XAG-2), has been found to be coexpressed wit h estrogen receptor (ER) in breast cancer cell lines by using suppress ion subtractive hybridization. Sequence analysis of clones obtained fr om a human breast adenocarcinoma MCF7 cDNA library suggests that at le ast three mRNA transcripts, differing in their 3'-untranslated regions , are transcribed from the hAG-2 gene. Northern blot analyses identifi ed two principal hAG-2 signals in all ER-positive breast carcinoma cel l lines that were absent in cell lines not expressing, or minimally ex pressing, ER. Coexpression of hAG-2 with ER suggests that hAG-2 may be involved in the tumor biology specific to the well-differentiated phe notype of hormonally-responsive breast cancers. (C) 1998 Academic Pres s.