Expression of a truncated form of hHb1 hair keratin in human breast carcinomas

Human hHb1 belongs to the type II hard keratin family and is physiologicall y expressed in hair shafts. In the present study, using specific 3' and 5' probes for hHb1, we established that breast carcinomas ectopically express a hHb1 5'-truncated mRNA, and that this transcript is restricted to maligna nt epithelial cells. Furthermore, an in vitro study indicated that it could be translated. We concluded that, in breast carcinomas, expression of trun cated hHb1 is related to epithelial cell transformation. Because the hHb1 g ene maps to 12q11-q13, a chromosome region known to present several breakpo ints in solid tumours, we propose that the hHb1 gene might represent a targ et for such alterations.