MUC4 expression is increased in dysplastic cervical disorders

The female uterine cenix has 2 characteristic populations of epithelial cel ls: the endocervix is composed by mucus-secreting cells that express severa l mucin genes, and the exocervix has a typical stratified squamous epitheli um and does not express secreted mucins. Among human mucin genes, the MUC4 sequence has a transmembrane domain, and its molecular structure suggests t hat it has a protective role and also may be implicated in intracellular si gnalling. The aim of this study is to analyze whether changes in the expres sion of MUC4 can be detected associated with the squamous dysplastic transf ormation of exocervical epithelium. MUC4 expression has been analyzed by im munohistochemistry, Western blotting, and in situ hybridization. Using immu nohistochemical techniques, MUC4 is found in normal endocervix (n = 11) and is absent or only focally detected in the normal stratified cervical epith elium (n = 18). In samples from squamous metaplasia (n = 9), MUC4 is variab ly expressed (10% to 50% positive cells), whereas MUC4 is strongly detected in dysplastic cervical epithelia. The greatest number of positive cells is found in samples with moderate and severe dysplasia in which MUC4 is detec ted in 100% of the analyzed samples (n = 16). These results have been confi rmed by Western blotting and by detection of MUC4 transcripts using in situ hybridization. The present data suggest that MUC4 is activated during the process of squamous dysplastic transformation and may be used as a marker f or this pathologic process. HUM PATHOL 32:1197-1202. Copyright (C) 2001 by W.B. Saunders Company.