Expression profile of epidermal differentiation complex genes in normal and anal cancer cells

Anal cancer originates from a peculiar histological region and provides a u seful model for investigating alterations in proliferation and/or different iation of neoplastic keratinocytes. Epidermal differentiation complex (EDC) genes, which form one of the major gene clusters in the human genome, are involved in the terminal differentiation of epithelial cells and in many in stances have been implicated in epithelial tumours. We constructed a DNA ma croarray capable of characterising the expression profiles of the entire ED C gene complex in normal mucosa and anal cancer biopsies of seven unrelated patients. Brain tissue and cultured keratinocytes were used as controls. A ll anal cancer samples showed expression profiles in which none of the EDC genes was silent, as evaluated by phosphor-imager analysis. Variance analys is showed significantly lower expression of SPRR2 with respect to SPRR1 or SPRR3, and significantly higher expression of S100A8 than of other S100A su bfamily members. At hierarchical clustering analysis, the four basaloid ana l cancer cases conglomerated in the top five positions. The macroarray meth od used by us provides the first demonstration of the expression profile of the EDC gene family in anal cancer, and is capable of producing significan t information on the subgrouping of epithelial tumours such as anal cancer.