Cell cycle analyses of extramammary Paget's disease.

The cell cycle of Paget cells in extramammary Paget's disease was investigated using microscopic analysis of the DNA content, and using immunohistochemistry for 5-bromodeoxyuridine (BrdU) incorporation. Stripped skin was treated with tetrasodium ethylendiamine tetraacetate dihydrate (EDTA) and trypsin, and epidermal cells suspensions were obtained. Microscopic analysis of the DNA content in the cells was performed. The resulting DNA histogram was close to the normal ploidy. Specimens from the involved skin were incubated with BrdU, and sections were immunostained with anti-BrdU monoclonal antibody. A few nuclei showed positive staining for BrdU. The present study showed that the proliferative potential of Paget cells in extramammary Paget's disease was low. This may explain why lesions of extramammary Paget's disease enlarge rather slowly.