title: Simple epithelial cytokeratin-expression in seborrheic keratosis.
abstract: The cytokeratin expression of seborrheic keratosis was studied by means of immunohistochemistry and compared with that of normal human skin. The following findings were obtained in seborrheic keratosis: (1) a partial lack of high molecular weight cytokeratin (#1/68 kD, #10/56.6 kD) in all ten cases examined; (2) the detection of cytokeratin typical for simple epithelia (#8/52.5 kD, #18/45 kD, #19/40 kD) in eight of ten cases; and (3) the detection of cytokeratin #5/58 kD in suprabasal cells in 5 of 10 cases. An immunoelectron-microscopic investigation, using an anti-keratin antibody against cytokeratin #19/40 kD, revealed a whirl-like arrangement of keratin filaments within immunoreactive cells, in contrast to a linear, parallel arrangement in non-immunoreactive cells. Cells known to express cytokeratin typical for simple epithelia, such as sweat gland cells or Merkel cells, were not observed. The altered cytokeratin gene-expression in seborrheic keratosis may be attributable to de-differentiation of tumor cells or potential re-differentiation towards embryonic keratinocytes.
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004848:Epithelium / Q000737:chemistry / Q000473:pathology / Q000648:ultrastructure; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000032:analysis* / Q000378:metabolism; D017492:Keratosis, Seborrheic / Q000378:metabolism* / Q000473:pathology; D008297:Male; D016253:Microscopy, Immunoelectron; D008875:Middle Aged; D012867:Skin / Q000737:chemistry* / Q000473:pathology / Q000648:ultrastructure
chemical_list: D007633:Keratins