title: Claudins 1, 2, 3, 4, 5 and 7 in solar keratosis and squamocellular carcinoma of the skin.
abstract: Claudins are tight junction proteins regulating the paracellular permeability of cell layers. We investigated the expression of claudins 1, 2, 3, 4, 5 and 7 in a sample set consisting of a total of 93 cases representing normal skin, actinic keratoses and squamous cell carcinomas of the skin. There were several changes found in claudin expression. Claudin 1 appeared to be progressively decreased in solar keratosis and skin squamous cell carcinomas compared to normal skin while expression of claudin 2 was increased. With claudins 3 and 5 occasional immunoreactivity was found in squamous cell carcinomas. Claudins 4 and 7 were variably expressed in skin neoplasia compared to normal skin. According to the results expression of claudins 1 and 2 change in parallel with the severity of the epidermal preneoplastic and neoplastic lesions thus probably influencing the disturbed epithelial polarity characteristic of these lesions. Claudin 1 under- and claudin 2 overexpression also lead to a leakier epithelial barrier function of the skin with a resulting damage to skin epithelial resistance. Other claudins investigated in this study did not show progressive changes even though occasional overexpression of them was found in skin squamous cell carcinoma.
authors.affiliation: Department of Pathology, Oulu University Hospital and University of Oulu Oulu, Finland.
authors.forename: Hanna-Riikka
authors.initials: HR
authors.lastname: Hintsala
authors.forename: Maria
authors.initials: M
authors.lastname: Siponen
authors.forename: Kirsi-Maria
authors.initials: KM
authors.lastname: Haapasaari
authors.forename: Peeter
authors.initials: P
authors.lastname: Karihtala
authors.forename: Ylermi
authors.initials: Y
authors.lastname: Soini
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000737:chemistry* / Q000473:pathology; D016022:Case-Control Studies; D062445:Claudin-1 / Q000032:analysis*; D062465:Claudin-3 / Q000032:analysis; D062506:Claudin-4 / Q000032:analysis; D062507:Claudin-5 / Q000032:analysis; D057167:Claudins / Q000032:analysis*; D005260:Female; D006801:Humans; D055623:Keratosis, Actinic / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011230:Precancerous Conditions / Q000737:chemistry* / Q000473:pathology; D012867:Skin / Q000737:chemistry* / Q000473:pathology; D012878:Skin Neoplasms / Q000737:chemistry* / Q000473:pathology
chemical_list: C568108:CLDN1 protein, human; C491875:CLDN2 protein, human; C568122:CLDN3 protein, human; C568157:CLDN4 protein, human; C107466:CLDN5 protein, human; C473255:CLDN7 protein, human; D062445:Claudin-1; D062465:Claudin-3; D062506:Claudin-4; D062507:Claudin-5; D057167:Claudins
keywords: Tight junction; actinic keratosis; claudins; dysplasia; squamocellular carcinoma