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Int J Clin Exp Pathol 2013;6(12):2855-2863

Original Article
Claudins 1, 2, 3, 4, 5 and 7 in solar keratosis and squamocellular carcinoma of the skin

Hanna-Riikka Hintsala, Maria Siponen, Kirsi-Maria Haapasaari, Peeter Karihtala, Ylermi Soini

Department of Pathology, Oulu University Hospital and University of Oulu, Oulu, Finland; Department of Oral and Maxillofacial Diseases, Kuopio
University Hospital, Kuopio, Finland; Department of Oncology and Radiotherapy, Oulu University Hospital and University of Oulu, Oulu, Finland;
Institute of Clinical Medicine, Pathology and Forensic Medicine, University of Eastern Finland, Cancer Center of Eastern Finland and
Department of Clinical Pathology, Kuopio University Hospital, Kuopio, Finland

Received August 28, 2013; Accepted October 9, 2013; Epub November 15, 2013; Published December 1, 2013

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. (IJCEP1308068).

Keywords: Tight junction, claudins, squamocellular carcinoma, dysplasia, actinic keratosis

Address correspondence to: Ylermi Soini, Institute of Clinical Medicine, Pathology and Forensic Medicine, University of Eastern Finland,
Yliopistonranta 1 C, FI-70210 Kuopio, Finland. Tel: +358 40 355 2754; Fax: +358 17 162753; E-mail: ylermi.soini@kuh.fi