title: Expression of cell cycle and apoptosis regulatory proteins in keratoacanthoma and squamous cell carcinoma.
abstract: Some authors view keratoacanthoma (KA) as a variant of squamous cell carcinoma (SCC), while others consider it a separate entity that must be distinguished from SCC. Involution displayed by KA is an important difference between these two entities. It has been suggested that apoptosis plays a role in the involution process of KA, although the exact trigger for it remains unclear. A hundred and fifty specimens were included in this study, 30 cases for each of the following groups: normal skin (NS), proliferative keratoacanthoma (pKA), regressing keratoacanthoma (rKA), well-differentiated squamous cell carcinoma (wdSCC), and poorly differentiated squamous cell carcinoma (pdSCC). They were immunohistochemically examined for the expression of p53, Ki-67, bak, and bcl-2. Significantly higher p53 and Ki-67 expressions were observed in all tumor lesions examined as compared with NS. There was higher bak expression in KAs compared to NS and a significant reduction of bak expression in pdSCC together with a significant reduction of bak expression in SCCs compared to pKA. Bcl-2 expression was similar in NS and SCCs, but was lower in rKA. We found a significant positive correlation between p53 and Ki-67, p53 and Bak in NS and examined skin tumors. Lower bcl-2 expression in conjunction with higher bak expression in rKA suggests a possible role of these apoptosis-regulating proteins in tumor regression. In contrast to this finding, a steady level of bcl-2 expression in pdSCC combined with lower bak expression levels and a high proliferation rate could contribute to progression and aggressiveness in these tumors. Bak and p53 expression is a sun-related and age-dependent process in NS and skin tumors.
authors.affiliation: Department of Dermatovenerology, Rijeka University Hospital, Rijeka, Croatia.
authors.forename: Tanja
authors.initials: T
authors.lastname: Batinac
authors.forename: Gordana
authors.initials: G
authors.lastname: Zamolo
authors.forename: Miran
authors.initials: M
authors.lastname: Coklo
authors.forename: Ita
authors.initials: I
authors.lastname: Hadzisejdic
authors.forename: Christophe
authors.initials: C
authors.lastname: Stemberger
authors.forename: Gordana
authors.initials: G
authors.lastname: Zauhar
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000473:pathology; D018797:Cell Cycle Proteins / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007636:Keratoacanthoma / Q000378:metabolism* / Q000473:pathology; D019394:Ki-67 Antigen / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012867:Skin; D012878:Skin Neoplasms / Q000378:metabolism / Q000473:pathology; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000378:metabolism
chemical_list: D051017:Apoptosis Regulatory Proteins; C494772:BAK1 protein, human; D018797:Cell Cycle Proteins; D019394:Ki-67 Antigen; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D050998:bcl-2 Homologous Antagonist-Killer Protein