| Abstract | Ciljevi: Keratoakantom je keratinizirajući kožni tumor s centralnim kraterastim udubljenjem, nejasnog uzroka. Obilježavaju ga brzi rast i česta spontana regresija. Protein povezan s citotoksičnim limfocitima T ili CTLA-4 inhibicijski je receptor iz obitelji CD28 koji zaustavlja aktivaciju reagirajućih T-stanica te posreduje suprimirajuće funkcije regulacijskih T-stanica. Cilj studije je utvrditi izražaj CTLA-4 u centru, bazi keratoakantoma i zdravom lateralnom rubu kože kao kontroli te ispitati ovisi li izražaj o stadiju keratoakantoma, spolu i dobi.
Materijali i metode: Istraživanje je obuhvatilo 30 uzoraka tkiva uklopljenog u parafinski blok, dobivenih nakon ekscizije keratoakantoma. U imunofluorescencijskom bojenju korišteno je anti–CTLA-4 zečje antitijelo (ab237712, Abcam, UK) te sekundarno antitijelo obilježeno fluoresceinom, a preparati su analizirani fluorescentnom mikroskopijom. Broj stanica pozitivnih na CTLA-4 izražen je u postotku u odnosu na ukupan broj stanica po vidnom polju (400 x).
Rezultati: Protein CTLA-4 izražen je u centru tumora u 28 (93.33%) slučajeva, na bazi tumora u 28 (93.33%) slučajeva, a značajno manje na zdravom lateralnom resekcijskom rubu, u 17 (56.67%) uzoraka. U centralnom dijelu tumora postoji statistički značajna razlika u izražaju CTLA-4 među stadijima keratoakantoma (P = 0.020). Postoji statistički značajna razlika između skupine s proliferativnnim stadijem i skupine s neodređenim stadijem keratoakantoma (P = 0.037) te između skupine s proliferativnim stadijem i skupine s regresijskim stadijem keratoakantoma (P = 0.022). Statistički značajna razlika prema spolu nije pronađena u ekspresiji CTLA-4 u centru tumora (P = 0.546), bazi tumora (P = 0.151), niti na zdravom lateralnom resekcijskom rubu (P = 0.914). Nije utvrđena statistički značajna razlika među dobnim skupinama s obzirom na ekspresiju CTLA-4 u centru tumora (P = 0.592), na bazi tumora (P = 0.888) te na zdravom resekcijskom rubu (P = 0.821).
Zaključci: Izražaj CTLA-4 je značajno veći u tumoru (centar i baza) nego na zdravom lateralnom resekcijskom rubu. Regresijski stadij keratoakantoma ima veći izražaj CTLA-4 nego proliferativni stadij. Spol i dob nisu povezani s izražajem CTLA-4. Za dodatna pojašnjenja uloge CTLA-4 u razvoju i/ili regresiji keratoakantoma, potrebna su daljnja istraživanja u smijeru fenotipizacije CTLA-4 pozitivnih stanica. |
| Abstract (english) | Objectives: Keratoacanthoma is a dome-shaped skin tumor with a centralized keratinous plug, characterized by initial rapid growth and often spontaneous regression. Cytotoxic T-lymphocyte-associated protein 4 or CTLA-4 is an inhibitory receptor, belonging to the CD28 immunoglobulin subfamily, that inhibits T cell activation and mediates regulatory T-cell suppressive activity. The aim of this study was to determine whether there is a difference in CTLA-4 expression in the keratoacanthoma center, at the base and in the healthy lateral resection margin as a control, as well as to determine whether it is dependent on keratoacanthoma stage, sex, and age.
Materials and methods: The study included 30 samples of paraffin-embedded tissue, obtained after KA excision. Anti–CTLA-4 rabbit antibody (ab237712, Abcam, UK) and a secondary antibody labeled with fluorescein were used for immunofluorescence staining. The slides were analyzed by fluorescence microscopy. The number of CTLA-4-positive cells was expressed as a percentage of the total number of cells per field of view (400 x).
Results: CTLA-4 protein was expressed in the tumor center in 28 (93.33%) cases, at the tumor base in 28 (93.33%) cases, and significantly less on the healthy lateral resection margin, in 17 (56.67%) samples. Statistically significant difference in CTLA-4 expression between the stages of KA was found in the central part of the tumor (P = 0.020). Also, statistically significant difference was found between the group with the proliferative stage and the group without exact stage of keratoacanthoma (P = 0.037), as well as between the group with the proliferative stage and the group with the regression stage of KA (P = 0.022). No statistically significant gender difference was found in CTLA-4 expression in the tumor center (P = 0.546), tumor base (P = 0.151), or at the healthy lateral resection margin (P = 0.914). No statistically significant difference was found between age groups with respect to CTLA-4 expression in the tumor center (P = 0.592), at the tumor base (P = 0.888), and at the healthy resection margin (P = 0.821).
Conclusions: CTLA-4 expression is significantly higher in the tumor (center and base) than on the healthy lateral resection margin. The regression stage of keratoacanthoma has a higher expression of CTLA-4 than the proliferative stage. Gender and age were not associated with CTLA-4 expression. To further clarify the role of CTLA-4 in the development and/or in the regression of keratoacanthoma, additional research is needed to determine the phenotype of CTLA-4 positive cells. |
