Expression of apoptotic, cell proliferation regulatory, and structural proteins in actinic keratosis and their association with dermal elastosis.
BACKGROUND
Actinic keratosis (AK) is a premalignant lesion caused by ultraviolet (UV) radiation and characterized by epithelial and connective tissue alterations. However, little is known about the link between connective and UV-damaged epithelial tissues in AK.


OBJECTIVE
To examine the potential relationship between connective tissue degeneration and molecular alterations in epithelial cells without evident morphologic changes, 30 cases of AK (8, grade I; 10, grade II; 12, grade III), divided into three grades according to the proportion of dermal elastosis (in grade I, up to 30% of collagen degeneration; in grade II, 30-60%; in grade III, more than 60%), were immunohistochemically analyzed for the expression of Ki67, p53, p63, bcl-2, E-cadherin, 34-betaE12, and CD99.


RESULTS
The increase in the solar elastosis grade was associated with an increase in positive cell numbers for all analyzed markers. Basal expression predominated in the lesions with low and moderate levels of connective tissue degeneration, while a basal and suprabasal expression pattern was prevalent in the lesions with high degeneration. In grade I and II lesions, proliferation marker, Ki67, expression was found to be significantly associated with the proapoptotic marker p53, while in grade III lesions, its expression was correlated with the anti-apoptotic marker, bcl-2.


CONCLUSIONS
These results demonstrate that the epithelial expression of apoptotic, cell proliferation, and structural proteins is augmented with the increase of the solar elastosis grade. Thus, the grade of solar elastosis could be a helpful morphologic marker in the assessment of neoplastic changes in sun-damaged skin.
da Silva
Tarcília Aparecida
TA
Department of Oral Surgery and Pathology, School of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil. tarcilia@odonto.ufmg.br
Coelho
Getúlio
G
Lorenzetti Bocca
Anamélia
A
Figueiredo Cavalcante Neto
Florêncio
F
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis / Q000502:physiology*; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic / Q000378:metabolism; D004547:Elastic Tissue / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D010787:Photosensitivity Disorders / Q000378:metabolism / Q000473:pathology*