COMPARATIVE ANALYSIS OF OCT4 AND CD44 IMMUNOEXPRESSION IN LOWER LIP EPIDERMOID CARCINOMA AND ACTINIC CHEILITIS
Carcinogenesis; Lower lip epidermoid carcinoma; Actinic cheilitis; Immunohistochemistry; OCT4; CD44.
The carcinogenesis process is characterized by the transformation of a normal cell into a malignant cell, due to cumulative genetic alterations, influenced by the genetic predisposition of the patient, as well as by environmental factors. In the lower lip, exposure to UV radiation is the main etiological factor associated with the development of epidermoid carcinomas and actinic cheilitis, and the latter have been considered lesions with potential for malignant transformation. By the hierarchical model theory in carcinogenesis, the development, growth and metastasis of cancer are driven by a small population of tumor stem cells, with multipower ability and self-renewal. Some markers such as CD44 and OCT4 have been used to identify these cells and provide information about diagnosis and prognosis in epidermoid carcinomas of many locations. The aim of this study was to compare the expression of OCT4 and CD44 in 40 cases of lower lip epidermoid carcinoma (LLEC) and 40 cases of actinic cheilitis (AC), being analyzed the clinicopathological features and immunoexpression of these proteins. OCT4 and CD44 expression was assessed semi-quantitatively by percentage of positive epithelial cells (PP) and intensity of expression (IE), resulting in total immunolabeling score (PIT) ranging from 0 to 7. OCT4 immunoexpression was shown to be both nuclear and cytoplasmic for most cases of AC and LLEC, while for CD44 it was membranous. No statistically significant differences were found between OCT4 and CD44 immunoexpression and clinicopathological parameters, except for lymph node metastasis in which there was a decrease in OCT4 expression in the core tumor of cases with lymph node metastasis. There was a negative and statistically significant correlation between the immunoexpression of these markers in the core tumor. Also, decreased CD44 expression was observed in LLEC cases when compared to AC cases. The results of this study suggest a higher participation of these proteins in early stages of carcinogenesis. In addition, the imbalance of OCT4 and CD44 immunoexpression in the tumor core suggests the presence of different subpopulations of neoplastic cells with distinct pluripotency phenotype, associated with different degrees of cell differentiation.