Expression profile of apoptotic and proliferative markers in oral lesions and its clinicopathological significance

Abstract

Introduction: Oral cavity is prone to a myriad of changes with advancing age as well as a result of the environmental and life style related factors. Genetic abnormalities are the primary cause of dysplastic, metaplastic, and neoplastic changes resulting in an imbalance between molecular mechanisms which regulate apoptosis and cell proliferation. Evaluating these parameters may not only help in identifying the individuals who are at a greater risk of developing carcinomas, but also carry significant prognostic value. Aim: The present study was undertaken with the aim of evaluating the expression profile of Bcl2 and Ki-67 as biomarkers in assessing the apoptotic and proliferative activity of Oral lesions and compare the topographical aspect of these lesions. Material and Methods: A cross sectional study of 31cases of oral lesions, immunohistochemically assessed for Bcl-2 and Ki67 for their expression pattern. Results: Expression of Ki-67 showed a linear increase from normal oral epithelium through various histological grades of Oral squamous cell carcinoma (OSCC). Expression of Bcl-2 was variable, defined by cytoplasmic granular staining in the epithelial cells. A decrease in mean positivity was seen from well differentiated OSCC to Moderately differentiated OSCC. Weak intensity of Bcl2 staining was seen in all the cases except one case of poorly differentiated oral squamous cell carcinoma. Conclusion:The pattern of expression of biomarkers, not only help in diagnosing oral lesion but also in identifying prognostic markers. Alterations in the expression of proteins related to cell proliferation and apoptosis are a strong indicator of the malignant transformation potential of certain lesions.

Exploring the Role of EZH2 and BCL2 in Demarcating Oral Verrucous Hyperplasia and Verrucous Carcinoma

“…Deng et al and Jairajpuri et al also observed similar expression pattern in group II and III; however, Thennevan et al suggested very limited expression in verrucous lesions. 12 17 Corresponding with the previous studies we concur that a proportional rise in the BCL2 expression from group I to III reflects its part in disease progression by increasing the survival rate of neoplastic cells and allowing clones of the neoplastic cells to proliferate and differentiate. In group IV, BCL2 immunoexpression was exaggerated and primarily confined to peripheral cells of the tumor islands similar to studies conducted by Juneja et al and Sudha and Hemavathy ( Fig.…”

“…10 Cytological atypia is often debated as a feature in verrucous lesions. 10 Our study exhibited 50% cases of group II and 33.3% group III cases positive for atypia which was far lesser than the results obtained by Jairajpuri et al and Thomas and Barrett who observed a 69.2 and 66% positivity, respectively, for atypia in group II 12,37 (►Fig. 4B).…”

“…3A). 12,32,33 The expression pattern of BCL2 in group II was variable which was predominantly confined to the basal and parabasal layer of the epithelium (►Fig. 3B).…”

“…Dysplastic, metaplastic, and neoplastic alterations are mostly caused by genetic defects leading to an imbalance in the molecular pathways which regulate apoptosis and cell growth. 12 Enhancer of zeste homolog (EZH2), is a histonelysin N-methyltransferase which forms a catalytic subunit of polycomb recessive complex (PRC2) for trimethylation of histone H3 at lysine 27 (H3K27me3) which play a vital role in cell proliferation and is a critical factor of pluripotency and differentiation of stem cells as well as aberrant gene expression during malignant transformation. 13,14 EZH2 has been previously associated with histological differentiation, mode of invasion, lymph node metastasis, and prognosis in OSCC.…”