Immunohistochemical Expression of Nibrin in Epithelial Dysplasia and OSCC: A Cross-Sectional Study

Abstract

Inherited defect in DNA repair capability is the fundamental problem causing mutations to be passed on to new generation of cells leading to cancer. The NBS1/Nibrin/p95 belongs to the family of the DNA double-strand break repair complex (hMre11 complex) which is a transcript of the mutated NBS gene, located on human chromosome 8q21 The protein complex containing nibrin binds to the edges of the DNA double-stranded break causing defective repair process. Nibrin also activates various signaling cascades such as; phosphatidylinositide 3-kinases PI3-kinase/Akt triggering the oncogenic process. Aims: The purpose of this research was to aid in the diagnosis of oral cancer and dysplastic lesions in Karachi population. Study Design: This cross-sectional study was conducted at a tertiary care hospital. All samples were recruited for the study after obtaining written informed consent from patients and seeking ethical approval from Ethic Review Committee Ziauddin University (Reference Code: 0330618FAOM), Karachi Pakistan. Place and Duration of Study: Ziauddin hospital north Nazimabad Karachi, November 2018 to September 2019. Methodology: Expression of Nibrin (NBS1) was evaluated by Immunohistochemistry on dysplasia and OSCC biopsies by H-Score method. The tumor was graded by broder system. Immunohistochemical analysis for nibrin was performed on the tumor block. Mean, frequency, percentages were calculated for quantitative variables, chi square was used for qualitative variables. A value <0.05 was considered as significant. Results: 92% OSCC cases were positive for Nibrin while 80% of oral dysplasia revealed Nibrin expression. This accounts for significant statistical association of Nibrin with OSCC (0.012*) and dysplasia (0.001*). Unfortunately, apart from moderaterly histological differentiation (0.012) none of these clinicopathological parameters showed statistical significance. Conclusion: We conclude that a Nibrin protein showed overexpression among 92% of OSCC patients out of total 100 cases and in 80% out of 30 cases of dysplasia so the association of histological grading with expression of Nibrin was significant and expression of Nibrin intensity with histological grading was significant as well. Our study suggests that this expression of Nibrin may be used as a diagnostic marker for potential OSCC patients.