Comparative Evaluation of SOX2 and p16 Expression in Intraepithelial Neoplasia and Invasive Cancer of Cervix

Introduction: SRY (Sex determining region Y)-Box Transcription Factor 2 (SOX2), a transcription factor functioning as a stem cell marker has been studied in many cancers for its role as an oncogene. This study evaluates the expression of SOX2 and protein 16 (p16) expression in cervical with the intent to establish their role as a diagnostic biomarker. Aim: To evaluate the nature of SOX2 expression in cervical cancer and in intraepithelial lesions of cervix and compare it with the expression of p16 with the intent to establish its role as a diagnostic biomarker. Materials and Methods: This study was a retrospective observational study conducted in the Department of Pathology, Chettinad Hospital and Research Institute. Chennai, Tamil Nadu, India from October 2018 to September 2019. Archival blocks for study were collected from cases between January 2012 to December 2017. Immunohistochemistry for SOX2 and p16 on 61 cases of cervical lesions including SCC, Low-grade Squamous Intraepithelial Lesion (LSIL), High-grade Squamous Intraepithelial Lesion (HSIL) and normal cervix were done. A chi-square analysis was used to determine the relationship of SOX2 and p16 expression in different lesions and compared the same. All collected data was tabulated and analysed by Statistical Package for Social Sciences (SPSS) version 23.0 and was compared by chi-square tests. Results: In the total 61 cases (majority with LSIL, n=21, 34.43%, SCC were 19 (31.15%), HSIL were 20 (32.79%) and adenosquamous carcinoma were 1 (1.64%), SOX2 (p-value <0.001) and p16 (p-value 0.0016) showed over-expression in SCC and HSIL with significant p-value, LSIL showed low expression. SOX2 and p16 expression was limited to the basal one-third in LSIL cases, whereas it was expressed up to two-third or full thickness in HSIL cases. Also, SOX2 and p16 had a significant relationship with p-value=0.001. SOX2 was sensitive for SCC with 84.21% sensitivity and p16 was sensitive for HSIL with 90% sensitivity. Conclusion: Both SOX2 and p16 show increasing expression as the lesion progresses from low grade dysplasia to high grade dysplasia and invasive cancer and can complement each other to make a definitive diagnosis.