Correlation Between Clinicopathological Characteristics of Breast Cancer and Immunohistochemical P16 Expression in Relation to Cell Cycle Regulation in Ductal Carcinoma in Situ and Invasive Ductal Carcinoma: A Preliminary Study

Objective: To investigate the correlation between breast cancer clinicopathological characteristics and P16 expression in Ductal Carcinoma in Situ (DCIS) and Invasive Ductal Carcinoma (IDC) through immunohistochemical analysis, to better understand the potential role of P16 as a biomarker for tumor progression and its association with clinical features. Methods: A total of 61 cases that were diagnosed with IDC between 2018 and 2022 were used in the current study. By accessing the patients’ archive files and paraffin blocks, the prevalence and intensity were investigated using immunohistochemical staining for p16. Results: Although no significant differences were detected in p16 density, prevalence, tubule formation, or histological grade (p > 0.05), there were significant relationships between mitosis and nuclear grade (p < 0.05). The statistical results showed a significant difference between axillary lymph node metastasis, p16 density, Estrogen-positive ER (+), and lymph vascular invasion (p = 0.050, p = 0.044, and p = 0.07, respectively). Conclusion: Especially the relationship between mitosis, nuclear grade, and p16 expression can be shown as the strongest indicator that brought new prognostic factors to the agenda.