Methylation Status of the RB1 Gene as a Diagnostic and Prognostic Tool in Breast Cancer: Correlations with Clinicopathological Features and Immunohistochemical Markers

Background The RB1 gene plays important role in regulating the cell cycle and has been implicated in various malignancies, including breast cancer. Methylation-specific PCR (MSP) was used to assess RB1 methylation, while immunohistochemical markers such as ER, PR, HER2, and Ki-67 were analyzed to correlate molecular changes with clinical characteristics. The findings demonstrate that aberrant RB1methylation is significantly linked to more aggressive tumor phenotypes, including higher histologic grade, advanced stage, and elevated Ki-67 expression. Furthermore, RB1 methylation status correlated with poor survival outcomes, suggesting its role as a prognostic biomarker. This study underscores the importance of RB1 methylation in breast cancer pathophysiology and its potential clinical utility. Method A total of 40 primary breast carcinoma tissue samples and 10 non-neoplastic breast tissue samples were collected from the pathology archives of medical institutions in Duhok, Iraq. Clinical and pathological data, including patient age, tumor size, stage, and grade, were retrieved from medical records. Hematoxylin and Eosin (H&E) staining was performed to confirm diagnosis. Immunohistochemical (IHC) staining was conducted for Ki-67, ER, PR, and HER2, while MSP was employed to evaluate RB1 methylation and its association with clinical parameters. Results All patients in this study were female, with 70% being over 50 years old. Immunohistochemical analysis revealed that ER, PR, and HER2 were negative in 65%, 70%, and 60% of cases, respectively, while 70% of tumors exhibited high Ki-67 expression. A significant correlation was found between Ki-67 expression and receptor status, as well as other clinicopathological features. RB1 methylation was identified in 24 cases (60%), demonstrating a strong association with tumor aggressiveness and immunohistochemical markers. Conclusion The study confirms the association between RB1 methylation and breast cancer progression. Evaluating RB1 methylation status could provide valuable diagnostic and prognostic insights, potentially guiding targeted therapeutic strategies.