Expression of Transgelin in Triple Negative and Non Triple Negative Breast Cancer: A Differential Study

Abstract

Introduction: Triple negative breast cancer (TNBC) is defined by the absence of ER expression, PR expression and HER2 amplification. No targeted treatment is available for TNBC and chemotherapy remains the best therapeutic option. However, in the case of recurrence or chemo-resistance, therapeutic options are very limited. TNBC presents a high rate of proliferation and is highly aggressive having low survival rate. As the complexity of this disease is being simplified over time, new targets are also being discovered for the treatment of this disease. Therefore, there is still need for new biomarkers, which would serve for targeted treatment. Transgelin was proposed as a new potential cancer biomarker. Altered expression of Transgelin has been described in a wide range of cancers, often with contradictory results. The aim of the study was to compare Transgelin expression across molecular subtypes of breast cancer, to identify if it can be used as a future molecular targeted protein for TNBC. Material and Methods: Transgelin immunohistochemistry was applied on 60 retrospectively collected paraffin blocks of patients presenting with invasive breast carcinoma (NST) having different molecular subtypes. Blocks were collected between 2015 and 2016 from Pathology department, Medical Research Institute, Egypt. Her2 equivocal cases were excluded from the study. Results: Transgelin expression was positive in 23 cases and negative in 37 cases. There was a statistically significant difference between (Transgelin +) and (Transgelin -) cases being highly expressed in TNBC in comparison to other molecular subtypes. It was also highly expressed in tumors with large size, high grade, positive lymph-vascular invasion status & lymph node metastasis. There was no statistically significant difference between (Transgelin+) and (Transgelin-) as regards age and Her2 status. Conclusions: Transgelin is an aggressive biomarker differentially expressed among the molecular breast cancer subtypes with high expression in TNBC. Transgelin may provide a potential target for future treatment of TNBC.