Clinicopathological significance of immunohistochemical expression of Filamin A in breast cancer.

Background: Filamin A is an actin-crosslinking protein expressed in many malignancies, although its prognostic and therapeutic role in breast cancer is not studied. There is enigma regarding its dual role in cancer, the tumor-progressing or tumor-suppressing effects depending on the site to which it localizes in the cell. The current study aimed to detect Filamin A expression in breast cancer and its association with other biomarkers and other clinicopathological parameters and established risk factors in breast cancer so that it can be a potential site for targeted therapy.

Materials and methods: One hundred female patients of histologically proven breast cancer who presented to our hospital over a 2-year period were included in the study. None of the patients received prior radiotherapy, chemotherapy, or immunotherapy. Patients with recurrent breast cancer are not included in the study. All study cases are subjected to immunohistochemistry for estrogen receptor, progesterone receptor, Her2 neu, and ki-67 from core biopsy tissue of cases diagnosed as breast carcinoma. Tissue sections were subjected to immunohistochemistry with anti-Filamin A.

Results: Filamin A is expressed in 69% of cases of invasive breast cancer in our study. There was no statistically significant relationship of Filamin A immunoexpression with histological grade, age, parity, oral contraceptive use, smokeless tobacco use, TNM staging, clinical staging, clinical prognostic staging, and also ER, PR, Her2 neu, and ki-67 status (P > 0.05). Thus, it appears to be an independent biomarker in breast carcinoma. Filamin A was expressed only in the cytoplasm in all our study cases. Filamin A expression can be observed in adjacent normal breast tissue and benign fibroadenoma tissues also, but the pattern of expression is mainly membranous with cytoplasmic positivity. The cytoplasmic expression is seen in malignant cells as well as normal breast and benign tumor sections implicating the dual role of Filamin A in breast cancer.

Conclusion: No significant correlation could be found between Filamin A expression and clinicopathological parameters in our study. The cytoplasmic expression is seen in malignant cells as well as normal breast and benign tumor sections implicating the dual role of Filamin A in breast cancer. Filamin A immunoexpression should be further correlated with metastasis-free survival period of breast cancer patients.