High claudin-4 antigen expression in triple-negative breast cancer by the immunohistochemistry method.

Background: Triple-negative breast cancer is a heterogeneous subtype of breast cancer. Claudin is an epithelial tight junctional protein, and also it is a receptor for clostridium perfringens enterotoxin and shows impairment of expression in several cancers. The chief purpose of this study is to assess the claudin-4 expression in triple-negative breast cancer (TNBC) Iranian patients and evaluate its correlation with some clinicopathological factors. Materials and Methods: In this study, 81 TNBC patients were evaluated for the claudin-4 expression by immunohistochemistry. The slides' staining intensity was examined and scored from 0 to 3. Then, slides were reviewed to assess the percentage of cells with membrane and cytoplasmic staining; the obtaining scores were 1-4. Finally, added the resulting two numbers from two stages, and the final number was a maximum of 7. Final scores of 0-3 were considered the low expression, and 4-7 were considered the high expression. Finally, the collected data were analyzed using the Chi-square test. Results: Eighty-one women with breast cancer and a mean age of 49 ± 12 years participated in the study. In 80% of the patients, there was a high expression of claudin-4 marker, and 20% had low expression. The expression level of the marker was not significantly correlated with age, tumor size, lymph node involvement, tumor grade, disease stage, Ki-67, and metastasis. Conclusion: The present study confirmed the high frequency of claudin-4 antigen expression in TNBC patients, and no significant correlation was observed between the expression of antigen and demographic or clinicopathological factors.