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

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.

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.

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.

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.