Evaluation of Claudin-1 and Ki-67 in Different Molecular Subtypes of Breast Ductal Carcinoma: Immunohistochemical Study

Abstract
Background: The role of claudin-1 in aggressiveness and increased metastatic phenotype is controversial issue in different cancers.
Aim of Study: Evaluation of immunohistochemical ex-pression of Claudin-1 and Ki-67 in different molecular subtypes of breast ductal carcinoma and correlation with other prognostic clinicopathologic factors.
Patients and Methods: This is a retrospective controlled Immunohistochemical study performed to examine the expres-sion of Claudin-1 and Ki-67 in 54 cases of breast ductal carcinoma (NST) with different molecular subtypes. Statistical analysis methods were used to evaluate the relationship between Claudin-1 and Ki-67 with various clinicopathological, parameters and molecular subtypes.
Results: 19 cases (35.2%) were Luminal A, 14 cases (25.9%) were Luminal B, 10 cases (18.5%) were Her2 En-riched, and 11 cases (20.4%) were Triple Negative (TN). There is a statistically significant correlation between claudin-1 & Ki-67 expression and various pathological parameters and molecular subtypes. High expression of both markers have direct significant correlation with poor prognostic factors as higher tumor grade and, higher nuclear grade, large tumor size, positive lymph node metastasis, positive distant metas-tasis, high stage, positive LVI and poor NPI. Luminal B and TN tumors have higher Ki-67 compared to other subtypes. TN tumors & Her2 enriched tumors have higher claudin-1 expression compared to other subtypes. All luminal A tumors have low expression of both Ki-67 and caludin1.
Conclusions: Claudin-1 overexpression is associated with poor prognostic factors and high Ki-67 proliferative index in breast ductal carcinoma and may have diagnostic role in discrimination between different molecular subtypes of breast ductal carcinoma.