CD1a expressionin Her2-positive breast carcinoma tissues and its prognostic implications

Aims: Dendritic cells are key players in initiating the primary immune response. Many studies have investigated the role of antigen-presenting cells in breast carcinoma, revealing associations between dendritic cell density, their spatial distribution within the tumor, and prognosis. CD1a is a glycosylated type I transmembrane protein that is frequently used as a dendritic cell marker in human tumors. This study aims to detect CD1a expression using immunohistochemical methods in a cohort of HER2-overexpressing breast carcinoma patients. It also analyzes the correlation of CD1a expression with prognostic parameters and overall survival outcomes. Methods: Patient records of individuals diagnosed with invasive breast carcinoma between 2003 and 2009 were retrieved from the digital pathology archive of İstanbul University İstanbul Faculty of Medicine Pathology Department. From this dataset, 48 cases were selected based on the following inclusion criteria: HER2 positivity confirmed. We applied cd1a immunohistochemically to all of these cases and compared the staining with prognostic data. Results: Any level of CD1a positivity was considered when evaluating the association between CD1a expression and survival/ prognostic factors. No statistically significant relationship was found between CD1a positivity and age, tumor size, lymph node involvement, or recurrence. No correlation was identified between CD1a positivity/negativity and the neoadjuvant status of the tumour. However, a significant association was observed between nuclear grade and CD1a positivity. No statistical correlation was found between 5-year total and disease-free survival and CD1a staining. Conclusion: Considering that HER2-positive tumors account for only 25–30% of breast carcinomas, our study focused on a particular and homogeneous patient group. A lower survival rate was expected because HER2 positivity is a known poor prognostic factor, and our cohort consisted of non-early-stage cases. Therefore, while a proportional relationship between CD1a positivity and survival was observed in HER2-positive cases, statistical significance was not achieved. Future studies should include larger patient populations or more heterogeneous cohorts in terms of prognostic features to obtain more conclusive results. In our study, CD1a positivity was significantly associated only with higher nuclear grade.