C5aR2 in Breast Cancer and Its Relationship with Clinicopathological Features

To determine the relation between C5aR2 and clinicopathological parameters of breast cancer.                   Study Design: Observational study.                                                                                                                                               Place and Duration of the Study: Department of Histopathology, PNS Shifa Hospital, Karachi, from January to June 2023.   Methodology: One hundred and twenty-eight women, aged 24-90 years with histologically proven diagnosis of breast cancer, were included in the study. Immunohistochemistry (IHC) was performed to evaluate the C5aR2 expression by its percentage and intensity. The C5aR2 staining was observed in membranes and/or cytoplasm. The immunoreactive score (IRS) was obtained and its association was analysed with clinicopathological parameters of breast cancer. SPSS version 27 was used to analyse the data.                      Results: The C5aR2 expression was higher in tumour cells (90.6%) compared to stromal cells (53.1%), predominantly exhibiting cytoplasmic localisation. Higher C5aR2 expression was observed in older age groups, higher-grade tumours, and ER/PR/HER2 and HER2 positive tumours. Moreover, tumours with poor treatment response also showed increased C5aR2 expression compared to those with good treatment response. Although no significant association was identified between C5aR2 expression and Ki67, increased C5aR2 expression has been found in tumours with high cell proliferation rates.

In this study, an association between tumour and stromal cell C5aR2 expression and age, grade, receptor status, proliferation rate, and post-treatment response was identified.

Breast cancer, C5aR2, Cancer associated fibroblasts, Immunohistochemistry, Ki67.