Immunohistochemical expression of chemokine receptor CXCR3 and its ligand CXCL 11 in basal cell carcinoma

Introduction: Basal cell carcinoma (BCC) is the most common type of skin cancer worldwide. The pathogenesis of BCC involves interplay between various environmental and genetic factors. It is believed that chemokines play a significant role in the modulation of cancer growth by generating autocrine and paracrine signaling effects. The present study was conducted to elucidate the expression of chemokine, CXCL11, and its receptor CXCR3, and their interaction with tumor cells and peri-tumoral stroma in various subtypes of BCC. Aim and Objectives: The aim of this study was to evaluate the immunohistochemical expression of chemokine CXCL11 and its receptor CXCR3 in various subtypes of BCC. Materials and Methods: The study included 40 cases of histopathologically confirmed BCC. Clinical and histopathological features of various tumor subtypes were noted. Immunohistochemistry was performed using antibodies against CXCL11 and CXCR3, and these were assigned scores 0, 1, and 2 on the basis of immunohistochemical expression. Results: The median age of study participants was 65.0 +/- 12.2 years with a male-to-female ratio of 1.5:1. The most common site was face, followed by neck, scalp, and back. The tumor subtypes included in the study were nodular (n = 20), pigmented (n = 8), infiltrating (n = 5), superficial (n = 4), and adenoid (n = 3). On immunohistochemistry, CXCR3 expression was seen in 34 (85%) cases with stromal inflammatory cells immunopositivity in 29 (72.5%) cases and tumor cells immunopositivity in 5 (12.5%) cases. CXCL11 expression was seen in 36 (90%) cases with weak expression in stroma and tumor in 18 cases and strong expression in the rest 18 cases. In individual subtypes, higher immunopositivity for CXCR3 and CXCL11 in tumor cells and peri-tumoral stroma was seen for nodular, infiltrating, and pigmented subtypes, compared to adenoid and superficial subtypes. Conclusion: Our study shows the enhanced expression of chemokine CXCL11 and its receptor CXCR3 in tumor cells and peri-tumoral stroma of BCC. This expression is greater in tumor cells of aggressive subtypes, i.e. nodular, infiltrating, and pigmented types. This suggests that receptor ligand pathway involving CXCR3 and CXCL11 plays a key role in pathogenesis of BCC, and blocking this pathway may result in inhibition of tumor growth. Thus, these chemokines may serve as future potential targets in developing novel therapeutic regimens against BCC.