CD47 expression in classic follicular lymphoma is associated with event-free survival

CD47 inhibits host cell phagocytosis by macrophages, leading to immune evasion. Upregulation of CD47 in many cancers including hematopoietic neoplasms correlates with poor prognosis. We evaluated CD47 expression in classic follicular lymphoma (FL) to ascertain its potential utility for targeted therapy. A cohort of 97 cases were studied by immunohistochemistry using a rabbit anti-CD47 monoclonal antibody and the results were correlated with clinicopathologic features, gene expression and clinical outcome. Our findings show that high CD47 expression (H-score ≥150) was significantly associated with a worse event-free survival at 12 months EFS12 and EFS24 months (P = 0.023 and 0.009 respectively), although no correlation was seen with overall survival (OS; P = 0.175) or other clinicopathologic parameters. In multivariate analysis, H-score retained its impact on both EFS12 and EFS24 (P = 0.027 and 0.0.012, respectively). Gene expression profiling revealed 11 genes that showed statistically significant differences in CD47-high versus CD47-low expressors in univariate but not in multivariate analysis and included MAPK12 and CCND2. Validation in larger case cohorts is required to further support the potential application of CD47-targeted approaches in patients with FL and to explore novel therapeutic strategies. In addition, differentially expressed genes in CD47-high versus CD47-low expressors raises potential areas of interest for further study.