CD47 expression in urothelial carcinoma and its correlation with histopathological findings

The incidence of bladder cancers (BCs) is increasing day by day in both males and females with increased smoking. New treatment protocols are required due to the long follow-up times and high recurrence rates. CD47 (integrin-associated protein) is a membrane receptor that is effective in normal and pathophysiological events such as apoptosis, proliferation, adhesion, and immunity. Phagocytosis of both normal and tumor cells is prevented, by binding to the ligand signal regulatory protein-1 (SIRP-1)α on macrophages. Anti-CD47 antibodies can eliminate the binding and may be effective in treatment.

The study included 194 cases with urothelial carcinoma (UC) who underwent transurethral resection (TUR) of the bladder and had been followed up for one year. Cytoplasmic and membranous staining was preferred for CD47-positive staining. Staining results were compared with tumor grades, pathologic tumor stage, recurrence, and metastasis grade.

The prevalence and intensity of CD47 staining in BCs were evaluated in this study. High-grade tumors were stained more pronouncedly compared with low-grade tumors and normal epithelium. The prevalence of CD47 staining was significant in pT2 (Pathological tumor stage 2, invades of muscularis propria) tumors, and its correlation with pTa (Pathological tumor stage a, noninvasive papillary carcinoma) tumors was significant ( P < 0.001). In the intensity evaluation, there was a significant difference between pTa and pT2 and between pT1 (Pathological tumor stage 1, invades lamina propria) and pT2 ( P = 0.003).

CD47 is expressed strongly in high-grade tumors. The prevalence and intensity of CD47 staining are high in pathologic tumor stage, recurrence, and distant metastases and are considered poor prognostic markers. We believe that anti-CD47 antibodies can be used as an alternative to the current treatment or in combination with other medications, and the systemic side effects that may occur with intravesical treatment can be prevented.