Increased B7-H3 Immunostaining is Associated with Muscle Invasiveness in Urinary Bladder Carcinoma

Urinary Bladder carcinoma (UBC) is a worldwide health issue. B7 homolog 3 protein (B7-H3), also known as cluster of differentiation 276 (CD276); it belongs to the B7 family of molecules and regulates the immune system's response to tumours. It is closely linked to the progression, metastasis, recurrence, and other undesirable clinical aspects of tumours, and is widely expressed in urologic tumours as well as other human malignancies as reported by previous studies. Targeting B7-H3 directly on tumour cells is a promising strategy. Such targeting would require knowledge about the amount of receptor on the cells and its distribution in the tissue. The present work is carried out to evaluate the immunohistochemical staining patterns of B7-H3 in UBC and their association with different clinicopathological parameters. Sixty tissue blocks of primary UBC were randomly selected for the current study. Goat anti-mouse/rabbit horseradish peroxidase, a two-step detection method, was used for the immunohistochemical staining. High cytoplasmic B7-H3 immunostaining (c-B7-H3) was observed in 55% of UBC patients while membranous immunostaining (m-B7-H3) was high in 48.3% of patients. Patients that showed high cytoplasmic B7-H3 immunostaining were associated with high-grade urothelial tumours (p=0.006) and state of muscle invasion (p=0.041). Positive membranous B7-H3 was significantly associated with higher age group (p=0.017), tumour histological subtype (p<0.001) and muscle invasion status (p=0.014)). Increased B7-H3 immunostaining is associated with muscle invasiveness in UBC which is suggestive that B7-H3 could have a role in promoting tumour progression.