Abstract
The aim of the present study was to investigate the expression levels of brain‑specific angiogenesis inhibitor‑1 (BAI‑1) in bladder transitional cell carcinoma (BTCC) at different stages and the mechanism by which it inhibits tumor endothelial cell proliferation. Normal bladder mucosa biopsy specimens were obtained as the control group, and human BTCC biopsy specimens were used as the study group. Immunohistochemical assays were used to detect the expression levels of BAI‑1, vascular endothelial growth factor (VEGF) and mutant p53, in addition to microvessel density (MVD) in the tissues. Western blotting was used to analyze the differential expression of BAI‑1 in the two samples. Statistical analysis was performed, which indicated that BAI‑1 expression levels in the normal bladder mucosa group were significantly higher than those in the BTCC group and were associated with clinical staging. BAI‑1 levels in the T1 stage BTCC tissues were higher than those in the T2‑4 stage BTCC tissues (P<0.05). BAI‑1 expression levels were negatively correlated with those of VEGF (r=‑0.661, P<0.001), mutant p53 (r=‑0.406, P=0.002) and with the MVD (r=‑0.675, P<0.001). BAI‑1 may be involved in the negative regulation of BTCC microvascular proliferation, and its expression may be associated with a reduction in p53 mutations.