Thrombospondin-1 expression in bladder cancer: association with p53 alterations, tumor angiogenesis, and tumor progression

Background: Thrombospondin-1 (TSP) is a 430-kd glycoprotein that is an important component of the extracellular matrix and is known to be a potent inhibitor of angiogenesis (i.e., formation of new blood vessels) both in vitro and in vivo. Several reports suggest that TSP possesses tumor suppressor function, possibly through its ability to inhibit tumor neovascularization. It has recently been shown that TSP expression is enhanced by the product of the p53 gene (also known as TP53). Purpose: We examined the role of TSP expression in tumor recurrence and overall survival in patients with invasive bladder cancer. We also examined the relationship between alterations in p53 protein expression, TSP expression, and tumor angiogenesis. Methods: Tumors from 163 patients (with a median follow-up of 7.7 years) who underwent radical cystectomy for invasive transitional cel