Advances in gene therapy for bladder cancer.

The efficacy of various currcntly available therapeutic strategies for bladder cancer is not always suffcient, especially for the advanced disease, recurrent superficial cancer, and treatment-resistant carcinoma in situ. Advances in genetic and molecular biology have led to novel approaches for cancer treatment. Gene therapy is currently one of the most promising strategies against various malignancies, and several clinical trials have been approved worldwide. Various strategies for modulating the genetic state have been applied in bladder cancer treatment, and encouraging results have been demonstrated both in vitro and in vivo. Although the therapeutic genes work dramatically when the transgenes are effectively expressed in the targeted cells, however, a sufficient rate of transduction cannot always be achieved. The most significant obstacle for clinical application of cancer gene therapy might be the method for sufficient delivery and expression of the therapeutic genes. Bladder is an easily accessible organ because of its anatomy; however, a glycosaminoglycan (GAG) layer on the bladder mucosa may protect integration of exo-delivered genetic vectors. Various strategies are applied for improving the transduction efficacy of the therapeutic genes into the bladder cancer cells. These strategies include the modification of adenoviral fibers, cotransduction of the materials for enhancing the viral infectivity, and disruption of the GAG layer. Recent advances in the field of gene therapy for bladder cancer are briefly summarized in this review.