Recent evidence suggests a role for both immunotherapy and chemotherapy in the treatment of transitional cell carcinoma. Glucan, a derivative of the cell wall of Saccharomyces cerevisiae and a potent immunostimulant, was used in combination with cyclophosphamide for treatment of implanted murine transitional cell carcinoma (
MBT2). Cyclophosphamide prevented tumor appearance when tumor burden was low and decreased tumor growth rate in larger tumor volumes, but was unable to eradicate established tumors. Glucan did not reduce tumor incidence but decreased animal mortality. These experimental observations may correlate well with clinical evidence and suggest future clinical use of these agents.