Studies from our laboratory demonstrate that lymphatic pump treatment (LPT) significantly decreases solid tumor formation in the lungs of rats with tumors. Therefore, the focus of these studies was to determine the immune mechanisms, both locally and systemically, responsible for this protection. The most significant finding of this study is that LPT exerts a tissue specific response in the lung. LPT significantly increased leukocyte numbers, including those of GALT-derived lymphocytes in the lung of tumor-bearing rats. Furthermore, LPT enhanced cytokine production by pulmonary leukocytes in vitro. Preliminary findings suggest that LPT does not promote lymphangiogenesis and metastasis during tumor development. Our results provide early experimental support for the use of LPT as an adjunctive therapy in patients with cancer.