The T-cell dysfunction associated with human cancer has been studied extensively. We have proposed to study the effects of various thymic hormones i.e. Thymosin F-F, Thymosin alpha 1, THF on some T-cells functions often deranged in human cancer. We tried to study in vitro a group of patients with a predilection to T-cell dysfunction i.e., patients with Neck cancer of advanced lung cancer. We have shown that incubation of cancer patients PBL with THF can restore their capacity to generate a GVH in the immunosuppressed rat (GVHR). We have also identified a radiosensitive thymic hormone responsive cell in the PBL of cancer patients. We plan to further characterize the nature of the suppressor cell in other suppressor cell assays. We plan to study additional thymic peptides such as Thymosin alpha 7 with a possible suppressor role in the GVH assay. We plan to study additional Thymic peptide as they become available. In addition a Phase I study, aimed at determining the capacity of in vivo treatment with thymic hormones to restore Cell Mediated Immunity is currently being initiated.