The malignant effect of cancer stems in part from the fact, that tumor cells have the capacity to infiltrate the neighboring tissue and to produce distant metastases when they reach circulation by blood and lymphatic vessels. Metastases pose the most serious challenge to cancer therapy, and are the leading cause of cancer death. In the majority of patients, by the time of diagnosis of primary malignant neoplasms, metastases have spread to regional or distant sites but only in the minority of these patients metastases can be clinically detected. Metastatic spread is also augmented under conditions in which the immune system of the host is damaged by genetic, viral or environmental factors. The inverse relationship between the development of metastases and the immune response, demonstrated in many experimental systems, is also a major problem in the use of chemotherapeutic agents.
Chemotherapy is considered as the most efficient anti-metastatic treatment modality.
Yet, Cytotoxic agents can damage cells of the bone marrow and the lymphoid organs leading to a reduction in the immune competence of the host, thus, rendering him vulnerable to opportunistic infections. The thymus is responsible for the production and education of T-lymphocytes, and is a source of peptides that regulate the immune response. Also, the therapeutic effectiveness of THF- g 2 was expressed by prolonging the survival of such treated animals. The main goal of our research project is to determine the immunotherapeutic effect of THF- g 2, when combined with anticancer drugs, in the treatment of metastatic Lung Carcinoma, Breast Carcinoma and Melanoma tumors. The involvement of immunological components in the arrest of metastatic growth achieved by the combined THF - chemotherapy treatment.