[Molecular biology approach to explain lymphatic metastasis]

The spread of tumor cells of solid tumors to the regional lymph nodes is an important step in the progression of the disease and also an important prognostic factor. While the significance of the prognostic value of the lymphatic progression had been detected long ago, only increased knowledge of the molecular anatomy and mechanisms involved in the lymphatic spread of tumor cells provided a beginning insight into the understanding of lymphatic metastasis. One group of important molecular factors consists of proteins produced by the tumor cells inducing a proliferation of lymphatic vessels into the primary tumor. The vascular endothelial growth factors have been identified as key factors in this process. In addition there are hints for the fact that chemokines, which are cytokine-like proteins taking part in the regulation of processes of inflammation, and their chemokine receptors control cellular key steps of lymphatic metastasis of tumor cells such as migration, proliferation, and invasion. In conclusion new data point to the possible inhibition of lymphatic spread by selective blockade of growth factor receptors or chemokine receptors. The growing insight into cellular understanding of the mechanisms involved in the metastasis of tumor cells into the lymphatics and lymph nodes will hopefully facilitate the development of new diagnostic and therapeutic tools in the treatment of cancer patients.