Breast cancer: New mechanism discovered for dissemination of metastatic tumor cells
Lymph nodes have an important filter function within the immune system and are arranged “in series” along lymphatic vessels. As a rule, malignant tumour cells first of all migrate into lymph vessels and the associated lymph nodes, where they form metastatic colonies. The sentinel lymph node is the lymph node closest to the primary tumour.
In the clinical diagnosis of breast cancer, for example, the exact size and number of tumour colonies in the lymph nodes close to the tumour site are an important prognostic factor for the development of metastases in the lung, brain or bones, for example. However, in order to reach these organs, the tumour cells must first of all pass from the lymphatic system into the vascular system. In order to design a targeted therapeutic blockade, it is necessary to understand the precise molecular processes involved in this transition. However, up until now, the corresponding underlying principles were not available.
As part of his PhD within the working group of the former head of MedUni Vienna’s Department of Pathology and professor emeritus, Dontscho Kerjaschki, and working closely with Michael Sixt’s laboratory at ISTA (Institute of Science and Technology Austria) in Klosterneuburg, Markus Brown (currently working at Genentec in San Francisco) infused fluorescent marker cells from a breast tumour directly into the lymph vessels of mice and monitored how they spread into the adjoining lymph node. He observed that, within a period of 48 hours, the infused tumour cells produced the molecular signs of increased aggression, migrated out of the solid tumour and found their way into special blood vessels in the lymph node. Even after such a short time, tumour cells are already circulating in the vascular system and forming pulmonary metastases.
The initial results of this basic pathogenesis research suggest that it is likely that such an entry point for tumour cells to invade the vascular system is also present in humans. These fundamental findings could represent a starting point for the conceptual development of new targeted therapeutic measures.
More information at https://www.meduniwien.ac.at/