METASTASES AND EXOSOMES

Most cancer patients do not die from the primary tumor but from its metastases, which are secondary tumors formed by cells that have separated from the primary tumor.

Often, the primary tumor suffers from a lack of oxygen that causes stress and starts the process of spreading metastases. According to one theory, the primary tumor, using a continuous molecular signal, prepares a favorable environment in healthy tissue, before the first cancer cell is transported by the bloodstream to the new site. The primary tumor releases exosomes which are vesicles covered by a lipid membrane that act as messengers and prompt cells to create fertile ground for metastasis.