It is when cancer cells break away from a tumour and enter the bloodstream and settle elsewhere in the body. Its not good at all. It is vital that malignant tumours are discovered quickly befor metastasis can occur.
Peter Thomas has written: 'Metastatic potential of human colorectal cancer cell lines' -- subject(s): Cancer, Cell Line, Colon (Anatomy), Colorectal Neoplasms, Immunology, Metastasis, Neoplasm Metatasis, Pathophysiology, Physiopathology, Rectum 'Companion guide to Far from the madding crowd for 'O' level students'