The biology of cancer metastasis or, 'you cannot fix it if you do not know how it works'.

The major cause of death from cancer is the relentless growth of metastases that are resistant to conventional therapy. The pathogenesis of a metastasis is complex and requires that tumor cells complete a sequence of potentially lethal interactions with various host factors. The finding in 1973 that metastasis is a selective process and the finding in 1977 that malignant neoplasms are heterogeneous and contain few preexisting metastatic subpopulations have added a new dimension to our understanding of cancer and its spread. This understanding is now contributing to the design of better therapies against disseminated metastasis.