NTU Undergraduates' research April 2014 - Biosciences | Page 52

With a total of 14.1 million deaths in 2012, cancer is one of the leading causes of global mortality.
Over 90% of cancer related deaths occur as a result of metastasis to distant organs, so the
understanding of why cancers migrate preferentially to specific organs is key in preventing these
deaths. The seed and soil theory is supported by extensive research, and explains the site-specific
metastasis of primary tumours. Facilitated by mechanical entrapment of tumour cells in distant
vasculature, and the seed and soil theory, preferential growth may occur as a result of
interactions between tumour cells and secondary sites, and is thought to be responsible for the
metastasis of certain cancers to specific sites. Further research is still required before the exact
mechanisms by which certain cancers metastasize to specific sites can be fully understood.