http://www.who.int/topics/cancer/en/
http://www.cancer.org/docroot/CRI/content
http://www.cancer.gov/cancertopics/wyntk/overview/page4
http://www.accessexcellence.org/AE/AEPC/NIH/gene13.html
http://www.nci.nih.gov/cancertopics/pdq/genetics/overview/healthprofessional
http://www.cancer.gov/dictionary/db_alpha.aspx