ABSTRACT
The genome of a particular individual, the cell type of the tumor, and the combination of accumulated genetic aberrations determine the type of cancer that develops. The characteristics of cancer cells, such as resistance to drugs and virulence, are strongly influenced by cell types, which dictate protein expression profiles, and in turn, influence signaling. The four most common cancers occurring worldwide are lung, breast, bowel, and prostate. Though in different locations, all are epithelial cell cancers, which, as a group, account for 80%-90% of all cancers. They are classified as carcinomas. It is common to describe breast cancer as consisting of two main types, ductal carcinomas, which develop in the lining of milk ducts, and lobular carcinomas, which develop in lobules. Sarcomas are tumors that arise from cells of mesochymal origin. They are cancers of the supporting tissues of the body, such as bone, muscle and blood vessels.
