Cancers derived from epithelial cells. This group includes many of the most common cancers, particularly in the aged, and include nearly all those developing in the breast, prostate, lung, pancreas, and colon.
Cancers arising from connective tissue (i.e. bone, cartilage, fat, nerve), each of which develop from cells originating inmesenchymal cells outside the bone marrow.
These two classes of cancer arise from hematopoietic (blood-forming) cells that leave the marrow and tend to mature in the lymph nodes and blood, respectively. Leukemia is the most common type of cancer in children accounting for about 30%.
Cancers derived from pluripotent cells, most often presenting in the testicle or the ovary (seminoma and dysgerminoma, respectively).
Cancers derived from immature “precursor” cells or embryonic tissue. Blastomas are more common in children than in older adults.