- Carcinoma: Malignant tumors derived from epithelial cells. This group represents the most common cancers, including the common forms of breast, prostate, lung and colon cancer.
- Sarcoma: Malignant tumors derived from connective tissue, or mesenchymal cells.
- Lymphoma and leukemia: Malignancies derived from hematopoietic (blood-forming) cells
- Germ cell tumor: Tumors derived from totipotent cells. In adults most often found in the testicle and ovary; in fetuses, babies, and young children most often found on the body midline, particularly at the tip of the tailbone; in horses most often found at the poll (base of the skull).
- Blastic tumor or blastoma: A tumor (usually malignant) which resembles an immature or embryonic tissue. Many of these tumors are most common in children.
Benign tumors (which are not cancers) are named using -oma as a suffix with the organ name as the root. For instance, a benign tumor of the smooth muscle of the uterus is called ''leiomyoma'' (the common name of this frequent tumor is ''fibroid''). Unfortunately, some cancers also use the -omasuffix, examples being melanoma and seminoma...