Carcinoma - Classification of Carcinomas

Classification of Carcinomas

Malignant neoplasms are exceptionally heterogeneous entities, reflecting the wide variety, intensity, and potency of various carcinogenic promoters.

To date, no simple and comprehensive method for classifying them has yet been devised and accepted within the scientific community.

Traditionally, however, malignancies have generally been classified into various taxa using a combination of criteria, including:

One commonly used classification scheme classifies these major cancer types on the basis of cell genesis, specifically:

1. Their (putative) cell (or cells) of origin
   1. Epithelial cells => carcinoma
   2. Non-hematopoietic mesenchymal cells => sarcoma
   3. Hematopoietic cells
      1. bone marrow-derived cells that normally mature in the bloodstream => Leukemia
      2. bone marrow-derived cells that normally mature in the lymphatic system => Lymphoma
   4. Germ cells => Germinoma

Other criteria that play a role in a cancer diagnosis include:

• The degree to which the malignant cells resemble their normal, untransformed counterparts
• the appearance of the local tissue and stromal architecture
• the anatomical location from which tumors arise
• genetic, epigenetic, and molecular features