According to their evolutionary foundation, cancers may be divided into ectodermal and mesodermal tumours. Ectodermal tumours originate from tissue at the body’s surface, skin and mucosa. But also cancers in organs derived from epithelial structures such as the gastro-intestinal, respiratory, and uro-genital tract belong to this group. Ectodermal tumours are designated carcinoma.
Bone, muscle, or the nervous system are derived from the mesoderm. Tumours derived from these tissues are designated sarcoma. But also the leukaemias, cancers of blood cells, belong to the group of mesodermal tumours.
While the most frequent cancerous diseases in women of industrialised countries are cancers of breast and colon, men most frequently suffer from prostate and lung cancer.