Cancer Mode of Infection Mode of Infection Cancers can develop in many different types of tissues. Carcinomas are cancers that develop in endodermal or ectodermal tissues or in the epithlial lining of internal organs and glands. Sarcomas are cancers that develop in mesodermal connective tissues. Lymphomas are cancers that develop in lymphoid tissues.
Leukemias are cancers that develop in lymphocytes or hematopoietic cells.
Though there are many different types of cancer, there are some consistent patterns and themes to the disease. Cancer is a state of uncontrolled cell growth. In healthy cells, cell growth is regulated by proto-oncogenes and tumor suppressor proteins. Mutations caused by a variety of factors can stimulate the development of proto-oncogenes into oncogenes and can affect the availability of tumor suppressor proteins. Mutations in proto-oncogenes can result in the constant stimulation of the cell growth pathway or the constant activation of growth receptors, even in the absence of stimulating signals.