Pathogenesis

Pathogenesis is the mechanism by which a certain etiological factor causes disease (pathos = disease, genesis = development).

Some forms of pathogenesis are:
 * Inflammation
 * Malignancy
 * Tissue breakdown

In most diseases, there are multiple pathogenetical processes at work. For example, certain cancers arise from dysfunction of the immune system (skin tumors and lymphoma after a renal transplant - which requires immunosuppression).

Often, a potential etiology is identified by epidemiological observations before a pathological link can be drawn between the cause and the disease.