Many steps are required to convert a normally functioning cell into a malignant one. The cancer cell must be able to multiply under conditions that a normal cell would not, as well as to invade surrounding tissue and spread throughout the body. Both genetic changes (e.g., the activation of oncogenes or inactivation of tumor suppressor genes) and epigenetic changes (e.g., the stimulation of cell proliferation) contribute to the development of cancers.
Carcinogenesis is a complex interplay of simultaneous and stepwise processes, including any combination of genetic, biologic, chemical, and environmental factors. Generally, carcinogenesis can be subdivided into three stages: initiation, promotion, and progression. Initiation is a result of some irreversible genetic alteration, which may be a mutation, transversion, transition, and/or small deletion in DNA. Promotion, considered to be reversible, has no basis in structural DNA alterations but does involve alterations in promoter-receptor interactions that mediate changes in genome expression. Progression is the final and irreversible stage of carcinogenesis, which is characterized by malignant growth. This pathway often involves the activation of proto-oncogenes and oncogenes, as well as the downregulation of tumor suppressor genes.
New research into carcinogenesis is prolific, and although many of what are thought to be the most important gene targets in carcinogenesis have been elucidated, it is likely we are nowhere near defining the total group of molecular alterations that lead to neoplasia.
cannot understand a word. info given are too summary and unconnected
Great explanation, It's great how the lecturer takes the time to guide our mental process. He´s so far my favorite lecturer.
Very annoying style of presentation. I do Cancer research for a living in the USA and I found a lot of problems with this presentation.
the way he explains , dat is funny. I see some nerds didnt like the lecture, meh get a life "nerds" :D