Oncogenesis Review Articles

 Oncogenesis or cancer formation is the expression of impaired cellular events in the favor of uncontrolled cell growth and proliferation. This occurs basically by disruptions in harmonious control effects of the growth-inducing, growth-inhibiting, apoptosis-regulating, and DNA-repairing mechanisms. A simplified understanding of these mechanisms is given in this chapter. In the first part of the chapter, regarding the concepts of susceptibility to and formation of cancers, the basic knowledge of cellular genetic content and events is reviewed.In the second part, molecular basis of oncogenesis is explained regarding the eight hallmarks of cancers. For better understanding, well-described examples of mechanisms responsible in musculoskeletal system tumors are given through the text. Certainly, cellular and molecular aspects of oncogenesis will continue to be the primary field of future investigations to reach better understanding, diagnosis, treatment, and prediction of prognosis of cancers.Four categories of genes have been identified that are involved in oncogenesis: (1) oncogenes that normally function to promote cellular growth and division in a programmed manner, but which can trigger unregulated proliferation when some aspect of their function or expression is altered, (2) tumor-suppressor genes, which normally act to suppress cellular growth and which can lead to uncontrolled proliferation when inactivated, (3) genes encoding DNA repair enzymes, which when dysfunctional lead to an increased accumulation of mutations in cancer-predisposing genes, and (4) metastasis-associated genes, which when activated allow cancer cells to disseminate and establish tumors in sites peripheral to the original neoplasm