Oncogenesis and tumour suppression

Two sets of genes are among the major driver of tumours, both malignant and benign: the oncogenes and the tumour suppressor genes. Oncogene refers to a gene that encodes for a protein (oncoprotein) in which excessive and unregulated activity can transform a normal cell into a cancer cell. As it is necessary for just one of the two gene copies to be abnormal, oncogenesis is defined as dominant. Tumour suppressor genes are known for their roles in inhibiting cell growth and have antitumour effects. According to the classic model, growth suppressor genes are recessive and therefore both copies have to be inactivated in order for an effect to be seen. Exception however occurs! Recently also non-coding mRNAs (i.e. an mRNA that is not translated into a protein) have been found to be able to induce oncogenic and suppressive effects. Finally, both some genes and some non-coding mRNA are able, in certain cellular contexts, to behave both as both an oncogenic and a suppressive factor.