| Popis: |
TP53 tumor suppressor gene mutations are the most frequent genetic alterations in human cancer affecting a specific gene. The occurrence of TP53 mutations is considerably influenced by cancer-initiating events, such as DNA damage, the aftermath of which is the promotion of cancer development through the loss of anti-proliferative activities, including apoptosis and cellular senescence. Over 27.000 TP53 gene mutations have been discovered and found in more than 50% of human cancers. The most frequent alterations are the point mutations with a single base substitution in gene segment encoding for DNA-binding domaine of p53 molecule, leading to the production of mutant protein that differs from the wild-type protein by one amino acid (missense mutations) usually causing the change in tertiary structure of gene product, thus preventing p53 to bind to DNA and activate transcription of target genes. The result of the mutations may also be the proteins with new, abnormal functions, and the ability to modulate expression of genes responsible for neoangiogenesis, resistance to chemotherapeutics and prevention of tumor initiation and promotion. In such circumstances, not only the mutant TP53 loses its tumor suppressive function, but acquires oncogenic potential and becomes an active participant in the neoplastic transformation of the cell.Vast heterogeneity of mutations and methodological approaches in p53 status assessment represent the main difficulties in rapid and effective integration of basic p53 research into clinical practice. |
