International Journal of Morphology
On-line version ISSN 0717-9502
ASSUMPCAO, Paulo Pimentel de et al. Chromosome Instability in Carcinomas . Int. J. Morphol. [online]. 2006, vol.24, n.3, pp. 335-338. ISSN 0717-9502. doi: 10.4067/S0717-95022006000400007.
In the current carcinogenesis models, the occurrence of increasing mutations and selection mechanisms favoring cell survival and higher proliferation rates are taken into account. Epigenetic mechanisms, among which DNA methylation stands out, also take part in oncogenesis. The characteristic of tumor cells that allows the increase of mutations is named genetic instability, encompassing two mechanisms: microsatellite instability, characterized by nucleotide alterations with errors in the DNA repair systems; and chromosomal instability, represented by aberrations occurring in large chromosome segments. Carcinomas are characterized by complex cytogenetic alterations and large gene amalgamations. Telomeric alterations, inadequately repaired DNA breaks, and deficiencies in the mitotic spindle checking systems are events capable of generating the chromosomal instability and aneuploidy which characterize more aggressive neoplasias. A better understanding of the chromosomal instability mechanisms can show the way towards a clinical utilization of such information, like developing more adequate therapeutic strategies, targeted at specific sites involved in the malignization process
Keywords : Chromosomal instability; Carcinomas; Aneuploidies.