[Chromosomal changes in cancers].
In addition to the chromosome changes common to cancers, recent development of cytogenetics in human cancers has revealed, the site of specific chromosome changes which characterize specific cancers. Such cancer-specific aberrations are generally reciprocal translocations or deletions, and in some cases the translocations have been unequivocally demonstrated to involve cellular oncogenes (c-onc) in the new transcriptional control of other genes. Chromosome changes relatively common to cancers are amplification of specific genes by chromosome duplication or selective amplification as manifested by double minutes or homogeneously staining regions, and genome reorganization by nondisjunction, somatic recombination, polyploidization-segregation or other parasexual recombinations. The importance of such genome reorganization in cancer development was discussed in relation to the possible involvement of cellular escape mechanisms.