Chromosomes and cancer

The development of modern cancer cytogenetics is briefly reviewed. The observation around 1950 that ascites tumors were excellent materials for chromosome analysis acted as an incitement both of cancer cytogenetics and of mammalian cytogenetics in general. The Philadelphia chromosome of chronic myelogenous leukemia (CML). discovered in 1960, was long unique in showing strict correlation between specific chromosomal deviation and malignant disease. Detailed chromosome analysis of large series of experimental tumors was needed to establish the distinction between significant and accidental chromosome deviations and to demonstrate that the former were nonrandom and formed predetermined patterns. These were correlated to the inducing factor rather than to the tissue type, from which the tumor developed. Systematic analysis of chromosomal aberrations in more than 600 human neoplasms, studied by our group or taken from the literature, showed that in 12 different tumor types most chromosomes were unaffected, the significant deviations being clustered to 10 of the 24 human chromosome types. It was suggested that genes of special importance to malignant development were located in a few specific chromosomes. The 2 obscure, cancer-associated phenomena of homogeneously staining chromosome regions and double minute chromosomes are briefly described and a tentative interpretation is proposed.