Chromosomes and cancer: current aspects.

Abstract

B EFORE THE TURN of the century scientists attempted to link abnormalities of mitotic cell division to the phenomenon of cancer. Originating with the observations of Von Hansemann on cellular imbalance, these theories were brought to a peak by the intense work of the Flemish cytologist Theodor Boveri. Boveri, working with mitotic irregularities in sea-urchin eggs, struggled to prove a connection between these abnormalities and neoplastic cell growth.’ He failed in this attempt but his work opened a field of investigation that continues to fascinate researchers. Although numerous cytogenetic observations of neoplasms were recorded by the early 1950s newer chromosome spreading techniques in the 1960s stimulated a wave of improved studies of tumor chromosomes.Z Further improvements in cell culture allowed better studies of leukemic cells. Notable among these was the work of P. C. Nowell and D. A. Hungerford leading to their description of the Philadelphia (Ph’) chromosome in chronic myeloid leukemia.3 In the 1970s the refined techniques of chromosome staining, producing a ‘banded’ or ‘striped’ chromosome appearance and allowing individual chromosome identification, led to fresh rounds of observations on the cytogenetics of leukemic and solid tumor cells. With these methods it became possible to identify specific chromosomes involved in neoplastic alteration and even to identify parts of chromosomes that were translocated or rearranged in neoplastic cells.4 These studies have now included a significant number of cases and some conclusions may be drawn, even though the field is still developing. Current information has made important contributions in two clinical and one research area. The clinical contributions are: (1) Demonstration of an abnormal chromosome karyotype in cells from a patient with clinical signs of neoplasm can confirm or establish a diagnosis of malignancy earlier than is possible without such studies. (2) Certain specific chromosome karyotype patterns may be reliable indicators of the anticipated clinical course including the patients response to therapy. Research with tumor chromosomes has perhaps posed more questions than it has provided