Chromosomes and causation of human cancer and leukemia. XII. Banding analysis of abnormal chromosomes in polycythemia vera.

The chromosome constitution of bone marrow cells was determined in 13 patients with polycythemia vera (PV). In 5 of these patients definite karyotypic abnormalities were found: 3 with 46,XY,Fq-; 1 with 46,XY,11q-, 13q-; and 1 with missing Y. The latter cytogenetic finding is thought not to be related to the PV. The 4 patients with partial deletions of chromosomes had been treated with 32P, and 3 of them with chemotherapy also. Karyotypes from 2 of these patients, 1 with 46,XY,20q-, and another with 46,XY,11q-,13q- were examined with G and/or Q banding. From the results of the banding analysis, it appears that the abnormal chromosomes were due to simple deletions at specific sites on their arms, particularly in the cases with the F abnormality (20q11). The breaks occurred in the regions C11q and D12q. The portions missing from the original chromosomes could not be found on any chromosome. Most patients with PV do not develop chromosomal abnormalities through the course of their disease; when such abnormalities appear (20q- in particular), they seem to result exclusively from radiation (and possibly chemo-) therapy. Thus, cytogenetic changes do not appear to play a crucial role in the genesis of PV.