Hairy cell leukemia: an analysis of the chromosomes of 26 patients

Fluorescence In Situ Hybridization: Trisomy 12 Follow-up In Hairy Cell Leukemia

Peripheral white blood cells from five patients with hairy cell leukemia (HCL) were studied applying fluorescence in situ hybridization (FISH) using heparinized peripheral blood, biotin-labeled chromosome 12-specific α satellite DNA probe and biotin fluorescein-labeled avidin to detect hybridization. This methodology is ideal to investigate the incidence of numerical chromosomal abnormalities of both interphase and metaphase cells. Blood samples from 28 normal subjects were included as control samples. Trisomy 12 was considered to be present when ≥4% of cells had three hybridization spots. Trisomy 12 was detected in three of the five patients at different stages of their evolution. Trisomy 12 was also evident in two patients upon relapse of the HCL. When treatment with interferon alfa (IFN) and steroids was started, clinical and analytical remission were achieved and trisomy 12 disappeared. In one patient trisomy 12 persisted regardless of treatment with IFN and a good clinical evolution. Our results show that trisomy 12 was detected in HCL with FISH at a higher frequency than that previously reported by cytogenetic analysis in either peripheral blood or in cultivated cell lines. These results indicate that the presence of trisomy 12 may be a useful marker for the presence of HCL cells, to check the percentage of trisomic cells and that trisomy 12 is also a useful marker to indicate the activity of the disease.

Application of cytogenetics in neoplastic diseases

This review will concern itself with the application of cytogenetic findings in neoplastic diseases. This application can be divided into two general categories: practical and theoretical. The practical applications reside in utilizing karyotypic changes, particularly in leukemias and lymphomas, not only for diagnostic purposes but also for predicting response to therapy and prognosis. This is especially evident in the various acute nonlymphocytic leukemias and in most of the acute lymphoblastic leukemias. Thus, a definite correlation exists between the cytogenetic findings and the various clinical, laboratory, and cytologic parameters of most of the leukemias. Undoubtedly, these leukemias will ultimately be classified and defined more in terms of their cytogenetic aspects than any other. Though the application in lymphoma is not at the same level as that in leukemia, developments in that field certainly indicate a similar utilization of the cytogenetic findings in these diseases. The presence or absence of a Ph1 chromosome in a chronic myelocytic leukemia has been utilized widely, not only in the diagnosis but also in the predictability of response; the cytogenetic findings have also been utilized in predicting the blastic phase of disease. The list of specific chromosome changes in various solid tumors is of a lesser number, but significant developments indicate that the applicability of chromosome changes in these diseases will, also, be established in the near future. The application of chromosome findings to theoretical aspects of malignancy has assumed an important place recently in the demonstration that so-called oncogenes (or proto-oncogenes) are located or associated with areas of human chromosomes in which breaks and translocations are involved. Thus, it appears that chromosome changes in human malignancy, once their specificity is established, are important parameters in the clinical and theoretical aspects of the disease. A discussion will also be given on primary vs. secondary chromosome changes and their significance in the biology and behavior of the malignancy.

Cytogenetic studies in patients with hairy cell leukemia

We performed cytogenetic studies on 58 patients with hairy cell leukemia (HCL) from 1975 to 1981. Analysable metaphase cells stained with Q-banding were obtained in 77 samples from 44 patients. Cells with abnormal chromosomes were found in both unstimulated and stimulated cultures of bone marrow and peripheral blood. Patients were classified in 6 groups. Group I, 2 patients with a clonal chromosome abnormality; group II, 13 patients with nonclonal structural abnormalities; group III, 5 patients with nonclonal numerical abnormalities; group IV, 19 patients with only a normal karyotype; group V, 15 patients with no or with fewer than 5 normal metaphase cells; group VI, 4 patients with questionable abnormal chromosomes. Common abnormalities were deletion of the long arm of No. 6 or +3 each in 3 patients, and +Y, +12 or +18 in 2 patients. Actuarial survival for each group was calculated from diagnosis and also from chromosome examination. The two patients with a clonal chromosome abnormality died within one year. Eight of 13 patients with nonclonal structural abnormalities died within 5 years after diagnosis, while none of 5 patients with nonclonal numerical abnormalities and 2 of 19 patients with normal chromosomes died within 5 years. The difference in the 5-year actuarial survival between patients with nonclonal abnormalities (groups II and III) and those with a normal karyotype was significant (p less than 0.05). The difference was more marked between patients with nonclonal structural abnormalities and those with a normal karyotype (p less than 0.01). Patients with nonclonal numerical abnormalities had a longer survival than those patients with nonclonal structural abnormalities (p less than 0.05). Thus, structural chromosome abnormalities in HCL may be a poor prognostic sign even when they are not clonal.