Cytogenetic study in acute myeloid leukaemia using peripheral blood samples sent by post

A single-center population-based consecutive series of 1500 cytogenetically investigated adult hematological malignancies: karyotypic features in relation to morphology, age and gender

During the 18-yr period 1976-93, a population-based series of 1586 adults with suspected or confirmed hematological malignancies were successfully cytogenetically investigated at a single center. Eighty-six cases were excluded due to unretrievable medical records or if analyzed only in remission or at relapse. The remaining 1500 medical records were reviewed regarding morphology and clinical parameters in order to investigate possible associations between karyotypic pattern (normal, 1, 2 or complex anomalies; specific abnormalities) and gender, age and morphological subgroups. The impact of time-period, i.e. 1976-87 vs. 1988-93, and referring center on cytogenetic findings was also studied. A total of 372 acute myeloid leukemias (AML), 389 myelodysplastic syndromes (MDS), 64 acute lymphoblastic leukemias (ALL) and 262 chronic myeloid leukemias (CML) were identified, altogether 1087 cases. Patients with other (n=261) or no hematological malignancies (n = 152) were excluded from the present analysis. Cytogenetic abnormalities were detected in 52% AML, 51 % MDS, 68% ALL and 97% CML, frequencies that did not differ significantly between the 2 time periods or referring centers. No significant age- or gender-related differences in karyotypic patterns were discerned in AML, MDS, ALL or CML, whereas the karyotypic patterns varied among the FAB groups in both AML (p= 0.001) and MDS (p < 0.001). The specific abnormalities t(8;21), t(15;17) and inv(16) were more common (p < 0.001) in younger AML patients and 5q- was more frequent in females with MDS (p<0.001). These findings indicate, in contrast to previous series, that neoplasia-associated karyotypic aberrations are not more common among older patients or in males.

Specific chromosome changes and nonoccupational exposure to potentially carcinogenic agents in acute leukemia in China

Cytogenetic studies were performed on 44 Chinese patients with acute leukemia. A high percentage of patients (37.5%) with t(8;21), t(15;17) or 17q- (in poorly banded preparations), and abnormalities involving 11q23 were noted in 32 unselected patients with ANLL. A similar high percentage was previously reported in Japan and in South Africa but not in western countries. Data on casual or other non-occupational exposure to potentially carcinogenic agents were obtained by interview with the patients at their first presentation. Most patients with these three major chromosomal changes had a history of exposure, whereas most other patients did not (p = 0.01). Patients with ANLL-M3 were more often exposed than were the other patients (4/6 vs 8/38, p = 0.03). The only common exposure was to organophosphate insecticides. Twenty seven cases of therapy-related leukemia were collected from the Chinese medical literature, and 12 out of 22 (55%) cases in which subtypes were specified were ANLL-M3. This was significantly higher than the percentage of M3 in de novo ANLL in China and also higher than that of therapy-related leukemia from western countries. Two patients had siblings who died of leukemia at a similar age. The two patients showed inv(16) and del(6q) respectively.

Cytogenetic analysis in 941 consecutive patients with haematologic disorders

Clinical and cytogenetic findings were reevaluated in 941 consecutive patients with suspected neoplastic haematological conditions studied during 1973-1984. A total of 1652 attempts at cytogenetic analysis with banding technique were performed in 240 patients with acute nonlymphocytic leukaemia (ANLL), 177 with chronic myeloid leukaemia (CML), 157 with myelodysplasia (MDS), 82 with myeloproliferative disorders (MPD), 114 with acute lymphoblastic leukaemia (ALL), 42 with non-Hodgkin lymphoma or other lymphoproliferative disorders (NHL + LPD), and 120 patients with benign disorders. Only 1 patient with a benign disorder had an acquired clonal chromosomal abnormality (diagnostic specificity 0.99), whereas abnormalities were detected in 50.0% of patients with malignant haematologic disorders (diagnostic sensitivity 0.50). Success rate was 73-74.4% in ALL, MPD, and NHL + LPD, versus 87-94% in ANLL, MDS, CML, and benign disorders. The frequencies of detected abnormalities in diagnostic subgroups were within the limits of previous reports. Striking differences in cytogenetic pattern in relation to age were found in MDS and ANLL. Results from 1973-80 were compared to 1981-84. In spite of a marked reduction in failure rate of bone marrow (BM) analyses in the second time period, the fraction of patients with only inadequate cytogenetic analyses and the frequencies of detected chromosome abnormalities remained essentially unchanged. Peripheral blood samples had a high failure rate, and seldom provided additional information to BM analyses. Delay in transportation time of samples did not in general affect the outcome of cytogenetic analysis, with possible exceptions for a higher failure rate in ALL and lower frequency of detected abnormalities in ANLL.

Correlation of karyotype with patient sex and age in acute myeloid leukemia

Karyotypes were determined in 109 patients with acute myeloid leukemia. The proportions of patients with nonclonal chromosomal abnormalities, with numeric changes only, and with severe chromosomal aberrations were all found to increase to a statistically significant degree with patient age. Most patients in whom less than half of all cells were abnormal were elderly males. These results indicate that the cell karyotype was less stable in elderly patients than in younger patients. A higher frequency of nonclonal chromosomal changes was found in patients with clonal abnormalities compared with those without such abnormalities. Male patients tended to gain chromosomes and had more hyperdiploid abnormalities than female patients, who tended to lose chromosomes and had more hypodiploid abnormalities. This trend of chromosomal gain in males and loss in females mainly involved chromosomes similar in size to the sex chromosomes. Three female patients with trisomy 8 and one with 7q+ and t(8;21) showed an X chromosome twisted into a spiral shape. The results indicate that the initial karyotype effects the formation of some numeric changes. These findings are discussed in relation to possible secondary chromosomal changes and karyotypic instability.

8;21 translocation in acute granulocytic leukaemia: cytological, cytochemical and clinical features

Thirty patients with the 8;21 translocation and three with closely related variants have been studied. Ages ranged from 3 to 64 years (mean 28.3). Thirty-one were entered into the MRC's 8th Acute Myeloid Leukaemia Trial. Twenty-nine (88%) achieved complete remission. Marrow smears from most patients showed granulocytic maturation (M2, FAB classification) with characteristic abnormalities, but at least six showed predominantly myeloblastic (M1) morphology. The blast cells were markedly heterogeneous with regard to size and nuclear cytoplasmic ratio. Typical staining patterns were observed in the blast cells using Sudan black B and diaminobenzidine peroxidase stains, and to a lesser extent with periodic acid-Schiff and chloroacetate esterase. Butyrate esterase was negative in all cases. Auer rods were present in the granulocyte precursors in 31 cases and in eosinophil precursors in two cases. In most cases the existence of the translocation was predicted from the cytological and cytochemical findings. Seven patients developed solid leukaemic deposits, principally in the mastoid cavities, orbital cavities or thoracic spine (extradural).

Groups of darkly stained chromosomes may be artifacts

Groups or conglomerations of darkly stained chromosomes (GDSC) observed in this study appeared to be artifacts as they were strictly technique dependent. Two methods of cell fixation were compared. In method I, fixative was added drop by drop to cell pellets and agitated continuously over a rotamixer. In method II, a few drops of fixative were added to hypotonic solution suspended with cells and mixed using a Pasteur pipette. In 11 patients with acute myeloid leukemia (AML) and in one patient with preleukemia studied using method I, no GDSC were found in the total of 325 metaphases examined. In 36 patients with AML, one with Klinefelter's syndrome and one with neutropenia studied using method II, GDSC were found in 18 patients. A further comparative study using different methods for cell fixation was performed in three patients. The frequency of cells with GDSC varied sharply with different methods used in two patients. In one patient the cells with GDSC were analyzed in detail. The number of darkly stained chromosomes in each cell was found to vary from 4 to 14 with a mean of 8.26 and D- and G-group chromosomes were preferentially involved.

A further study on quicker re-entry of chromosomally abnormal cells to active proliferation and preferential death of chromosomally normal cells during ageing of specimens in acute myeloid leukemia (AML)

Quicker re-entry of chromosomally abnormal cells to active proliferation under culture conditions was observed in cultured peripheral blood samples, old or fresh, but not in cultured bone marrow samples. In 10 patients with AML studied using peripheral blood, the mitotic index (MI) rose after 24 h in culture and reached a peak after 48 h in culture in AA patients (with all abnormal karyotypes); the MI rose after 24 h in culture and reached a peak after 48, 72 or 96 h in culture in AN patients (mixed normal and abnormal karyotypes); the MI remained at much lower level until after 72, 96 or 120 h of culture in NN patients (all normal karyotypes). The MI at 24 and 48 h of culture was significantly higher in AN and AA patients than in NN patients. A significantly increased frequency of chromosomally normal cells after prolonged culture was observed in one patient with t(8;21). The results of this study also suggest that chromosomally normal cells are more likely to die off than are abnormal ones during ageing of specimens.

Double minutes in acute myeloid leukemia

Five out of 110 patients with acute myeloid leukemia (AML) showed double minutes (DM) in cytogenetic preparations. DM were found to occur predominantly in elderly patients, and in erythroleukemia or acute myelomonocytic leukemia. The five patients were apparently divided into two groups according to the number of DM per cell. Patients with few sets of DM had exclusively complex karyotypes and a poor prognosis while patients with numerous DM had otherwise normal or nearly normal karyotypes and a good prognosis. Data on 11 previously reported cases of AML with DM were collected from the literature and consistent results were revealed except that several of the 11 patients were diagnosed as having acute myeloblastic leukemia (M1 and M2 in the FAB classification), which is apparently due to differences in diagnostic criteria. Therefore, numerous or few DM in a cell might relate to different entities. When the number of DM was small they might have resulted from breakdown of existing chromosomes.

Correlation between chromosomal pattern, cytological subtypes, response to therapy, and survival in acute myeloid leukaemia

Chromosomal karyotypes were determined with standard G-banding in 103 patients with acute myeloid leukaemia (AML). Abnormal clones were present in 52 (50.5%). Higher frequencies of abnormalities were observed in male than in female patients and in erythroleukaemia (EL) than in other subtypes of AML. Abnormalities were more frequent in myeloblastic (AMyL) than in myelomonocytic leukaemias (AMML) and mixtures of both normal and abnormal karyotypes were more common among elderly patients; these differences, though of marginal statistical significance, are consistent with previous reports. 9 of 10 cases with 5 or more aberrant chromosomes and 6 of 8 cases with unidentified marker chromosomes were either AMML or EL. Remission rates, median survivals and relative death rates were collated in 82 patients, in relation to the karyotype patterns NN (all normal), AN (mixed normal and abnormal) and AA (all abnormal). The differences between the groups did not reach statistical significance. Serial cytogenetic studies were performed in 10 patients. New karyotype changes emerged in only 1 of 6 relapses. 4 examples of t(8;21) and 2 of t(15;17) were found. 1 case of AMML showed trisomy 8 and double minute chromosomes. 1 case of EL showed 2 marker chromosomes with homogeneously staining regions.