Nonrandom additional chromosome changes in acute nonlymphocytic leukemia with inv(16)(p13q22)

Five patients with acute nonlymphocytic leukemia and inv(16)(p13q22), all with additional chromosome changes, are reported. Three were diagnosed as having acute myelomonocytic leukemia (FAB-M4), and the other two as having acute monocytic leukemia (FAB-M5b). All five patients had abnormal eosinophils in the bone marrow at diagnosis. Two had a deletion of the long arm of chromosome #7, del(7)(q31), and a trisomy of chromosome #22. These changes have been reported frequently in acute nonlymphocytic leukemia with inv(16), but are extremely rare in leukemias with other specific rearrangements including t(9;22), t(8;21), and t(15;17). Our findings and review of the literature indicate that inv(16) is observed not only in acute myelomonocytic leukemia but also in acute monocytic leukemia, and that del(7q) and +22 are nonrandomly associated with inv(16) as additional abnormalities. No significant differences in the clinical features seem to exist between the patients with only inv(16) and those with inv(16) and additional chromosome changes, except for the lower white blood cell count in the latter group.     

Cytogenetic findings in secondary acute nonlymphocytic leukemia.

We have report the results of cytogenetic studies carried out in eight patients with acute nonlymphocytic leukemia developed after primary neoplasias. In seven of the reported cases, clonal chromosome aberrations were found, some being specific of de novo acute nonlymphocytic leukemia (ANLL). Numerical abnormalities were detected, such as the total monosomy of chromosomes 5, 7, 21, trisomy of chromosomes 8, 11, 15, and duplication of chromosome Y. Structural changes were also observed: a del(12)(p12), a del(16)(q22), the translocations t(3;5)(p21;q35),t(3;7)(p21;q35), and t(12;14)(p12;q32) and other changes involving chromosome 8. The finding of a hypertetraploid karyotype with complex structural chromosome aberrations in a patient with erythroleukemia, developed after non-Hodgkin's lymphoma, is of particular interest. Data reported in this work are discussed with regard to the relationship between secondary and de novo ANLL and the finding of chromosome aberrations other than total or partial monosomy of chromosomes 5 and 7 is emphasized.     

Chromosome studies on 30 Chinese patients with acute nonlymphocytic leukemia in Taiwan

Cytogenetic studies were performed on 32 consecutive Chinese patients with de novo acute nonlymphocytic leukemia (ANLL) in Taiwan. Of the 30 patients with adequate specimens, 20(66%) had clonal chromosome abnormalities. Structural rearrangements were detected in 18 of them. Seven (four were children) of the 16 patients with M2 ANLL had t(8;21). All six patients with acute promyelocytic leukemia (APL; M3 subtype) had t(15;17). Two patients with M4 type leukemia and abnormal bone marrow eosinophils had inv(16)(p13q22). Another M4 patient with a mild increase of morphologically normal eosinophils in the bone marrow had an abnormal chromosome #16, t(1;16)(q21;p13) in which 16q22 was not involved. One patient with M5 ANLL had t(9;11). Only two patients had a numerical change as the sole abnormality. None of the patients had loss or deletion of chromosome #5 or loss of chromosome #7, and only one had a deletion of 7q. This study revealed a high incidence of t(8;21), t(15;17), and a low incidence of -5/5q- or -7/7q- in Chinese patients with ANLL.     

Quantitative acute leukemia cytogenetics.

Using literature data on cytogenetic abnormalities in 3,612 cases of acute myeloid leukemia (AML) and 1,551-cases of acute lymphocytic leukemia (ALL), we have attempted to quantify the information value of finding the typical ALL- and AML-associated chromosome aberrations. Sensitivity, specificity, and predictive value of finding or not finding a given aberration were calculated for several diagnostic scenarios: for the differential diagnosis between ALL and AML when the patient is known to have acute leukemia, for the differential diagnosis among AML FAB subtypes in a patient with known AML, and for the differential diagnosis between ALL FAB subtypes in a patient with known ALL. The specificities were generally high, close to 1. The highest sensitivities in AML were found for +8, t(15;17)(q22;q11), t(8;21)(q22;q22), and -7 (all greater than 0.1), and in ALL for t(9;22)(q34;q11), t(4;11)(q21;q23), and +21 (again all greater than 0.1). In the AML subtypes, the highest sensitivities were 0.89 for t(15;17)(q22;q11) in M3, followed by 0.40 for t(8;21)(q22;q22) in M2, 0.30 for inv(16)(p13q22)/del(16)(q22)/t(16;16)(p13;q22) in M4, and 0.16 for t(9;11)(p21;q23) in M5. In the ALL subtypes, the highest sensitivities were 0.71 and 0.11 for t(8;14)(q24;q32) and t(8;22)(q24;q11), respectively, in L3, 0.23 for t(9;22)(q34;q11) in L2, and 0.18 and 0.13 for +21 and t(4;11)(q21;q23), respectively, in L1. The highest (1.0) positive predictive values in the AML versus ALL comparison were found for t(1;3)(p36;q21), inv(3)(q21q26), t(6;9)(p23;q34), t(7;11)(p15;p15), t(8;16)(p11;p13), t(8;21)(q22;q22), t(15;17)(q22;q11), and, as sole anomalies, for +4, +9, and +11. In the reverse comparison, ALL versus AML, positive predictive values of 1.0 were found for t(1;14)(p32-34;q11), dup(I)(q12-21q31-32), t(2;8)(p12;q24), t(8;14)(q24;q32), t/dic(9;12)(p11-12;p11-13), t(10;14)(q24;q11), and t(11;14)(p13;q11). Among the AML subgroups, the highest predictive values were: 1.0 for M3 if t(15;17), 0.91 for M2 if t(8;21), 0.86 for M4 if inv/del(16)/t(16;16), and 0.82 for M5 if t(9;11). Among the ALL subtypes, positive predictive values of greater than 0.8 were reached only for the L3-associated aberrations t(2;8) (1.0), t(8;14) (0.95), t(8;22) (0.87), and dup(I) (0.80). The highest negative predictive values were in AML 0.98 that the disease is not M3 if t(15;17) is not found, and in ALL 0.96 that the patient does not have L3 if a t(8;14) is not detected.     

Geographic heterogeneity of neoplasia-associated chromosome aberrations

Using a database comprising 13,266 cytogenetically abnormal neoplasms, the geographic heterogeneity of neoplasia-associated chromosomal abnormalities was investigated by comparing the frequencies of characteristic aberrations in consecutive series of patients with the same diagnosis. Significant frequency differences between geographic areas were found for the aberrations +8, i(17q), +19, and an additional Ph1 chromosome in chronic myeloid leukemia (CML); -5, 5q-, and +8 in acute nonlymphocytic leukemia (ANLL); t(8;21) in ANLL-M2; t(15;17) in ANLL-M3; 5q- and -7 in myelodysplastic syndromes (MDS); t(9;22) and +21 in acute lymphocytic leukemia (ALL); t(14;18) in follicular lymphoma; -8 and -22/22q- in meningioma; and structural abnormalities of 12q in pleomorphic adenoma of the salivary glands (PAS). No geographic incidence variation was detected for -7 and +21 in ANLL; +8 in MDS; 6q- and +8 in ALL; +12 in chronic lymphocytic leukemia; 6q- in non-Hodgkin's lymphoma (NHL); t(8;14) in Burkitt's lymphoma; t(11;22) in Ewing's sarcoma; i(12p) in germ cell tumors; 1p- in neuroblastoma; structural abnormalities of 3q, 8q, and 9p in PAS; or 3p- in renal cell carcinoma. Intraregional frequency similarities between cytogenetically identical abnormalities in related tumor types were also analyzed. No significant correlations were found regarding the incidence of 5q- in ANLL and MDS, 6q- in ALL and NHL, -7 in ANLL and MDS, +8 in ANLL and CML, +8 in ANLL and MDS, +8 in ALL and ANLL, or +21 in ALL and ANLL. The findings indicate that some geographic heterogeneity of tumor-associated aberrations exists both in hematologic neoplasms and in solid tumors.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cytogenetic studies in acute nonlymphocytic leukemia

Cytogenetic studies were performed in 74 untreated patients with acute nonlymphocytic leukemia (ANLL) between 1985 and 1988. Among 56 patients who were examined successfully at the time of diagnosis, 36 had abnormal karyotypes (64.2%). The distribution of chromosome abnormalities was uneven, according to the categories of the French-American-British (FAB) nomenclature. The highest frequency of chromosome abnormalities was observed in ANLL M4 with bone marrow (BM) eosinophilia (M4Eo). Numerical changes were observed in 11 cases; chromosome 8 was most frequently gained (11 patients), whereas chromosome 7 was most frequently lost (4 patients). Structural rearrangements were detected in 18 patients. Involvement of 16q22 was noted in 7 patients, 5q− was noted in 5, t(8;21) in 3, t(1;7) in 2, del(20) in 2, and involvement of 11q23 was noted in 2. The inversion of chromosome 16 was restricted to the M4Eo subtype. This study identified a novel abnormality [inv(2) (p11.2q11.2)] that had not been reported previously by other investigators.     

1058例急性非淋巴细胞白血病的细胞遗传学分析

目的：评估我国大系列急性非淋巴细胞白血病（acute nonlymphocytic leukemia,ANLL)的核型状况。方法：采用直接法和短期培养法制备骨髓细胞染色体,并以R显带为主、G显带为辅对1058例初治的ANLL患者进行染色体核型分析。结果：本组中630例（60％）有克隆性染色体异常。主要异常核型共有25种,其中11种为特异性染色体重排,见于481例,占核型异常患者总数的76％。单纯＋8（21例）为常见的数目异常。t(15;17)(211例）和t（8;21）（200例）为最常见的结构异常。1．1％的M2、72％的M3、71％的M4EO、50％的M2、6％的M5和1．4％的M2分别有t（7;11）、t(15;17)、inv(16)、t(8;21)、t/del(11q23)和t/del(12p)异常,而100％的t(7;11)、100%的t（15;17）、100％的inv(16)、88．5％的t(8;21）、83％的t/del(11q23)和62％的t/del（12p)分别见于M2、M3、M4E0、M2、M5和M2亚型患者。结论：联合应用R带和G带两种常规显带技术,60％的ANLL患者可检出克隆性染色体异常且主要为特异性染色体重排。它们和特定的FAB亚型相关,因而核型是ANLL诊断和分型的一项重要指标。     

Three new cases of chromosome 3 rearrangement in bands q21 and q26 with abnormal thrombopoiesis bring further evidence to the existence of a 3q21q26 syndrome.

Defects of 3q in bands q21 and q26 have been reported in more than 70 cases of acute nonlymphocytic leukemia (ANLL), myelodysplastic syndrome (MDS), and myeloproliferative disorder (MPD) in blast crisis. In this paper three additional patients are described: patient 1 with refractory anemia with excess of blasts in transformation (RAEB-T) and inv(3)(q21q26), patient 2 with RAEB-T and t(3;3)(q21;q26), and patient 3 with myelofibrosis with myeloid metaplasia (MMM) in blast crisis and inv(3)(q21q26). In addition to 3q rearrangements, monosomy 7 and del(7)(q22q36) were observed in patients 1 and 2, respectively. In the three patients, the most characteristic clinical features were elevated platelet counts, marked hyperplasia with dysplasia of the megakaryocytes, and poor prognosis. Although disturbance of thrombopoiesis was not systematically observed in all patients with t(3;3)(q21;q26), inv(3)(q21q26), and ins or dup(3)(q21----q26), study of the 77 cases reported and of the three cases presented here brings further evidence to the existence of a cytogenetic syndrome involving bands q21 and q26 simultaneously, which represents a subtype of ANLL, MDS, and MPD, characterized by normal or elevated platelet counts, hyperplasia with dysplasia of megakaryocytes, multilineage involvement, young median age of patients with MDS, preferential involvement of women in t(3;3), high incidence of chromosome 7 defects in MDS and ANLL, short duration of the MDS phase, no response to chemotherapy, short survival, and por prognosis.     

Inversions and tandem translocations involving chromosome 14q11 and 14q32 in T-prolymphocytic leukemia and T-cell leukemias in patients with ataxia telangiectasia

Ataxia telangiectasia (AT) and T-prolymphocytic leukemia (T-PLL) have similar chromosome abnormalities. Cytogenetic findings reported in 5 patients with AT who developed T-cell leukemia revealed: inv(14)(q11q32) (1 case), tandem translocations of chromosome 14 with breakpoints at q11 and q32 (3 cases), and int. del(14)(q11q32) (1 case). Additional abnormalities were present in 4 patients of whom two had trisomy for 8q. Of 27 patients with T-PLL but without AT, investigated by us, 17 had inv(14)(q11q32) and 3 had tandem rearrangement of chromosome 14 with breaks at 14q11 and q32; 15 of them also had rearrangements resulting in trisomy 8q. Two of the leukemias supervening on AT had morphology and clinical course suggestive of T-PLL. Two other cases of AT studied by us developed typical T-PLL at a young age (18 and 39 years). T-cell clones carrying an inv(14), tandem t(14;14) and t(X;14) can be present in AT for long periods of time without evolving into leukemia. In T-PLL, inv(14) and t(14;14) always occurs with other chromosome abnormalities. We suggest that these additional chromosome abnormalities may be required for the leukemic transformation of AT. This is supported by one of the two AT cases studied by us in which a long-standing t(X;14) clone evolved with the formation of t(1;14)(p21;q11), t(8;22)(q24;q11) at the time of the development of T-PLL.     

Interphase fluorescence in situ hybridization overcomes pitfalls of G-banding analysis with special reference to underestimation of chromosomal aberration rates

Fluorescence in situ hybridization (FISH) is suitable for detecting different types of chromosome aberrations on interphase nuclei even in specimens with no or few chromosome metaphases. However, it is not known why FISH is superior to conventional G-banding analysis. The sensitivity of interphase FISH was compared to that of G-banding analysis in 288 leukemia/lymphoma patients for 10 different types of chromosome aberrations: t(9;22) (M- and m-BCR), t(8;21), 11q23 abnormalities, t(15;17), del(5)/-5, del(13)/-13, +8, -7, and +12. The results revealed that t(15;17) positive cells could not proliferate well in culture, leading to underestimation of abnormality by G-banding. Monosomy 7 in acute myelocytic leukemia (AML) and myelodysplastic syndrome (MDS) as well as trisomy 12 and deletion chromosome 13 in chronic lymphocytic leukemias (CLL) were also severely underestimated by G-banding. On the other hand, no discrepancies were observed in t(8;21), t(9;22), translations involving 11q23, or in trisomy 8. These findings indicate the superiority of interphase FISH over conventional cytogenetics for detecting chromosome abnormalities in small clones, especially for monosomy 7 or (15;17) translocations.     

Chromosome abnormalities in 16 Finnish patients with Burkitt's lymphoma or L3 acute lymphocytic leukemia

Eleven patients with Burkitt's lymphoma (BL), i.e., small noncleaved non-Hodgkin's lymphoma, and 5 patients with Burkitt-type acute lymphocytic leukemia (ALL-L3) were selected for chromosome study. Two of the 16 patients had no B-cell markers, but the erythrocyte marker--glycophorin A--was present on the surface of the leukemic blasts. The critical breakpoint at 8q24 was detected in 14 of the 16 patients, whereas this aberration was not detected in any of the 134 patients belonging to other subgroups of non-Hodgkin's lymphoma or ALL that we studied during the same period. In addition to the t(8;14)(q24;q32), the following translocations with the breakpoint at 8q24 were seen: t(2;8)(p11;q24), t(8;11)(q24;q13) in BL, and t(2;8;14)(p11 or p12;q24;q32) in ALL. Additional aberrations seen more than once were trisomy #7 and abnormalities in chromosomes #1, #11, and #13.     

Cytogenetics of agnogenic myeloid metaplasia: a study of 61 patients

Agnogenic myeloid metaplasia (AMM) or idiopathic myelofibrosis is a chronic myeloproliferative disorder characterized by fibrotic bone marrow, extramedullar haematopoiesis, and a leukoerythroblastic picture in circulating blood. The cytogenetic data on AMM are scanty and no recurring chromosome abnormality has been associated with the natural course of this disease. Trisomy 1q, del(13q), del(20q), and trisomy 8, appear in about two thirds of patients with demonstrable chromosome aberrations. We report on the cytogenetic analyses of 61 consecutive patients with AMM studied at diagnosis. The metaphases could not be found in 10/61 (16.4%) patients, and chromosome studies were successful in 51 patients. Twenty-one patients (41%) had an abnormal clone, whereas 30 (59%) patients had a normal karyotype. Most frequent pathological findings included trisomy 8 (either alone or within a complex karyotype) in five patients, aberrations of chromosome 12 (translocation in two, monosomy in two, and trisomy in one patient), and aberrations of chromosome 20 (interstitial deletion in two, monosomy in two, and trisomy in one patient). We also detected aberrations of chromosome 13 (translocation in two and an interstitial deletion and trisomy in one patient each) and chromosome 18 (derivative 18 in two patients and a monosomy and deletion in one patient each). Three patients exhibited complex aberrations involving several chromosomes, sometimes with a mosaicisam. A near-tetraploid karyotype was observed in a single patient. Balanced translocations [t(2;16)(q31;q24), t(5;13)(q13;q32), t(12;13)(p12;q13), and t(12;16)(q24;q24)] were present in four patients. While the series of patients studied displayed chromosomal aberrations that are frequently observed in AMM, we found some new abnormalities (balanced translocations and polyploidy) that are rarely observed in AMM.     

Cytogenetics of childhood acute nonlymphocytic leukemia

Interest in more precise subclassification of the acute leukemias by cytogenetic criteria led us to identify and characterize the full range of chromosomal abnormalities in 121 children with de novo acute nonlymphocytic leukemia (ANLL). Only 21% of the cases had normal karyotypes; 62% had consistent or recurrent alterations, most commonly inv(16) or del(16), t(8;21), t(15;17), t(9;11), t(11;V) or del(11), and -7 or 7q-; and 17% had miscellaneous, apparently random, clonal abnormalities. Statistically significant associations between chromosomal abnormalities and the morphologic/cytochemical subtypes of ANLL, defined by criteria of the French-American-British (FAB) cooperative group were demonstrated for the t(8;21) in M1 and M2 leukemia, t(15;17) in M3, t(9;11) in M5, and translocations involving 11q23 other than t(9;11) [t(11;V)] or del(11q) in M4 and M5. The chromosome 16 inversion was not restricted to the M4 subtype, as is generally reported, and was not uniformly associated with increased and/or abnormal marrow eosinophils. None of these 121 cases were characterized by the Philadelphia chromosome, nor did any have the t(6;9), t(16;16), or inv(3), which have been noted previously in this disease. In addition to confirming several recognized correlations between recurrent structural chromosome abnormalities and FAB subtypes, this study identified novel abnormalities that have not been reported by others. It also disclosed an unusual heterogeneity of chromosome 16 abnormalities with respect to their distribution among FAB subtypes, their association with marrow eosinophilia, and their participation with other chromosomes in translocations.     

Cytogenetic subtype involving chromosome 13 in lipoma. Report of three cases

We report three lipomas with rearrangements of chromosome 13. The karyotype of the tumors studied were 45,XX,-8,+der(8)t(8;13)(q22;q12),del(10)(p12),-13; 46,XY,del(13)(q12q22), and 46,XY,t(11;12)(q23;q13),del(13)(q12q22), respectively, revealing common involvement of band 13q12 in the rearrangement. Three other lipomas with aberrations of bands 13q12-q13 have been reported, suggesting that such tumors with abnormalities of chromosome 13 could represent a subgroup of lipoma in addition to those already reported with abnormalities of chromosomes 12q and 6p. The rearrangements of #13 in all these cases also involved loss of the band 13q14 to which the antioncogene associated with retinoblastoma and osteosarcoma is localized. Detailed clinical, histopathologic, and molecular studies should help to further characterize the various cytogenetically defined subgroups of lipoma.     

Clonal chromosome aberrations in Philadelphia-negative cells from chronic myelocytic leukemia patients treated with imatinib mesylate: report of two cases

Imatinib mesylate (tested as STI571), an abl kinase inhibitor, induces sustained, complete hematologic and cytogenetic responses in chronic myelocytic leukemia (CML) patients; however, emergence of clonal chromosomal aberrations in Philadelphia-negative (Ph-) cells during treatment has been reported. We describe two CML patients in chronic phase who presented with complete cytogenetic responses during imatinib mesylate therapy but developed new clonal chromosomal rearrangements in Ph- cells. The first patient presented with a duplication of chromosome 1, dup(1)(q21q42), and the second showed two new clonal aberrations consisting of inv(1)(q12q32) and del(7)(q22) in the same clone.     

Complex chromosome 9, 20, and 22 rearrangements in acute lymphoblastic leukemia with duplication of BCR and ABL sequences

Cytogenetic analysis was performed on bone marrow cells from a 28-year-old woman who was diagnosed with acute lymphoblastic leukemia (ALL). Her karyotype was: 46,XX,t(9;22)(q34;q11)[6]/47, XX,+8,t(9;22)(q34;q11)[4]/47,XX,+8,t(9;22)(q34;q11),del(20)(q11)[2]/46, XX,t(9;22)(q34;q11),del[20](q11)[7]/45,XX,der(9)t(9;22)(q34;q11),-20,-22 , +mar1[8]/45,XX,der(9)t(9;22)(q34;q11),-20,-22,+mar2[3]. Both marker chromosomes are dicentric and have the same size and banding pattern but different primary constrictions. Fluorescence in situ hybridization (FISH) demonstrated that both markers were derived from chromosomes 9, 20, and 22. FISH with the bcr/abl probe showed fusion of the BCR gene with the ABL gene; however, this fusion signal was present in duplicate on both marker chromosomes. To our knowledge, duplication of the BCR/ABL fusion signal on a single chromosome arm has not been reported before, except for the extensive amplification of BCR/ABL fusion signals in the leukemic cell line K-562. These data demonstrate that the marker chromosomes are the result of complex genomic rearrangements. At the molecular level, the BCR/ABL fusion gene encodes the p190 fusion protein. Similar findings have never been observed in any case of ALL.     

Trisomy 21 is a recurrent secondary aberration in childhood acute lymphoblastic leukemia with TEL/AML1 gene fusion.

TEL/AML1 gene fusion is the most frequent genetic lesion in pediatric acute lymphoblastic leukemia (ALL). It occurs as a consequence of the cryptic chromosomal translocation t(12;21)(p13;q22). In a cohort of 50 RT-PCR-positive TEL/AML1 patients, karyotype examination by GTG banding and fluorescence in situ hybridization (FISH) allowed us to identify chromosome anomalies in addition to the already existing t(12;21). Secondary aberrations were found in 29 out of 41 patients (71%) at initial diagnosis and in all 9 patients with relapse. Structural rearrangements affected chromosome arms 2p, 2q, 5q, 9p, 12p (n = 2), 6q, 11p (n = 3), and 21q (n = 4). An extra chromosome 21 was found to be the most frequent anomaly. It was detected in 6 out of 41 patients at initial diagnosis (15%) and in 7 out of the 9 patients at relapse. No karyotype with trisomy 21 exceeded 47 chromosomes. Gain of chromosome 21 was the sole anomaly in GTG-banding analysis in 2/41 patients at initial diagnosis and in 4/9 at relapse. Notably, chromosome painting analysis performed in 11 out of the 13 patients with an extra chromosome 21 revealed duplication of the normal chromosome 21 in 8, and duplication of der(21)t(12;21) in 3 patients. Furthermore, gain of der(21)t(12;21) chromosome was confined exclusively to the relapse patients.     

Common cytogenetic findings in gastric cancer

Cytogenetic analysis was performed in five cases of intestinal type gastric carcinoma. Three cases were near-diploid and two others were near-triploid. The chromosomes involved were: #9 (four cases), #8 (three cases), #1, and #7 (two cases each). The nonrandom chromosomal abnormalities included aberrations of chromosome #9 as trisomy or i(9q) or 9p+ marker chromosome and excess of 8q material (i.e., trisomy or i(8q) chromosome). Our results indicate that abnormalities of chromosome #9 are a common feature in a subgroup of intestinal type gastric cancers and that there are common cytogenetic abnormalities in gastric and large bowel cancer.     

Clonal chromosome abnormalities in two liposarcomas

Two liposarcomas were analyzed with chromosome banding technique. The sole chromosomal abnormality in one of the tumors, a mixed type (myxoid and round cell) liposarcoma, was t(12;16)(q13;p11), a rearrangement previously reported to be associated with myxoid liposarcoma. The other tumor, a pleomorphic liposarcoma, displayed massive numerical rearrangements (modal chromosome number 94-112), and numerous, mostly unidentifiable, marker chromosomes. The following clonal structural aberrations were recognized: del(1)(p22), del(1)(q23), t(7;?)(p22;?), i(17q), and t(19;?)(q13;?).     

Recessive cancer genes in meningiomas? An analysis of 31 cases

Cytogenetic studies on 31 human meningiomas revealed clonal abnormalities in 14 of them. Monosomy 22 was present in three cases as the only abnormality, and in five it was associated with monosomy 18, monosomy 14, loss of X, loss of Y, and trisomy 20, respectively. We found a number of rearrangements involving chromosome #22: an i psu dic(22)(pter----q11::q11----pter) in two cases and a t(18;22)(q12;q11) in another case. Two cases showed a complex translocation involving #7 and #14: t(2;7;14)(q23;q36;q22) and t(1;7;14)(q25;q32;q22), respectively. Other clonal chromosome abnormalities were del(1p) (present in two cases); der(9)t(9;?)(q34;?); der(7)t(7;?)(q31;?); der(22)t(22;?)(q11;?); and a 9p+ chromosome. The relevance for the pathogenesis of human meningiomas of these chromosome anomalies is also discussed with reference to the previous literature. The possible involvement of recessive cancer genes present on the long arm of chromosome #22 is also discussed.