Atlas of Genetics and Cytogenetics in Oncology and Haematology
del(6q) abnormalities in lymphoid malignancies
| Identity |
| Note | deletion of the long arm of chromosome 6 (del(6q)) is more frequently described in lymphoid proliferations than in other hematological malignancies; del(6q) is observed in acute lymphoblastic leukemia (ALL), in chronic lymphocytic leukemia (CLL), in prolymphocytic leukemia and in non-Hodgkin lymphomas (NHL) (15% cases, sometimes associated with t(14;18)(q32;q21)); these deletions are mainly reported to be terminal, but also interstitial. |
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| del(6q) - Courtesy Diane H. Norback, Eric B. Johnson, Sara Morrison-Delap Cytogenetics at theWaisman Center; R- banding (right) - Editor | |
| Clinics and Pathology |
| Disease | childhood B-cell acute lymphoblastic leukemia (B-ALL) |
| Phenotype / cell stem origin | lack of specificity for a particular immunophenotype |
| Epidemiology | found in 5-15% of patients after conventional cytogenetic analysis, in 30% after FISH analysis, in 5 to 25% of cases in loss of heterozygosity studies. |
| Prognosis | not significantly different from patients lacking a 6q rearrangement |
| Disease | childhood T-cell acute lymphoblastic leukemia (T-ALL) |
| Epidemiology | del(6q) is one of the most frequent cytogenetic aberration occurring in 10-20% of cases and often associated with 14q11 or del(9p) abnormalities. |
| Prognosis | outcome similar to cases with normal diploid karyotypes |
| Disease | adult acute lymphoblastic leukemia |
| Phenotype / cell stem origin | T-cell phenotype found in 50% of cases (ALL) |
| Epidemiology | del(6q) in adult-ALL occur with a lower frequency (5%) than in children and is reported predominantly in young adult (15 to 40 years aged). |
| Prognosis | patients with a 6q change tented to have longer event free survival (EFS) (median: 11 months; 3 years EFS: 47%) than did patients without 6q changes (median EFS: 7 month; 3 years EFS: 20%). |
| Disease | B-cell small lymphocytic lymphomA |
| Epidemiology | del(6)(q21q23) is the most common recurrent cytogenetic abnormality in this disease |
| Clinics | in cases with del(6q), a morphological appearance of peripheral blood large prolymphocytes, a mature B-cell phenotype and a typical clinical course of other well-differentiated lymphocytic neoplams are described |
| Disease | atypical chronic lymphocytic leukemia |
| Prognosis | complex karyotypes with +12, del(13)(q14), del(11q), del(6)(q21q23) and possible 4q or 10q anomalies are associated with a poor prognosis. |
| Disease | multiple myeloma |
| Phenotype / cell stem origin | multiple myeloma (MM) is a malignant plasma cell proliferation of mature differentiated B-cell. |
| Epidemiology | del (6q) in multiple myeloma represent 15% of cases of MM |
| Prognosis | del(6q) are more frequent in the hypodiploid group of multiple myeloma, bearing a worse prognosis (med survival of 1.5 yr). |
| Cytogenetics |
| Cytogenetics Morphological | the frequency of the deletions is difficult to estimate by conventional cytogenetic analysis because small interstitial deletions are beyond the sensitivity of the technique; furthermore, many studies have reported conflicting data on the putative region of overlap and the number of region involved; the break occurs predominantly in 6q21, but 6q15 is also often described; overall, del(6q) cases encompassed the 6q21 band. in acute lymphoblastic leukemia (ALL), del(6q) is the sole anomaly in about 30% of cases, or associated with other structural abnormalities such as del(12p) (early pre-B ALL), del(9p) (B and T-cell immunophenotype), specific aberrations, such as t(4;11), t(1;19), t(9;22), t(12;21) or with random chromosomal changes. |
| Genes involved and Proteins |
| Note | 6q21 band loss suggests the presence of a recessive tumour suppressor gene whose absence might contribute to malignant transformation and development of both T and precursor B-ALLs; the lack of specificity for a particular immunophenotype may imply that the gene or genes affected by 6q abnormalities are broadly active in the multistep process of lymphoid leukemogenesis. Putative tumour suppressor gene(s) on chromosome arm 6q remains to be identified; to demonstrate this loss of heterozygosity of informative markers (LOH) was analysed using PCR amplification of polymorphic microsatellite sequences; using polymorphic markers located from the 6q14-15 to telomere, LOH was detected in 5 to 25% of childhood ALL cases. Regarding LOH results, two distinct regions were identified: - first region flanked by D6S283 and D6S302 loci at 6q21-22 - second region flanked by D6S275 and D6S283 loci at 6q21 Using LOH analysis on several cases, the authors demonstrated an identical 6q21-22 structure at diagnosis and at relapse, suggesting that 6q deletion may be an initial event in leukemogenesis and may occur less frequently during progression of the disease. |
| External links |
| Other database | del(6q) abnormalities in lymphoid malignancies | Mitelman database (CGAP - NCBI) |
| Bibliography |
| Abnormalities of the long arm of chromosome 6 in childhood acute lymphoblastic leukemia. |
| Hayashi Y, Raimondi SC, Look AT, Behm FG, Kitchingman GR, Pui CH, Rivera GK, Williams DL |
| Blood. 1990 ; 76 (8) : 1626-1630. |
| PMID 2207332 |
| Clinical and morphologic features of B-cell small lymphocytic lymphoma with del(6)(q21q23). |
| Offit K, Louie DC, Parsa NZ, Filippa D, Gangi M, Siebert R, Chaganti RS |
| Blood. 1994 ; 83 (9) : 2611-2618. |
| PMID 8167342 |
| A low rate of loss of heterozygosity is found at many different loci in childhood B-lineage acute lymphocytic leukemia. |
| Cavˆ© H, Guidal C, Elion J, Vilmer E, Grandchamp B |
| Leukemia : official journal of the Leukemia Society of America, Leukemia Research Fund, U.K. 1996 ; 10 (9) : 1486-1491. |
| PMID 8751467 |
| Cytogenetic abnormalities in adult acute lymphoblastic leukemia: correlations with hematologic findings outcome. A Collaborative Study of the Group Franˆßais de Cytogˆ©nˆ©tique Hˆ©matologique. |
| Blood. 1996 ; 87 (8) : 3135-3142. |
| PMID 8605327 |
| Chromosome aberrations in atypical chronic lymphocytic leukemia: a cytogenetic and interphase cytogenetic study. |
| Bigoni R, Cuneo A, Roberti MG, Bardi A, Rigolin GM, Piva N, Scapoli G, Spanedda R, Negrini M, Bullrich F, Veronese ML, Croce CM, Castoldi G |
| Leukemia : official journal of the Leukemia Society of America, Leukemia Research Fund, U.K. 1997 ; 11 (11) : 1933-1940. |
| PMID 9369429 |
| Delineation of a 6 cM commonly deleted region in childhood acute lymphoblastic leukemia on the 6q chromosomal arm. |
| Gˆ©rard B, Cavˆ© H, Guidal C, Dastugue N, Vilmer E, Grandchamp B |
| Leukemia : official journal of the Leukemia Society of America, Leukemia Research Fund, U.K. 1997 ; 11 (2) : 228-232. |
| PMID 9009085 |
| Cytogenetics adds independent prognostic information in adults with acute lymphoblastic leukaemia on MRC trial UKALL XA. MRC Adult Leukaemia Working Party. |
| Secker-Walker LM, Prentice HG, Durrant J, Richards S, Hall E, Harrison G |
| British journal of haematology. 1997 ; 96 (3) : 601-610. |
| PMID 9054669 |
| Frequency and clinical significance of cytogenetic abnormalities in pediatric T-lineage acute lymphoblastic leukemia: a report from the Children's Cancer Group. |
| Heerema NA, Sather HN, Sensel MG, Kraft P, Nachman JB, Steinherz PG, Lange BJ, Hutchinson RS, Reaman GH, Trigg ME, Arthur DC, Gaynon PS, Uckun FM |
| Journal of clinical oncology : official journal of the American Society of Clinical Oncology. 1998 ; 16 (4) : 1270-1278. |
| PMID 9552025 |
| 6q deletions in acute lymphoblastic leukemia and non-Hodgkin's lymphomas. |
| Merup M, Moreno TC, Heyman M, Rˆnnberg K, Grandˆ©r D, Detlofsson R, Rasool O, Liu Y, Sˆderhˆ§ll S, Juliusson G, Gahrton G, Einhorn S |
| Blood. 1998 ; 91 (9) : 3397-3400. |
| PMID 9558398 |
| Frequent loss of heterozygosity on the long arm of chromosome 6: identification of two distinct regions of deletion in childhood acute lymphoblastic leukemia. |
| Takeuchi S, Koike M, Seriu T, Bartram CR, Schrappe M, Reiter A, Park S, Taub HE, Kubonishi I, Miyoshi I, Koeffler HP |
| Cancer research. 1998 ; 58 (12) : 2618-2623. |
| PMID 9635588 |
| Contributor(s) |
| Written | 12-1998 | Christophe Brigaudeau and Chrystele Bilhou-Nabera |
| Laboratoire d'Hématologie, Hôpital du Haut-Lévêque, CHU de Bordeaux, Ave de Magellan, 33 604 Pessac, France |
| Citation |
| This paper should be referenced as such : |
| Brigaudeau C and Bilhou-Nabera C . del(6q) abnormalities in lymphoid malignancies. Atlas Genet Cytogenet Oncol Haematol. December 1998 . URL : http://AtlasGeneticsOncology.org/Anomalies/del6qID1148.html |
| © Atlas of Genetics and Cytogenetics in Oncology and Haematology | indexed on : Mon May 12 18:11:35 2008 |
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