| Written | 1999-06 | François Desangles |
| Laboratoire de Biologie, Hopital du Val de Grace, 75230 Paris, France |
| Identity |
| ICD-Topo | C420,C421,C424 BLOOD, BONE MARROW, & HEMATOPOIETIC SYS |
| ICD-Morpho | 9861/3 AML with mutated NPM1; AML with mutated CEBPA; Acute myeloid leukaemia, NOS |
| ICD-Morpho | 9920/3 Therapy-related myeloid neoplasms |
| ICD-Morpho | 9989/3 Myelodysplastic syndrome, unclassifiable |
| Atlas_Id | 1093 |
| Note | -7/del(7q) in childhood blood malignancies exhibits a specific pattern of pathogenesis; chromosome 7 anomalies are not rare in acute lymphocytic leukaemia (ALL); they occur in balanced translocations involving 7p15 or 7q34 in T lineage and 7q22 or 7q32 in B proliferations; monosomy 7 is present in 5 to 6 % of ALL, most often as a secondary anomaly of the t(9;22); the association t(9;22), -7 is present in 16 % of the Ph1+ ALL, i.e. in 3% of ALL as a whole; we will hereunder focuse on -7/del(7q) in adult myeloproliferations |
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| del(7q) G- banding - Courtesy Jean-Luc Lai and Alain Vanderhaegen | |
| Clinics and Pathology |
| Disease | myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML); they may occur de novo, or be secondary to an exposure to chemical mutagens or to chemotherapy treatments with alkylating agents; may probably also be secondary to immunosuppressive therapy for severe aplastic anemia |
| Phenotype / cell stem origin | |
| Epidemiology | -7 is the most frequent abnormality in secondary myeloid disorders, found in 51% of the cases in a series of 246 cases, while del(7q) was found in 7%, and a partial monosomy 7 as a result of an unbalanced translocation in 8% of cases; in contrast, -7/del(7q) is found in 10% of de novo myeloid disorders; the sex ratio is 1.5 male for 1 female; the proportion of adults with a -7 myeloid disorder grows dramatically after 60 years |
| Clinics | characterized by infectious susceptibility, quick aggravation, and treatment resistance |
| Prognosis | monosomy 7 is classified as a poor prognostic criterium by the International Prognostic Scoring System; the actuarial relapse rate at one year is 82 %, and the 7-yr actuarial event-free survival is 6 %; after an allogeneic bone marrow transplantation, -7 is predictive of an unfavorable outcome |
| Cytogenetics |
| Cytogenetics Morphological | deletion (7q) is always interstitial; cluster of breakpoints in 7q11 to 7q36, is a with two common minimal zones in q22 and in q32-34 |
| Cytogenetics Molecular | using loss of heterogygocity (LOH) studies and YAC libraries, a 2 to 3 Mb segment in 7q22 has been designated as the proximal common deleted area; the 7q33-34 zone is the consensual area for the distal deletion; LOH studies suggest that a specific mechanism, such as mitotic recombination in bone marrow stem cell leading to homozygosity in both granulocytes and lymphocytes, may be implicated |
| Additional anomalies | -5/del(5q), found in 40 to 60 % of the secondary MDS cases; trisomy 8 |
| Variants | the balanced translocation t(1;7)(q10;p10), and many unbalanced translocation, having for consequence a partial monosomy 7 of the 7q22 to 7q34 bands may, in a way, be considered as variants |
| Genes involved and Proteins |
| Note | -7/del(7q) is not only frequent in secondary MDS or AML, but also in leukemias occurring in individuals with constitutional syndromes including predisposition to myeloid disorders; these findings suggest the presence of a putative myeloid leukemia suppressor gene in the commonly deleted genomic segment 7q22 and even multiple genes in 7q22 -31.1 that are playing a role in leukemogenesis; candidate genes are : |
| Bibliography |
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| PMID 8445946 |
| Molecular cytogenetic delineation of deletions and translocations involving chromosome band 7q22 in myeloid leukemias. |
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| PMID 7093525 |
| Neutrophil dysplasia is not a specific feature of the abnormal chromosomal clone in myelodysplastic syndromes. |
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| PMID 10374851 |
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| PMID 1868912 |
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| PMID 9218106 |
| Molecular definition of a narrow interval at 7q22.1 associated with myelodysplasia. |
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| PMID 8611680 |
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| Allelotyping of acute myelogenous leukemia: loss of heterozygosity at 7q31.1 (D7S486) and q33-34 (D7S498, D7S505). |
| Koike M, Tasaka T, Spira S, Tsuruoka N, Koeffler HP |
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| PMID 10071086 |
| Cytogenetic and molecular delineation of a region of chromosome 7 commonly deleted in malignant myeloid diseases. |
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| Blood. 1996 ; 88 (6) : 1930-1935. |
| PMID 8822909 |
| Molecular anatomy of chromosome 7q deletions in myeloid neoplasms: evidence for multiple critical loci. |
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| PMID 9520444 |
| Childhood monosomy 7: epidemiology, biology, and mechanistic implications. |
| Luna-Fineman S, Shannon KM, Lange BJ |
| Blood. 1995 ; 85 (8) : 1985-1999. |
| PMID 7718870 |
| Cytogenetic abnormalities in primary myelodysplastic syndrome are highly predictive of outcome after allogeneic bone marrow transplantation. |
| Nevill TJ, Fung HC, Shepherd JD, Horsman DE, Nantel SH, Klingemann HG, Forrest DL, Toze CL, Sutherland HJ, Hogge DE, Naiman SC, Le A, Brockington DA, Barnett MJ |
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| PMID 9731047 |
| Deletion of the acetylcholinesterase locus at 7q22 associated with myelodysplastic syndromes (MDS) and acute myeloid leukaemia (AML). |
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| PMID 8637218 |
| Cytogenetic clonality analysis in myelodysplastic syndrome: monosomy 7 can be demonstrated in the myeloid and in the lymphoid lineage. |
| van Lom K, Hagemeijer A, Smit E, Hählen K, Groeneveld K, Löwenberg B |
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| PMID 7475268 |
| Citation |
| This paper should be referenced as such : |
| Desangles, F |
| -7/del(7q) in adults |
| Atlas Genet Cytogenet Oncol Haematol. 1999;3(3):139-140. |
| Free journal version : [ pdf ] [ DOI ] |
| On line version : http://AtlasGeneticsOncology.org/Anomalies/del7qID1093.html |
| Other genes implicated (Data extracted from papers in the Atlas) [ 7 ] |
| Genes | ABL1 | ASXL1 | BCR | DMTF1 | MECOM | FGFR1 | RARA |
| Translocations implicated (Data extracted from papers in the Atlas) |
| del(7q) in adults | |
| External links |
| REVIEW articles | automatic search in PubMed |
| Last year articles | automatic search in PubMed |
| All articles | automatic search in PubMed |
| © Atlas of Genetics and Cytogenetics in Oncology and Haematology | indexed on : Mon May 14 13:38:06 CEST 2018 |
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