i(8)(q10) in ALL

2017-06-01   Adriana Zamecnikova 

1.Kuwait Cancer Control Center, Department of Hematology, Laboratory of Cancer Genetics, Kuwait; annaadria@yahoo.com


Isochromosomes are nonrandom chromosomal anomalies in acute lymphoblastic leukemia (ALL), but relatively few patients ALL and i(8)(q10) have been reported. In the majority of cases, i(8)(q10) was part of complex karyotypes, suggesting that it is a secondary chromosomal abnormality in ALL associated with clonal evolution.

Clinics and Pathology


Acute lymphoblastic leukemia

Phenotype stem cell origin

Associated with B-lineage immunophenotype with exception of 1 chronic myeloid leukaemia (CML) with lymphoid blast crisis of B-cell type who developed a secondary T-cell ALL (Dawson et al., 1999) case and 2 biphenotypic leukemia (Sulak et al.,1990; Saikevich et al., 1991) patients.


At least 40 reported cases (21 males, 19 females aged 0 to 85 years; median age 17 years) were described. Nearly half the cases were children: 2 female infants (OMalley et al., 1988; Pui et al., 1991) and 12 pediatric cases aged 0 to 15 years (Pollak & Hagemeijer 1987; Krance et al., 1992; Pui et al., 1992; Rafi et al., 2000; An et al., 2008; Suenobu et al., 2010; Chapiro et al., 2011; Harrison et al., 2014; Olsson et al., 2015; Yasuda et al., 2016; Zhang et al., 2016) or young adults aged 17 to 24 years old ( Mossafa et al., 1994; Tang et al., 1998; Jarosova et al., 2000; Soriani et al., 2011; Harrison et al., 2014; Safavi et al., 2015) (Table 1).
46,idem,t(9;10)(p13;q22) or t(9;10) (p22;q24)
2F/0 46,XX,ins(11;4)/46,idem,del(5)(q15q33)/46,idem,del(5),i(8)(q10)/46,idem,t(2;4)(q33;p16),del(5)/47,idem,+8/

3M/8577-87,XY,-X,-Y,del(5)(q23)x2,i(8)(q10)x2,add(22)(q13),inc        Bilineage or biphenotypic leukemia
6M/6343,XY,t(1;9)(q?32;p?24),-2,der(3)t(3;12;17)(p?14;p?11;q?25),-5,i(8)(q10),-12,der(17)t(3;12;17)       Bilineage or biphenotypic leukemia
7M/13 46,XY,i(8)(q10),t(12;17)(p13;q21)
8M/10 46,XY,i(7)(q10),t(9;22)(q34;q11)/48,idem,i(8)(q10),+i(8)(q10)x2
11F/60 46,XX,t(9;22)(q34;q11)/46,idem,i(8)(q10)
12M/44 46,XY,i(8)(q10),t(9;22)(q34;q11)
13F/24 46,XX,del(6)(q21q24),i(8)(q10)
15F/42 47,XX,dup(1)(q21q32),add(2)(p11),+7,i(8)(q10),t(8;22)(q24;q11)/47,idem,-dup(1),+trp(1)(q21q32)
16F/36 53,XX,+4,t(9;22)(q34;q11),i(8)(q10),+18,+19,+der(22)t(9;22)x2
19F/21 46,XX,i(7)(q10),i(8)(q10),t(9;22)
21M/3946,Y,t(X;11),i(7)(q10),dup(8)(q21q22)/46,idem,i(8)(q10)/45,idem,-Y       T-cell ALL after chemotherapy for CML
26F/14 45,XX,i(8)(q10),dic(9;12)(p11;p11),der(17)t(?X;17)(?q12;?p11)
29M 47,XY,i(8)(q10),+21c
30F/13 45,XX,t(9;22)(q34;q11),add(10)(q22),-12,der(12)t(12;12)(p13;q13),i(17)(q10)/45,idem,i(8)(q10)
46,X,-X,+1,t(2;16)(p10;q10),+8,-9,t(9;22),add(10),-12,der(12),-13,i(17)(q10),+18,add(19)(p13),del(19)(q?),+21,-22,+mar/47,idem,+8       therapy for neuroblastoma
32M/7 46,XY,t(14;20)(q32;q12)/46,idem,i(8)(q10)
35F/19 44,XX,i(8)(q10),-10,add(11)(q23),add(12)(p13),-14,add(14)(q32),add(15)(q25), +16,add(21)(q22),-22,+mar
1.Pollak & Hagemeijer 1987; 2.OMalley et al., 1988; 3.Sulak et al.,1990; 4.Kageyama et al., 1991; 5.Pui et al., 1991; 6.Saikevich et al., 1991; 7.Krance et al., 1992; 8.Pui et al., 1992; 9.Dewald et al., 1993; 10.Tuszynski et al., 1993; 11-13.Mossafa et al., 1994; 14.Pirc-Danoewinata et al., 1995; 15.Martineau et al., 1996; 16-17.Rieder et al., 1996; 18.Pabst et al., 1996; 19.Tang et al., 1998; 20.Dabaja et al., 1999; 21.Dawson et al., 1999; 22.Jarosova et al., 2000; 23.Rafi et al., 2000; 24.Rieder et al., 2003; 25.Strefford et al., 2007; 26-27.An et al., 2008; 28.Coyaud et al., 2010; 29.Kowalczyk et al., 2010; 30.Suenobu et al., 2010; 31.Soriani et al., 2011; 32.Chapiro et al., 2013; 33-36.Harrison et al., 2014; 37.Olsson et al., 2015; 38.Safavi et al., 2015; 39.Yasuda et al., 2016; 40.Zhang et al., 2016.
Abbreviations: M, male; F, female.


As it occurs rarely as a sole anomaly only in sporadic cases in ALL, thus the prognosis is uncertain; patients with favorable primary aberrations and i(8)(q10) may maintain favorable clinical outcome similar to patients with +8; its combination with unfavorable primary anomaly or complex anomalies may lead to the worst prognosis.

Result of the Chromosomal Anomaly


Partial chromosome 8q gain resulting from an isochromosome i(8)(q10) is a nonrandom chromosomal anomaly in ALL. It occurs rarely as a sole anomaly and is mainly observed together with primary chromosome aberrations, most frequently with t(9;22)(q34;q11). Therefore, the occurrence of i(8)(q10) in ALL may signal clonal evolution, often associated with disease progression. The consequence of the formation of i(8)(q10) is gain of 8q and loss of 8p, leading to imbalances in gene dosage. As trisomy 8 is among the most common secondary chromosome changes in hematological malignancies, it is likely that gain of 8q, but not the loss of 8p is important in leukemogenesis. In this regard it is interesting to note, that while extra chromosome 8 is a common clonal evolution marker for progression in CML, the occurrence of i(8)(q10) has been only rarely described during CML transformation. While differential diagnosis between blast transformation of CML and Ph1(+) ALL may be difficult, particularly in cases identified initially in blastic crisis, it is possible that i(8)(q10) is a specific secondary anomaly to t(9;22)(q34;q11) in a pre-B immunophenotype ALL.


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Atlas Image
Partial karyotypes with isochchromosome i(8)(q10) (A). Fluorescence in situ hybridization with LSI MYC probe hybridizing to 8q24 (Vysis/Abott Molecular, US) showing end-to-end joining of homologous chromosomes 8 at the telomeres (B). It can be hypothesized that telomeric fusion of homologous chromosomes can promote creation of an unstable dicentric chromosome potentially causing an unbalanced translocation product. However, the precise consequences of telomere fusion events and their role in formation of isochromosomes remain unclear.


Adriana Zamecnikova

i(8)(q10) in ALL

Atlas Genet Cytogenet Oncol Haematol. 2017-06-01

Online version: http://atlasgeneticsoncology.org/haematological/2052/i(8)(q10)-in-all