The most common chromosomal abnormalities in myelodysplastic syndrome (MDS) and 
acute myeloid leukemia (AML) are -5/del(5q) and -7/del(7q). When -5/del(5q) and 
-7/del(7q) coexist in patients, a poor prognosis is typically associated. Given 
that -5/del(5q) and/or -7/del(7q) often are accompanied with additional 
recurrent chromosomal alterations, genetic change(s) on the accompanying 
chromosome(s) other than chromosomes 5 and 7 may be important factor(s) 
affecting leukemogenesis and disease prognosis. Using an integrated analysis of 
karyotype, FISH and array CGH results in this study, we evaluated the smallest 
region of overlap (SRO) of chromosomes 5 and 7 as well as copy number 
alterations (CNAs) on the other chromosomes. Moreover, the relationship between 
the CNAs and del(5q) and -7/del(7q) was investigated by categorizing the cases 
into three groups based on the abnormalities of chromosomes 5 and 7 [group I: 
cases only with del(5q), group II: cases only with -7/del(7q) and group III: 
concurrent del(5q) and del(7q) cases]. The overlapping SRO of chromosome 5 from 
groups I and III was 5q31.1-33.1 and of chromosome 7 from groups II and III was 
7q31.31-q36.1. A total of 318 CNAs were observed; ~ 78.3% of them were 
identified on chromosomes other than chromosomes 5 and 7, which were defined as 
'other CNAs'. Group III was a distinctive group carrying the most high number 
(HN) CNAs, cryptic CNAs and 'other CNAs'. The loss of TP53 was highly associated 
with del(5q). The loss of ETV6 was specifically associated with group III. These 
CNAs or genes may play a secondary role in disease progression and should be 
further evaluated for their clinical significance and influence on therapeutic 
approaches in patients with MDS/AML carrying del(5q) and/or -7/del(7q) in 
large-scale, patient population study.