Preponderant in myeloid disorders.

Myelodysplasic syndromes (MDS) in 60 % of cases.
Acute myeloid leukemia (AML) in 30%, most commonly AML-M2 but reported in all FAB subtypes; frequently with preceeding MDS.
Myeloproliferative neoplasms (MPN) represent the remaining 10% of cases.
Lymphoid disorders: very rare, half of cases being multiple myeloma with the der(1;7) as the sole abnormality (raising the possibility of an underlying MDS), the other half in various lymphoid disorders chronic lymplocytic leukemia (CLL), Burkitt lymphoma/leukemia, follicular lymphoma), most often part of a complex karyotype (Geisler et al., 1997; Hsiao et al., 2005; Al-Bahar et al., 2010)
Others: reported in only one case each of bilineage or biphenotypic acute leukemia with a t(9;22) (Sanada et al. 2007), sarcoma (Roberts et al., 2008) and carcinoma (Jin et al., 2002) with complex karyotypes and in two cases of aplastic anemia (Kim et al., 2010).

MDS cases: most commonly RA (60%).
AML cases: most commonly M2 but has been reported in all FAB subtypes.
MPN cases: reported in a few cases of polycythemia vera, essential thrombocythemia, chronic myelomonocytic leukemia and idiopathic myelofibrosis.

Found in 1.5-6% of MDS, 0.2-2% of AML and rarely in MPN. Older adults mostly (median late 50s, early 60s. male predominance (4M/1F), influenced partly by the preponderance of males in a large study of Japanese MDS cases with der(1;7) (Sanada et al., 2007).

MDS: There is some controversy as to the prognosis of the der(1;7) with trisomy 1q and monosomy 7q. A better outcome of der(1;7) compared to -7/del(7q) cases was shown in a retrospective study including 77 cases (Sanada et al., 2007), while there was no statistical difference in overall survival between der(1;7) versus del(7q) versus -7 in several studies including a smaller number of patients (Slovak et al., 2009; Hussain et al., 2012).
AML: In the UKMRC trials, the der(1;7) may be included in the "-7/del(7q)" group, associated with a poor prognosis (Grimwade et al., 2010). In the CALGB 8461 study, loss of 7q was associated with an intermediate prognosis (Byrd et al., 2002).

Unbalanced whole-arm translocation with two chromosomes 1, a derivative chromosome including the long arm of chromosome 1 and the short arm of chromosome 7, and a chromosome 7 resulting in trisomy for 1q / monosomy for 7q. The balanced form may have been reported once in a secondary AML-M2 case (Higuchi et al., 1995).

85% of cases are not complex if the unbalanced der(1;7) with extra chromosome 1 is considered as a single abnormality ("single abnormality" in 50% of cases, one additional abnormality in the remaining 35%). The most frequent additional abnormalities are: +8 (50%); del(20q) (20%); +21 or +9 (3% each).
A cytogenetically unrelated, abnormal clone is found in 5% of cases, 80% in MDS, 20% in AML. Loss of Y, -7 and +8 are the most common abnormalities.

NHL