The unbalanced translocation of der(1;7)(q10;p10) is relatively rare in myeloid neoplasms, which was reported at frequencies of 2% in de novo myelodysplastic syndrome (MDS), 0.5% in de novo acute myeloid leukemia (AML) and 3–7% in therapy-related myeloid neoplasms. Although chromosome 7 abnormality is generally considered as a poor prognostic factor in MDS and AML, it is still unclear whether or not this unbalanced translocation has a negative impact on prognosis. In addition, there appears to be some unique clinicopathological features such as male predominance, low blast counts, high hemoglobin level, presence of eosinophilia and a high rate of sole chromosomal abnormality.
We retrospectively analyzed 122 der(1;7)(q10;p10) and -7/del(7q) adult patients with MDS or AML who were diagnosed at our institute between February 1995 and March 2010. According to the French-American-British (FAB) classification, 29 patients had AML (M0, n=5; M1, n=6; M2, n=10; M4, n=3; M5, n=1; M6, n=4) and 93 patients had MDS (RA, n=50; RARS, n=2; RAEB, n=35; RAEB-t, n=3; CMML, n=3). We compared the clinicopathological features and outcome of 33 der(1;7) patients with those of 89 -7/del(7q) patients.
The median age was 71 years for the der(1;7) patients and 67 years for -7/del(7q) patients (p=0.29). Male predominance was observed in both patients in the der(1;7) and the -7/del(7q) (p=0.52). The proportion of the sole abnormality in the der(1;7) was significantly higher than that in the -7/del(7q) (58% vs 13%, p<0.001). Among the MDS patients, the hemoglobin level, platelet counts and rates of eosinophil between the der(1;7) and -7/del(7q) patients were significantly different (9.1g/dl vs 7.4g/dl, p=0.006; 16.1×109/L vs 7.0×109/L, p<0.001; 6.5% vs 1.0%, p<0.001, respectively). The median survival time (MST) of the der(1;7) patients was significantly better than that of the -7/del(7q) patients (22.1 months vs 10.2 months, respectively, P=0.002). A subgroup analysis of the MDS patients revealed that the MST of the der(1;7) patients was significantly better than that of the -7/del(7q) patients (22.1 months vs 12.1 months, respectively, P=0.004). According to the international prognostic scoring system (IPSS) for MDS patients, the MST was 39.4 months for intermediate-1 risk group, 12.7 months for intermediate-2 risk group and 7.2 months for high risk group (p=0.005). A multivariate analysis revealed that the der(1;7) was associated with a significantly better MST, even after adjusting IPSS and other prognostic factors including age, additional chromosome abnormality, and prior exposure to chemotherapy and/or radiation therapy.
Our study suggested that the der(1;7) might be a subgroup characterized by distinct clinicopathologic features and outcome among patients with MDS and AML.
No relevant conflicts of interest to declare.
Asterisk with author names denotes non-ASH members.