Pentasomy 8q in therapy-related myelodysplastic syndrome due to cyclophosphamide therapy for fibrosing alveolitis.
Trisomy 8/8q is a common cytogenetic event in myelocytic malignancies, ranging from myelodysplastic syndrome (MDS) to acute myelocytic leukemia (AML) to blastic transformation of chronic myelocytic leukemia. Isochromosome 8q results in the same gene dosage effect. Duplication of i(8q), resulting in pentasomy 8q, has been reported only in two cases of AML. A patient with fibrosing alveolitis on prolonged cyclophosphamide treatment developed therapy-related MDS. Karyotyping, FISH, and CGH analysis showed a duplicated i(8q) among other complex abnormalities. The clinical features of 11 cases of myelocytic leukemia with pentasomy and hexasomy 8/8q were summarized. Compared with trisomy and tetrasomy 8, significant features included reduced median survival (90 days), treatment refractoriness (even with transplantation), monocytic differentiation, trilineage dysplasia, and radiation or toxin exposure. Increasing copy numbers of chromosome 8/8q may therefore be a marker of advanced leukemic evolution, exposure to toxins, underlying myelodysplasia, and an overall poor prognosis.
Au
Wing Y
WY
Department of Medicine, University of Hong Kong, Queen Mary Hospital, Hong Kong, China. auwing@hotmail.com
Ma
Shiu-Kwan
SK
Wan
Thomas S
TS
Man
Cornelia
C
Kwong
Yok-Lam
YL
D000368:Aged; D002871:Chromosome Banding; D002898:Chromosomes, Human, Pair 8 / Q000235:genetics*; D003520:Cyclophosphamide / Q000009:adverse effects* / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D009190:Myelodysplastic Syndromes / Q000139:chemically induced* / Q000150:complications / Q000235:genetics*; D011658:Pulmonary Fibrosis / Q000150:complications* / Q000188:drug therapy* / Q000235:genetics
D003520:Cyclophosphamide