Recent progress in sequencing studies has suggested that somatic mutations can be used in clinical sequencing for predicting prognosis and selecting treatment options in myelodysplastic syndrome (MDS). A 48-year-old man was diagnosed with refractory cytopenia with multilineage dysplasia that is classified as a subtype of high-risk MDS based on both revised International Prognostic Scoring System and refined WHO classification based Prognostic Scoring System. He received a bone marrow transplant from an HLA-matched sibling donor at X＋87 months because of disease progression. Targeted sequencing of 69 genes in bone marrow cells at X＋82 months revealed mutations in BCOR and U2AF1 genes. Variant allele frequencies of these mutations were almost unchanged in the bone marrow examined from X＋9 months to X＋80 months, but they subsequently decreased. Neither of these mutations was detected in the bone marrow at X＋88 months, a month after transplantation. The mutations often found in secondary leukemia or high-risk MDS were not detected in our patient. These serial genetic conditions may correspond to the relatively stable disease course over a long time.
Keywords: BCOR; Myelodysplastic syndrome; U2AF1.