When the analysis was matching with

When the analysis was matching with propensity score, OS was still significantly longer in JAK2+ patients (median not reached versus 73 months, p=.031) whereas JAK2 status had no significant prognostic value for OS in IPSS intermediate-2 and high patients (p=.18).
Discussion In this series, which is to our knowledge the first to focus on MDS with JAK2V617F mutation other than RARS-T, we found JAK2+ cases to have higher WBC, ANC and platelet counts and fewer marrow blasts than JAK2− MDS, but no significant difference in cytogenetics and IPSS. JAK2+cases had significantly lower risk of AML progression and better OS than JAK 2− patients, an OS advantage which persisted in a matched case control analysis based on age, gender, marrow blast percentage and IPSS. Recently, in a large series of 439 MDS, Bejar et al. found no prognostic value to JAK2V617F mutation but only 13 (3%) of the patients had JAK2V617F mutation. In addition, whether some of those patients had RARS-T was not indicated [10]. Finally, only 64% of the JAK2+ cases had lower risk IPSS in Bejar et al. series, compared to 80% in our study. Indeed, we found the favorable prognosis of JAK2V617F mutation to be mainly restricted to lower risk IPSS. Thus, we found that MDS other than RARS-T with JAK2V617F mutation were associated with laboratory features (higher WBC, ANC, platelet count) with better outcome. However, prospective studies precisely evaluating the impact of this mutation are required to confirm our findings.
Acknowledgments
Case report A 17-year-old female presented with pain in the left hip joint in April 2010. Radiography revealed a radiolucent region at the greater trochanter of the left survivin (baculoviral IAP repeat-containing protein 5) (21-28) weight (Fig. 1A). Computed tomography (CT) and magnetic resonance imaging (MRI) revealed an osteolytic tumor at the greater trochanter of the left femur (Fig. 1B and C). Blood analyses showed an elevated white blood cell (WBC) count of 130,200/µL; a decreased hemoglobin level of 9.4g/dL; and an increased platelet count of 465,000/µL. The differential leukocyte count revealed 3.4% blasts, 0.4% promyelocytes, 9.2% myelocytes, 1.8% metamyelocytes, 53.6% neutrophils, 12.4% eosinophils, and 15.6% basophils. Examination of the bone marrow showed increased cellularity due to granulocytic proliferation with a maturation pattern similar to that observed in peripheral blood, with a blast count of 6.5% and a basophil count of 5.6%. Chromosomal analyses of the bone marrow cells revealed an t(9;22) (q34;q11.2) abnormality. The type of BCR-ABL fusion transcripts was major BCR-ABL which led to a p210 fusion protein. A biopsy specimen of the left femur tumor revealed extramedullary blast proliferation with fibrosis (Fig. 2a). An immunohistochemical study demonstrated the blast cells were partially positive for CD68 (KP-1) (Fig. 2b), CD68 (PGM-1), and myeloperoxidase, and negative for terminal deoxynucleotidyl transferase (TdT), CD3, CD79a, and CD34. Chromosomal analyses of the tumor cells of the left femur also revealed a t(9;22)(q34;q11.2) abnormality. The diagnosis was extramedullary myeloid blast crisis of chronic myelogenous leukemia (CML). Initially she was administered imatinib (400mg once daily). The WBC count in peripheral blood decreased rapidly. She achieved a complete hematologic response within 23 days after the initiation of imatinib therapy. Radiography revealed that the radiolucent region at the greater trochanter of the left femur had also improved. However, the pain in her left hip joint suddenly worsened on the 54th day of imatinib treatment. Radiography and CT showed that the osteolytic tumor at the greater trochanter of the left femur had enlarged. The WBC count of peripheral blood was 3800/µL with normal differential leukocyte count. Examination of the bone marrow showed that the bone marrow remained in a chronic phase with a minor cytogenetic response. Mutation of the BCR-ABL kinase domain was not detected. [18F]Fluorodeoxyglucose positron emission tomography (FDG-PET) revealed that abnormal uptake of FDG was limited to the tumor in the left femur. Because of the severe pain and the risk of pathological fracture, she was treated with involved field radiotherapy at 30Gy. In addition, imatinib was switched to dasatinib (70mg, twice daily) because the residual tumor was considered to be resistant to imatinib.