Analysis of internal tandem duplications of FLT3 (FLT3/ITD) was performed on bone marrow samples obtained at diagnosis and relapse from 108 adult patients with de novo acute myeloid leukemia (AML) to determine the role of this mutation in leukemic relapse. Eighty-three patients had wild-type FLT3 at both diagnosis and relapse, 16 had FLT3/ITD at both stages, whereas 8 had acquired the mutation and 1 had lost it at relapse. Using Genescan analysis, we found that FLT3/ ITD levels at first relapse were significantly higher than those at diagnosis (mean ؎ SE, 40.5% ؎ 4.8% versus 17.9% ؎ 3.6%, P < .001). The increase in mutation levels at relapse as compared with diagnosis did not correlate with the difference in blast cell percentages at both stages (P ‫؍‬ .777). A hemizygous deletion of wild-type FLT3 was found in 4 patients at relapse compared to none at diagnosis. Nine of the 11 patients carrying a single mutation at diagnosis relapsed with an identical mutation. All 6 patients with more than one FLT3/ ITD mutation at diagnosis showed changes in mutation patterns and levels at first relapse; however, each patient retained at least one mutation in the relapse sample. The changes of mutation patterns had implications for the monitoring of minimal residual disease. Our results suggest that FLT3/ITD may contribute as the initial transforming event in AML, and relapse can reflect the selection and outgrowth of a mutant clone or evolution of a new clone harboring this mutation. (Blood.

BACKGROUNDThe clinical relevance of mutations of the FMS‐like tyrosine kinase 3 (FLT3) gene in specific cytogenetic subgroups is not clear. The authors examined internal tandem duplication (ITD) and Asp835 mutations of FLT3 in patients with acute promyelocytic leukemia (APL) to determine the incidence of these mutations and to analyze the results for correlations with clinicohematologic features and outcome.METHODSBone marrow samples from 107 patients with APL were analyzed. Isoforms of PML‐RARα were identified using a reverse transcription–polymerase chain reaction assay. A standard polymerase chain reaction (PCR) assay was used to detect FLT3/ITD mutations. Asp835 mutations were analyzed by PCR amplification of exon 20 followed by EcoRV digestion. All aberrant PCR products subsequently were sequenced.RESULTSTwenty‐two patients had FLT3/ITD mutations: 9 of 63 patients with L‐type PML/RARα, 13 of 34 patients with S‐type PML/RARα, and 0 of 10 patients with V‐type PML/RARα (P = 0.005). The incidence of FLT3/ITD mutations was significantly higher in patients with S‐type PML/RARα than in patients with L‐type PML/RARα or V‐type PML/RARα. Twenty patients had Asp835 mutations (L‐type PML/RARα: n = 11; S‐type PML/RARα: n = 8; V‐type PML/RARα: n = 1). The frequency of Asp835 mutations was not significantly different among patients with different PML/RARα isoforms (P = 0.582). Three patients had both ITD and Asp835 mutations. The microgranular variant (M3v) form of leukemia was found to be associated with a higher frequency of ITD (P = 0.002) but not with a higher frequency of Asp835 mutations (P = 1.000); analysis of clinicohematologic variables revealed no significant differences in FLT3 mutation incidence among other patient subgroups. There was no significant difference in complete remission rate, overall survival, or event‐free survival between patients with ITDs and those without ITDs or between patients with Asp835 mutations and those without Asp835 mutations.CONCLUSIONSThe current study found that ITD or Asp835 mutations of the FLT3 gene were present in 36.4% of patients with APL; however, these mutations had no prognostic impact. FLT3/ITD frequently was associated with S‐type PML/RARα and with the M3v form of leukemia. Cancer 2003;98:1206–16. © 2003 American Cancer Society.DOI 10.1002/cncr.11636

Unlike previous reports from Taiwan, in the present study, GBS was found to be the leading pathogen in early-onset sepsis. GBS screening and intrapartum antibiotic prophylaxis guidelines should be used in Taiwan to prevent early neonatal sepsis. The most common causative microorganisms of late-onset sepsis were CONS and Candida species. Candida parapsilosis was associated with a high mortality rate.

Diffuse large cell lymphoma involving bone marrow is not uncommon, but primary, de novo, bone marrow diffuse large B cell lymphoma (DLBCL) is rare. To understand the clinical features and outcomes of this distinct entity, we collected 12 cases in 5 years from a single-center database. They accounted for 1.16% of lymphoma, or 2.65% of diffuse large B cell lymphoma. Nine cases presented with fever of unknown origin. Lactate dehydrogenase levels were elevated in all but one case. Nine cases belonged to the high-risk group according to their international prognosis indexes (score 4 or 5). Four patients received no chemotherapy, all of whom died within 1 month. Four patients received cyclophosphamide, adriamycin, vincristine, and prednisolone (CHOP)-like chemotherapy, and their median survival was 13 months. Finally, four patients received rituximab 375 mg/m(2) in addition to CHOP-like chemotherapy. All of them had complete remission and three are still alive without relapse. We concluded that primary bone marrow DLBCL is a rare but distinctive subtype of lymphoma. The prognosis for this entity is poor but rituximab-based treatment is promising for improving its outcomes.