The hypereosinophilic syndrome may result from a novel fusion tyrosine kinase - FIP1L1-PDGFRalpha - that is a consequence of an interstitial chromosomal deletion. The acquisition of a T674I resistance mutation at the time of relapse demonstrates that FIP1L1-PDGFRalpha is the target of imatinib. Our data indicate that the deletion of genetic material may result in gain-of-function fusion proteins.
Idiopathic hypereosinophilic syndrome (HES) and chronic eosinophilic leukemia (CEL) comprise a spectrum of indolent to aggressive diseases characterized by unexplained, persistent hypereosinophilia. These disorders have eluded a unique molecular explanation, and therapy has primarily been oriented toward palliation of symptoms related to organ involvement. Recent reports indicate that HES and CEL are imatinib-responsive malignancies, with rapid and complete hematologic remissions observed at lower doses than used in chronic myelogenous leukemia (CML). These BCR-ABL-negative cases lack activating mutations or abnormal fusions involving other known target genes of imatinib, implicating a novel tyrosine kinase in their pathogenesis. A bedside-to-benchtop translational research effort led to the identification of a constitutively activated fusion tyrosine kinase on chromosome 4q12, derived from an interstitial deletion, that fuses the platelet-derived growth factor receptor-␣ gene (PDGFRA) to an uncharacterized human gene FIP1-like-1 (FIP1L1). However, not all HES and CEL patients respond to imatinib, suggesting disease heterogeneity. Furthermore, approximately 40% of responding patients lack the FIP1L1-PDGFRA fusion, suggesting genetic heterogeneity. This review examines the current state of knowledge of HES and CEL and the implications of the FIP1L1-PDGFRA discovery on their diagnosis, classification, and management.
IntroductionProtean biologic and clinical presentations characterize idiopathic hypereosinophilia (HES). HES is similar to other diseases given the moniker "diagnosis of exclusion," in that limited understanding of the pathogenesis of the disease has hampered therapeutic advances. The demonstration of increased myeloblasts or clonality or the development of either granulocytic sarcoma or acute myeloid leukemia helps clarify the origin of some cases of chronic eosinophilic leukemia. 1 In a subset of patients, hypereosinophilia is related to excessive secretion of eosinophilopoietic cytokines from a clonal population of lymphocytes. 2 The identification of FIP1-like-1-platelet-derived growth factor receptor-␣ (FIP1L1-PDGFRA) in cases of HES/CEL adds to a growing list of activated fusion tyrosine kinases linked to the pathogenesis of chronic myeloproliferative disorders. 3 It is unique, however, because it is the first description of a gain-of-function fusion protein resulting from a cryptic interstitial deletion between genes rather than a reciprocal chromosomal translocation. The FIP1L1-PDGFR␣ fusion protein transforms hematopoietic cells, and its kinase activity is inhibited by imatinib at a cellular 50% inhibitory concentration (IC 50 ) 100-fold lower than BCR-ABL. 3 Acquisition of an imatinib resistance mutation in the adenosine triphosphate (ATP)-binding domain of PDGFRA in a relapsed patient previously responsive to imatinib supports a critical role for FIP1L1-PDGFR␣ in the pathogenesis of disease and demonstrates that FIP1L1-PDGFR␣ is the therapeutic target of imatinib. 3 The identification of t...
Infections in pregnancy with Ureaplasma urealyticum have been associated with a wide range of adverse outcomes, such as early abortion, stillbirth, prematurity, and neonatal morbidity and mortality. Causality has been difficult to demonstrate secondary to the high prevalence of asymptomatic lower genital tract (LGT) colonization and culture data from inaccessible or potentially contaminated sites.Between 1985 and 1989,2461 second-trimester genetic amniocenteses were evaluated at the cytogenetics section of the Children's Hospital Medical Center of Akron. All were cultured for the genital mycoplasmas: MycopZasma hominis and Ureaplasma ureafyticum. A total of nine patients were positive, all for Ureaplasma urealyticum, with one patient excluded because of subsequent therapeutic abortion. In addition, complete follow-up data, such as indication for amniocentesis, serum alpha-fetoprotein levels, gestational age at parturition, and outcome of pregnancy, were available on 86 Ureaplasma-negative (U -) patients during an approximate 2-year span within the time-frame of the study. This was in part due to physician response to a questionnaire sent after amniocentesis.Of the eight positive cultures, 100 per cent were associated with an adverse outcome, defined as fetal loss or premature delivery. This was significant compared with the Ugroup (P
Objectives: Non-melanoma skin cancer is the most common malignancy in US, with an annual incidence of in excess of 1.5 million cases. In the majority of cases, locoregional treatment is curative and systemic therapy is not indicated. Platinum-based chemotherapy regimens have been used most commonly in refractory cases. The use of cetuximab, a monoclonal antibody targeting epidermal growth factor receptor [EGFR], has been reported for skin cancer treatment. This current study evaluated eight cases of locally advanced and refractory basal cell or squamous cell cancers which were treated with cetuximab.Methods: This is a retrospective study on eight patients who had received cetuximab for treatment of cutaneous carcinoma since 2007 at Southern Illinois University School of Medicine (SIU-SOM) Medical Oncology clinic.Results: Three of the four patients with basal cell carcinoma and two of the four patients with squamous cell carcinoma maintained remission on treatment.. The main side effect was acneiform rash which required termination of treatment for one patient and dose reduction in another.Conclusion: The study indicates that cetuximab may have a beneficial role for patients with non-melanoma cutaneous carcinomas that are refractory to standard therapy.
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