Functional Characterization of FLT3 Receptor Signaling Deregulation in Acute Myeloid Leukemia by Single Cell Network Profiling (SCNP)

Molecular characterization of the FMS-like tyrosine kinase 3 receptor (FLT3) in cytogenetically normal acute myeloid leukemia (AML) has recently been incorporated into clinical guidelines based on correlations between FLT3 internal tandem duplications (FLT3-ITD) and decreased disease-free and overall survival. These mutations result in constitutive activation of FLT3, and FLT3 inhibitors are currently undergoing trials in AML patients selected on FLT3 molecular status. However, the transient and partial responses observed suggest that FLT3 mutational status alone does not provide complete information on FLT3 biological activity at the individual patient level. Examination of variation in cellular responsiveness to signaling modulation may be more informative.Using single cell network profiling (SCNP), cells were treated with extracellular modulators and their functional responses were quantified by multiparametric flow cytometry. Intracellular signaling responses were compared between healthy bone marrow myeloblasts (BMMb) and AML leukemic blasts characterized as FLT3 wild type (FLT3-WT) or FLT3-ITD. Compared to healthy BMMb, FLT3-WT leukemic blasts demonstrated a wide range of signaling responses to FLT3 ligand (FLT3L), including elevated and sustained PI3K and Ras/Raf/Erk signaling. Distinct signaling and apoptosis profiles were observed in FLT3-WT and FLT3-ITD AML samples, with more uniform signaling observed in FLT3-ITD AML samples. Specifically, increased basal p-Stat5 levels, decreased FLT3L induced activation of the PI3K and Ras/Raf/Erk pathways, decreased IL-27 induced activation of the Jak/Stat pathway, and heightened apoptotic responses to agents inducing DNA damage were observed in FLT3-ITD AML samples. Preliminary analysis correlating these findings with clinical outcomes suggests that classification of patient samples based on signaling profiles may more accurately reflect FLT3 signaling deregulation and provide additional information for disease characterization and management.These studies show the feasibility of SCNP to assess modulated intracellular signaling pathways and characterize the biology of individual AML samples in the context of genetic alterations

Biomarkers in nasopharyngeal carcinoma and ionizing radiation

© Springer Science+Business Media Dordrecht 2015.Cancer of the nasopharynx is an epithelial cancer developed in the retro-nasal area in the nasal cavity. Nasopharyngeal carcinoma (NPC) is prevalent in the endemic regions including Southern China and Southeast Asia. The primary tumor of NPC is small and usually causes no symptoms. Patients often present with bilateral glands enlargement and local/regional lymph node metastasis leading to poor prognosis and local control rate. Therefore, there is a desperate need to develop early diagnosis method to improve the treatment outcome. Detection of EBV-derived biomarkers in tissues and EBV DNA in the peripheral blood of NPC patients opens up the possibility to monitor the disease using molecular markers with high sensitivity. Among the biomarkers in tissue, in situ hybridization for EBER remains to be the most efficient and reliable way because EBER is the most abundantly expressed viral transcript. In addition to diagnosis value, EBER, EBNA1, and LMP1 levels in tissue after radiation therapy could serve as biomarkers to evaluate response to radiotherapy. In light of the detection of EBV DNA in plasma, serum, nasal brush, and saliva, EBV DNA is particularly useful for periodic monitoring of NPC patients. A systematic review has revealed that circulating EBV DNA could be applied as noninvasive diagnostic biomarker for NPC. Moreover, the close association of circulating EBV DNA with the clinical outcomes of treatment provided new tool to predict the treatment outcome. Nevertheless, circulating EBV DNA was not detectable in all the undifferentiated NPC patients, and EBV latent infection was not associated with WHO-1 NPC, which limits the utility of EBV DNA. Further studies are warranted to identify complementary biomarkers originating from the human cancer cells to overcome the limitation of EBV-based biomarkers in NPC screening and monitoring treatment outcome.Link_to_subscribed_fulltex

Molecular markers in acute myeloid leukaemia

An increasing number of cytogenetic and molecular genetic aberrations have been identified in acute myeloid leukaemia (AML), highlighting the biological heterogeneity of the disease. Moreover, the characterisation of specific molecular abnormalities provides the basis for targeted therapies, such as all trans retinoic acid (ATRA) and arsenic trioxide treatment in acute promyelocytic leukaemia or tyrosine kinase inhibitors in AML with FLT3 mutations. Several cytogenetic and molecular genetic changes have been shown to be prognostically relevant and have been acknowledged in the latest WHO classification of AML as separate entities. A detailed marker assessment at diagnosis is crucial for risk-stratification of AML patients, allowing the identification of those at high risk of relapse, who may benefit from early allogeneic stem cell transplantation. Finally, molecular markers are important for the detection of minimal residual disease after initial therapy and during long-term follow-up, which enables a more tailored treatment approach for individual AML patients.</p