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Oncogenic somatic mutations in plasmablastic lymphoma.
Figure 1. Summary of the mutations found in 18 out of 30 cases (60%) analyzed by targeted exonic next-generation sequencing. Epstein-Barr virus (EBV) positivity of tumor cells and human immunodeficiency virus (HIV) infection by the patient are shown, together with the status of the MYC gene as determined by interphase fluorescence in situ hybridization (FISH). The pattern of somatic mutations is heterogeneous with a trend to a higher rate of mutations in EBV-positive cases. The most common genetic events in plasmablastic lymphoma are mutations (including translocations, amplifications and point mutations) in the MYC gene. Previously undescribed abnormalities in plasmablastic lymphoma such as STAT3 (16% of cases), BRAF, MYD88, NOTCH2 and TP53 mutations were also identified (see details in Table 1).
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Figure 2. STAT3 mutations in plasmablastic lymphoma. (A) STAT3 mutations were found in five cases (16%), all of which were positive for Epstein-Barr virus. Interestingly all but one (STAT3pD566Y) of the mutations involved the SH2 domain of the STAT3 protein. (B) The mean phosho-STAT3 expression for SH2 domain- mutated cases (2 cases with available mutational and immunohistochemical data) was 249 nuclei per high power field (40x), whereas that for STAT3 wild-type cases was 28 nuclei per high power field. Thus, STAT3 SH2 domain mutations led to phosphoSTAT3 (Tyr705) protein overexpression. (C) Representative microphotographs of phosphoSTAT3 (Tyr705) protein expression in plasmablastic lymphoma.
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