No abstract

Purpose: KIT mutations, the most prevalent genetic event in gastrointestinal stromal tumors (GIST), are associated with malignant features and poor prognosis. Aggressive GISTs possess a high propensity to spread to the liver. This study aimed to explore the role of KIT mutations in GIST liver metastasis.Experimental Design: A total of 170 GISTs were used to determine the association between KIT mutations and liver metastasis. Immunohistochemistry was performed to assess the correlation of KIT mutations with CXCR4 and ETV1 expression. Genetic and pharmacologic methods were used to study the regulation of CXCR4 and ETV1 by KIT mutations.Results: Codons 557 and 558 in KIT exon 11 were deletion hot spots in GISTs. KIT exon 11 deletions involving codons 557-558 were highly associated with liver metastasis. Overexpression of mutant KIT with exon 11 codons 557-558 deletion (KIT D557-558) increased GIST cell motility and liver metastasis. Mechanistically, overexpression of KIT D557-558 in GIST cells increased ETV1 and CXCR4 expression. CXCR4 knockdown counteracted KIT D557-558-mediated cell migration. Moreover, KIT D557-558-induced CXCR4 expression could be abolished by silencing ETV1. The chromatin immunoprecipitation assay showed that ETV1 directly bound to the CXCR4 promoter. After ERK inhibitor PD325901 treatment, the upregulation of ETV1 by KIT D557-558 was prevented. In addition, KIT exon 11 codons 557-558 deletion enhanced CXCL12-mediated GIST cell migration and invasion.Conclusions: KIT exon 11 557-558 deletion upregulates CXCR4 through increased binding of ETV1 to the CXCR4 promoter in GIST cells, which thus promotes liver metastasis. These findings highlighted the potential therapeutic targets for metastatic GISTs.

Using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), this study analyzed the saliva obtained from patients with oral cancer and compared these mass spectra with those obtained from healthy controls. Saliva without pre-treatment was mixed directly with a sinapinic acid matrix. Alpha-amylase (57 kDa) dominated the high mass range in the MALDI mass spectra of the saliva from healthy subjects, but the peak was suppressed for patients with oral cancer and was replaced by a peak at m/z 66 k in the spectra of patients' samples (15 out of 20). Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) with in-gel tryptic digestion combined with matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) was employed to characterize this 66-kDa protein, which was thus shown to be albumin. However, based on SDS-PAGE results, concentrations of both alpha-amylase and albumin in patients' saliva were significantly higher than those in healthy subjects. This discrepancy was shown to be due to MALDI suppression effects due to the albumin. MALDI-MS thus has potential as a possible rapid diagnostic screening tool for oral cancer.

The rare recurrent translocation of (8;9)(p22;p24) with PCM1-JAK2 fusion was recently characterized in diverse hematological malignancies. Most of them are atypical chronic myeloid leukemia (CML) or other myeloproliferative disorders (MPD), and are predominantly in the male. We report a female patient with acute myeloid leukemia (AML) initially presenting with normal karyotype and negative HLA-DR expression who achieved complete remission after standard chemotherapy. The disease relapsed 7 months later with cytogenetic change of t(8;9)(p22;p24). Flow cytometry analysis showed evolutional change of immunophenotype from negative to positive HLA-DR expression and fluorescence in situ hybridization (FISH) analysis demonstrated a PCM1-JAK2 fusion gene. We speculate that the cytogenetic change of t(8;9)(p22;p24) may induce HLA-DR immunophenotypic switch and a coordination of the two evolutional changes may play a role in leukemic cell progression.