RESUMEN
BACKGROUND/AIM: Approximately, 15-50% of families affected by hereditary diffuse gastric cancer (HDGC) exhibit CDH1 germline mutations. CDH1 gene encodes E-cadherin, protein essential to the cell-cell contact of gastric epithelium. Studies have shown that hsa-miR-9 participates in this protein downregulation. Moreover, MYC is responsible for the transcription of hsa-miR-9-3. In the present study, hsa-miR-9 expression and MYC copy number variation were investigated to elucidate the hsa-miR-9 role in HDGC. PATIENTS AND METHODS: Tumor samples were obtained from nine individuals with HDGC history belonging to four Brazilian families. Then, relative quantification of hsa-miR-9 expression and MYC gene copy number variation analysis were performed by real-time PCR. RESULTS: In all the samples, an overexpression of hsa-miR-9 and an increased MYC copy number (≥3 copies) were observed. CONCLUSION: hsa-miR-9 acts as an oncomiR in HDGC. In addition, we suggest that hsa-miR-9 acts as second event in individuals with HDGC carrying CDH1 gene germinline mutations.
Asunto(s)
MicroARNs/genética , Proteínas Proto-Oncogénicas c-myc/genética , Neoplasias Gástricas/genética , Adulto , Anciano , Antígenos CD , Cadherinas/genética , Variaciones en el Número de Copia de ADN , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Biliary tract cancers are aggressive malignancies that include gallbladder cancer and tumors of intra- and extrahepatic ducts and have a poor prognosis. Surgical resection remains the main curative therapy. Nevertheless, numerous patients experience recurrence even after radical surgery. This scenario drives the research to identify biliary tract cancer biomarkers despite the limited progress that has been made. Recently, a large number of studies have demonstrated that deregulated expression of microRNAs is closely associated with cancer development and progression. In this review, we highlight the role and importance of microRNAs in biliary tract cancers with an emphasis on utilizing circulating microRNAs as potential biomarkers. Additionally, we report several single-nucleotide polymorphisms in microRNA genes that are associated with the susceptibility of biliary tract tumors.
RESUMEN
Alterations in epigenetic control of gene expression play an important role in many diseases, including gastric cancer. Many studies have identified a large number of upregulated oncogenic miRNAs and downregulated tumour-suppressor miRNAs in this type of cancer. In this review, we provide an overview of the role of miRNAs, pointing to their potential to be useful as diagnostic and/or prognostic biomarkers in gastric cancer. Moreover, we discuss the influence of polymorphisms and epigenetic modifications on miRNA activity.