RESUMEN
Current clinical problems in colorectal cancer (CRC) diagnostics and therapeutics include the disease complexity, tumor heterogeneity, and resistance to targeted therapeutics. In the present study, we examined 171 CRC adenocarcinomas from Greek patients undergoing surgery for CRC to determine the frequency of KRAS, BRAF, and PIK3CA point mutations from different areas of tumors in heterogeneous specimens. Ninety two out of 171 (53.8%) patients were found to bear a KRAS mutation in codons 12/13. Of the 126 mutations found, 57.9% (73/126) were c.38G>A mutations (p.G13D) and 22.2% (28/126) were c.35G>T (p.G12V). Remarkably, RAS mutations in both codons 12 and 13 were recorded in the same tumor by pyrosequencing. Moreover, differences in KRAS mutations between tumor center and periphery revealed tumor heterogeneity in 50.7% of the specimens. BRAF c.1799T>A (V600E) mutations were moderately detected in 4/171 (2.3%) specimens, whereas most PIK3CA mutations were revealed by pyrosequencing 6/171 (3.5%). Remarkable tumor heterogeneity is revealed, where double mutations of KRAS in the same tumor and different KRAS mutation status between tumor core and margin are detected with high frequency. It is expected that these findings will have a major impact in cancer diagnosis and personalized therapies.
Asunto(s)
Neoplasias Colorrectales/genética , Fosfatidilinositol 3-Quinasas/genética , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Proto-Oncogénicas/genética , Proteínas ras/genética , Fosfatidilinositol 3-Quinasa Clase I , Codón , Análisis Mutacional de ADN , Femenino , Humanos , Masculino , Mutación Puntual , Proteínas Proto-Oncogénicas p21(ras)RESUMEN
Previous studies have uncovered several transcription factors that determine biological alterations in tumor cells to execute the invasion-metastasis cascade, including the epithelial-mesenchymal transition (EMT). We sought to investigate the role of miR-21 in colorectal cancer regulation. For this purpose, miR-21 expression was quantified in a panel of colorectal cancer cell lines and clinical specimens. High expression was found in cell lines with EMT properties and in the vast majority of human tumor specimens. We demonstrate in a cell-specific manner the occupancy of MIR-21 gene promoter by AP-1 and ETS1 transcription factors and, for the first time, the pattern of histone posttranslational modifications necessary for miR-21 overexpression. We also show that Integrin-ß4 (ITGß4), exclusively expressed in polarized epithelial cells, is a novel miR-21 target gene and plays a role in the regulation of EMT, since it is remarkably de-repressed after transient miR-21 silencing and downregulated after miR-21 overexpression. miR-21-dependent change of ITGß4 expression significantly affects cell migration properties of colon cancer cells. Finally, in a subgroup of tumor specimens, ROC curve analysis performed on quantitative PCR data sets for miR-21, ITGß4, and PDCD4 shows that the combination of high miR-21 with low ITGß4 and PDCD4 expression is able to predict presence of metastasis. In conclusion, miR-21 is a key player in oncogenic EMT, its overexpression is controlled by the cooperation of genetic and epigenetic alterations, and its levels, along with ITGß4 and PDCD4 expression, could be exploited as a prognostic tool for CRC metastasis.
Asunto(s)
Proteínas Reguladoras de la Apoptosis/metabolismo , Neoplasias Colorrectales/genética , Epigénesis Genética , Redes Reguladoras de Genes , Integrina beta4/genética , MicroARNs/genética , Proteínas de Unión al ARN/metabolismo , Biomarcadores de Tumor/metabolismo , Línea Celular Tumoral , Neoplasias Colorrectales/metabolismo , Neoplasias Colorrectales/patología , Transición Epitelial-Mesenquimal , Histonas/metabolismo , Humanos , Integrina beta4/metabolismo , MicroARNs/metabolismo , Metástasis de la Neoplasia , Procesamiento Proteico-Postraduccional , Proteína Proto-Oncogénica c-ets-1/metabolismo , Factor de Transcripción AP-1/metabolismoRESUMEN
BACKGROUND: The aim of this retrospective study was to analyze the results of incisional hernia laparoscopic and open surgery, focusing on the morbidity and postoperative implications. MATERIALS AND METHODS: A group of 106 (42 men, 64 women) patients suffering from incisional hernias were treated with either a laparoscopic (30) or an open (76) placement of a prosthetic mesh between January 1997 and December 2004. The age and gender of the patients, the size and type of the mesh, operation note, the length of postoperative hospital stay, and morbidity were recorded. RESULTS: An expanded polytetrafluoroethylene (ePTFE) mesh was used in 103 patients, whereas a polypropylene mesh was used in 3 patients. In the open technique, 3 patients with the ePTFE prosthetic material developed a mesh infection and required a mesh removal, which was easily performed under local anesthesia. Moreover, 2 patients from the same group developed a hernia recurrence. As for the laparoscopic approach, the only complication observed was one hernia recurrence. Finally, it should be mentioned that 1 patient with a polypropylene mesh developed a colocutaneous fistula. CONCLUSIONS: The benefits of the laparoscopic mesh technique, compared to the open technique, include a shorter hospital stay, less postoperative pain, and possibly, a reduction in wound and mesh complications. Regarding the recurrence rate, the two techniques show similar results.