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Purpose: The miRNA-regulating enzymes Dicer and Drosha exhibit aberrant expression in several cancer types. Dicer and Drosha play a crucial role during the angiogenetic process in vitro and, for Dicer, in vivo. We aimed to investigate the potential role of Dicer and Drosha in predicting response to Bevacizumab-based therapy in advanced colorectal cancer (CRC) patients., Methods: Dicer and Drosha mRNA levels were analysed in formalin-fixed paraffin-embedded specimens from patients affected by advanced CRC treated with or without Bevacizumab-containing regimens (n=116 and n=50, respectively) and from patients with diverticulosis as control group (n=20). The experimental data were obtained using qRT-PCR, analysed comparing Dicer and Drosha expression levels in tumour samples versus normal mucosa and then compared to clinical outcome., Results: The tumour samples from Bevacizumab-treated patients showed a significantly higher Drosha expression (P<.001) versus normal mucosa, while Dicer levels did not differ. Intriguingly, we found that low Dicer levels predicted a longer progression-free survival (PFS) (P<.0001) and overall survival (OS) (P=.009). In addition, low Dicer levels were associated with better response to Bevacizumab-based treatments versus high Dicer levels (1.7% complete responses and 53.4% partial responses versus 0% and 32.7%, respectively; P=.0067). Multivariate analysis identified three independent predictors of improved OS: high performance status (PS) (relative risk (RR) 1.45; P=.011), lower organs involvement (RR 0.79; P=.034) and low Dicer expression (RR 0.71; P=.008). Conversely, Drosha levels were not associated with prognosis and outcome associated with treatment. In non-Bevacizumab-treated patients, Dicer and Drosha expression did not correlate with outcome., Conclusion: These findings suggest that low Dicer mRNA levels seem to be independent predictors of favourable outcome and response in patients affected by advanced CRCs treated with Bevacizumab-based therapy., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Epigenetic alterations, such as CpG islands methylation and histone modifications, are recognized key characteristics of cancer. Glycogenes are a group of genes which epigenetic status was found to be changed in several tumors. In this study, we determined promoter methylation status of the glycogene beta-1,4-galactosyltransferase 1 (B4GALT1) in colorectal cancer patients. Methylation status of B4GALT1 was assessed in 130 colorectal adenocarcinomas, 13 adenomas, and in paired normal tissue using quantitative methylation specific PCR (QMSP). B4GALT1 mRNA expression was evaluated in methylated/unmethylated tumor and normal specimens. We also investigated microsatellite stability and microsatellite instability status and KRAS/BRAF mutations. Discriminatory power of QMSP was assessed by receiving operating curve (ROC) analysis on a training set of 24 colorectal cancers and paired mucosa. The area under the ROC curve (AUC) was 0.737 (95% confidence interval [CI]:0.591-0.881, P = 0.005) with an optimal cutoff value of 2.07 yielding a 54% sensitivity (95% CI: 35.1%-72.1%) and a specificity of 91.7% (95% CI: 74.1%-97.7%). These results were confirmed in an independent validation set where B4GALT1 methylation was detected in 52/106 patients. An inverse correlation was observed between methylation and B4GALT1 mRNA expression levels (r = -0.482, P = 0.037). Significant differences in methylation levels and frequencies was demonstrated in invasive lesions as compared with normal mucosa (P = 0.0001) and in carcinoma samples as compared with adenoma (P = 0.009). B4GALT1 methylation is a frequent and specific event in colorectal cancer and correlates with downregulation of mRNA expression. These results suggest that the glycogene B4GALT1 represent a valuable candidate biomarker of invasive phenotype of colorectal cancer., (Copyright © 2012 Wiley Periodicals, Inc.)

PML regulates a wide range of pathways involved in tumorigenesis, such as apoptosis, which is also one of the main mechanisms through which oxaliplatin and fluoropyrimidine exert their antineoplastic activity. The present study aims to investigate PML expression as a predictive factor of oxaliplatin/fluoropyrimidine therapy efficacy. Seventy-four metastatic colorectal cancer patients who received oxaliplatin/floropyrimidine-based first line therapy have been included in this retrospective study. PML expression was assessed by immunohistochemistry. PML down-regulation was detected in 39 (52.7%) patients (14 complete and 25 partial PML loss). RR was significantly lower (25.6%) in patients with PML down-regulation than in patients with preserved PML expression (60%) (P = 0.006). Median TTP was 5.5 months when PML was down-regulated versus 11.9 months in case of preserved PML expression (P < 0.0001). A statistical significant difference was also detected in OS (15.6 and 24.5 months, respectively, P = 0.003). The impact of PML down-regulation on TTP and OS was statistically significant also in a multivariate model. This study represents the first evidence of a possible correlation between PML protein expression and outcome of metastatic colorectal cancer patients treated with oxaliplatin/fluoropyrimidine-based first line therapy., (Copyright © 2011 Wiley Periodicals, Inc.)