microRNAs (miRNAs) have been proposed as promising molecular biomarkers for diagnosis, prognosis, and responsive therapeutic targets in different types of cancer, including colorectal cancer (CRC). In this study, we evaluated the expression levels of 84 cancer-associated miRNAs in a cohort of 39 human samples comprising 13 peritumoral and 26 tumoral tissues from surgical specimens of CRC patients. KRAS mutations were detected in 11 tumoral samples. In a first analysis, we found 5 miRNAs (miR-215-5p, miR-9-5p, miR-138-5p, miR378a-3p, and miR-150-5p) that were significantly downregulated and one upregulated (miR-135b-5p) in tumoral tissues compared with the peritumoral tissues. Furthermore, by comparing miRNA profile between KRAS mutated CRC tissues respect to wild type CRC tissues, we found 7 miRNA (miR-27b-3p, miR-191-5p, miR-let7d-5p, miR-15b-5p, miR-98-5p, miR-10a-5p, and miR-149-5p) downregulated in KRAS mutated condition. In conclusion, we have identified a panel of miRNAs that specifically distinguish CRC tissues from peritumoral tissue and a different set of miRNAs specific for CRC with KRAS mutations. These findings may contribute to the discovering of new molecular biomarkers with clinic relevance and might shed light on novel molecular aspects of CRC.

中文翻译：

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基于miRNA的KRAS突变和野生型结直肠癌的分子标记：一项探索性研究。

microRNA（miRNA）已被提出作为在包括结直肠癌（CRC）在内的不同类型癌症中的诊断，预后和响应性治疗靶标的有前途的分子生物标记。在这项研究中，我们评估了39例人类样本中84种与癌症相关的miRNA的表达水平，这些样本包括CRC患者手术标本中的13种肿瘤周围组织和26种肿瘤组织。在11个肿瘤样本中检测到KRAS突变。在首次分析中，我们发现5个miRNA（miR-215-5p，miR-9-5p，miR-138-5p，miR378a-3p和miR-150-5p）被显着下调，而一个被上调（miR-135b） -5p）与肿瘤周围组织相比。此外，通过比较KRAS之间的miRNA图谱突变的CRC组织相对于野生型CRC组织，我们发现了7个miRNA（miR-27b-3p，miR-191-5p，miR-let7d-5p，miR-15b-5p，miR-98-5p，miR-10a-5p和miR-149-5p）在KRAS突变的条件下下调。总而言之，我们已经鉴定出一组专门区分肿瘤周围组织和CRC组织的miRNA，以及一组特定的具有KRAS突变的CRC特异的miRNA 。这些发现可能有助于发现与临床相关的新分子生物标志物，并可能为CRC的新分子方面提供启示。