Dataset Information

Somatic targeted mutation profiling of colorectal cancer precursor lesions.

ABSTRACT:

Background

Most colorectal cancers (CRC) arise from precursor lesions. This study aimed to characterize the mutation profile of colorectal cancer precursor lesions in a Brazilian population.

Methods

In total, 90 formalin-fixed paraffin-embedded colorectal precursor lesions, including 67 adenomas, 7 sessile serrated lesions, and 16 hyperplastic polyps, were analyzed by next-generation sequencing using a panel of 50 oncogenes and tumor suppressor genes. The genetic ancestry of the patients was estimated.

Results

Somatic driver mutations were identified in 66.7% of cases, including alterations in APC (32.2%), TP53 (20.0%), KRAS (18.9%), BRAF (13.3%) and EGFR (7.8%). Adenomas displayed a higher number of mutations, mainly in APC, compared to serrated polyps (73.1% vs. 47.8%, p = 0.026). Advanced adenomas had a significantly higher frequency of mutation in KRAS and a high overall mutation rate than early adenomas (92.9% vs. 59%, p = 0.006). A high degree of ancestry admixture was observed in the population studied, with a predominance of European components (mean of 73%) followed by African (mean of 11.3%). No association between genetic ancestry and type of lesions was found. The mutation profile of Brazilian colorectal precursor lesions exhibits alteration in APC, KRAS, TP53, and BRAF at different frequencies according to lesion type.

Conclusions

These results bestow the knowledge of CRC's biologic history and support the potential of these biomarkers for precursor lesions detection in CRC screening of the Brazilian population.

SUBMITTER: Dos Santos W

PROVIDER: S-EPMC9238170 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BACKGROUND:Circulating microRNAs (miRNAs) are emerging as promising biomarkers for cancer. The objective of the current study was to investigate the potential of circulating cell-free miRNAs as biomarkers for colorectal cancer (CRC) and its precursor lesion, colorectal adenoma. METHODS:The serum levels of 800 miRNAs were assessed in a discovery set of 21 patients with CRC, 19 patients with adenoma, and 21 healthy controls using the NanoString miRNA analysis platform. Significantly differentially expressed miRNAs were examined further in a validation cohort of 34 patients with CRC, 33 patients with adenoma, and 35 healthy controls using Fluidigm quantitative polymerase chain reaction assays. RESULTS:The ratios between the expression values of the differentially expressed miRNAs were computed. Three miRNA ratios (miR-17-5p/miR-135b, miR-92a-3p/miR135b, and miR-451a/miR-491-5p) were validated for discriminating patients with adenoma and those with CRC from the healthy control group, and 5 miRNA ratios (let-7b/miR-367-3p, miR-130a-3p/miR-409-3p, miR-148-3p/miR-27b, miR-148a-3p/miR-409-3p, and miR-21-5p/miR-367-3p) were validated for discriminating patients with CRC from those with adenoma and healthy controls. The area under the receiver operating characteristic curve values for the 3 miRNA ratios in discriminating patients with adenoma from healthy controls were 0.831 and 0.735, respectively, in the discovery and validation sets. The area under the receiver operating characteristic curve values for the 5 miRNA ratios in discriminating patients with CRC from those with adenoma were 0.797 and 0.732, respectively, in the discovery and validation sets. Pathway analysis revealed that target genes regulated by the miRNAs from the miRNA ratios were enriched mainly in metabolism-related and inflammation-related pathways. CONCLUSIONS:The data from the current study suggest that circulating miRNAs can distinguish patients with CRC and those with adenoma and may represent novel biomarkers for the early, noninvasive detection of CRC. Cancer 2018;124:785-96. © 2017 American Cancer Society.