Analysis of the Clinicopathological Characteristics of Stage I–III Colorectal Cancer Patients Deficient in Mismatch Repair Proteins

e15607 Background: Colorectal cancer is one of the most common malignancies worldwide. Approximately 85% of colorectal cancers are thought to result from adenoma. However, the molecular mechanism of adenoma transformation into colorectal cancer is still unclear. Methods: Ninety-nine adenoma patients aged from 25 to 78 years old were enrolled in this study. We collected tissue sample from each patient and 77 matched blood samples. Pathological subtypes included tubular villous adenomas, villous adenomas, tubular adenomas, high-grade intraepithelial neoplasia, and polyps. Eighty-one stage I colorectal cancer patients (CRC I) were also enrolled in this study. All samples underwent Next-generation sequencing with a panel of 405 cancer related genes. Results: Mutational profiles of adenoma and CRC I patients were compared. The top 5 most frequently mutated genes in adenoma were APC (71%), KRAS (41%), ATM (33%), RIF1 (31%), SYNE1 (28%). While in CRC I patients, top 5 mutated genes were APC (78%), TP53 (57%), TTN (35%), KRAS (33%) and TCF7L2 (22%). There were significant differences between TP53 and TTN by chi-square test. The frequency, number and TMB of mutations in stage I colorectal cancer patients were significantly higher than those in various adenoma subtypes. Stage I colorectal cancer patients have more mutated genes enriched in the Wnt and Notch pathways than adenoma patients. We analyzed mutation signatures in CRC I and adenoma patients, and CRC I were more focused on mutation signatures of mismatch repair such as signature 1, signature 6, signature 10, and signature 15. A total of 391 mutations were identified in tissue samples, while 130 mutations were found in plasma cell-free DNA, with 116 mutations shared between them. The two genes with the highest consistency between tissue and blood were PAX7 and KMT2D. Conclusions: TP53 and TTN are associated with the transition from CRC I to adenoma, and Wnt and Notch pathways may also be involved. PAX7 and KMT2D mutations frequently found in adenoma tissue and blood cfDNA demonstrate the diagnostic potential of these two genes in clinic.

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HER2 and BRAF mutation in colorectal cancer patients: a retrospective study in Eastern China

PeerJ ◽

10.7717/peerj.8602 ◽

2020 ◽

Vol 8 ◽

pp. e8602 ◽

Cited By ~ 1

Author(s):

Xiangyan Zhang ◽

Jie Wu ◽

Lili Wang ◽

Han Zhao ◽

Hong Li ◽

...

Keyword(s):

Colorectal Cancer ◽

Eastern China ◽

Growth Factor Receptor ◽

Disease Free Survival ◽

Molecular Classification ◽

Clinicopathological Characteristics ◽

Stage I ◽

Chinese Patients ◽

Poor Differentiation ◽

Colorectal Cancer Patients

Objective To investigate the frequency and prognostic role of the human epidermal growth factor receptor 2 gene (HER2) and BRAF V600E gene mutation in Chinese patients with colorectal cancer (CRC). Methods Clinicopathological and survival information from 480 patients with stage I–III CRC were reviewed and recorded. HER2 amplification was analyzed by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), BRAF V600E mutation was tested by IHC and Sanger sequencing. The relationship between HER2 and BRAF V600E mutation status and clinicopathological characteristics and outcomes were determined. Results The amplification of HER2 and BRAF V600E mutation were identified in 27 of 480 (5.63%) and 19 of 480 (3.96%) CRC patients, respectively. HER2 amplification significantly correlated with greater bowel wall invasion (P = 0.041) and more advanced TNM stage (I vs. II vs. III; 0 vs 5.78% vs. 7.41%, P = 0.013). Patients suffering from tumors with poor differentiation had a higher incidence rate of BRAF V600E mutation than those with moderate/well differentiation (7.77% vs 2.92%, P = 0.04). HER2 amplification was an independent prognostic factor for worse disease-free survival (DFS) (HR = 2.53, 95% CI: 1.21–5.30, P = 0.014). Conclusion The prevalence of HER2 amplification and BRAF V600E mutation in stage I–III CRC patients in Chinese was 6% and 4%, respectively, and HER2 amplification appeared to be associated with a worse DFS. More comprehensive molecular classification and survival analysis are needed to validate our findings.

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