Cost-effective low-coverage whole-genome sequencing assay for the risk stratification of gastric cancer

Li-Ping Ye; Xin-Li Mao; Xian-Bin Zhou; Yi Wang; Shi-Wen Xu; Sai-Qin He; Zi-Liang Qian; Xiao-Gang Zhang; Li-Juan Zhai; Jin-Bang Peng; Bin-Bin Gu; Xiu-Xiu Jin; Ya-Qi Song; Shao-Wei Li

doi:10.4251/wjgo.v14.i3.690

Cost-effective low-coverage whole-genome sequencing assay for the risk stratification of gastric cancer

World J Gastrointest Oncol. 2022 Mar 15;14(3):690-702. doi: 10.4251/wjgo.v14.i3.690.

Authors

Li-Ping Ye¹, Xin-Li Mao¹, Xian-Bin Zhou¹, Yi Wang¹, Shi-Wen Xu², Sai-Qin He¹, Zi-Liang Qian³, Xiao-Gang Zhang⁴, Li-Juan Zhai⁵, Jin-Bang Peng¹, Bin-Bin Gu¹, Xiu-Xiu Jin¹, Ya-Qi Song⁶, Shao-Wei Li¹

Affiliations

¹ Key Laboratory of Minimally Invasive Techniques & Rapid Rehabilitation of Digestive System Tumor of Zhejiang Province, Taizhou Hospital of Zhejiang Province Affiliated to Wenzhou Medical University, Linhai 317000, Zhejiang Province, China.
² Taizhou Hospital of Zhejiang Province, Wenzhou Medical University, Linhai 317000, Zhejiang Province, China.
³ Suzhou Hongyuan Biotech Inc., Suzhou 215000, Zhejiang Province, China.
⁴ Catcher Bio Inc., Hangzhou 310000, Zhejiang Province, China.
⁵ Department of Medicine, Catcher Bio Inc., Hangzhou 310000, Zhejiang Province, China.
⁶ Taizhou Hospital of Zhejiang Province, Zhejiang University School of Medicine, Linhai 317000, Zhejiang Province, China.

Abstract

Background: Gastric cancer (GC), a multifactorial disease, is caused by pathogens, such as Helicobacter pylori (H. pylori) and Epstein-Barr virus (EBV), and genetic components.

Aim: To investigate microbiomes and host genome instability by cost-effective, low-coverage whole-genome sequencing, as biomarkers for GC subtyping.

Methods: Samples from 40 GC patients were collected from Taizhou Hospital, Zhejiang Province, affiliated with Wenzhou Medical University. DNA from the samples was subjected to low-coverage whole-genome sequencing with a median genome coverage of 1.86 × (range: 1.03 × to 3.17 ×) by Illumina × 10, followed by copy number analyses using a customized bioinformatics workflow ultrasensitive chromosomal aneuploidy detector.

Results: Of the 40 GC samples, 20 (50%) were found to be enriched with microbiomes. EBV DNA was detected in 5 GC patients (12.5%). H. pylori DNA was found in 15 (37.5%) patients. The other 20 (50%) patients were found to have relatively higher genomic instability. Copy number amplifications of the oncogenes, ERBB2 and KRAS, were found in 9 (22.5%) and 7 (17.5%) of the GC samples, respectively. EBV enrichment was found to be associated with tumors in the gastric cardia and fundus. H. pylori enrichment was found to be associated with tumors in the pylorus and antrum. Tumors with elevated genomic instability showed no localization and could be observed in any location. Additionally, H. pylori-enriched GC was found to be associated with the Borrmann type II/III and gastritis history. EBV-enriched GC was not associated with gastritis. No statistically significant correlation was observed between genomic instability and gastritis. Furthermore, these three different molecular subtypes showed distinct survival outcomes (P = 0.019). EBV-positive tumors had the best prognosis, whereas patients with high genomic instability (CIN+) showed the worst survival. Patients with H. pylori infection showed intermediate prognosis compared with the other two subtypes.

Conclusion: Thus, using low-coverage whole-genome sequencing, GC can be classified into three categories based on disease etiology; this classification may prove useful for GC diagnosis and precision medicine.

Keywords: Epstein-Barr virus infections; Gastric cancer; Genetic components; Helicobacter pylori infections; Precision medicine; Whole-genome sequencing.