Genome Sequencing of Four Gastric Biopsies Flags Shared Gene Annotations in H. pylori Infection

Researchers have carried out an exploratory whole-genome sequencing analysis of gastric biopsy samples from four adults infected with cagA-positive Helicobacter pylori, describing shared genomic annotations rather than testing any disease association. The study, published in Molecular Biology Reports, examined specimens from patients with different documented clinical and histological findings, including active gastritis, normal histology with positive H. pylori screening assays, gastric ulcer, and intestinal-type adenocarcinoma. The sequencing was performed using paired-end reads of 2 × 151 base pairs, achieving an approximate mean mappable depth of 37.7×.

Rather than focusing on individual patient histories, the team compiled variant-associated gene sets across the samples and asked which biological terms and pathways appeared repeatedly when those gene sets were annotated against standard databases. Annotation relied on over-representation analysis using three widely used collections: KEGG, Reactome, and Gene Ontology. Within each analysis, significance was assessed with Benjamini–Hochberg correction to control the false discovery rate.

The authors then took the unusual step of auditing the term-level outputs themselves, checking for denominator consistency, gene-family representation, and overlapping membership between terms, an approach intended to make the descriptive results traceable and reproducible. Across six analysis sets and five annotation collections, the study identified 141 statistically significant term occurrences, which collapsed into 94 distinct database–term pairs once duplicates and overlapping definitions were accounted for. This consolidation highlights how heavily annotated gene sets can produce redundant pathway signals, particularly when large gene families dominate the input lists.

One finding illustrates that problem directly. The intersection of significant-term contributors from three principal analysis sets contained 133 genes, of which 124 were olfactory-receptor genes. From the remaining signals, the researchers selected three genes for literature-informed discussion: COL3A1, which encodes a collagen chain involved in extracellular-matrix structure; ICAM1, an adhesion molecule implicated in inflammatory responses; and COLEC12, a collectin family member.

These choices reflect the study's framing around sustained inflammation, stromal responses, and extracellular-matrix remodeling in H. pylori-associated gastric disease. Variant-level inspection of the displayed alleles showed that five of six had global frequencies above 20% in the gnomAD genome database, indicating they are common in the general population. The exception was ICAM1 rs542476616, which is rare globally.

The authors emphasize that no association between these variants and any clinical category was tested, and that the four specimens came from unrelated adults with different documented findings. The study's conclusions are deliberately restrained. The recurrence of COL3A1, ICAM1, and COLEC12 across the annotation analyses does not establish diagnostic performance or a disease-associated variant effect, and the design explicitly avoids inferring within-patient progression from the different clinical categories represented.

The four-sample scope means the observations are descriptive by construction. What the work does offer is a transparent, term-level accounting of shared genomic annotations in cagA-positive gastric biopsies, together with a demonstration of how annotation artifacts can be identified and reported. The authors position the three highlighted genes as candidates motivating further genotype-confirmed and clinically adjudicated investigation, rather than as markers of disease.

For researchers studying H. pylori-associated gastric pathology, the analysis provides a documented starting point for larger, adequately powered studies that can test whether these genomic signals hold any clinical meaning.

Subject of Research: Whole-genome sequencing of cagA-positive Helicobacter pylori-associated gastric biopsies

Article Title: Exploratory whole-genome sequencing of cagA-positive Helicobacter pylori-associated gastric biopsies: descriptive observations in COL3A1, ICAM1, and COLEC12

Article References: Dhyaee, N. A. H., & Mahmood, S. S. (2026). Exploratory whole-genome sequencing of cagA-positive Helicobacter pylori-associated gastric biopsies: descriptive observations in COL3A1, ICAM1, and COLEC12. Molecular Biology Reports, 53(1), 1831. https://doi.org/10.1007/s11033-026-13032-x

Image Credits: AI Generated

DOI: 10.1007/s11033-026-13032-x

Keywords: Helicobacter pylori, whole-genome sequencing, gastric biopsy, COL3A1, ICAM1, COLEC12, gene ontology, over-representation analysis, gastric adenocarcinoma, gastritis, variant annotation, cagA