Evidence map›Paper›PMID 40892238›Full record

ArticleVirchows Archiv : an international journal of pathology2026

Immunohistochemical "null" pattern of all four mismatch repair proteins in Lynch syndrome-associated small bowel adenocarcinoma: a case report and comprehensive genomic profiling.

Satoko Kageyama, Masayuki Ota, Takanori Aihara, Kaito Nakama, Jun-Ichiro Ikeda

Abstract readCase Reports
PubMed Full text at PMC Publisher
In one paragraph

Article in Virchows Archiv : an international journal of pathology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors.

Satoko KageyamaDepartment of Diagnostic Pathology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-Ku, Chiba, Japan.
Masayuki OtaDepartment of Diagnostic Pathology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-Ku, Chiba, Japan. masaota@chiba-u.jp.ORCID http://orcid.org/0000-0001-6837-7312
Takanori AiharaDepartment of Pathology, Chiba University Hospital, 1-8-1 Inohana, Chuo-Ku, Chiba, Japan.
Kaito NakamaDepartment of Diagnostic Pathology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-Ku, Chiba, Japan.
Jun-Ichiro IkedaDepartment of Diagnostic Pathology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-Ku, Chiba, Japan.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Immunohistochemistry for mismatch repair (MMR) proteins is important for evaluating the molecular background of MMR-deficient tumors, including those with Lynch syndrome (LS). The four major MMR proteins function as heterodimers (MLH1/PMS2 and MSH2/MSH6), and usually only one of the MMR subsystems is impaired. However, rare cases of concurrent immunohistochemical loss of all four MMR proteins, termed "null" phenotype, have been reported. We present the first reported case of small bowel adenocarcinoma (SBA) showing a null-phenotype. A 62-year-old man developed jejunal cancer. Immunohistochemical analysis showed complete loss of all four MMR proteins in the entire tumor. Genetic testing revealed LS with a germline pathogenic variant in MSH2, and somatic mutations in MSH2 and MLH1 were also detected. No BRAF V600E mutation was found. Combined with comprehensive cancer genomic profiling, this report provides insight into an exceptional MMR-deficient tumor and SBA, a relatively rare disease given its surface area.

Indexed as

AdenocarcinomaBiomarkers, TumorColorectal Neoplasms, Hereditary NonpolyposisDNA Mismatch RepairJejunal NeoplasmsMutL Protein Homolog 1MutS Homolog 2 ProteinDNA-Binding ProteinsHumansImmunohistochemistryMaleMiddle AgedMismatch Repair Endonuclease PMS2PhenotypeBiomarkers, TumorDNA-Binding ProteinsG-T mismatch-binding proteinMismatch Repair Endonuclease PMS2MLH1 protein, humanMSH2 protein, humanMutL Protein Homolog 1MutS Homolog 2 ProteinPMS2 protein, humanImmunohistochemistryJejunumLynch syndromeMismatch repair proteinNull-phenotypeSmall bowel adenocarcinoma

Identifiers

PMID40892238
PMCPMC13477455

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.