A novel embryo biopsy morphological analysis and genetic integrality criterion system significantly improves the outcome of preimplantation genetic testing.

PURPOSE: While efforts have been made to establish blastocyst grading systems in the past decades, little research has examined the quality of biopsy specimens. This study is the first to correlate the morphology of biopsied trophectoderm (TE) cells to their quality and subsequent genetic testing results of preimplantation genetic testing (PGT), through an innovative Morphological Analysis and Genetic Integrality Criterion (MAGIC) system. METHODS: Biopsied TE cells were first evaluated according to the MAGIC procedure, followed by whole-genome amplification (WGA) and library construction, and then sequenced using the Illumina X Ten Platform. Copy number variation (CNV) and allele drop-out (ADO) rates as well as test failure rates were compared and analyzed. RESULTS: Our data explores the relationship between TE cell morphology and its quality and final genetic testing outcome, which is established based on the MAGIC system. MAGIC guarantees that only high- or good-quality TE cells are used for genetic testing to generate excellent data uniformity and lower ADO rates. Low-quality cells containing biopsied TE cell mass are responsible for the "background noise" of CNV analysis. CONCLUSION: The MAGIC application has effectively decreased the false-positive mosaicism, hence to ensure the stability and veracity of detection results, to avoid misdiagnoses, and to improve accuracy, as well as to avoid re-biopsy procedures. The study also contributes to understand how the IVF laboratory and the molecular biology laboratory depend on each other to achieve good-quality PGT results, which are clinically relevant for the patients.

Efficacy of Preoperative Biopsy in Predicting the Newly Proposed Histologic Grade of Resected Lung Adenocarcinoma.

A novel histologic grading system for invasive lung adenocarcinomas (LUAD) has been newly proposed and adopted by the World Health Organization (WHO) classification. We aimed to evaluate the concordance of newly established grades between preoperative biopsy and surgically resected LUAD samples. Additionally, factors affecting the concordance rate and its prognostic impact were also analyzed. In this study, surgically resected specimens of 222 patients with invasive LUAD and their preoperative biopsies collected between January 2013 and December 2020 were used. We determined the histologic subtypes of preoperative biopsy and surgically resected specimens and classified them separately according to the novel WHO grading system. The overall concordance rate of the novel WHO grades between preoperative biopsy and surgically resected samples was 81.5%, which was higher than that of the predominant subtype. When stratified by grades, the concordance rate of grades 1 (well-differentiated, 84.2%) and 3 (poorly differentiated, 89.1%) was found to be superior compared to grade 2 (moderately differentiated, 66.2%). Overall, the concordance rate was not significantly different from biopsy characteristics, including the number of biopsy samples, biopsy sample size, and tumor area size. On the other hand, the concordance rate of grades 1 and 2 was significantly higher in tumors with smaller invasive diameters, and that of grade 3 was significantly higher in tumors with larger invasive diameters. Preoperative biopsy specimens can predict the novel WHO grades, especially grades 1 and 3 of surgically resected specimens, more accurately than the former grading system, regardless of preoperative biopsy or clinicopathologic characteristics.

The risk of essential fatty acid insufficiency in patients with inflammatory bowel diseases: fatty acid profile of phospholipids in serum and in colon biopsy specimen.

Introduction: The aim of the study was to address the fatty acid (FA) status and its relationship with disease activity in patients with inflammatory bowel disease (IBD). Methods: FA levels of the phospholipid fraction in serum and a colon biopsy specimen were measured in 17 patients with IBD. Results: A negative correlation between the histological activity of inflammation of the disease and the ratio of polyunsaturated FAs/no polyunsaturated FAs was observed. Moreover, the level of that ratio was lower in patients with IBDs as compared to controls. Conclusions: The FA profile in serum and in a colon biopsy specimen in patients with IBD is characteristic for essential fatty acid insufficiency.

Diagnostic Utility of the PD-L1 Immunostaining in Biopsy Specimens of Patients with Biliary Tract Neoplasms.

BACKGROUND: Anti-programmed death 1/programmed death ligand 1 (PD1/PD-L1) antibodies have been successfully used as treatment agents for several solid tumors; however, it is difficult to predict their effectiveness. We evaluated whether biopsy specimens could predict the positive status of PD-L1 in surgically resected tissue. METHODS: Among 91 patients who underwent tissue sampling with endoscopic or liver biopsy before surgery for biliary tract neoplasms in an academic center, 45 (49%) patients were selected for retrospective analysis because the quality and quantity of their biopsy specimens were adequate for histologic evaluation. We performed immunohistochemical staining to investigate the PD-L1 expression in both resected and biopsy specimens. The percentage of the positively stained cells was calculated for subsequent use in the correlation investigation. RESULTS: The biopsy methods were endoscopic retrograde cholangiopancreatography (ERCP) in 28 cases, percutaneous liver biopsy in 10 cases, and endoscopic ultrasound fine-needle aspiration in 7 cases. Among the 45 patients, when patients with > 10% positive tumor cells in surgically resected tissues were regarded as truly positive PD-L1, the positive and negative concordance rates between surgically resected tissues and biopsy samples were 56% (5/9) and 100% (36/36), respectively. With regard to the use of preoperative biopsy as a diagnostic tool, all (5/5) PD-L1-positive patients had a positive resected specimen. The accuracy of each biopsy method was as follows: ERCP, 89% (25/28); fine-needle aspiration, 86% (6/7); and liver biopsy, 100% (10/10). CONCLUSIONS: Biopsy samples could be a surrogate material for the assessment of the PD-L1 expression with substantial positive and high negative concordance rates.

Immunohistochemical investigation of cytokine expression levels as biomarkers in transrectal ultrasound-guided needle biopsy specimens of prostate adenocarcinoma.

Cytokines influence the biological behaviour of prostate cancer (PC) and may influence patient outcome and serve as useful prognostic biomarkers. The aim of the present study was to evaluate cytokine expression levels in prostatic needle biopsy specimens and the association with clinicopathological characteristics of patients with PC. A total of 18 patients with PC who underwent transrectal ultrasound (TRUS) guided prostate biopsy were included in the clinical study. These patients were naïve to radiotherapy (RT) or androgen deprivation therapy prior to TRUS biopsy and clinical follow up data was collected. Cytokine expression levels were analysed by using immunohistochemistry and Spearman's correlation test was used to determine the correlation between cytokine expression and clinicopathological characteristics. Expression levels of pro-inflammatory TNF-α and IL-6 decreased as Gleason score (GS) increased; however, a statistically significant difference was not detected. A statically significant correlation was observed between needle biopsy specimen and pre-RT plasma sample expression levels of pro-inflammatory TNF-α and IL-6 (P=0.01 and P=0.05, respectively) and anti-inflammatory TGF-ß1 (P=0.05). However, further studies are needed to confirm these results using a larger sample size to confirm the prognostic value of pro-inflammatory TNF-α and IL-6 and anti-inflammatory TGF-ß1 in patients with PC.

Implementation of a Novel Web-Based Lesion Selection Tool to Improve Acquisition of Tumor Biopsy Specimens.

Introduction: For maximum utility of molecular characterization by next-generation sequencing (NGS) and better understanding of tumor microenvironment with immune correlates analysis, biopsy specimens must yield adequate tumor tissue, and sequential biopsy specimens should sample a consistent site. We developed a web-based lesion selection tool (LST) that enables management and tracking of the biopsy specimen collections. Methods: Of 145 patients, the LST was used for 88 patients; the other 57 served as controls. We evaluated consistency of the lesion biopsied in longitudinal collections, number of cores obtained, and cores with adequate tumor cellularity for NGS. The Fisher exact test and Wilcoxon rank sum test were used to identify differences between the groups. Results: The analysis included 30 of 88 (34%) patients in the LST group and 52 of 57 (91%) in the control group. The LST workflow ensured 100% consistency in the lesions biopsied compared with 75% in the control group in longitudinal collections and increased the proportion of patients in whom at least five cores were collected per biopsy. Conclusions: The novel LST platform facilitates coordination, performance, and management of longitudinal biopsy specimens. Use of the LST enables sampling of the designated lesion consistently, which is likely to accurately inform us the effect of the treatment on tumor microenvironment and evolution of resistant pathways. Such studies are important translational component of any clinical trials and research as they guide the development of next line of therapy, which has significant effect on clinical utility. However, validation of this approach in a larger study is warranted.

Deconvolution Tactics and Normalization in Renal Spatial Transcriptomics.

The kidney is composed of heterogeneous groups of epithelial, endothelial, immune, and stromal cells, all in close anatomic proximity. Spatial transcriptomic technologies allow the interrogation of in situ expression signatures in health and disease, overlaid upon a histologic image. However, some spatial gene expression platforms have not yet reached single-cell resolution. As such, deconvolution of spatial transcriptomic spots is important to understand the proportion of cell signature arising from these varied cell types in each spot. This article reviews the various deconvolution strategies discussed in the 2021 Indiana O'Brien Center for Microscopy workshop. The unique features of Seurat transfer score methodology, SPOTlight, Robust Cell Type Decomposition, and BayesSpace are reviewed. The application of normalization and batch effect correction across spatial transcriptomic samples is also discussed.

Significance of mesothelin expression in preoperative endoscopic biopsy specimens for colorectal cancer prognosis.

Mesothelin (MSLN) is a cell surface glycoprotein that is normally expressed in the mesothelial cells but highly expressed in several malignant tumors, where the high expression is generally associated with poor prognosis. In this work, 512 patients with stage III colorectal cancer (CRC) were examined to ascertain the prognostic value of MSLN expression in preoperative endoscopic biopsy specimens. MSLN expression was evaluated by immunohistochemical staining. The tumor cells were MSLN-positive in 61 of the 512 patients (11.9%). MSLN expression was associated with a shorter disease-specific survival (DSS) period (5-year DSS = 68.7%, P = 0.0008). Besides, by multivariate analysis, MSLN expression was identified to be a marker of poor prognosis by multivariate analysis (P = 0.0033, hazard ratio (HR) = 2.31) as well as macroscopic type (P = 0.047, HR = 1.82) among the factors that can be evaluated preoperatively. MSLN-positive patients had a significantly poorer prognosis regardless of adjuvant chemotherapy administration (P = 0.0081 and P = 0.0018 for surgery alone and chemotherapy, respectively). MSLN-positive patients in the adjuvant chemotherapy group exhibited a significantly lower risk of recurrence when compared with those in the surgery alone group (P = 0.0090). In conclusion, high MSLN expression observed in preoperative endoscopic biopsy specimens of stage III CRC was an independent poor prognostic factor. Preoperative evaluation of MSLN by immunohistochemical staining might be applied to select individuals for intensive preoperative chemotherapy among the stage III CRC patients.

Heterogeneous programmed death-ligand 1 expression in gastric cancer: comparison of tissue microarrays and whole sections.

BACKGROUND: Programmed death-ligand 1 (PD-L1) expression determines the eligibility for anti-PD-1 treatment in patients with advanced gastric cancer, but evidence indicates that PD-L1 staining is heterogeneous. Patients who are ineligible for radical surgery could be tested for PD-L1 expression with biopsy staining, but it is unclear if a small biopsy is representative of the PD-L1 status of the whole tumor. The aim of our study was to determine how many biopsy specimens are needed to accurately reflect the objective status of PD-L1 expression in whole sections. METHODS: We built tissue microarrays (TMAs) as substitutes for core biopsies, collecting 6 cores per case from 152 gastric cancer specimens. All of the slides and TMAs underwent PD-L1 immunohistochemical staining, and PD-L1 expression in at least 1% of tumor cells or immune cells was defined as positive. RESULTS: It was necessary to randomly select multiple cores from TMAs to reach a suitable agreement rate (> 90%) and Cohen's κ value (> 0.8) between TMAs and whole sections. We defined the PD-L1 staining status from the whole section as the standard. The evaluation of five randomly selected cores from TMAs agreed well with the evaluation of whole sections. The sensitivity, specificity and the area under the curve (AUC) of the receiver-operating characteristic (ROC) were 0.93, 0.92, and 0.922 (95% confidence interval (CI) 0.863-0.982), respectively. CONCLUSIONS: We conclude that PD-L1 expression among TMA samples had different degrees of relevance to the corresponding surgical specimens, which indicates that at least five biopsies might be necessary to characterize patients taking anti-PD-1 treatment.

Intraepithelial CD163+ macrophages in tongue leukoplakia biopsy: A promising tool for cancer screening.

OBJECTIVE: Oral leukoplakia has mixed and differing histopathological features, and it is thus difficult to reach an accurate histological diagnosis of oral leukoplakia based on a local biopsy alone. We recently demonstrated the significance of CD163+ macrophages in oral carcinogenesis. Herein we sought to determine whether CD163+ macrophages in biopsy specimens of oral leukoplakia help identify the overall histological nature of the lesion. PATIENTS AND METHODS: Twenty-six patients with tongue leukoplakia who underwent a histological examination by both a preoperative local biopsy and consecutive total excision were enrolled. We evaluated clinicopathological factors and the expression of CD163+ macrophages based on a retrospective comparison of the histological diagnostic concordance between the biopsies and excisions. RESULTS: Seventeen patients (diagnostic-agreement group) were diagnosed with squamous intraepithelial lesion based on both the biopsy and the excision. Nine patients (diagnostic-discrepancy group) were diagnosed with invasive cancer by excision, although invasive cancer was not observed in their biopsy specimens. Compared to the diagnostic-agreement group, the diagnostic-discrepancy group had more tongue leukoplakia with non-homogenous or high numbers of intraepithelial CD163+ macrophages. CONCLUSION: The evaluation of intraepithelial CD163+ macrophages in local biopsy specimens from tongue leukoplakia patients is a promising tool for cancer screening.

[Application of tissue-marking dyes for pathologic examination of surgical and autopsy specimens]. / Primenenie markirovochnykh krasitelei pri patologo-anatomicheskom issledovanii operatsionnogo materiala.

OBJECTIVE: To assess the applicability of imported tissue-marking dyes and the samples of experimental dyes and decorative acrylic paints to mark the resection margins of a surgical specimen. MATERIAL AND METHODS: Three sets of tissue-marking dyes: 2 imported sets and 1 experimental set, each containing red, orange, yellow, green, blue, purple, and black dyes, and a set of decorative acrylic paints containing black, blue, light blue, green, yellow, ocher, orange, magenta, and purple dyes. The experimental dyes and imported ones were used to mark tonsillar fragments obtained at tonsillectomy. The set of experimental dyes and that of decorative acrylic paints were used to stain the fragments of autopsy specimens (the skeletal muscles, pancreas, and large bowel). The tissues obtained at autopsy were marked before and after fixation in 40% formalin for 30 min and 24 hours. The specimens were subjected to standard tissue processing. Paraffin blocks were cut into 5-µm sections that were stained with hematoxylin and eosin. To estimate resection margin marking, each specimen was examined by 7 researchers who independently assessed the covering ability of a dye and its color in the paraffin block and microslides. RESULTS: All researchers correctly identified purple, black, and green colors from the three sets of dyes in the surgical tonsillar specimen. When examining the autopsy specimens, all the experts correctly recognized magenta and green decorative acrylic paints and black and blue experimental dyes. The time of fixation and the type of tissue did not affect the color of a dye in the paraffin block and tissue specimen. CONCLUSION: Some of experimental dyes and decorative acrylic paints are highly competitive with imported tissue-marking dyes in their characteristics, are correctly recognized in the block and tissue specimen under a microscope, and can be proposed to mark the resection margins of the examined tissues.

Vitamin D Receptor Level in Biopsy Specimen of Patients with Ulcerative Colitis: Results from a Center in Western Anatolia.

BACKGROUND: Ulcerative colitis (UC) is a chronic, inflammatory bowel diseases characterized by uncontrolled inflammatory condition of the colon and rectal mucosa marked by recurrent periods of remission and exacerbation. Vitamin D receptor (VDR) is a member of the steroid receptor family that mediates the effects of vitamin D by regulating transcription of multiple cellular genes. We aimed to evaluate vitamin d receptor level in biopsy specimen of patients with UC in this study. METHODS: VDR levels were retrospectively studied in colon biopsy specimens of UC patients. The Spearman's rho correlation analysis, The Kolmogorov-Smirnov, Mann Whitney U, and chi-square tests were used for statistical analysis. The p values below 0.05 were considered statistically significant. RESULTS: Study included 112 UC patients (65 male and 47 female) and 30 controls (19 female and 11 male) who had normal results in biopsy examinations carried out due to various reasons. VDR levels of UC patients were statistically lower than control subjects, and was not associated with duration of the disease and place of involvement. CONCLUSIONS: VDR is an important receptor in the pathogenesis of UC, and optimizing vitamin D levels could have a therapeutic role in UC.

Histological and ultrastructural evaluation of human decellularized matrix as a hernia repair device.

Recently, interest has been increasing for human decellularized matrices, due to their ability to reduce numerous side effects related to hernia repair. To date, only animal studies investigated the biological interaction post-implant of human decellularized matrices for soft tissue repair. Therefore, the aim of this study was to evaluate the morphological response one year post implant of human decellularized matrix, through morphological analysis of human biopsies. The histological and ultrastructural results revealed a perfect cellular repopulation and neoangiogenesis, with minimal inflammatory response and a well-organized collagen matrix. The results have indicated that this scaffold can be an effective treatment for hernia.

CT-guided aspiration lung biopsy for EGFR and ALK gene mutation analysis of lung cancer.

The present study investigated the rates of detection and the positive rates of computed tomography (CT)-guided aspiration of lung biopsy for epidermal growth factor receptor (EGFR) gene and anaplastic lymphoma kinase (ALK) gene, and analyzed the relationship between gene mutation and clinical characteristics to improve the rate of related factors of gene detection. The clinical data and CT-guided aspiration biopsy specimen of 250 patients with lung cancer. Data showed that the rate of EGFR gene mutation was 41.2% (103/250) in biopsy specimens of non-small cell lung cancer patients. The rate of EGFR gene mutation of adenocarcinoma (56.6%, P<0.01) was higher than other types of lung cancer. ALK gene mutation of patients in phase IV was obviously higher than that of patients not in phase IV (18.5 and 1.8%, P<0.01). The rate of EGFR gene detection was 83.2% (208/250). The rate of detection of tumor cells >50 was higher. The rate of ALK protein immunohistochemical detection was 87.2%, and the rate of coarse needle biopsy detection was higher than that of the fine needle (91 and 72%, P<0.01), but the positive rate between coarse needle biopsy and fine needle biopsy had no difference (P>0.05). The rate of detection was associated with tumor cell number (P<0.05), and had no correlation with the proportion of tumor cells (P>0.05). The rate of detection of EGFR and ALK genes was associated with tumor cell number and had no correlation with the proportion of tumor cells. The rate of detection is higher when the number of tumor cells is more than 50.

Element bioimaging of liver needle biopsy specimens from patients with Wilson's disease by laser ablation-inductively coupled plasma-mass spectrometry.

A laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) method is developed and applied for the analysis of paraffin-embedded liver needle biopsy specimens of patients with Wilson's disease (WD), a rare autosomal recessive disorder of the copper metabolism causing various hepatic, neurological and psychiatric symptoms due to a copper accumulation in the liver and the central nervous system. The sample set includes two WD liver samples and one negative control sample. The imaging analysis was performed with a spatial resolution of 10 µm. Besides copper, iron was monitored because an elevated iron concentration in the liver is known for WD. In addition to this, both elements were quantified using an external calibration based on matrix-matched gelatine standards. The presented method offers low limits of detection of 1 and 5 µg/g for copper and iron, respectively. The high detection power and good spatial resolution allow the analysis of small needle biopsy specimen using this method. The two analyzed WD samples can be well differentiated from the control sample due to their inhomogeneous copper distribution and high copper concentrations of up to 1200 µg/g. Interestingly, the WD samples show an inverse correlation of regions with elevated copper concentrations and regions with high iron concentrations.

Factors influencing the concordance of histological subtype diagnosis from biopsy and resected specimens of lung adenocarcinoma.

OBJECTIVES: Lung adenocarcinoma is heterogeneous, characterized by various histological subtypes. Determination of the predominant histological subtype (lepidic, papillary, acinar or solid-predominant) has been shown to correlate with genetic abnormalities and clinicopathological features. Although subtyping using small biopsy samples is important for tailored approaches to clinical management, limited data exist on the concordance of predominant subtype between resected specimens and biopsy specimens. MATERIALS AND METHODS: We compared the diagnosed predominant subtypes in resected specimens and matched biopsy specimens in a series of 327 lung adenocarcinomas. The accuracy of preoperative diagnosis by biopsy and the factors that influence concordance with resected specimen analysis were examined. RESULTS: In 211 of the 326 patients (66.0%), the predominant adenocarcinoma subtype diagnosed from biopsy matched the findings of resection analysis. Overall, the concordance rate in biopsy samples with larger tumor areas (≥ 0.7 mm(2)) was significantly higher than in those with smaller tumor area (<0.7 mm(2); 71.2% vs 60.7%, respectively; p=0.015). In the biopsy samples with smaller tumor areas, the concordance rate was 77% in lepidic subtype, 71% in papillary subtype, 60% in solid subtype, and 40% in acinar subtype. Concordance rate in the biopsy samples with larger tumor area was higher in papillary and solid subtypes (88% and 76%, respectively), but remained low in acinar subtype (37%). CONCLUSION: The current results indicate that accuracy of adenocarcinoma subtyping based on small biopsy samples is influenced by tumor area. Our study also suggests that subtyping of acinar histology using biopsy specimen is particularly error-prone.

Banff study of pathologic changes in lung allograft biopsy specimens with donor-specific antibodies.

BACKGROUND: The diagnosis of antibody-mediated rejection (AMR) in the lung transplant is still an area under investigation. We performed a blinded multicenter study to determine if any statistically significant histologic findings in transbronchial biopsy specimens from lung transplant patients correlate with the presence of donor-specific antibodies (DSAs). METHODS: We asked 9 pathologists with experience in lung transplantation to evaluate 161 lung transplant biopsy specimens for various histologic parameters. The findings were correlated with antibody status positive for DSAs, positive for non-DSAs, and no antibodies (NABs) present. The significance of each histologic variable was reviewed. RESULTS: We found no statistically significant association with acute cellular rejection, airway inflammation, or bronchiolitis obliterans and the presence or absence of antibodies. However, biopsy specimens with DSAs had a statistically significant difference vs NABs in the setting of acute lung injury, with or without diffuse alveolar damage (p = 0.0008), in the presence of capillary neutrophilic inflammation (p = 0.0014), and in samples with endotheliitis (p = 0.0155). In samples with complement 4d staining, there was a trend but no statistically significant difference between specimens associated with DSAs and specimens with NABs. CONCLUSIONS: Capillary inflammation, acute lung injury, and endotheliitis significantly correlated with DSAs. The infrequently observed diffuse staining for complement 4d limits the usefulness of this stain.

A comparison of the diagnostic efficacy in type 1 autoimmune pancreatitis based on biopsy specimens from various organs.

BACKGROUND: Comprehensive immunostaining evaluation of the biopsy specimens from various organs with type 1 autoimmune pancreatitis (AIP) has not been elucidated. Our aim was to clarify which of these biopsy specimens and counting method could be a useful tool for supporting the diagnosis of AIP. METHODS: We retrospectively evaluated biopsy specimens from pancreas (n = 19), stomach (n = 28), duodenum (n = 27), duodenal papilla (n = 25), colon (n = 19), liver (n = 11), bile duct (n = 24), and minor salivary gland (n = 13) in 36 patients with AIP. Positive IgG4 immunostaining (>10 plasma cells/high-power field [HPF]) and positive IgG4/IgG ratio (>40%) of biopsy specimens from 8 sites of 6 organs in one HPF and an average from 3 HPFs were compared between AIP and controls. RESULTS: The sensitivity of IgG4 immunostaining for AIP in one HPF were 16% in pancreas, 14% in stomach, 15% in duodenum, 52% in duodenal papilla, 11% in colon, 27% in liver, 21% in bile duct and 8% in minor salivary gland, respectively. The positive IgG4 immunostaining of the duodenal papilla in one HPF showed the highest sensitivity (52%) and accuracy (73%) among the 8 sites. It also showed the highest sensitivity among 4 different counting methods (IgG4 immunostaining in one HPF and 3 HPFs, both IgG4 immunostaining and IgG/IgG4 ratio in one HPF and 3 HPFs), but there were no significant differences with respect to specificity and accuracy. CONCLUSIONS: IgG4 immunostaining of swollen duodenal papilla with more than 10 IgG4-positive plasma cells in at least one HPF is useful for supporting the diagnosis of AIP.

Development of new PCR primers by comparative genomics for the detection of Helicobacter suis in gastric biopsy specimens.

BACKGROUND: Although the infection rate of Helicobacter suis is significantly lower than that of Helicobacter pylori, the H. suis infection is associated with a high rate of gastric mucosa-associated lymphoid tissue (MALT) lymphoma. In addition, in vitro cultivation of H. suis remains difficult, and some H. suis-infected patients show negative results on the urea breath test (UBT). MATERIALS AND METHODS: Female C57BL/6J mice were orally inoculated with mouse gastric mucosal homogenates containing H. suis strains TKY or SNTW101 isolated from a cynomolgus monkey or a patient suffering from nodular gastritis, respectively. The high-purity chromosomal DNA samples of H. suis strains TKY and SNTW101 were prepared from the infected mouse gastric mucosa. The SOLiD sequencing of two H. suis genomes enabled comparative genomics of 20 Helicobacter and 11 Campylobacter strains for the identification of the H. suis-specific nucleotide sequences. RESULTS: Oral inoculation with mouse gastric mucosal homogenates containing H. suis strains TKY and SNTW101 induced gastric MALT lymphoma and the formation of gastric lymphoid follicles, respectively, in C57BL/6J mice. Two conserved nucleotide sequences among six H. suis strains were identified and were used to design diagnostic PCR primers for the detection of H. suis. CONCLUSIONS: There was a strong association between the H. suis infection and gastric diseases in the C57BL/6 mouse model. PCR diagnosis using an H. suis-specific primer pair is a valuable method for detecting H. suis in gastric biopsy specimens.