Objective: In patients with Helicobacter pylori-negative gastric mucosa-associated lymphoid tissue (MALT) lymphoma, eradication therapy is only effective in some cases, suggesting that infections with non-H. pylori Helicobacter (NHPH) species may also be involved. Therefore, we examined the prevalence of infection with Helicobacter suis, an NHPH, in gastric MALT lymphoma patients.

Methods: We examined the H. suis infection status of 15 patients with H. pylori-negative gastric MALT lymphoma. To examine the infection prevalence through species-specific PCR analysis, DNA was extracted from the lymphoma lesion and the background gastric mucosa. We compared the PCR products amplified from DNA extracted from different lesions.

Results: H. suis was detected in 3 of the 15 cases (20.0%), but only in the background gastric mucosa and not in the lymphoma lesion. H. suis was completely eradicated in all three cases and two of the three cases exhibited complete remission of the lymphoma.

Conclusion: These results indicated that H. suis infection may be involved in the pathogenesis of gastric MALT lymphoma. We conclude that it is desirable to use multiple biopsies, including the background mucosa, to evaluate NHPH infection in gastric MALT lymphoma patients.

Efforts to identify biomarkers for neuroblastoma (NB) have been ongoing, but no definite biomarker has been identified in peripheral blood. We proposed the use of plasma exosomal miRNAs as biomarkers of unfavorable NB patient outcomes. Exosomal miRNAs isolated from 31 plasma and 37 tissue samples, many from the same NB patients, were sequenced using a next-generation sequencing instrument. We analyzed the correlation between miRNA expression levels in plasma and tissue samples with International Neuroblastoma Risk Group staging system (INRGSS) outcome and MYCN status. We chose differentially expressed miRNAs with similar expression patterns in plasma and tissue samples in each of the three analysis groups and combined those miRNAs to find the optimal combination with the potential to be considered as a biomarker. MicroRNA-92a-3p was found to be significantly upregulated in deceased patients (p = 0.017), miR-375 was upregulated in INRGSS stage M patients (p = 0.002), and plasma miR-92a-3p and miR-99a-5 levels were upregulated in patients with MYCN amplification (p = 0.007 and 0.006). The combination of miR-92a-3p, miR-375, and miR-99a-5p levels was shown to be a statistically significant predictor of NB patient outcomes (AUC = 0.726, p = 0.001, 95% CI = 0.612–0.841, sensitivity = 77%, specificity = 56.7%). Thus, the combination of miR-92a3p, miR-375, and miR-99a-5p may potentially be used as a biomarker for unfavorable NB patient outcomes. However, further validation is required in a larger number of NB patients.

Background: Streptococcus gallolyticus ssp. pasteurianus is a commensal bacterium of the alimentary tract in humans and animals. This microorganism not only causes sepsis, endocarditis, and meningitis but is also associated with colorectal tumors. We report herein a rare case of S. gallolyticus ssp. pasteurianus bacteremia in a patient with concomitant colon cancer and aggressive malignant lymphoma during the neutropenic period after chemotherapy against lymphoma.

Case presentation: A 79-year-old man was found to have an adenoma in the ascending colon, and endoscopic mucosal resection (EMR) was planned to remove the lesion. However, he was diagnosed with diffuse large B-cell lymphoma during the pre-operation examination. The EMR was postponed, and he received rituximab, cyclophosphamide, etoposide, vincristine, and prednisolone (R-CEOP). He had a neutropenic fever with positive blood cultures for S. gallolyticus ssp. pasteurianus during the first course of R-CEOP. He improved as soon as cefepime was administered. Bacteremia did not recur thereafter, and he underwent EMR after completing six cycles of R-CEOP. The histological diagnosis of the colon tumor was well-differentiated adenocarcinoma in adenoma. Streptococcus gallolyticus ssp. pasteurianus was not detected in the culture of the resected tissue.

Conclusion: Although there have been few reports of bloodstream infection due to S. gallolyticus ssp. pasteurianus in patients with hematological malignancies undergoing cytotoxic chemotherapy, physicians should investigate the presence of coexisting colorectal tumors when this bacterium is isolated from blood cultures.