No abstract

Highlights An internal hernia after retroperitoneal laparoscopic nephrectomy is rare. Retroperitoneal approach has the risk of making mesocolic defects directly. To prevent internal hernia, we should close the mesenteric defects intraoperatively.

In the original article, Akihiko Kawahara's first name is incorrect. It is correct as reflected here.

Microsatellite instability (MSI) and tumor mutational burden (TMB) are indicators of the tumor mutational load, which can lead to immune cell recruitment. By contrast, the number of tumor-infiltrating T cells (TITs) is indicative of the host immune response to tumor cells. The present study evaluated if the expression of mismatch repair (MMR) proteins can be used as a precise tool to assess immunogenicity in the tumor microenvironment. A total of 73 colorectal cancer cases were enrolled in the present study. MMR protein expression was assessed using four-antibodies immunohistochemistry (IHC) targeting MLH1, MSH2, MSH6 and PMS2. TIT was assessed through IHC by counting CD3 + and CD8 + cells in tumor. The enrolled cases were classified into four groups according to MMR and TIT status i) Mismatch repair-proficient (pMMR) and a high number of TITs (pMMR/TIT-H); ii) pMMR and a low number of TITs (pMMR/TIT-L); iii) mismatch repair-deficient (dMMR) and TIT-H (dMMR/TIT-H); and iv) dMMR/TIT-L]. The present study evaluated the clinicopathological characteristics of the four groups, in addition to the difference of TMB. TMB analysis was counted the number of the somatic mutations through multi-genes panel using next-generation sequencing. Clinicopathological characteristics, including age, sex, pathological depth of invasion and lymph node metastasis, were not found to be statistically different between dMMR/TIT-H and dMMR/TIT-L groups. Tumors among pMMR/TIT-H group were associated with poorly differentiation compared with those in pMMR/TIT-L group (P=0.025). The median TMB among the dMMR/TIT-H group was the highest in four groups but the median TMB was <10 muts/Mb in dMMR/TIT-L, pMMR/TIT-H and pMMR/TIT-L groups, respectively. However, one tumor in the pMMR/TIT-H group showed high TMB. The present findings suggest that assessing MMR status alone may not be sufficient to precisely evaluate the antitumor immune response in the tumor microenvironment.

Signet ring cell carcinoma (SRCC) is a rare pathological type of colorectal cancer, of which the clinicopathological features and genetic background have not yet been fully investigated. Previous research has focused on the optimization of colorectal cancer treatment utilizing consensus molecular subtyping (CMS). However, it is not known what type of CMS would be designated to SRCC treatment. In the current study, of 1,350 patients diagnosed with colorectal cancer who underwent surgery, 14 were diagnosed with SRCC. The case-control cohort that fit the clinical background of the SRCC case was constructed. Statistical comparison between the SRCC group and the case-control cohort was performed among clinicopathological variables. SRCC and well to moderately adenocarcinoma case mRNA were submitted to microarray analysis and CMS analysis. Compared with the case-control cohort, the SRCC group was located more in the right-sided colon, the lymphatic invasion was more severe and the peritoneal dissemination was more frequent. The cancer-specific survival and the progression-free survival were significantly worse in the SRCC group compared with the case-control cohort. Microarray and CMS analysis identified that one SRCC case was significantly well assigned in the CMS 4 group and the other case was assigned in the CMS 1 group. Gene set analysis revealed the upregulation of EMT related genes and the downregulation of fatty acid, glycolysis, differentiation, MYC, HNF4A, DNA repair genes. In conclusion, the clinical characteristics of SRCC are severe but there is a possibility of the presence of different phenotypes according to CMS analysis.