Kouki Otsuka

Ten‐year experience of totally laparoscopic liver resection in a single institution

Recent developments in liver surgery include the introduction of laparoscopic liver resection. The aim of the present study was to review a single institutions 10‐year experience of totally laparoscopic liver resection (TLLR).

Tumor budding at the invasive front of colorectal cancer may not be associated with the epithelial-mesenchymal transition

Tumor budding is thought to reflect the epithelial-mesenchymal transition (EMT). However, the molecular mechanism linking tumor buds and the EMT remains unclear. Here, we examined the induction of tumor budding and EMT and their association with EMT-related proteins (ZEB1, TWIST, SNAIL, and SLUG) in colorectal cancer (CRC). Immunohistochemical expression of pan-cytokeratin was examined for identification of tumor budding in 101 CRCs. Grading of tumor budding was classified into low- and high-grade groups. Tissue microarray was conducted to identify tumor budding sites. The expression of E-cadherin, ZEB1, TWIST, SNAIL, and SLUG was examined in areas of tumor budding and the surrounding tumor stroma using a double-immunostaining method. Specifically, pan-cytokeratin and EMT-related proteins were assessed by double immunostaining. Low or no expression of E-cadherin was found in areas of tumor budding. Moreover, ZEB1, TWIST, SNAIL, and SLUG were not expressed in regions of tumor budding. However, the expression level of ZEB1 in the stromal cells surrounding tumor budding was significantly more frequent than that of TWIST, SNAI, and SLUG. In addition, the expression of EMT-related proteins in surrounding stromal cells was significantly greater in areas of high-grade tumor budding than in low-grade areas. Our present results suggest that EMT-related proteins play a minor role in forming tumor buds. In addition, our findings suggest the existence of subtypes of stromal cells in CRC with phenotypical and functional heterogeneity.

Molecular differences in the microsatellite stable phenotype between left-sided and right-sided colorectal cancer

Differences in the pathogenesis of microsatellite stable (MSS) sporadic colorectal cancers (CRCs) between left‐sided CRC (LC) and right‐sided CRC (RC) have not been clarified. To identify pathogenesis‐related genomic differences between MSS CRCs within the two locations, we performed a comprehensive molecular analysis using crypt isolation with samples from 92 sporadic CRCs. Microsatellite instability (MSI; high and low/negative) and DNA methylation status (low methylation epigenome; intermediate methylation epigenome [IME] or high methylation epigenome [HME]) were determined using polymerase chain reaction (PCR) microsatellite analysis and PCR‐bisulfite pyrosequencing, respectively. Additionally, mutations in the TP53, KRAS, BRAF and PIK3CA genes were examined using PCR‐bisulfite pyrosequencing (for KRAS and BRAF mutations) or PCR‐single conformation polymorphism (for TP53 and PIK3CA mutations), followed by sequencing of aberrant bands. Finally, a genome‐wide study using a copy number alteration (CNA)‐targeted single nucleotide polymorphism array was performed. Ninety‐two CRCs were classified into 71 MSS and 21 MSI phenotypes. We examined 71 CRCs with the MSS phenotype (LC, 56; RC, 15). Mutations in KRAS were associated with RC with the MSS phenotype, whereas mutations in TP53 were more frequently found in LC with the MSS phenotype. There were significant differences in the frequencies of KRAS and TP53 mutations in the IME between LC and RC with the MSS phenotype. Although CNA gains were associated with LC with the MSS phenotype, CNA losses were not major alterations associated with the MSS phenotype. These findings suggested that the molecular pathogenesis of the MSS phenotype in LC was different from that in RC.

Vascular Invasion and Stromal S100A4 Expression at the Invasive Front of Colorectal Cancer are Novel Determinants and Tumor Prognostic Markers

Object: The aim of the present study was to investigate the clinicopathological characteristics and prognostic factors associated with sporadic colorectal cancer (CRC). We examined the clinicopathological findings and immunohistochemical expression of tumor prognostic markers at tumor budding sites to determine their predictive value for patient prognosis. Materials and Methods: Immunohistochemical examination was performed by tissue microarray (TMA) of specimens from 106 patients with CRC. On hematoxylin and eosin (H&E)-stained tumor tissue slides, a representative area of tumor budding at the invasive front was selected for the construction of a TMA. Immunostaining for matrix metalloproteinase-7 (MMP7), the laminin-5 (ln-5) γ2 chain and S100A4 was performed to determine the association between patient survival and these markers. Results: Clinicopathological variables were also assessed. Tumor location, histological type, degree of lymphatic invasion and vascular invasion, tumor stage, epithelial expression of S100A4, stromal cell expression of S100A4 and expression of the ln-5γ2 chain were associated with an increased risk of mortality. Five factors were retained in the multivariate logistic regression analysis. Specifically, the tumor location, degree of lymphatic invasion and vascular invasion, tumor stage and stromal cell expression of S100A4 remained significant predictors of patient survival after controlling for the other variables. Conclusion: Vascular invasion and stromal expression of S100A4 in the tumor budding areas correlated with patient survival. Stromal immunostaining of S100A4 may be useful for identifying high-risk patients with advanced CRC.

Analysis of the DNA methylation level of cancer-related genes in colorectal cancer and the surrounding normal mucosa

BackgroundTwo molecular pathways promote the development of colorectal cancer (CRC). One is termed “microsatellite stable” (MSS) whereas the other is characterized by “microsatellite instability” (MSI or MIN). In addition, the CpG island methylation phenotype is known to be an important alteration as a third molecular type. Thus, DNA methylation is thought to provide potential biomarkers for assessment of cancer risk in normal mucosa. In addition, it is also known that colonic location is an important parameter in the development of CRC.MethodsWe examined the surrounding normal mucosa in three parts of the colon. Next, we quantified DNA methylation levels of SFRP1, SFRP2, SFRP5, DKK2, DKK3, mir34b/c, RASSF1A, IGFBP7, CDKN2A, and MLH1 in isolated cancerous glands and crypts of normal colorectal mucosa adjacent to CRCs using a pyrosequencer.ResultsDNA methylation levels of SFRP1, SFRP2, DKK2, and mir34b/c were significantly higher in CRCs with an MSS phenotype than in those with an MSI phenotype. The average level of methylation in normal crypts did not decrease with the distance from the tumor, irrespective of microsatellite status or the tumor location. DNA methylation levels in SFRP1 and SFRP2 genes in normal crypts were significantly higher in left-side than right-side CRC with an MSS phenotype. Finally, the genes were classified into three types based on the methylation frequencies in normal crypts, including type I (SFRP1 and SFRP2I), type II (DKK2 and mir34b/c), and type III (others).ConclusionsOur results showed that DNA methylation of SFRP1 and SFRP2 might be useful to predict cancer risk of surrounding normal mucosa. In addition, a field effect may be present in CRC, affecting both adjacent and non-adjacent normal mucosa.

Molecular profiling and genome-wide analysis based on somatic copy number alterations in advanced colorectal cancers

To characterize somatic alterations in colorectal cancer (CRC), we conducted a genome‐scale analysis of 106 CRC specimens. We assessed comprehensive somatic copy number alterations (SCNAs) in these CRC specimens. In addition, we examined microsatellite instability (MSI; low and high), genetic mutations (KRAS, BRAF, TP53, and PIK3CA), and DNA methylation status (classified into low, intermediate, and high type). We stratified molecular alterations in the CRCs using a hierarchical cluster analysis. The examined CRCs could be categorized into three subgroups using hierarchical cluster analysis. Tumors in subgroup 1 were characterized by a low frequency of SCNAs and a high frequency of MSI‐high status, whereas tumors in subgroups 2 and 3 were closely associated with a high frequency of SCNAs. Tumors in subgroup 1 were preferentially present in the right‐sided colon and showed frequent MSI‐high status. Subgroup 3 was distinguished by specific alterations, including gains at 1q23‐44, 1p11‐36, 10q11‐26, 10p11‐13, 12q24‐24, and 13q33‐33. In contrast, tumors in subgroup 2 were characterized by copy‐neutral LOH at 12p12‐13, 1q24‐25, and 10q22. In addition, KRAS mutations were more frequently found in subgroup 3 than in subgroup 1. TP53 mutations and intermediate levels of DNA methylation were common alterations in the three subgroups. SCNAs contributed to sporadic CRC, and there were three subgroups based on SCNAs that played a different role in driving the development of this disease.

Comprehensive molecular analysis based on somatic copy number alterations in intramucosal colorectal neoplasias and early invasive colorectal cancers

It is unclear whether somatic copy number alterations (SCNAs) contribute to the development of colorectal cancer (CRC). Here, we aimed to identify the molecular profiles of early colorectal carcinogenesis based on SCNAs and determine the associations of other molecular abnormalities for the detection of neoplasia in both intramucosal neoplasia (IMN) and invasive CRC with invasion into the muscular layer without metastasis (early invasive CRC). A single nucleotide polymorphism array was used to examine 100 colorectal IMNs (low-grade adenoma [LGA], 40; high-grade adenoma [HGA], 25; intramucosal adenocarcinoma [IMA], 35) and early invasive CRC (20 tumors). In addition, genetic mutations (KRAS, BRAF), TP53 overexpression, microsatellite instability (MSI), and DNA methylation (low, intermediate, high) were examined. Hierarchical clustering analysis based on the SCNA pattern was carried out to identify molecular profiles in IMNs and early invasive CRC. Colorectal tumors were classified into three subgroups based on SCNA patterns. Subgroup 1 was characterized by multiple SCNAs, subgroup 3 was closely associated with infrequent SCNAs, and subgroup 2 was an intermediate subgroup in SCNA pattern between subgroups 1 and 3. Although mutations in KRAS were commonly found in all three subgroups, overexpression of TP53 was observed primarily in subgroup 1 and 2. DNA methylation showed a low/intermediate type. Finally, no MSI was detected. Each subgroup was correlated with histology (subgroup 1, early invasive CRC; subgroup 2, LGA; subgroups 2 and 3, HGA and IMA). Considerable SCNAs may be required for acquisition of invasive ability in CRC. Our results provide novel insights into early CRC.

Gastrointestinal: Idiopathic myointimal hyperplasia of mesenteric veins: Gastrointestinal: Idiopathic myointimal hyperplasia of mesenteric veins

A 68-year-old man was referred to our institution because of persisting constipation, mucous stool, and abdominal fullness in December 2016. Colonoscopy and abdominal computed tomography at the referring hospital revealed an edematous change in the left colon and increase in the fat density of the left-side mesentery. The patient was thus diagnosed as mesenteric panniculitis, and prednisolone at a dose of 50 mg/day was started. However, his symptoms did not improve. On admission, he had mild anemia (hemoglobin 10.5 g/dL), hypoproteinemia (total protein 5.6 g/dL and albumin 3.0 g/dL), and elevated C-reactive protein (2.92 mg/dL). Barium enema revealed tubular narrowing with thumbprinting in the descending and sigmoid colon (Fig. 1a). Colonoscopy showed circumferential and segmental ulcer with luminal narrowing (Fig. 1b,c). These findings suggested that the patient had been suffering from chronic venous ischemic disease, such as idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) or mesenteric inflammatory veno-occlusive disease. He underwent a left hemi-colectomy with Hartmann’s procedure. Macroscopically, the resected specimen showed a segmental ulcer with severe stenosis and contraction in the left side of the colon (Fig. 2a). Histologically, there were veins of markedly thickened wall without inflammatory cell infiltrates in the submucosa and in the subserosa (Fig. 2b). Elastica-Masson staining revealed that the venous intimal layer was characterized by hyperplasia of the elastic fiber and fibrous tissue (Fig. 2c), together with deposition of mucopolysaccharide identified by Alcian blue staining (Fig. 2d). We thus made a final diagnosis of IMHMV. Idiopathic myointimal hyperplasia of mesenteric veins is a venous ischemic disease primarily affecting the mesenteric vein by intimal thickening. Most of the reported cases were previously healthy men, and the disease affected the left side of the large bowel. Because the main symptoms were chronic abdominal pain, diarrhea, and bloody stools, cases of IMHMV had been misdiagnosed as inflammatory bowel disease. It has also been reported that IMHMV is refractory to medical treatment, and it frequently requires surgical resection of the affected large bowel. We believe that IMHMV should be one of the differential diagnoses for cases of chronic and stenosing colitis of obscure origin.

Laparoscopy-assisted appendectomy through an umbilical port in children.

Introduction: We report surgical techniques for single‐incision laparoscopy‐assisted surgery (SILAS) in the treatment of pediatric acute appendicitis.

Effect of Preoperative Methylprednisolone Administration on Coagulation and Fibrinolytic Status in Patients Undergoing Esophageal Cancer Surgery.

食道癌術後には過大侵襲により凝固亢進状態が生じ術後合併症, 臓器障害の発生に関与することが知られている. 食道癌術後凝固線溶系に対するメチルプレドニゾロン (MP) 術前投与の効果を検討する目的で胸部食道癌20例を対象として, MP10mg/kg投与群10例 (MP群), 対照群10例 (C群) を無作為に割り付け検討を行った. 術後C群では血小板数の低下, APTTの延長, AT-III, Plgの低下と凝固亢進, 線溶抑制状態を認めたが, MP群ではAPTTの延長とAT-IIIおよびPlgの低下が有意に抑制されていた. IL-6, CRP, 尿中NAGはMP群で有意に低値で推移し, 人工呼吸期間, SIRS期間も短縮していた. 食道癌手術侵襲に対する術後凝固亢進状態はMP術前投与により制御可能であり, 凝固線溶系上からも術後臓器障害および手術侵襲の軽減に関与するものと考えられた.