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Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms that are usually localized in the mesothelium of soft tissues. Although SFTs of pleural origin are common, SFTs arising in the small intestine are extremely rare, and there are few reports of laparoscopic resection of these tumors. A 74-year-old woman presented to her local physician with intermittent pain in the lower abdomen. Computed tomography showed a 25 mm mass in the ileum with extramural protrusion and small intestine capsule endoscopy showed a submucosal tumor-like elevation covered by normal mucosa. The diagnosis was ileal tumor, which was removed by laparoscopic partial resection of the small intestine. Macroscopically, the tumor was found to be a substantial mass within subplasmalemmal fatty tissue that had no continuity with the muscular layer. Histological analysis showed proliferation of homogeneous spindle-shaped cells against a background of fibrous stroma. Immunostaining was positive for STAT6 and negative for KIT, Dog1, and S100, and SFT was diagnosed. The tumor was low risk according to Demicco's risk classification. In conclusion, a less invasive laparoscopic procedure is preferable if the tumor can be resected completely without applying excessive external force that results in seeding of tumor cells in the abdominal cavity.

The heterotopic submucosal gland (HSG) is a common incidental finding in gastrectomy specimens. The majority of HSGs are small incidental lesions, which are also known as gastritis cystica profunda. However, larger lesions may appear as an inverted growth of well-organized mucosa referred to as gastric inverted polyps.To determine whether genetic alterations are involved in HSG development, we analyzed 63 gastric HSG lesions using targeted next-generation sequencing and immunohistochemistry.Histologically, HSG lesions consistently had areas of pyloric gland differentiation with variable extent of foveolar differentiation. Although the background mucosa showed intestinal metaplasia in most cases (98%), intestinal-type epithelium was seen in only one HSG lesion (2%). Sequencing analysis identified activating KRAS, BRAF, CTNNB1, and GNAS mutations in 34 (54%), 1 (2%), 1 (2%), and 7 (11%) lesions, respectively. HSG lesions harboring a KRAS mutation were more likely to present extensive foveolar differentiation (P = 0.013) and absence of parietal cells (P = 0.0081). Five HSG lesions had a dysplastic component, and concordant genetic alterations were detected between the non-dysplastic and dysplastic areas of two lesions that were successfully analyzed. Immunohistochemical staining demonstrated diffuse expression of mutant KRAS protein in lesions with the most common genetic alteration, KRAS G12D.Our study demonstrated that a major proportion of HSGs were proliferative lesions associated with oncogenic mutations, with more than half of lesions harboring activating KRAS mutations.

Purpose Gastric cancer with para-aortic node (PAN) metastasis has a chance to be cured with multidisciplinary treatment of D2 and PAN dissection (PAND) following neoadjuvant chemotherapy (NAC), but its prognosis remains unsatisfactory. To establish a better multidisciplinary treatment, a better surrogate endpoint is needed. The present study focused on a pathological complete response at the PANs alone as a new surrogate endpoint and evaluated its prognostic value. Methods The study examined patients who received radical gastrectomy with D2 and PAND after NAC for gastric cancer with PAN metastasis from 2004 to 2015. The study compared five methods of evaluating the response to NAC: RECIST, clinical disappearance of PANs (cPAN), histological response of the primary tumor defined by Japanese Classification of Gastric Carcinoma (JCGC histological criteria) and Becker's criteria, and pathological disappearance of PANs (pPAN). The efficacy of these methods was compared using the hazard ratio (HR) for death between responders and non-responders. Results Thirty-two patients were analyzed. The respective HR and 5-year overall survival rates of responders and non-responders were 1.316 and 49.1% vs. 60.0% by RECIST, 1.106 and 52.9% vs. 52.5% by cPAN, 0.246 and 71.3% vs. 28.6% by JCGC histological criteria, 0.239 and 76.2% vs. 36.8% by Becker's criteria, and 0.074 and 81.0% vs. 0.0% by pPAN. Conclusions A pathological complete response at the PANs had the lowest HR and clearly differentiated the survival, suggesting it might be a good surrogate endpoint for identifying future candidates for NAC in multidisciplinary treatment for gastric cancer with PAN metastasis.

The clinical sequencing of tumors is usually performed on formalin-fixed, paraffin-embedded samples and results in many sequencing errors. We identified that most of these errors are detected in chimeric reads caused by single-strand DNA molecules with microhomology. During the end-repair step of library preparation, mutations are introduced by the mis-annealing of two single-strand DNA molecules comprising homologous sequences. The mutated bases are distributed unevenly near the ends in the individual reads. Our filtering pipeline, MicroSEC, focuses on the uneven distribution of mutations in each read and removes the sequencing errors in formalin-fixed, paraffin-embedded samples without over-eliminating the mutations detected also in fresh frozen samples. Amplicon-based sequencing using 97 mutations confirmed that the sensitivity and specificity of MicroSEC were 97% (95% confidence interval: 82–100%) and 96% (95% confidence interval: 88–99%), respectively. Our pipeline will increase the reliability of the clinical sequencing and advance the cancer research using formalin-fixed, paraffin-embedded samples., Masachika Ikegami and Shinji Kohsaka et al. develop MicroSEC, a computational pipeline to filter sequencing artifacts from archival formalin-fixed and paraffin-embedded samples. Given that archival FFPE tissue is of great interest for genomic analysis, but difficult to reliably analyze, this tool may improve the ability of researchers to probe sequencing data from these samples.

Recent studies highlighted the clinicopathological heterogeneity of non-ampullary duodenal adenomas and adenocarcinomas, but the detailed process of the malignant transformation remains unclear. We analyzed 144 adenomas and 54 adenocarcinomas of the non-ampullary duodenum for immunohistochemical phenotypes, genetic alterations, and mismatch repair (MMR) status to probe their histogenetic relationship. The median ages of patients with adenoma and adenocarcinoma were the same (66 years). Adenomas were histologically classified as intestinal-type adenoma (n = 124), pyloric gland adenoma (PGA, n = 10), gastric-type adenoma, not otherwise specified (n = 9), and foveolar-type adenoma (n = 1). Protein-truncating APC mutations were highly frequent in adenomas (85%), with the highest prevalence in intestinal-type adenomas (89%), but rare in adenocarcinomas (9%; P = 2.1 × 10–23). Close associations between phenotypic marker expression and genetic alterations were observed in adenomas, but not in adenocarcinomas, excluding the common association between GNAS mutations and MUC5AC expression. MMR deficiency was more frequent in adenocarcinomas (20%) than in adenomas (1%; P = 2.6 × 10–6). One MMR-deficient adenoma and three MMR-deficient adenocarcinomas occurred in patients with Lynch syndrome. Additionally, three other patients with an MMR-deficient adenocarcinoma fulfilled the revised Bethesda criteria. The discrepant APC mutation frequency between adenomas and adenocarcinomas suggests that APC-mutated adenomas, which constitute the large majority of non-ampullary duodenal adenomas, are less prone to malignant transformation. Non-ampullary duodenal adenocarcinomas frequently exhibit MMR deficiency and should be subject to MMR testing to determine appropriate clinical management, including the identification of patients with Lynch syndrome.

Peritoneal metastasis, a hallmark of incurable advanced gastric cancer (GC), presently has no curative therapy and its molecular features have not been examined extensively. Here we present a comprehensive multi-omic analysis of malignant ascitic fluid samples and their corresponding tumor cell lines from 98 patients, including whole-genome sequencing, RNA sequencing, DNA methylation and enhancer landscape. We identify a higher frequency of receptor tyrosine kinase and mitogen-activated protein kinase pathway alterations compared to primary GC; moreover, approximately half of the gene alterations are potentially treatable with targeted therapy. Our analyses also stratify ascites-disseminated GC into two distinct molecular subtypes: one displaying active super enhancers (SEs) at the ELF3, KLF5 and EHF loci, and a second subtype bearing transforming growth factor-β (TGF-β) pathway activation through SMAD3 SE activation and high expression of transcriptional enhancer factor TEF-1 (TEAD1). In the TGF-β subtype, inhibition of the TEAD pathway circumvents therapy resistance, suggesting a potential molecular-guided therapeutic strategy for this subtype of intractable GC. Tanaka and colleagues perform a comprehensive multi-omic characterization of peritoneal metastasis of gastric cancer to define molecular subtypes and actionable therapeutic targets.

Etoposide plus cisplatin (EP) and irinotecan plus cisplatin (IP) are commonly used as community standard regimens for advanced neuroendocrine carcinoma (NEC).To identify whether EP or IP is a more effective regimen in terms of overall survival (OS) in patients with advanced NEC of the digestive system.This open-label phase 3 randomized clinical trial enrolled chemotherapy-naive patients aged 20 to 75 years who had recurrent or unresectable NEC (according to the 2010 World Health Organization classification system) arising from the gastrointestinal tract, hepatobiliary system, or pancreas. Participants were enrolled across 50 institutions in Japan between August 8, 2014, and March 6, 2020.In the EP arm, etoposide (100 mg/m2/d on days 1, 2, and 3) and cisplatin (80 mg/m2/d on day 1) were administered every 3 weeks. In the IP arm, irinotecan (60 mg/m2/d on days 1, 8, and 15) and cisplatin (60 mg/m2/d on day 1) were administered every 4 weeks.The primary end point was OS. In total, data from 170 patients were analyzed to detect a hazard ratio (HR) of 0.67 (median OS of 8 and 12 months in inferior and superior arms, respectively) with a 2-sided α of 10% and power of 80%. The pathologic findings were centrally reviewed following treatment initiation.Among the 170 patients included (median [range] age, 64 [29-75] years; 117 [68.8%] male), median OS was 12.5 months in the EP arm and 10.9 months in the IP arm (HR, 1.04; 90% CI, 0.79-1.37; P = .80). The median progression-free survival was 5.6 (95% CI, 4.1-6.9) months in the EP arm and 5.1 (95% CI, 3.3-5.7) months in the IP arm (HR, 1.06; 95% CI, 0.78-1.45). A subgroup analysis of OS demonstrated that EP produced more favorable OS in patients with poorly differentiated NEC of pancreatic origin (HR, 4.10; 95% CI, 1.26-13.31). The common grade 3 and 4 adverse events in the EP vs IP arms were neutropenia (75 of 82 [91.5%] patients vs 44 of 82 [53.7%] patients), leukocytopenia (50 of 82 [61.0%] patients vs 25 of 82 [30.5%] patients), and febrile neutropenia (FN) (22 of 82 [26.8%] patients vs 10 of 82 [12.2%] patients). While incidence of FN was initially high in the EP arm, primary prophylactic use of granulocyte colony-stimulating factor effectively reduced the incidence of FN.Results of this randomized clinical trial demonstrate that both EP and IP remain the standard first-line chemotherapy options. Although AEs were generally manageable, grade 3 and 4 AEs were more common in the EP arm.Japan Registry of Clinical Trials: jRCTs031180005; UMIN Clinical Trials Registry: UMIN000014795.

Emergent scientific evidence indicates the central role of cancer-associated fibroblasts in determining whether the microenvironment of cancer works as friend or foe of the host; however, there is no unified histological evaluation framework of fibrotic stroma in colorectal cancers. Myxoid stroma and keloid-like collagen are site-specific histopathological features generated by cancer-associated fibroblasts, which appear exclusively in the tumor front during desmoplastic reaction. On the basis of these two stromal components, desmoplastic reaction is categorized into three patterns—immature, intermediate and mature—using hematoxylin and eosin staining. In January 2020, a prospective randomized clinical trial, JCOG1805, to elucidate the value of adjuvant chemotherapy in stage II colorectal cancer patients with pathological risk factors of recurrence was launched in Japan, in which intermediate/immature desmoplastic reaction is one of the four risk factors selected as inclusion criteria. This paper covers the diagnostic criteria for the desmoplastic reaction classification being used in the JCOG1805 study., The present article illustrates the diagnostic criteria of desmoplastic reaction classification, a novel prognostic factor in colorectal cancer, used in the JCOG1805 trial conducted by the Japan Clinical Oncology Group.

Organoids derived from epithelial tumors have recently been utilized as a preclinical model in basic and translational studies. This model is considered to represent the original tumor in terms of 3D structure, genetic and cellular heterogeneity, but not tumor microenvironment. In this study, we established organoids and paired cancer-associated fibroblasts (CAFs) from surgical specimens of colorectal carcinomas (CRCs), and evaluated gene expression profiles in organoids with and without co-culture with CAFs to assess interactions between tumor cells and CAFs in tumor tissues. We found that the expression levels of several genes, which are highly expressed in original CRC tissues, were downregulated in organoids but re-expressed in organoids by co-culturing with CAFs. They comprised immune response- and external stimulus-related genes, e.g., REG family and dual oxidases (DUOXs), which are known to have malignant functions, leading tumor cells to proliferative and/or anti-apoptotic states and drug resistant phenotypes. In addition, the degree of differential induction of REG1 and DUOX2 in the co-culture system varied depending on CAFs from each CRC case. In conclusion, the co-culture system of CRC organoids with paired CAFs was able to partially reproduce the tumor microenvironment.

Cancer chemoresistance is often attributed to the presence of cancer stem cell (CSC)-like cells, but whether they are homogeneously chemoresistant remains unclear. We previously showed that in colon tumors, a subpopulation of LGR5+ CSC-like cells driven by TCF1 (TCF7), a Wnt-responsive transcription factor, were responsible for tumorigenicity. Here we demonstrate that the tumorigenic subpopulation of mouse LGR5+ cells exists in a slow-cycling state and identify a unique 22-gene signature that characterizes these slow-cycling CSC. Seven of the signature genes are specifically expressed in slow-cycling LGR5+ cells from xenografted human colon tumors and are upregulated in colon cancer clinical specimens. Among these seven, four genes (APCDD1, NOTUM, PROX1, and SP5) are known to be direct Wnt target genes, and PROX1 was expressed in the invasive fronts of colon tumors. PROX1 was activated by TCF1 to induce CDKN1C and maintain a slow-cycling state in colon cancer organoids. Strikingly, PROX1 was required for recurrent growth after chemotherapeutic treatment, suggesting that inhibition of slow-cycling CSC by targeting the TCF1–PROX1–CDKN1C pathway is an effective strategy to combat refractory colon cancer in combination with conventional chemotherapy. Significance: These findings illustrate the importance of a slow-cycling CSC subpopulation in colon cancer development and chemoresistance, with potential implications for the identified slow-cycling CSC signatures and the TCF1–PROX1–CDKN1C pathway as therapeutic targets.

In the nationwide cancer genome screening project SCRUM‐Japan GI‐SCREEN, 2590 archival formalin‐fixed paraffin‐embedded (FFPE) tumor tissues from 19 institutions were analyzed with two tissue‐based next‐generation sequencing (NGS) panels at the Clinical Laboratory Improvement Amendments (CLIA)‐certified College of American Pathologists (CAP)‐accredited central laboratory. The Oncomine Cancer Research Panel (OCP; 143 genes) succeeded in producing validated results for only 68.3% of the samples (%OCP‐success). CE‐IVD (25 genes) succeeded in 45.9% of the OCP‐failed samples, leading to an overall NGS success (%combined‐success) rate as high as 82.9%. Among 2573 samples, the DNA‐integrity (ΔC t)‐high (ΔC t 6.3 or polymerase chain reaction‐failed, n = 409; 5.6% and 24.7%). Other factors associated with NGS success included the FFPE‐sample storage period (

Background/Aims: The accurate assessment of the depth of invasion of early gastric cancer (EGC) is critical to determine the most appropriate treatment option. However, it is difficult to distinguish shallow submucosal (SM1) invasion from deeper submucosal (SM2) invasion. We investigated the diagnostic performance of endoscopic ultrasonography (EUS) using a miniature probe for EGC with suspected SM invasion. Methods: From April 2008 to June 2018, EGCs with suspected SM invasion were analyzed retrospectively. The EGCs examined by a 20 MHz high-frequency miniature probe was included in our study. Esophago-gastric junction cancers and patients treated by chemotherapy before resection were excluded. The sensitivity and specificity for the detection of SM2 invasion by EUS were compared with those of white light imaging (WLI). Additionally, factors related to depth underestimation or overestimation were investigated using multivariate analysis. Results: A total of 278 EGCs in 259 patients were included in the final analysis. The sensitivity and specificity for SM2 or deeper by EUS were 73.7% (87/118) and 74.4% (119/160), respectively. The sensitivity and specificity by WLI were 47.5% (56/118) and 68.1% (109/160), respectively. The sensitivity of EUS was significantly superior to that of conventional endoscopy (p

Although gastric cancer is one of the Lynch syndrome (LS)-related tumors, the clinicopathological features of gastric cancer in patients with LS remain uncertain. To investigate the incidence risk and clinicopathological features of gastric neoplasms in LS, we conducted a retrospective cohort study in Japanese LS patients. LS patients with pathogenic mismatch repair (MMR) gene variants were extracted from the LS registry of the National Cancer Center Hospital, Japan. Cumulative risks of gastric neoplasm, including dysplasia and cancer, were estimated using the Kaplan–Meier method. Gastric atrophy was evaluated endoscopically and/or histologically. Immunohistochemical staining for MMR proteins was performed for all available specimens. Of 118 eligible patients, 26 patients were diagnosed with 58 gastric neoplasms. The cumulative incidence of gastric neoplasm was 41.0% (95% confidence interval, 26.9–55.0) at the age of 70. Of these, 13 (50%) patients developed synchronous and/or metachronous multiple gastric neoplasms. Among the 49 gastric neoplasms available for detailed pathological evaluation, all were associated with intestinal metaplasia. Immunohistochemically, 42 (86%) were MMR-deficient. The individuals with gastric atrophy had a significantly higher risk of developing gastric neoplasms compared with those without gastric atrophy (26 cases/54 individuals vs. 0 cases/53 individuals) (P = 0.026). LS patients, particularly those with atrophic gastritis, are at high risk of gastric neoplasm and often develop multiple tumors. Endoscopic surveillance for gastric cancer is recommended for LS patients, especially those with atrophic gastritis.

Pyloric gland adenoma (PGA) is an uncommon variant of gastric adenoma exhibiting pyloric gland/mucous neck cell differentiation. We present a sporadic PGA associated with a large fundic gland polyp (FGP) in a woman in her 40 s without Helicobacter pylori infection. The polyp, measuring 25 mm in size, was located in the middle gastric body and was removed by endoscopic submucosal dissection. Histological examination revealed three morphologically distinct components: FGP, FGP with large cysts, and PGA. A genetic analysis identified a truncating APC mutation in all the three components, supporting their histogenetic relationship. Additionally, a GNAS mutation was detected in two components, FGP with large cysts and PGA, whereas a KRAS mutation was exclusively found in the PGA component. Thus, despite the unusual presentation, the PGA component harbored prototypical genetic alterations. The differential genetic alterations observed in the three components imply that they represent stepwise progression from FGP to PGA.

Gastric cancers can develop even after Helicobacter pylori (H. pylori) eradication in 0.2–2.9% cases per year. Since H. pylori is reported to directly activate or inactivate cancer-related pathways, molecular profiles of gastric cancers with current and past H. pylori infection may be different. Here, we aimed to analyze whether profiles of point mutation and gene amplification are different between the two groups. Current or past infection by H. pylori was determined by positive or negative amplification of H. pylori jhpr3 gene by PCR, and past infection was established by the presence of endoscopic atrophy. Among the 90 gastric cancers analyzed, 55 were with current infection, and 35 were with past infection. Target sequencing of 46 cancer-related genes revealed that 47 gastric cancers had 68 point mutations of 15 different genes, such as TP53 (36%), KRAS (4%), and PIK3CA (4%) and that gene amplification was present for ERBB2, KRAS, PIK3CA, and MET among the 26 genes assessed for copy number alterations. Gastric cancers with current and past infection had similar frequencies of TP53 mutations (38% and 31%, respectively; p = 0.652) and oncogene activation (20% and 29%, respectively; p = 0.444). Gastric cancers with current and past infection had comparable profiles of genetic alterations.

Background Sebaceous carcinoma is a rare but progressive malignant skin cancer, and the incidence is approximately five times higher in post-transplant patients than in people who have not received kidney transplants. Sebaceous carcinoma is sometimes found concurrently with visceral cancers and a genetic abnormality, Muir–Torre syndrome. We report the case of a female kidney transplant recipient with sebaceous carcinoma concurrent with colon cancer 10 years after transplantation. Case presentation A 43-year-old woman was admitted due to a rapidly progressive tumor on her head. Histologically, the tumor was diagnosed as sebaceous carcinoma. We diagnosed her with Muir–Torre syndrome based on the following evidence: 1) high prevalence of microsatellite instability in gene locus assay, 2) absence of mismatch repair proteins in the sebaceous carcinoma on immunohistochemical analysis, and 3) a genetic mutation of 1226_1227delAG in the MSH2 exon 7 in the lesion detected by DNA sequencing analysis. Several reports have shown an association between immunosuppressive agents and latent Muir–Torre syndrome progression. Therefore, the progression of colon cancer in this case originated from her genetic mutation for Muir–Torre syndrome and long-term use of immunosuppressive agents. Conclusion This case report not only highlights the importance of adequate diagnosis and therapy for Muir–Torre syndrome, but also suggests the further prevention of the development of malignant tumors in kidney transplant recipients. Physicians should be mindful that sebaceous carcinoma in kidney transplant recipients is highly concurrent with Muir–Torre syndrome.

Highly accurate risk assessment of recurrence may improve adjuvant treatment practice in stage II colorectal cancer (CRC), which lacks definite prognostic factors. Recent studies indicate the importance of stroma in determining cancer behavior, although there are few histopathologic criteria for its evaluation. A pathology review of 679 stage II CRC patients (1980-2005) was conducted at an institution. Desmoplastic reaction (DR) results were classified as mature, intermediate, or immature depending on the presence of hyalinized collagen bundles and myxoid stroma observed at the extramural desmoplastic front on hematoxylin-eosin-stained slides. Pathologically, 430, 180, and 69 tumors were classified into the mature, intermediate, and immature groups, respectively. On the basis of the DR results, 5-year recurrence rate was found to have a wide range of 9.1% to 30.7%; 5-year relapse-free survival (RFS) rates were highest in the mature group (85.2%), followed by the intermediate (77.1%), and immature (60.9%) groups. Multivariate analyses revealed an independent effect of DR pattern on RFS. In addition, 446 patients treated at 4 independent institutions (2007-2008) were examined as a second cohort for result validation, revealing an adverse prognostic impact of unfavorable DR and identifying DR categorization as an independent prognostic factor. In both cohorts, Harrell's concordance index for RFS was higher than the other conventional factors in the DR including T stage. Categorizing DR pattern based on the histologic products of fibroblasts at the desmoplastic front help elucidate their important biological role in cancer development, thus providing clinically useful prognostic information regarding stage II CRC.

Superficially serrated adenoma (SuSA) is a recently proposed subtype of colorectal serrated lesion. We here report a sigmoid colon cancer derived from SuSA, which exhibited aggressive clinical behavior. Endoscopically, the tumor appeared as a superficial elevated lesion with a large nodule. Histological examination of the surgically resected material showed tubular adenocarcinoma associated with SuSA. Although tumor invasion was limited to the submucosal layer, lymph node and extranodal metastases were detected. The patient subsequently developed peritoneal metastases and died 15 months after surgery. Molecular analyses identified a KRAS mutation and a novel PRR15L-RSPO2 fusion, which retains the entire coding region of RSPO2, in both SuSA and adenocarcinoma components. The present study demonstrates the malignant potential of SuSA and expands the spectrum of RSPO fusions in colorectal neoplasms.

Next-generation sequencing (NGS) of tumor tissue (ie, clinical sequencing) can guide clinical management by providing information about actionable gene aberrations that have diagnostic and therapeutic significance. Here, we undertook a hospital-based prospective study (TOP-GEAR project, 2nd stage) to investigate the feasibility and utility of NGS-based analysis of 114 cancer-associated genes (the NCC Oncopanel test). We examined 230 cases (comprising more than 30 tumor types) of advanced solid tumors, all of which were matched with nontumor samples. Gene profiling data were obtained for 187 cases (81.3%), 111 (59.4%) of which harbored actionable gene aberrations according to the Clinical Practice Guidelines for Next Generation Sequencing in Cancer Diagnosis and Treatment (Edition 1.0) issued by 3 major Japanese cancer-related societies. Twenty-five (13.3%) cases have since received molecular-targeted therapy according to their gene aberrations. These results indicate the utility of tumor-profiling multiplex gene panel testing in a clinical setting in Japan. This study is registered with UMIN Clinical Trials Registry (UMIN 000011141).

Background: Little is known about the clinicopathological characteristics of superficial spreading-type esophageal carcinoma extending ≥5 cm along the long axis of the esophagus. This study was aimed at investigating the frequency of lymph node metastasis (LNM) in patients with superficial spreading-type esophageal carcinoma. Methods: We reviewed the data of 320 patients with superficial esophageal squamous cell carcinoma who had undergone esophagectomy with lymph node dissection at our hospital between 1986 and 2010. The incidence of LNM was compared between the spreading (≥5 cm) and nonspreading (< 5 cm) types. Results: The multivariate analysis revealed significant differences in the likelihood of LNM depending on the lymphovascular invasion, the infiltrative growth pattern (INF)-c, and the depth. There was no difference in the LNM frequency between nonspreading and spreading type in the patients with epithelium (EP)-lamina propria, muscularis mucosa (MM)-submucosa (SM)1 and SM2/3 lesions. The frequencies of LNMs (nonspreading-type vs. spreading-type tumors) in the patients with MM-SM1 lesions were 7/47 (14.9%) versus 4/25 (16%) and those in the patients with SM2/3 lesions were 22/58 (37.9%) versus 4/14 (28.9%), when the lesions did not have lymphovascular invasion and INF-c. Conclusions: Endoscopic resection can be selected for ­EP-SM1 lesions, regardless of whether the lesions are of the spreading type or nonspreading type.

Colorectal traditional serrated adenomas (TSAs) are often associated with precursor polyps, including hyperplastic polyps and sessile serrated adenoma/polyps. To elucidate the molecular mechanisms involved in the progression from precursor polyps to TSAs, the present study analyzed 15 precursor polyp-associated TSAs harboring WNT pathway gene mutations. Laser microdissection-based sequencing analysis showed that BRAF or KRAS mutations were shared between TSA and precursor polyps in all lesions. In contrast, the statuses of WNT pathway gene mutations were different between the 2 components. In 8 lesions, RNF43, APC, or CTNNB1 mutations, were exclusively present in TSA. RNF43 mutations were shared between the TSA and precursor components in 3 lesions; however, they were heterozygous in the precursor polyps whereas homozygous in the TSA. In 4 lesions with PTPRK-RSPO3 fusions, RNA in situ hybridization demonstrated that overexpression of RSPO3, reflecting PTPRK-RSPO3 fusion transcripts, was restricted to TSA components. Consistent with the results of the genetic and in situ hybridization analyses, nuclear β-catenin accumulation and MYC overexpression were restricted to the TSA component in 13 and 12 lesions, respectively. These findings indicate that the WNT pathway gene alterations are acquired during the progression from the precursor polyps to TSAs and that the activation of the WNT pathway plays a critical role in the development of TSA rather than their progression to high-grade lesions.

Aim: Depending upon the degree of DNA degradation of formalin-fixed and paraffin-embedded tissue samples, accuracy of measurement by Infinium MethylationEPIC BeadChip assay (Illumina, CA, USA) was assessed. Materials & methods: DNA quality of six formalin-fixed and paraffin-embedded lung tissue samples with different formalin fixation periods was assessed by Illumina quality control, DNA copy number and DNA integrity number value. Infinium data from restored bisulfite treated DNA were compared with datum from a fresh-frozen sample. Results: The correlation coefficient decreased from 0.993 to 0.970 depending upon DNA degradation, even if the Illumina quality control was met. Exclusion of specific probes improved the correlation regardless of tissue. Conclusion: Poor DNA quality can be assessed as an amplifiable DNA copy number and DNA integrity number value. Probe filtering has the potential to improve assay accuracy.

Introduction Patients with high-risk T1 colorectal cancer (CRC) after endoscopic resection (ER) should undergo surgery in view of the risk of lymph node metastasis. Although additional surgery can potentially prevent recurrence, there is a paucity of data and longitudinal studies exploring this potential. Hence, this study aimed to evaluate the prolonged influence of ER before additional surgery on recurrence in T1 CRC. Methods Between January 2004 and October 2015, 162 patients who underwent secondary surgery (SS) after ER ([ER + SS] group) and 392 consecutive patients with T1 CRC who underwent primary surgery at our institution were retrospectively analyzed. Recurrence was analyzed in these 2 groups. High-risk CRC patients were histologically defined according to the Japanese Society for Cancer of the Colon and Rectum guidelines (2016) for the treatment of CRC. Data were analyzed based on clinical and histological features, including lymph node metastasis, and the number of lymph nodes evaluated. Results The recurrence rate was comparable between the ER + SS and primary surgery groups, with no significant difference (P = 0.625, log-rank test). There was no significant difference in the recurrence in patients receiving adjuvant chemotherapy in both groups (7.4% vs 10.4%, P = 0.27). The difference in the mean number of lymph nodes dissected between both groups was also not significant (24.3 vs 25.3, P = 0.43). Discussion There was no significant difference in recurrence rates between patients undergoing ER before surgery and those undergoing primary surgery for high-risk T1 CRC. Hence, ER may be acceptable for high-risk T1 CRC.

Prediction of tissue origin of esophagogastric junction (EGJ) adenocarcinomas can be important for therapeutic decision, but no molecular marker is available. Here, we aimed to develop such a marker taking advantage of tissue-specific profiles of DNA methylation. DNA methylation profiles of gastric adenocarcinomas (GACs) were obtained by an Infinium HumanMethylation450 BeadChip array, and those of esophageal adenocarcinoma (EACs) were obtained from the TCGA database. DNA from formalin-fixed paraffin-embedded (FFPE) samples was analyzed by bisulfite pyrosequencing. In the screening set, 51 of 145,841 CpG sites in CpG islands were methylated at significantly higher levels in 30 GACs compared to those in 30 EACs. Among them, SLC46A3 and cg09177106 were unmethylated in all the 30 EACs. Predictive powers of these two markers were successfully confirmed in an independent validation set (18 GACs and 18 EACs) (SLC46A3, sensitivity = 77.8%, specificity = 100%; cg09177106, sensitivity = 83.3%, specificity = 94.4%), and could be applied to FFPE samples (37 GACs and 18 EACs) (SLC46A3, P = 0.0001; cg09177106, P = 0.0028). On the other hand, EAC-specific markers informative in the FFPE samples could not be isolated. Using these GAC-specific markers, nine of 46 (19.6%) TCGA EGJ adenocarcinomas were predicted to be GACs. Two GAC-specific markers, SLC46A3 and cg09177106, had a high specificity for identifying the tissue origin of EGJ adenocarcinoma.

The CpG island methylator phenotype (CIMP) is associated with prognosis and drug sensitivity in multiple cancer types. In gastric cancer, the CIMP is closely associated with Epstein-Barr virus (EBV) infection and AT-rich interactive domain 1A (ARID1A) mutations, a component of the SWI/SNF chromatin remodeling complex. However, the involvement of SWI/SNF defects in CIMP induction has been unclear. In this study, we demonstrate a causal role of ARID1A loss-of-function in CIMP induction. Mutations of SWI/SNF components, especially ARID1A, was associated with the CIMP, as well as EBV infection, in gastric cancers, and also in uterine endometrial and colorectal cancers, which are not affected by EBV infection. Genome-wide DNA methylation analysis showed that ARID1A knockout (KO) in cultured 293FT cells and gastric epithelial cells, GES1, induced aberrant DNA methylation of a substantial number of CpG sites. DNA methylation was induced at genomic regions with high levels of pre-existing histone H3 lysine 27 trimethylation (H3K27me3) and those with acquired H3K27me3 by ARID1A KO. These results showed that the ARID1A mutation induced aberrant DNA methylation, and this is likely to be one of the potential mechanisms of CIMP induction.

ALK, ROS1 and NTRK fusions are involved in the tumorigenesis of various organs, including colorectal cancer. This study aims to clarify the prevalence of these fusions in colorectal cancer in the Japanese population. Immunohistochemical analysis of 1012 specimens of colorectal cancer revealed two NTRK-positive cases (0.2%) whereas no ALK- or ROS1-positive cases were identified. Reverse transcription polymerase chain reaction (RT-PCR) detected an LMNA-NTRK1 fusion in a case of adenosquamous carcinoma and a TPM3-NTRK1 fusion in a case of tubular adenocarcinoma. Both NTRK1 fusion-positive cases lacked activating mutations in KRAS and BRAF and were mismatch repair-deficient with loss of MLH1 and PMS2 expression and MLH1 promoter methylation. Our results show that receptor tyrosine kinase fusions are rare but present in colorectal cancers in Japanese patients, with a prevalence similar to that reported in other countries.

BACKGROUND AND AIM Superficially serrated adenoma (SuSA) is a recently proposed subtype of colorectal serrated lesions. It is characterized by distinct clinicopathological and molecular features, including mixed serrated and adenomatous histology and frequent genetic alterations involving KRAS and RSPO. This study aimed to characterize the endoscopic features of isolated and traditional serrated adenoma (TSA)-associated SuSAs. METHODS We retrospectively evaluated the endoscopic findings of 25 isolated SuSAs and 21 TSA-associated SuSAs that were histologically and molecularly characterized. RESULTS SuSAs appeared as a sessile polyp or slightly elevated lesion located mostly in the sigmoid colon and rectum (88%). The size was between 3 and 20 mm (median, 6 mm). Most of them exhibited KRAS mutations (96%) and RSPO fusions/overexpression (92%). Endoscopically, many lesions had a whitish color (84%), a distinct border (96%), an irregular border (76%), and a lobulated surface (72%). However, diminutive lesions exhibited overlapping features with hyperplastic polyps. On narrow-band imaging, vessel patterns were invisible or appeared as lacy microvessels in most lesions (80%). Chromoendoscopy invariably showed stellar or elongated/branched stellar pits, indicating a serrated microarchitecture. Most TSA-associated SuSAs typically presented as polyps with a two-tier raised appearance, consisting of whitish lower and reddish higher components corresponding to a SuSA and a TSA, respectively. CONCLUSIONS SuSAs exhibit several characteristic endoscopic features on white-light and image-enhanced endoscopy. Diminutive lesions exhibit endoscopic features overlapping with hyperplastic polyps. Nonetheless, the endoscopic diagnosis of larger and TSA-associated SuSAs may be feasible.

Background Gastrointestinal stromal tumors (GIST) arising from sites other than the gastrointestinal (GI) tract, termed extra-gastrointestinal stromal tumors (EGIST), are rare. Among EGIST, those with platelet-derived growth factor receptor alpha (PDGFRA) mutations are even rarer, with only a few cases reported. About 80% of GIST has KIT mutations, and 10% of GIST have PDGFRA mutations, which commonly affect the TK2 domain (exon 18). Among the exon 18 mutations, the D842V substitution is limited to gastric GIST. In EGIST, the degree of KIT and PDGFRA mutations varies on where the location of the tumor is, and it is suggested that omental EGIST is similar to gastric GIST. Adjuvant imatinib therapy is recommended for high-risk GIST; however, it is known that imatinib is less effective against GIST with a PDGFRA D842V mutation. Case presentation A 75-year-old man was referred to our hospital with an extrinsic tumor of the lesser curvature of the gastric body. Intraoperative findings showed a tumor located outside of the lesser omentum with no connection between the tumor and the gastric wall. The tumor was subsequently resected. Pathological examination indicated a GIST arising in the lesser omentum measuring 70 mm in its longer dimension. Because the tumor had a PDGFRA mutation (D842V substitution), imatinib was suspected to lack efficacy to the tumor. Thus, although the tumor was considered clinically to have a high risk of recurrence, adjuvant imatinib therapy was not indicated. The patient has been free of recurrence for 29 months since the surgery. Conclusion We described a case of EGIST with a PDGFRA mutation arising in the lesser omentum. And we reviewed 57 cases of omental EGIST and showed that the clinicopathological characteristics and mutation status in omental EGIST were very similar to gastric GIST. In particular, PDGFAR D842V mutation rate in omental EGIST seemed as high as that in gastric GIST. These results suggested that omental EGIST is strongly related to gastric GIST, so the behavior of omental EGIST might be akin to gastric GIST. However, further studies are required to determine the prognosis and the necessity of adjuvant therapy for EGIST with a PDGFRA mutation.

Cancer-associated fibroblasts (CAFs) tend to have tumor-promoting capacity, and can provide therapeutic targets. Even without cancer cells, CAF phenotypes are stably maintained, and DNA methylation and H3K27me3 changes have been shown to be involved. Here, we searched for a potential therapeutic target in primary CAFs from gastric cancer and a mechanism for its dysregulation. Expression microarray using eight CAFs and seven non-CAFs (NCAFs) revealed that serum amyloid A1 (SAA1), which encodes an acute phase secreted protein, was second most upregulated in CAFs, following IGF2. Conditioned medium (CM) derived from SAA1-overexpressing NCAFs was shown to increase migration of gastric cancer cells compared with that from control NCAFs, and its tumor-promoting effect was comparable to that of CM from CAFs. In addition, increased migration of cancer cells by CM from CAFs was mostly canceled with CM from CAFs with SAA1 knockdown. Chromatin immunoprecipitation (ChIP)-quantitative PCR showed that CAFs had higher levels of H3K27ac, an active enhancer mark, in the promoter and the two far upstream regions of SAA1 than NCAFs. Also, BET bromodomain inhibitors, JQ1 and mivebresib, decreased SAA1 expression and tumor-promoting effects in CAFs, suggesting SAA1 upregulation by enhancer activation in CAFs. Our present data showed that SAA1 is a candidate therapeutic target from gastric CAFs and indicated that increased enhancer acetylation is important for its overexpression.

Spontaneous regression of cancer is a rare phenomenon, with 33 colorectal cancer cases reported between 1900 and 2020.1-4 Spontaneous regression is defined as the partial or complete disappearance of a tumor without treatment.1,3 Several factors may be involved in this process, including biopsy, mechanical stress, humoral factors, and infection.1,5 However, no concrete evidence for the mechanistic insights has been indicated.

Colorectal carcinogenesis in familial adenomatous polyposis (FAP) follows a conventional adenoma-carcinoma sequence. However, previous studies have also reported the occurrence of traditional serrated adenomas (TSAs) in patients with FAP. In the present study, we analyzed the clinicopathologic and molecular features of 37 TSAs from 21 FAP patients. Histologically, the majority of FAP-associated TSAs showed typical cytology and slit-like serration; however, ectopic crypt formation was infrequent. Next-generation sequencing and Sanger sequencing identified KRAS and BRAF V600E mutations in 18 (49%) and 14 (38%) TSAs, respectively. Somatic APC mutations were detected in 26 lesions (84% of analyzed cases). Three lesions had BRAF non-V600E mutations, and 2 of them had a concurrent KRAS mutation. Seven TSAs (19%) were associated with a precursor polyp, 6 with a hyperplastic polyp, and 1 with a sessile serrated lesion, and all of them showed the BRAF V600E mutation. Additional sequencing analysis of 4 TSAs with a precursor polyp showed that the BRAF V600E mutation was shared between the TSA and precursor components, but APC mutations were exclusive to the TSA component in all the analyzed lesions. None of the lesions showed the high CpG island methylation phenotype. These results indicate that FAP-associated TSAs frequently have KRAS or BRAF mutations, similar to sporadic cases, and second-hit somatic APC mutations are commonly involved in their tumorigenesis as in other FAP-associated tumors. Although progression to adenocarcinoma is likely rare, tumorigenesis via the serrated pathway occurs in patients with FAP.

The aim of this pilot study is to investigate the diagnostic yield of probe-based confocal laser endomicroscopy (pCLE) in the evaluation of depth of invasion in colorectal lesions. Patients with colorectal lesions eligible for either endoscopic treatment or surgery were enrolled in the study. Tumor’s depth of invasion was classified as mucosal or slight submucosal (M-SM1) and deep submucosal invasion or deeper (SM2 or deeper). White light endoscopy (WLE), magnifying narrow band imaging (M-NBI), and magnifying chromoendoscopy (M-CE) were used to assess colorectal lesions, and pCLE was used to identify tumor’s features related to SM2 or deeper. The diagnostic classification of depth of invasion was obtained by correlating pCLE findings with histology results (on-site diagnosis). All colorectal lesions were stratified by a second endoscopist who was blinded to any clinical and histological information with the use of WLE, M-NBI, M-CE, and pCLE (off-line review). A total of 22 colorectal lesions were analyzed: seven were adenoma, ten intramucosal cancer, and five SM2 or deeper cancer. With respect to pCLE findings, loss of crypt structure was seen in all SM2 or deeper cancers and only in one M-SM1 lesion. Sensitivity, specificity, and accuracy of WLE, M-NBI, and M-CE in off-line review were 60/94/86, 60/94/86, and 80/94/91%, respectively. Sensitivity/specificity/accuracy of pCLE in off-line review were 80/94/91%, respectively. The inter-observer agreement of pCLE between on-site diagnosis and off-line review was 0.64 (95%CI 0.27–1.0). pCLE may represent a useful tool to evaluate the depth of invasion in colorectal lesions.

Background Growing evidence suggests the importance of stroma in determining cancer biology and recent studies have identified that genes closely associated with poor prognosis subtypes of colorectal cancer are expressed by the stroma rather than epithelial cancer cells. We aimed to clarify the prognostic value of the novel histologic classification of desmoplastic reaction in stage III colorectal cancer. Methods A pathologic review was conducted for 466 stage III colorectal cancer patients in a single Japanese institution (1999–2006). Desmoplastic reaction was classified as mature, intermediate, or immature according to existence of hyalinized collagen bundles and myxoid stroma, both appear exclusively at the desmoplastic front. An additional 432 patients treated at four independent institutions (2007–2008) were examined as a second cohort to validate the results. Results According to desmoplastic reaction, 164, 133, and 169 patients were classified as mature, intermediate, and immature, respectively. Five-year relapse-free survival rates were highest in the mature group (86.0%), followed by the intermediate (73.7%) and immature (50.9%) groups. An adverse prognostic impact of desmoplastic reaction was invariably observed in stage IIIB, which contained 71% of stage III cases. Harrell's concordance index for relapse-free survival was greater in desmoplastic reaction (0.66) than any conventional tumor-associated prognostic factors including tumor node metastasis substage (0.62) and tumor grade (0.53). Similar results were observed in the second cohort, wherein desmoplastic reaction categorization was the most influential prognostic factor. Conclusion Histologic desmoplastic reaction categorization could be a key to solve the issue of prognostic heterogeneity in stage III colorectal cancer, thereby enhancing the value of tumor node metastasis stage.

We describe a series of colorectal polyps characterized by mixed adenomatous and serrated features, herein referred to as superficially serrated adenomas. Twenty superficially serrated adenomas were obtained from 11 female and 9 male patients aged 62-87 years. Most lesions endoscopically appeared as small sessile polyps, but larger lesions were plaque-like (2-20 mm; median, 5 mm). Eighteen lesions (90%) were located in the sigmoid colon or rectum. They consisted primarily of straight, adenomatous glands but showed serration confined to the superficial layer. Immunohistochemistry revealed CK20 expression in the upper layer. Proliferating cells, determined by their expression of Ki-67, were localized to the middle to bottom layers. Genetic analyses identified KRAS mutations in 19 lesions and a BRAF mutation in one lesion. Furthermore, RSPO fusions and/or overexpression were observed in 18 lesions and truncating APC mutations were observed in the two remaining lesions. Consistent with the presence of WNT pathway gene alterations, all superficially serrated adenomas showed focal or diffuse nuclear β-catenin accumulation. Since concurrent KRAS mutations and RSPO fusions are reportedly common in traditional serrated adenomas, we reviewed 129 traditional serrated adenomas and found 15 lesions (12%) that were associated with superficially serrated adenoma components. Remarkably, all but one superficially serrated adenoma-associated traditional serrated adenoma exhibited concurrent KRAS mutations and RSPO fusions/overexpression. The present study suggests that superficially serrated adenoma is a morphologically and molecularly distinct type of colorectal serrated polyp that is histogenetically related to traditional serrated adenoma.

Although recent findings of cancer biology research indicate that prognostic power arises from genes expressed by stromal cells rather than epithelial cells, desmoplastic reaction (DR) has not been completely examined as a prognostic marker for colorectal cancer. A pathologic review of 821 stage II and III patients who underwent R0 resection for colorectal cancer at 4 independent institutions was conducted. DR was classified as mature, intermediate, or immature based on the existence of hyalinized keloid-like collagen and myxoid stroma at the extramural desmoplastic front. Totally, 325, 282, and 214 patients were classified as having mature, intermediate, and immature DR, respectively. DR significantly influenced the recurrence rate in the liver, lung, and peritoneum (P≤0.0001 to 0.01). Five-year relapse-free survival (RFS) rate was the highest in the mature group (85.7%), followed by the intermediate (77.3%) and immature (50.4%) groups. A significant adverse impact of immature stroma on RFS was observed in subset analyses of the 4 institutions. Multivariate analysis revealed that DR, along with T and N stages, is an independent prognostic factor. On the basis of Harrell's concordance index, the prognostic power of DR categorization (0.67) in stratifying RFS was greater than any other conventional prognostic factors, including TNM (0.64), N (0.62) and T stages (0.59), venous invasion (0.59), and tumor grade (0.54). Characterizing DR based on the histologic products of activated fibroblasts is valuable for evaluating prognostic outcomes. To our knowledge, this is the first study reporting a greater prognostic power of histology of the fibrotic stroma than that of tumor factors.

Sessile serrated adenoma/polyps (SSA/Ps) are believed to be the major precursor of serrated pathway-derived colorectal carcinomas. To better characterize the process of progression from SSA/Ps to carcinomas, we analyzed 46 SSA/Ps with dysplasia and 45 SSA/Ps without dysplasia using targeted next-generation sequencing and immunohistochemistry. Among the WNT pathway genes analyzed, protein-truncating mutations of RNF43, APC, and ZNRF3 were identified in 23 (50%), 4 (9%), and 3 (7%) SSA/Ps with dysplasia, respectively. In contrast, SSA/Ps without dysplasia rarely had WNT pathway gene mutations, except for 3 lesions with RNF43 mutations (7%). None of the SSA/Ps had CTNNB1 mutations or RSPO fusions. Thus, WNT pathway gene mutations were more common in SSA/Ps with dysplasia than in SSA/Ps without dysplasia (P=3.0×10). Consistently, nuclear β-catenin accumulation and MYC overexpression, indicative of active WNT signaling, were present in most of the SSA/Ps with dysplasia, but were rare in those without dysplasia. BRAF (86%) or KRAS mutations (7%) were identified in the majority of SSA/Ps, regardless of the presence or absence of dysplasia. MLH1 expression was lost in 14 SSA/Ps with dysplasia (30%). The majority of MLH1-deficient SSA/Ps with dysplasia had RNF43 mutations (86%), most of which were frameshift mutations involving mononucleotide repeats. In contrast, MLH1-retained lesions had less frequent RNF43 mutations with no hot spots (34%), and 4 had APC mutations (13%). These results suggest that WNT pathway gene mutations are involved in the development of dysplasia in SSA/Ps and that MLH1-deficient and MLH1-retained SSA/Ps with dysplasia exhibit distinct mutation profiles of WNT pathway genes.

Lynch syndrome is a cancer predisposition syndrome caused by germline mutations in mismatch repair (MMR) genes. MMR deficiency is a ubiquitous feature of Lynch syndrome-associated colorectal adenocarcinomas; however, it remains unclear when the MMR-deficient phenotype is acquired during tumorigenesis. To probe this issue, the present study examined genetic alterations and MMR statuses in Lynch syndrome-associated colorectal adenomas and adenocarcinomas, in comparison with sporadic adenomas. Among the Lynch syndrome-associated colorectal tumors, 68 of 86 adenomas (79%) and all adenocarcinomas were MMR-deficient, whereas all the sporadic adenomas were MMR-proficient, as determined by microsatellite instability testing and immunohistochemistry for MMR proteins. Sequencing analyses identified APC or CTNNB1 mutations in the majority of sporadic adenomas (58/84, 69%) and MMR-proficient Lynch syndrome-associated adenomas (13/18, 72%). However, MMR-deficient Lynch syndrome-associated adenomas had less APC or CTNNB1 mutations (25/68, 37%) and frequent frameshift RNF43 mutations involving mononucleotide repeats (45/68, 66%). Furthermore, frameshift mutations affecting repeat sequences constituted 14 of 26 APC mutations (54%) in MMR-deficient adenomas whereas these frameshift mutations were rare in MMR-proficient adenomas in patients with Lynch syndrome (1/12, 8%) and in sporadic adenomas (3/52, 6%). Lynch syndrome-associated adenocarcinomas exhibited mutation profiles similar to those of MMR-deficient adenomas. Considering that WNT pathway activation sufficiently drives colorectal adenoma formation, the distinct mutation profiles of WNT pathway genes in Lynch syndrome-associated adenomas suggest that MMR deficiency commonly precedes adenoma formation.

Aims Traditional serrated adenoma (TSA) is a rare but distinct type of colorectal polyp. Our previous study showed that PTPRK–RSPO3 fusions are frequent and characteristic genetic alterations in TSAs. This study aimed to characterize comprehensively the prevalence and variability of RSPO fusions in colorectal TSAs. Methods and results We examined RSPO expression and explored novel RSPO fusions in 129 TSAs, including 66 lesions analysed previously for WNT pathway gene mutations. Quantitative polymerase chain reaction (qPCR) analyses identified three and 43 TSAs overexpressing RSPO2 and RSPO3, respectively, whereas the expression of RSPO1 and RSPO4 was marginal or undetectable in all cases. RSPO overexpression was always mutually exclusive with other WNT pathway gene mutations. Known PTPRK–RSPO3 fusions were detected in 37 TSAs, all but one of which overexpressed RSPO3. In addition, rapid amplification of cDNA ends revealed three novel RSPO fusion transcripts, an NRIP1–RSPO2 fusion and two PTPRK–RSPO3 fusion isoforms, in six TSAs. Overall, 43 TSAs had RSPO fusions (33%), whereas four TSAs (3%) overexpressed RSPO in the absence of RSPO fusions. TSAs with RSPO fusions showed several clinicopathological features, including distal localization (P = 0.0063), larger size (P = 0.0055), prominent ectopic crypt foci (P = 8.4 × 10−4), association of a high-grade component (P = 1.1 × 10−4), and the presence of KRAS mutations (P = 4.5 × 10−5). Conclusions The present study identified RSPO fusion transcripts, including three novel transcripts, in one-third of colorectal TSAs and showed that PTPRK–RSPO3 fusions were the predominant cause of RSPO overexpression in colorectal TSA.

Although the number of gastric cancer patients aged ≥85 years indicated for endoscopic submucosal dissection (ESD) has increased, little is known about the outcomes and prognostic factors. This study aimed to investigate the clinical outcomes and prognostic factors for overall survival (OS) of patients aged ≥85 years who underwent ESD for gastric cancer.We retrospectively reviewed 108 patients aged ≥85 years with 149 gastric cancers treated by ESD between 1999 and 2014 at our institution. The clinical outcomes and prognosis were evaluated. Furthermore, the relationships between patient and lesion characteristics with OS were determined using the Kaplan-Meier method and a Cox proportional hazards model.All patients had Eastern Cooperative Oncology Group performance status (PS) of 0 to 1. En bloc, R0, and curative resections were achieved in 98.0%, 91.3%, and 72.7%, respectively, without severe adverse events requiring surgery. During a median follow-up period of 40.2 months (range, 1.8-108.7 months), 23 patients died, including 2 of gastric cancer. The 3-year (54.3% vs 95.9%) and 5-year (54.3% vs 76.3%) OS rates were significantly lower in patients with a low (44.6) as opposed to a higher (≥44.6) prognostic nutritional index (PNI) (P .001). The PNI was independently prognostic of OS (hazard ratio, 7.0; 95% confidence interval, 2.2-22.9; P = .001).ESD is feasible for gastric cancer patients aged ≥85 years with good PS. However, low PNI was found to be prognostic of reduced OS, indicating the need to evaluate the PNI in determining whether to perform ESD.

Background and study aim Endoscopic submucosal dissection (ESD) is known as a curative treatment for colorectal superficial neoplasms. There is however a need for more long-term clinical data to establish the full advantages of colorectal ESD regarding very low recurrence rates. The aim of this retrospective study was to determine long-term clinical outcomes of colorectal ESD. Methods A total of 423 lesions treated by ESD for colorectal adenoma/dysplasia or adenocarcinoma between 1998 and 2008 at a single high volume referral center were included. We conducted a retrospective survey on patients with follow-up and obtained complete 1-, 3-, and 5-year outcome data for 358 (85 %), 292 (69 %), and 209 (49 %) lesions, respectively. Curative resection was defined when the pathological specimen had carcinoma-free resection margins, irrespective of piecemeal or en bloc resection, without submucosal deep invasion (≥ 1000 µm), lymphovascular involvement, or a poorly differentiated adenocarcinoma component. Results After a median 4.9 years of follow-up, the 3-year overall cumulative endoscopic recurrence rate and cancerous recurrence rate were 2.9 % (95 % confidence interval [95 %CI] 1.2 – 4.7) and 1.1 % (0 – 2.1), respectively. The 5-year overall cumulative endoscopic recurrence and cancerous recurrence rates were 3.8 % (1.7 – 5.9) and 1.6 % (0.1 – 3.0), respectively. In 361 lesions eligible for endoscopic follow-up, the 3-year endoscopic recurrence and cancerous recurrence rates were 2.4 % (0.8 – 4.1) and 0.4 % (0 – 1.4), respectively. Multivariate analysis revealed that piecemeal resection and submucosal deep tumor invasion were associated with recurrence. Conclusions The current study demonstrated favorable long-term clinical outcomes of colorectal ESD when en bloc curative resection is achieved.

BackgroundNivolumab, a programmed cell death protein 1 (PD-1) inhibitor, showed promising activity for the treatment of advanced esophageal squamous-cell carcinoma in a phase II study (ONO-4538-07; JapicCTI­No.142422). We explored serum microRNA (miRNA) candidate predictive markers of the response to nivolumab.MethodsIn the phase II study, 19 patients received nivolumab (3 mg/kg IV Q2W) at National Cancer Center Hospital. The expression of 2565 serum miRNAs before and during treatment was analyzed using a 3D-Gene Human miRNA Oligo Chip (Toray Industries, Inc.). Immune-related response evaluation criteria used to evaluate response and miRNA expression were compared between responders and non-responders. The top 20 miRNAs by accuracy in receiver operating characteristic curve analysis were identified by leave-one-out cross-validation, and those with the area under curve values > 0.8, cross-validated accuracy > 0.8, and a 0.5 difference in the average log2 expression level between responders and non-responders were further analyzed.ResultsOf the 19 patients, five responded to nivolumab. We identified miRNAs related to the response to nivolumab, including one detected in the serum before treatment (miR-1233-5p; AUC = 0.895) and three present after treatment (miR-6885-5p, miR-4698 and miR-128-2-5p; AUC = 0.93, 0.97 and 0.93, respectively).ConclusionsCandidate miRNAs capable of predicting the response to nivolumab were identified in the serum of patients with advanced esophageal squamous-cell carcinoma in ONO-4538-07.

Traditional serrated adenoma (TSA) is the least common type of colorectal serrated polyp, which exhibits considerable morphological and molecular diversity. We examined the spectra of alterations in MAPK and WNT pathway genes and their relationship with clinicopathological features in 128 TSAs. Sequencing analyses identified BRAF V600E, BRAF non-V600E, KRAS, and NRAS mutations in 77, 3, 45, and 1 lesion, respectively. Collectively, 124 lesions (97%) had mutations in MAPK pathway genes. Alterations in WNT pathway genes were identified in 107 lesions (84%), including RSPO fusions/overexpression, RNF43 mutations, ZNRF3 mutations, APC mutations, and CTNNB1 mutations in 47, 45, 2, 13, and 2 lesions, respectively. Ten lesions (8%) harbored GNAS mutations. There was significant interdependence between the altered MAPK and WNT pathway genes. RSPO fusions/overexpression was significantly associated with KRAS mutations (31/47, 66%), whereas most RNF43 mutations coexisted with the BRAF V600E mutation (40/45, 89%). Histologically, extensive slit-like serration was more common in lesions with the BRAF V600E mutation (71%) and those with RNF43 mutations (87%). Prominent ectopic crypt formation was more prevalent in lesions with RSPO fusions/overexpression (58%) and those with GNAS mutations (100%). Our observations indicate that TSAs mostly harbor various combinations of concurrent WNT and MAPK gene alterations. The associations between genetic and morphological features suggest that the histological diversity of TSA reflects the underlying molecular heterogeneity.

Aims Traditional serrated adenoma (TSA) is an uncommon type of colorectal serrated polyp. RSPO fusions, which potentiate WNT signalling, are common and characteristic genetic alterations in TSA. The aim of this study was to further characterise the prevalence and variation of RSPO fusions in TSA. Methods and results Quantitative polymerase chain reaction (PCR) analysis of 99 TSAs revealed overexpression of RSPO2 and RSPO3 in six and 29 lesions, respectively. Reverse transcription PCR identified previously reported PTPRK-RSPO3 fusion transcripts in all 29 TSAs with RSPO3 overexpression, confirming that PTPRK-RSPO3 is the predominant RSPO fusion in TSAs. Among the six lesions with RSPO2 overexpression, two overexpressed full-length RSPO2. An EIF3E-RSPO2 fusion, which is a known recurrent RSPO fusion in colorectal cancer, was detected in three lesions. In addition, rapid amplification of cDNA ends identified a novel PIEZO1-RSPO2 fusion in one TSA. All of the four TSAs with RSPO2 fusions concurrently had KRAS mutations and showed the classic histological features. Conclusions The present study identified EIF3E-RSPO2 and PIEZO1-RSPO2 in TSAs. Our observations expand the spectrum of RSPO fusions in TSAs, and suggest that TSAs are precursors of colorectal cancers with these RSPO2 fusions.

BACKGROUND: Magnifying Narrow Band Imaging (NBI) during colonoscopy is a reliable method for differential and depth diagnoses of colorectal lesions. This study examined the diagnostic yield of magnifying NBI based on the Japan NBI Expert Team (JNET) classification in a clinical setting using a large-scale clinical practice database. Types 1, 2A, 2B and 3 correspond to the histopathological classifications of hyperplastic polyp/sessile-serrated polyp, low-grade intramucosal neoplasia, high-grade intramucosal neoplasia/shallow submucosal invasive cancer, and deep submucosal invasive cancer, respectively. METHODS: The prospective records of colonoscopy reports and pathological data of 1558 consecutive superficial colorectal lesions removed by colonoscopy were retrospectively analysed. After excluding 156 lesions, the documented JNET classifications of the remaining 1402 colorectal lesions were analysed. Diagnostic yield was analysed and also compared between expert endoscopists and nonexpert endoscopists. RESULTS: The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were respectively 75%, 96%, 74%, 96% and 93% for type 1; 91%, 70%, 92%, 67% and 87% for type 2A; 42%, 95%, 26%, 98% and 93% for type 2B; and 35%, 100%, 93%, 98% and 98% for type 3. Nonexpert and expert endoscopists alike had specificity, NPV and accuracy >90% for types 1, 2B and 3, and a sensitivity and PPV >90% for type 2A. Type 2B had a low sensitivity of 42% because it included various histological features. CONCLUSIONS: The JNET classification proved useful in a clinical setting both for expert and nonexpert endoscopists, as was expected from the original JNET definition, but type 2B requires further investigation using pit pattern diagnosis.