Comprehensive clinicopathological characteristics and mucin core protein expression profiles of bronchiolar adenoma.

AIMS: Bronchiolar adenoma (BA) is a novel entity in the 2021 WHO classification of lung tumours. The expression profile of mucin core proteins in BAs is not clear. The aim of this study was to clarify the expression profiles of mucins and to validate the clinicopathologic and molecular features of BAs. METHODS AND RESULTS: We examined the clinicopathological, immunohistochemical, and molecular features of 20 BAs. Our cohort comprised 10 proximal and 10 distal BAs. Only seven of 18 patients (39%) were accurately diagnosed with BA at the time of intraoperative consultation. The frequent genetic alterations were BRAF V600E (35%) and KRAS (30%) mutations, which were mutually exclusive. The expression of MUC1, MUC4, and MUC5B was observed in all cases and that of MUC5AC and MUC6 was observed in nine (45%) and five (25%) cases, respectively. MUC4 was diffusely expressed in 18 cases. In contrast, MUC1, MUC5AC, MUC5B, and MUC6 displayed a patchy expression pattern. These expression patterns were similar to that of bronchiolar epithelium in normal lung tissue. In addition, overexpression of MUC1 and MUC4 on the entire cell surface was not observed in any of the BAs, suggesting their benign nature. CONCLUSION: BA commonly exhibits diffuse MUC4 and patchy MUC1 and MUC5B expression. Its unique expression pattern is probably attributed to mucin expression specific to the bronchiolar epithelium. These results confirm the clinicopathologic and molecular characteristics of BA, including the difficulty in intraoperative frozen section diagnosis and the broad morphologic spectrum of BA derived from the bronchiolar epithelium.

Tyrosine kinase alterations in colorectal cancer with emphasis on the distinct clinicopathological characteristics.

AIMS: Tyrosine kinase (TK) alterations, such as anaplastic lymphoma kinase (ALK) fusion, neurotrophic tyrosine receptor kinase (NTRK) fusion, c-ros oncogene 1 (ROS1) fusion and mesenchymal-epithelial transition factor (MET) exon 14 skipping, have been reported in colorectal cancers (CRC). We have previously reported CRCs with NTRK fusion among our cohort. However, their clinicopathological features have not been fully elucidated. METHODS AND RESULTS: Tissue microarray (TMA)-based immunohistochemistry (IHC) was performed on 951 CRC lesions from 944 patients. IHC was evaluated as positive or negative for ALK and ROS1 and 0 to 3+ for c-MET. For ALK and ROS1 IHC-positive cases, RNA-based imbalanced gene expression assays, Archer FusionPlex assays and reverse transcription-polymerase chain reaction (RT-PCR) followed by Sanger sequencing were performed. For c-MET IHC 3+ cases, RT-PCR followed by Sanger sequencing were performed. ALK IHC was positive in three cases (0.2%) and all showed imbalanced ALK gene expression. The following ALK fusions were confirmed: EML4 (exon 21)::ALK (exon 20), EML4 (exon 6)::ALK (exon 19) and HMBOX1 (exon 6)::ALK (exon 20). Two showed microsatellite instability-high/mismatch repair (MMR)-deficient, and all were located in the right colon. ROS1 IHC was positive in one case; however, imbalanced expression and ROS1 fusion was negative. Forty-two cases (4.4%) showed c-MET IHC3+. MET exon 14 skipping was confirmed in nine cases. All cases were microsatellite stable/MMR-proficient, and eight were located in the left colon and rectum. CONCLUSIONS: CRCs with these TK alterations had distinct clinicopathological features. Together with our previous study, 15 cases (1.6%) harboured targetable TK alterations (three NTRK fusion, three ALK fusion, nine MET exon 14 skipping).

Expression of paired box 9 defines an aggressive subset of lung adenocarcinoma preferentially occurring in smokers.

AIMS: A distinct subset of lung adenocarcinomas (LADs), arising from a series of peripheral lung cells defined as the terminal respiratory unit (TRU), is characterised by thyroid transcription factor 1 (TTF-1) expression. The clinical relevance of transcription factors (TFs) other than TTF-1 remains unknown in LAD and was explored in the present study. METHODS AND RESULTS: Seventy-one LAD samples were subjected to high-throughput transcriptome screening of LAD using cap analysis gene expression (CAGE) sequencing data; CAGE provides genome-wide expression levels of the transcription start sites (TSSs). In total, 1083 invasive LAD samples were subjected to immunohistochemical examination for paired box 9 (PAX9) and TTF-1 expression levels. PAX9 is an endoderm development-associated TF that most strongly and inversely correlates with the expression of TTF-1 TSS subsets. Immunohistochemically, PAX9 expression was restricted to the nuclei of ciliated epithelial and basal cells in the bronchi and bronchioles and the nuclei of epithelial cells of the bronchial glands; moreover, PAX9 expression was observed in 304 LADs (28%). PAX9-positive LADs were significantly associated with heavy smoking, non-lepidic subtype, EGFR wild-type tumours and PD-L1 expression (all P < 0.0001). All these characteristics were opposite to those of TRU-type LADs with TTF-1 expression. PAX9 expression was an independent prognostic factor for decreased overall survival (P = 0.022). CONCLUSIONS: Our results revealed that PAX9 expression defines an aggressive subset of LADs preferentially occurring in smokers that may arise from bronchial or bronchiolar cells.

Comparison of ASCL1, NEUROD1, and POU2F3 expression in surgically resected specimens, paired tissue microarrays, and lymph node metastases in small cell lung carcinoma.

Subtypes of small cell lung carcinoma (SCLC) are defined by the expression of ASCL1, NEUROD1, and POU2F3 markers. The aim of our study was to explore the extent to which the intratumoral heterogeneity of ASCL1, NEUROD1, and POU2F3 may lead to discrepancies in expression of these markers in surgical samples and their matched tissue microarray (TMA) and lymph node (LN) metastatic sites. METHODS AND RESULTS: The cohort included 77 patients with SCLC. Immunohistochemical examinations were performed on whole slides of the primary tumour, paired TMAs, and metastatic LN sites. Samples with H-scores >50 were considered positive. Based on the ASCL1, NEUROD1, and POU2F3 staining pattern, we grouped the tumours as follows: ASCL1-dominant (SCLC-A), NEUROD1-dominant (SCLC-N), ASCL1/NEUROD1 double-negative with POU2F3 expression (SCLC-P), and negative for all three markers (SCLC-I). In whole slides, 40 SCLC-A (52%), 20 SCLC-N (26%), 15 SCLC-P (20%), and two SCLC-I (3%) tumours were identified. Comparisons of TMAs or LN metastatic sites and corresponding surgical specimens showed that positivity for ASCL1, NEUROD1, and POU2F3 in TMAs (all P < 0.0001) or LN metastatic sites (ASCL1, P = 0.0047; NEUROD1, P = 0.0069; POU2F3, P < 0.0001) correlated significantly with that of corresponding surgical specimens. CONCLUSION: The positivity for these markers in TMAs and LN metastatic sites was significantly correlated with that of corresponding surgical specimens, indicating that biopsy specimens could be used to identify molecular subtypes of SCLC in patients.

Randomised clinical trial: 3-year interim analysis results of the VISION trial to evaluate the long-term safety of vonoprazan as maintenance treatment in patients with erosive oesophagitis.

BACKGROUND: VISION is a randomised, phase 4, open-label, parallel-group, multicentre study conducted in 33 centres in Japan. The aim of this study was to assess the long-term safety of vonoprazan for maintenance treatment of healed erosive oesophagitis versus lansoprazole. METHODS: Patients with endoscopically diagnosed erosive oesophagitis were randomised 2:1 to once-daily vonoprazan 20 mg or lansoprazole 30 mg, for a 4- to 8-week healing phase. Patients with endoscopically confirmed healing entered a 260-week maintenance phase with a once-daily starting dose of vonoprazan 10 mg or lansoprazole 15 mg. Primary endpoint was change in gastric mucosal histopathology. RESULTS: Of 208 patients (vonoprazan, n = 139; lansoprazole, n = 69) entering the healing phase, 202 entered the maintenance phase (vonoprazan, n = 135; lansoprazole, n = 67). At 3 years, 109 vonoprazan-treated and 58 lansoprazole-treated patients remained on treatment. Histopathological evaluation of gastric mucosa showed that hyperplasia of parietal, foveolar and G cells was more common with vonoprazan than lansoprazole at week 156 of the maintenance phase. There was no marked increase in the occurrence of parietal, foveolar and G cell hyperplasia among patients in the vonoprazan group from week 48 to week 156. Histopathological evaluation of the gastric mucosa also showed no neoplastic changes in either group. No new safety issues were identified. CONCLUSIONS: In this interim analysis of VISION, no new safety concerns were identified in Japanese patients with healed erosive oesophagitis receiving vonoprazan or lansoprazole as maintenance treatment for 3 years. (CT.gov identifier: NCT02679508; JapicCTI-163153; Japan Registry of Clinical Trials: jRCTs031180040).

Clinicopathological features of appendiceal goblet cell adenocarcinoma in Japan: a multicenter retrospective study.

PURPOSE: In the 5th edition of the World Health Organization classification, appendiceal goblet cell adenocarcinoma (GCA) is categorized separately from neuroendocrine tumors and other appendiceal adenocarcinomas. We clarified the clinicopathological characteristics of Japanese appendiceal GCA. METHODS: We designed a retrospective multicenter cohort study and retrieved the data of patients with appendiceal neoplasms and histologically diagnosed appendiceal goblet cell carcinoid (GCC) treated from January 2000 to December 2017 in Japan. The available GCC slides were reviewed and diagnosed with a new grading system of GCA. RESULTS: A total of 922 patients from 43 institutions were enrolled; of these, 32 cases were patients with GCC (3.5%), and 20 cases were ultimately analyzed. The 5-year survival rate was 61.4% (95% confidence interval: 27.4-83.2), and the median survival time was 93.1 months. For peritoneal metastasis, regional lymph node metastasis was a significant factor (p = 0.04), and Grade 3 was a potential factor (p = 0.07). No peritoneal metastasis was observed in either T1/2 patients (n = 2) or Grade 1 patients (n = 4). We were unable to detect any significant factors associated with regional lymph node metastasis. CONCLUSION: For peritoneal metastasis, regional lymph node metastasis was a significant factor, and Grade 3 was a potential factor.

Clinical characteristics and long-term prognosis of type 1 gastric neuroendocrine tumors in a large Japanese national cohort.

OBJECTIVES: Optimal management of type 1 gastric neuroendocrine tumors (T1-GNETs) remains unknown, with few reports on their long-term prognosis. This study investigated the clinical characteristics and long-term prognosis of T1-GNETs. METHODS: We reviewed the medical records of patients diagnosed with T1-GNET during 1991-2019 at 40 institutions in Japan. RESULTS: Among 172 patients, endoscopic resection (ER), endoscopic surveillance, and surgery were performed in 84, 61, and 27, respectively, including 27, 77, and 2 patients with pT1a-M, pT1b-SM, and pT2 tumors, respectively. The median tumor diameter was 5 (range 0.8-55) mm. Four (2.9%) patients had lymph node metastasis (LNM); none had liver metastasis. LNM rates were significantly higher in tumors with lymphovascular invasion (LVI) (15.8%; 3/19) than in those without (1.1%; 1/92) (P = 0.016). For tumors <10 mm, LVI and LNM rates were 18.4% (14/76) and 2.2% (2/90), respectively, which were not significantly different from those of tumors 10-20 mm (LVI 13.3%; 2/15, P = 0.211; and LNM 0%; 0/17, P = 1.0). However, these rates were significantly lower than those of tumors >20 mm (LVI 60%; 3/5, P = 0.021; and LNM 40%; 2/5, P = 0.039). No tumor recurrence or cause-specific death occurred during the median follow-up of 10.1 (1-25) years. The 10-year overall survival rate was 97%. CONCLUSIONS: Type 1 gastric neuroendocrine tumors showed indolent nature and favorable long-term prognoses. LVI could be useful in indicating the need for additional treatments. ER for risk prediction of LNM should be considered for tumors <10 mm and may be feasible for tumors 10-20 mm. TRIAL REGISTRATION: The study protocol was registered in the University Hospital Medical Information Network (UMIN) under the identifier UMIN000029927.

HLA Class I Expression Is Associated with DNA Damage and Immune Cell Infiltration into Dysplastic and Neoplastic Lesions in Ulcerative Colitis.

Human leukocyte antigen class I (HLA-I) is considered a genetic pathogen for ulcerative colitis (UC). This study aimed to investigate the significance of DNA damage and HLA-I expression in infiltrating immune cells and immune checkpoint protein PD-L1 expression in dysplasia/colitic cancer (CC) and sporadic colorectal cancer (SCRC). We performed immunohistochemical staining for HLA-I, PD-L1, γH2AX (DNA damage marker), and immune cell markers such as CD8, FOXP3, CD68, and CD163 (in surgically resected specimens from 17 SCRC patients with 12 adjacent normal mucosa (NM) and 9 UC patients with 18 dysplasia/CC tumors. The ratio of membrane HLA-I-positive epithelial cells in UC and dysplasia/CC tissues was significantly higher than that in NM and SCRC. High HLA-I expression in dysplasia/CC was associated with high positivity of γH2AX and PD-L1 expression compared to SCRC. The infiltration of CD8-positive T cells and CD68-positive macrophages in HLA-I-high dysplasia/CC was significantly higher than in UC and SCRC. Dysplasia/CC specimens with DNA damage exhibited high levels of HLA-I-positive epithelial cells with high CD8- and CD68-positive immune cell infiltration compared to UC and SCRC specimens. Targeting DNA damage in UC may regulate immune cell infiltration, immune checkpoint proteins, and carcinogenesis by modulating DNA damage-induced HLA-I antigen presentation.

High platelet-to-lymphocyte ratios in triple-negative breast cancer associates with immunosuppressive status of TILs.

BACKGROUND: Rating lymphocytes (TILs) are a prognostic marker in breast cancer and high TIL infiltration correlates with better patient outcomes. Meanwhile, parameters involving immune cells in peripheral blood have also been established as prognostic markers. High platelet-to-lymphocyte ratios (PLRs) and neutrophil-to-lymphocyte ratios (NLRs) are related to poor outcomes in breast cancer, but their mechanisms remain unknown. To date, TILs and these parameters have been examined separately. METHODS: We investigated the relationship between TILs and the peripheral blood markers, PLR and NLR, in the same patients, using surgical specimens from 502 patients with invasive breast carcinoma without preoperative chemotherapy. For analysis of triple-negative breast cancer (TNBC) patient outcomes, 59 patients who received preoperative chemotherapy were also examined. For immune cell profiling, multiplexed fluorescent immunohistochemistry (mfIHC) of CD3, CD4, CD8, FOXP3 and T-bet, was conducted. RESULTS: A positive correlation between PLR and TIL was observed in TNBC (P = 0.013). On mfIHC, tumors in patients with high PLR and NLR contained more CD3+CD4+FOXP3+ T-cells (P = 0.049 and 0.019, respectively), while no trend was observed in CD8+ T-cells. TNBC patients had different patterns of outcomes according to TIL and PLR, with the TIL-high/PLR-low group having the lowest rate of disease relapse and death, and the longest distant metastasis-free and overall survivals, while the TIL-low/PLR-high group had the shortest survivals. CONCLUSIONS: Our data suggest that the combination of PLR with TIL assessment may enable more accurate prediction of patient outcomes with TNBC.

Sessile serrated lesions: Clinicopathological characteristics, endoscopic diagnosis, and management.

The 2019 World Health Organization (WHO) Classification of Tumours of the Digestive System (5th edition) introduced the term "sessile serrated lesion" (SSL) to replace the term "sessile serrated adenoma/polyp" (SSA/P). SSLs are early precursor lesions in the serrated neoplasia pathway that result in colorectal carcinomas with BRAF mutations, methylation for DNA repair genes, a CpG island methylator phenotype, and high levels of microsatellite instability. Some of these lesions can rapidly become dysplastic or invasive carcinomas that exhibit high lymphatic invasion and lymph node metastasis potential. The 2019 WHO classification noted that dysplasia arising in an SSL most likely is an advanced polyp, regardless of the morphologic grade of the dysplasia. Detecting SSLs with or without dysplasia is critical; however, detection of SSLs is challenging, and their identification by endoscopists and pathologists is inconsistent. Furthermore, indications for their endoscopic treatment have not been established. Moreover, SSLs are considered to contribute to the development of post-colonoscopy colorectal cancers. Herein, the clinicopathological and endoscopic characteristics of SSLs, including features determined using white light and image-enhanced endoscopy, therapeutic indications, therapeutic methods, and surveillance are reviewed based on the literature. This information may lead to more intensive research to improve detection, diagnosis, and rates of complete resection of these lesions and reduce post-colonoscopy colorectal cancer rates.

Linked color imaging improves visibility of colorectal serrated lesion by high color contrast to surrounding mucosa.

OBJECTIVES: This study aimed to objectively evaluate the efficacy of linked color imaging (LCI) in diagnosing colorectal serrated lesions by utilizing visibility scores and color differences. METHODS: We examined 89 serrated lesions, including 36 hyperplastic polyps (HPs), 47 sessile serrated lesions (SSLs), and six traditional serrated adenomas (TSAs). Visibility changes were scored by six endoscopists as follows: 4, excellent; 3, good; 2, fair; and 1, poor. Furthermore, images obtained by white-light imaging (WLI) or LCI were assessed using the CIELAB color space in the lesion and adjacent mucosa. We calculated the mean color values (L*, a*, and b*) measured at five regions of interest of the sample lesion and surrounding mucosa and derived the color difference (ΔE*). RESULTS: The visibility scores of both HPs and SSLs in LCI were significantly higher than that in WLI (HPs, 3.67/2.89, P < 0.001; SSLs, 3.07/2.36, P < 0.001). Furthermore, SSLs showed a significantly higher L* value and significantly lower a* and b* values in LCI than the adjacent mucosae (L*, 61.76/58.23, P = 0.016; a*, 14.91/17.58, P = 0.019; b*, 20.42/24.21, P = 0.007), while WLI produced no significant difference in any color value. A similar trend was apparent in HPs. In all serrated groups, LCI revealed significantly greater ΔE* values between the lesion and adjacent mucosa than WLI (HPs, 11.54/6.12; SSLs, 13.43/7.67; TSAs, 35.00/22.48). CONCLUSION: Linked color imaging showed higher color contrast between serrated lesions and the surrounding mucosae compared with WLI, indicating improved visibility of colorectal serrated lesion using LCI.

Guidelines for Colorectal Cold Polypectomy (supplement to "Guidelines for Colorectal Endoscopic Submucosal Dissection/Endoscopic Mucosal Resection").

The Japan Gastroenterological Endoscopy Society published the second edition of the "Guidelines for Colorectal Endoscopic Submucosal Dissection/Endoscopic Mucosal Resection" in 2019 to clarify the indications for colorectal endoscopic mucosal resection (EMR) and endoscopic submucosal dissection and to ensure appropriate preoperative diagnoses as well as effective and safe endoscopic treatment in front-line clinical settings. Endoscopic resection with electrocautery, including polypectomy and EMR, is indicated for colorectal polyps. Recently, the number of facilities introducing and implementing cold polypectomy without electrocautery has increased. Herein, we establish supplementary guidelines for cold polypectomy. Considering that the level of evidence for each statement is limited, these supplementary guidelines must be verified in clinical practice.

Plasma cell infiltration and treatment effect in breast cancer patients treated with neoadjuvant chemotherapy.

BACKGROUND: Tumour-infiltrating lymphocyte (TIL)-high breast tumours have a high rate of pathological complete response (pCR) with neoadjuvant chemotherapy. In our routine pathological diagnoses of biopsy specimens from pCR cases, we have observed a high infiltration of plasma cells (PCs). A positive correlation of PCs with favourable patient outcome has recently been reported, but little is known about how PCs contribute to local tumour immunity. METHODS: We retrospectively examined biopsy specimens from 146 patients with invasive breast cancer who received neoadjuvant chemotherapy. CD138+ PC infiltration was assessed by immunohistochemistry. Multiplexed fluorescent immunohistochemistry (mfIHC) with T and B cell markers was also conducted to elucidate the profile of immune cells. RESULTS: Greater PC infiltration was observed in the pCR group (p = 0.028) and this trend was confirmed in another patient cohort. With mfIHC, we observed significantly more CD8+, T-bet+CD4+, and CD8+FOXP3+ T cells, total B cells and PCs in pCR cases. Such cases were also characterised by high expression of both PD-1 and PD-L1 on B cells and PCs. In patients with hormone receptor-negative tumours, high PC infiltration was correlated with significantly longer disease-free survival (p = 0.034). CONCLUSIONS: We found that higher PC infiltration in biopsy specimens before neoadjuvant chemotherapy was associated with pCR. With mfIHC, we also revealed that the local cytotoxic immune response was clearly enhanced in pCR cases, as was the infiltration of B cells including PCs. Moreover, higher PC levels were correlated with favourable outcomes in hormone receptor-negative breast cancer patients.

Diffuse expression of MUC6 defines a distinct clinicopathological subset of pulmonary invasive mucinous adenocarcinoma.

Invasive mucinous adenocarcinoma (IMA) of the lung is a unique variant of lung adenocarcinoma. Aberrant mucin expression is associated with cancer development and metastasis. However, the clinicopathological significance of mucin expression in IMA is not fully understood. Herein, we evaluated the clinicopathological, immunohistochemical, and molecular characteristics of 70 IMA tumors. EGFR, KRAS, GNAS, and TP53 mutations were assessed by PCR-based sequencing. Next-generation sequencing was used to assess cases without EGFR/KRAS mutations. A NanoString-based screening for fusions was performed in all IMAs without mitogenic driver mutations. Expression of mucins (MUC1, MUC2, MUC4, MUC5AC, and MUC6) was evaluated by immunohistochemistry and categorized as follows: negative (<10% of tumor cells), patchy expression (<90% of tumor cells), or diffuse expression (≥90% of tumor cells). Immunohistochemical testing for transcription factors (TTF-1, CDX2, HNF1ß, HNF3α, HNF3ß, and HNF4α) was also performed. As expected, KRAS mutations were the most common (in 67% of cases), followed by small numbers of other alterations. Patchy or diffuse expression of MUC1, MUC2, MUC4, MUC5AC, and MUC6 was observed in 52% or 6%, 3% or 0%, 30% or 3%, 26% or 73%, and 59% or 27% of cases, respectively. Furthermore, all IMAs were generally positive for HNF1ß (100%), HNF3α (100%), HNF3ß (100%), and HNF4α (99%) but were positive less often for TTF-1 (6%) and CDX2 (9%). Overall, there was no significant correlation between mucin expression and transcription factor expression. Unexpectedly, diffuse expression of MUC6 was significantly associated with KRAS-wild-type tumors (p = 0.0008), smaller tumor size (p = 0.0073), and tumors in female patients (p = 0.0359) in multivariate analyses. Furthermore, patients with tumors exhibiting diffuse MUC6 expression had significantly favorable outcomes. Notably, none of these patients died of the disease. Our data suggested that diffuse expression of MUC6 defines a distinct clinicopathological subset of IMA characterized by wild-type KRAS and possibly less aggressive clinical course.

Comprehensive clinicopathological and molecular analysis of primary malignant melanoma of the oesophagus.

AIMS: This study was performed to elucidate the clinicopathological characteristics, genetic alterations and therapeutic targets of primary malignant melanoma of the oesophagus (PMME). METHODS AND RESULTS: The clinicopathology and molecular pathology of 13 PMME cases and 10 skin malignant melanoma (SKMM) cases were analysed with next-generation sequencing (NGS) and immunohistochemistry. The 3-year overall survival rate and the median survival time for PMME patients were 23.1% and 11.9 months, respectively. Three (23.1%) and eight (61.5%) PMME cases showed a papillary structure and lymph node metastasis, respectively. DNA and RNA hybridization capture-based NGS analysis revealed that NF1 was the most frequently mutated gene (30%) in 10 of the PMME cases. Other mutations detected in PMME included SF3B1 (20%), KRAS (10%), BRCA2 (10%), KIT (10%) and TP53 (10%) mutations. Commonly detected BRAF mutations in SKMM were not detected in PMME. Immunohistochemistry and mutation status were concordant between p53/c-Kit and TP53/KIT, respectively. Focal expression of programmed death-ligand 1 was observed in one PMME sample. The tumour mutation burden in PMME was significantly lower than that in SKMM (P = 0.030). No PMME case showed high microsatellite instability. RNA sequencing revealed a distinctive pattern with respect to RNA expression. T-cell co-stimulation differed between PMME and SKMM. CONCLUSIONS: The RAS-mitogen-activated protein kinase pathway is one of the main pathways involved in PMME. The genetic profile of PMME was similar to that of mucosal/acral melanoma, but differed from the SKMM profile. A subset of PMMEs may contain actionable mutations. Immunotherapy seemed to be less effective for most PMMEs in this series.

Histological characteristics of lung adenocarcinoma with uncommon actionable alterations: special emphasis on MET exon 14 skipping alterations.

AIMS: In the evolving era of precision medicine, increasing emphasis is placed on detecting molecular alterations driving the development of specific cancers and targeting them with matched therapies that can yield the best outcomes for patients. Lung adenocarcinomas with uncommon actionable alterations, including MET exon 14 skipping (METex14), ERBB2 and BRAF mutations, are rare and poorly characterised cancers. METHODS AND RESULTS: To more clearly understand the histopathological features of lung adenocarcinoma with uncommon actionable alterations, we compared the histological features of 678 cases with mitogenic driver alterations from 996 surgically resected lung adenocarcinomas. Genomic data from our cohort revealed METex14, ERBB2 and BRAF mutations in 13, 16 and 15 cases, respectively. Patients who had lung adenocarcinoma with METex14 were often elderly females. Histological features such as clear cell features (23%), hyaline globules (31%) and nuclear pleomorphism (39%) were the most frequently identified in METex14-positive cases; among those, three cases (23%) had tumour cells with bizarre giant or multilobulated nuclei. Additionally, the micropapillary pattern was the most frequently identified in ERBB2-mutated lung adenocarcinoma (31%). Lung adenocarcinoma with BRAF mutations tended to be less invasive, and the BRAF V600E mutation was identified in only one case with lepidic adenocarcinoma. Immunohistochemically, all METex14, ERBB2 and BRAF-positive tumours, except for invasive mucinous adenocarcinoma, were positive for thyroid transcription factor 1 (TTF-1). CONCLUSIONS: Our data from Japanese patients showed that lung adenocarcinoma with METex14 had unique clinicopathological characteristics: tumour cells with marked nuclear pleomorphism, hyaline globules and expression of TTF-1 in elderly women who never or lightly smoked.

Integrated genetic and epigenetic analysis of cancer-related genes in non-ampullary duodenal adenomas and intramucosal adenocarcinomas.

The molecular and clinical characteristics of non-ampullary duodenal adenomas and intramucosal adenocarcinomas are not fully understood because they are rare. To clarify these characteristics, we performed genetic and epigenetic analysis of cancer-related genes in these lesions. One hundred and seven non-ampullary duodenal adenomas and intramucosal adenocarcinomas, including 100 small intestinal-type tumors (90 adenomas and 10 intramucosal adenocarcinomas) and 7 gastric-type tumors (2 pyloric gland adenomas and 5 intramucosal adenocarcinomas), were investigated. Using bisulfite pyrosequencing, we assessed the methylation status of CpG island methylator phenotype (CIMP) markers and MLH1. Then using next-generation sequencing, we performed targeted exome sequence analysis within 75 cancer-related genes in 102 lesions. There were significant differences in the clinicopathological and molecular variables between small intestinal- and gastric-type tumors, which suggests the presence of at least two separate carcinogenic pathways in non-ampullary duodenal adenocarcinomas. The prevalence of CIMP-positive lesions was higher in intramucosal adenocarcinomas than in adenomas. Thus, concurrent hypermethylation of multiple CpG islands is likely associated with development of non-ampullary duodenal intramucosal adenocarcinomas. Mutation analysis showed that APC was the most frequently mutated gene in these lesions (56/102; 55%), followed by KRAS (13/102; 13%), LRP1B (10/102; 10%), GNAS (8/102; 8%), ERBB3 (7/102; 7%), and RNF43 (6/102; 6%). Additionally, the high prevalence of diffuse or focal nuclear ß-catenin accumulation (87/102; 85%) as well as mutations of WNT pathway components (60/102; 59%) indicates the importance of WNT signaling to the initiation of duodenal adenomas. The higher than previously reported frequency of APC gene mutations in small bowel adenocarcinomas as well as the difference in the APC mutation distributions between small intestinal-type adenomas and intramucosal adenocarcinomas may indicate that the adenoma-carcinoma sequence has only limited involvement in duodenal carcinogenesis. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Hepatocellular adenoma, approximately half and predominantly inflammatory subtype, in 38 Japanese patients with several differences in age, gender, and clinical background factors from Western populations.

AIM: Hepatocellular adenoma (HCA) has a lower prevalence in Japan than in Western countries and HCA subtypes have been reported for only a few Japanese patients. We analyzed HCA subtype data 38 patients from 23 hospitals in Japan in order to examine character and difference between Western countries. METHODS: To confirm HCA and to analyze subtypes, we performed immunohistochemical examinations. RESULTS: Thirty-eight cases were found to have HCA without cirrhosis. The male/female ratio was 18/20. Ages ranged from 15 to 79 (average, 43.2) years. Male and elder patients are not rare, furthermore, most of elder patients are male. Glycogen storage disease, past history of medicament use, hepatitis B virus surface antigen-positivity, antihepatitis C virus -positivity, diabetes mellitus, obesity, lipid metabolism disorder and alcoholism were present in of 6, 8, 1, 1, 6, 6, 4, and 6 cases, respectively. As to HCA subtypes, HNF1alpha-inactivated HCA, beta-catenin activated HCA (b-HCA), inflammatory HCA (IHCA) and unclassified HCA (U-HCA) accounted for nine (23.7%), four (10.5%), 17 (44.7%) and eight (21.1%) cases, respectively. Two cases showed coexistence of HCA and hepatocellular carcinoma (HCC) at surgery, and another had HCC which had been detected 23 years after HCA diagnosis. The HCA subtype of one of the former cases was U-HCA, while the remaining two had b-HCA and U-HCA. CONCLUSIONS: In Japanese HCA cases, the proportions of U-HCA, male and elder cases were slightly higher than in Western countries, and most of elder patients were male. IHCA was however common regardless of race, and was assumed to be the predominant subtype of HCA.

Dynamic diagnosis of early gastric cancer with microvascular blood flow rate using magnifying endoscopy (with video): A pilot study.

BACKGROUND AND AIM: Magnifying endoscopy (ME) diagnostic algorithm for early gastric cancer (EGC) relies on qualitative features such as microvascular (MV) architecture and microsurface structure; however, it is a "static" diagnostic algorithm that uses still images. ME can visualize red blood cell flow within subepithelial microvessels in real time. Here, we evaluated the utility of using the MV blood flow rate in combination with ME for the diagnosis of EGC as a retrospective study. METHODS: Patients with differentiated-type EGC (n = 10) or patchy redness (n = 10) underwent ME with blue laser imaging. The mean MV blood flow rates of EGC, patchy redness, and background mucosa were calculated by the mean movement distance of one tagging red blood cell using split images of ME with blue laser imaging videos. We compared the mean MV blood flow rate between EGC, patchy redness, and background mucosa and also calculated the MV blood flow imaging ratio (inside lesion/background mucosa) between EGC and patchy redness. RESULTS: Mean MV blood flow rate was significantly lower in EGC (1481 µm/s; range 1057-1762) than in patchy redness (3859 µm/s; 2435-5899) or background mucosa (4140.6 µm/s; 2820-6247) (P < 0.01). The MV blood flow imaging ratio was significantly lower in EGC (0.39; 0.27-0.62) than in patchy redness (0.90; 0.78-1.1) (P < 0.01). CONCLUSIONS: Dynamic diagnosis with MV blood flow rate using ME may be useful for the differential diagnosis of EGC and patchy redness. Endoscopic assessment of dynamic processes within the gastric mucosa may facilitate the diagnosis of EGC.

Application of artificial intelligence using a convolutional neural network for diagnosis of early gastric cancer based on magnifying endoscopy with narrow-band imaging.

BACKGROUND AND AIM: Magnifying endoscopy with narrow-band imaging (ME-NBI) has made a huge contribution to clinical practice. However, acquiring skill at ME-NBI diagnosis of early gastric cancer (EGC) requires considerable expertise and experience. Recently, artificial intelligence (AI), using deep learning and a convolutional neural network (CNN), has made remarkable progress in various medical fields. Here, we constructed an AI-assisted CNN computer-aided diagnosis (CAD) system, based on ME-NBI images, to diagnose EGC and evaluated the diagnostic accuracy of the AI-assisted CNN-CAD system. METHODS: The AI-assisted CNN-CAD system (ResNet50) was trained and validated on a dataset of 5574 ME-NBI images (3797 EGCs, 1777 non-cancerous mucosa and lesions). To evaluate the diagnostic accuracy, a separate test dataset of 2300 ME-NBI images (1430 EGCs, 870 non-cancerous mucosa and lesions) was assessed using the AI-assisted CNN-CAD system. RESULTS: The AI-assisted CNN-CAD system required 60 s to analyze 2300 test images. The overall accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of the CNN were 98.7%, 98%, 100%, 100%, and 96.8%, respectively. All misdiagnosed images of EGCs were of low-quality or of superficially depressed and intestinal-type intramucosal cancers that were difficult to distinguish from gastritis, even by experienced endoscopists. CONCLUSIONS: The AI-assisted CNN-CAD system for ME-NBI diagnosis of EGC could process many stored ME-NBI images in a short period of time and had a high diagnostic ability. This system may have great potential for future application to real clinical settings, which could facilitate ME-NBI diagnosis of EGC in practice.