Precancerous nature of intestinal metaplasia with increased chance of conversion and accelerated DNA methylation.

OBJECTIVE: The presence of intestinal metaplasia (IM) is a risk factor for gastric cancer. However, it is still controversial whether IM itself is precancerous or paracancerous. Here, we aimed to explore the precancerous nature of IM by analysing epigenetic alterations. DESIGN: Genome-wide DNA methylation analysis was conducted by EPIC BeadArray using IM crypts isolated by Alcian blue staining. Chromatin immunoprecipitation sequencing for H3K27ac and single-cell assay for transposase-accessible chromatin by sequencing were conducted using IM mucosa. NOS2 was induced using Tet-on gene expression system in normal cells. RESULTS: IM crypts had a methylation profile unique from non-IM crypts, showing extensive DNA hypermethylation in promoter CpG islands, including those of tumour-suppressor genes. Also, the IM-specific methylation profile, namely epigenetic footprint, was present in a fraction of gastric cancers with a higher frequency than expected, and suggested to be associated with good overall survival. IM organoids had remarkably high NOS2 expression, and NOS2 induction in normal cells led to accelerated induction of aberrant DNA methylation, namely epigenetic instability, by increasing DNA methyltransferase activity. IM mucosa showed dynamic enhancer reprogramming, including the regions involved in higher NOS2 expression. NOS2 had open chromatin in IM cells but not in gastric cells, and IM cells had frequent closed chromatin of tumour-suppressor genes, indicating their methylation-silencing. NOS2 expression in IM-derived organoids was upregulated by interleukin-17A, a cytokine secreted by extracellular bacterial infection. CONCLUSIONS: IM cells were considered to have a precancerous nature potentially with an increased chance of converting into cancer cells, and an accelerated DNA methylation induction due to abnormal NOS2 expression.

A comprehensive appraisal of HER2 heterogeneity in HER2-amplified and HER2-low colorectal cancer.

BACKGROUND: This study aimed to elucidate the clinicopathological and molecular features of HER2-amplified and HER2-low colorectal cancers (CRCs). We also characterised HER2 expression statuses in CRCs focusing on their intratumoral heterogeneity and alterations in metastatic lesions to establish practical HER2 status assessment. METHODS: We evaluated 1009 CRCs for HER2 expression and HER2 amplification by immunohistochemistry and FISH, respectively, and correlated the results to clinicopathological and molecular data. For HER2-positive tumours, HER2 expression in metastatic lesions was also assessed. RESULTS: Twenty-five HER2-amplified (2.5%) and 46 HER2-low tumours (4.6%) were identified. HER2-amplified tumours consistently lacked a mucinous component and HER2-low tumours tended to be in the right colon, but no other clinicopathological features were noted. KRAS, NRAS or BRAF mutations were detected in only two HER2-amplified tumours (8%), whereas 23 HER2-low tumours (50%) had one of these mutations. Most HER2-amplified and HER2-low tumours showed a homogeneous or mosaic HER2 expression pattern and a clustered heterogeneous expression pattern was rather rare. HER2 expression was maintained in most metastatic lesions in both HER2-amplified (93%) and HER2-low tumours (81%). CONCLUSIONS: These results suggest that biopsy-based assessment of primary lesions is appropriate for the identification of CRC patients eligible for systemic HER2-targeted therapy.

Clinicopathological and molecular characteristics of RSPO fusion-positive colorectal cancer.

BACKGROUND: RSPO fusions that lead to WNT pathway activation are potential therapeutic targets in colorectal cancer (CRC), but their clinicopathological significance remains unclear. METHODS: We screened 1019 CRCs for RSPO fusions using multiplex reverse transcription-PCR. The RSPO fusion-positive tumours were subjected to whole-exome sequencing (WES). RESULTS: Our analysis identified 29 CRCs with RSPO fusions (2.8%), consisting of five with an EIF3E-RSPO2 fusion and 24 with PTPRK-RSPO3 fusions. The patients were 17 women and 12 men. Thirteen tumours (45%) were right-sided. Histologically, approximately half of the tumours (13/29, 45%) had a focal or extensive mucinous component that was significantly more frequent than the RSPO fusion-negative tumours (13%; P = 8.1 × 10-7). Four tumours (14%) were mismatch repair-deficient. WES identified KRAS, BRAF, and NRAS mutations in a total of 27 tumours (93%). In contrast, pathogenic mutations in major WNT pathway genes, such as APC, CTNNB1 and RNF43, were absent. RSPO fusion status did not have a statistically significant influence on the overall or recurrence-free survival. These clinicopathological and genetic features were also confirmed in a pooled analysis of previous studies. CONCLUSION: RSPO fusion-positive CRCs constitute a rare subgroup of CRCs with several characteristic clinicopathological and genetic features.

NTRK fusion-positive colorectal cancer in Japanese population.

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.

Identification of serum microRNAs predicting the response of esophageal squamous-cell carcinoma to nivolumab.

BACKGROUND: Nivolumab, 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; JapicCTI-No.142422). We explored serum microRNA (miRNA) candidate predictive markers of the response to nivolumab. METHODS: In 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. RESULTS: Of 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). CONCLUSIONS: Candidate 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.

Re-infection of Toxoplasma gondii after HSCT presenting lymphadenopathy resembling recurrence of lymphoma.

Toxoplasma gondii (T. gondii) reactivation is one of the fatal complications after hematopoietic stem cell transplantation (HSCT); however, re-infection has not been reported. Here, we report a case of mycosis fungoides in which cervical lymphadenopathy developed after HSCT. Initially, recurrent lymphoma was suspected. However, biopsy of the lymph node showed typical histology of toxoplasmosis and serology showed re-infection of T. gondii. Toxoplasmosis needs to be differentiated for cases with lymphoadenopthy after HSCT.

Uterine Leiomyosarcoma Masquerading as a Malignant Perivascular Epithelioid Cell Tumor: A Diagnostic Challenge.

Uterine sarcomas with myomelanocytic differentiation have been reported to be diagnostically challenging. We report a case of uterine leiomyosarcoma with extensive perivascular epithelioid cell tumor (PEComa)-like areas and extrauterine metastases. The patient was a 49-year-old gravida 3 para 2 Japanese woman with no relevant medical history. She noticed a vaginal mass with bleeding. Imaging examination revealed a uterine tumor and multiple liver and lung metastases. The vaginal tumor (3.5 cm) was resected and diagnosed as a malignant PEComa based on morphology and myomelanocytic marker expression. Clinically used targeted sequencing (FoundationOneCDx™) revealed gene alterations in RB1, TP53, and ATRX but not TSC1/2. Despite administration of an mTOR inhibitor, the tumor size increased, and subsequently, hysterectomy was performed to relieve the symptoms. The uterine tumor was composed of conventional leiomyosarcoma showing RB1 loss, wild-type TP53 staining, and retained ATRX expression, as well as adjacent predominant PEComa-like components with RB1 loss, TP53 overexpression, and ATRX loss, identical to the characteristics of the vaginal tumor. In the uterine tumor, both HMB-45 and MITF were weak to moderately positive for approximately 40% of tumor cells while Melan-A was negative. The tumor was finally diagnosed as leiomyosarcoma with PEComa-like features. This case exemplifies the tumorigenesis of diagnostically challenging tumors with myomelanocytic differentiation and demonstrates the importance of integrating multiple types of information, including genomic profiling, in making a correct diagnosis leading to appropriate treatment.

Sporadic and Familial Adenomatous Polyposis-associated Foveolar-type Adenoma of the Stomach.

Gastric foveolar-type adenoma (FA) is a rare benign neoplasm occurring either sporadically or in patients with familial adenomatous polyposis (FAP). However, the molecular features of FA and the relationship between sporadic and syndromic lesions remain unclear. In this study, we performed clinicopathological, immunohistochemical, and genetic analyses of 18 sporadic and 30 FAP-associated FAs. Most sporadic and FAP-associated FAs were located in the upper or middle third of the stomach, on a background of fundic gland mucosa. Most lesions were low-grade, but 3 lesions had a high-grade component. Sporadic FAs included 2 morphologically distinct subtypes, that is, flat and raspberry-like FAs, which we distinguished based on the endoscopic features. Seven lesions were regarded as flat FAs, appearing as large, slightly elevated lesions and measuring 11 to 87 mm in size. Conversely, 10 raspberry-like FAs were small bright-red polyps, measuring 2 to 8 mm in size. FAP-associated FAs, particularly larger lesions, exhibited morphologic features resembling flat FAs but varied significantly in size (2 to 103 mm). Mutation analysis identified APC and KRAS mutations in all flat FAs but never in raspberry-like FAs. Remarkably, somatic APC and KRAS mutations were also detected in 19 (63%) and 27 (90%) of FAP-associated FAs, respectively. This indicates that they are genetically equivalent to sporadic, flat FAs. This study showed that sporadic FA includes at least 2 morphologically and genetically distinct subtypes: flat and raspberry-like FA. Furthermore, flat FA represents a sporadic counterpart of FAP-associated FA.

Microcystic stromal tumor of the ovary: a recurrent case with somatic CTNNB1 missense mutation.

Microcystic stromal tumors (MCSTs) of the ovary are rare sex cord-stromal tumors that are considered benign neoplasms because almost all cases display unilateral, localized lesions and have benign outcomes, except for one recurrent case with familial adenomatous polyposis and another initial metastatic case with a CTNNB1 mutation. We report herein a sporadic case that relapsed as intra-abdominal spread 9 years and 1 month after primary left salpingo-oophorectomy for torsion of the ovarian tumor pedicle. The tumor relapsed as multiple disseminations at the subabdominal wall, Douglas pouch, and omentum. Histologically, the tumor cells formed microcysts and infiltrated the surrounding adipose tissue, similar to the invasive implants of ovarian epithelial borderline tumors. Mutation analysis of the recurrent tumor revealed a somatic CTNNB1 p.S33Y activated missense mutation and a germline KDR p.Q472H variant. In conclusion, long-term clinical follow-up may be needed to detect any recurrence of MCST, irrespective of familial adenomatous polyposis.

Activating KRAS and GNAS mutations in heterotopic submucosal glands of the stomach.

BACKGROUND: 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. METHODS: To determine whether genetic alterations are involved in HSG development, we analyzed 63 gastric HSG lesions using targeted next-generation sequencing and immunohistochemistry. RESULTS: 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. CONCLUSIONS: 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.

Identification of Novel Diagnostic Markers for Malignant Pleural Mesothelioma Using a Reverse Translational Approach Based on a Rare Synchronous Tumor.

Although the routine use of immunohistochemistry has improved the accuracy of histopathologic diagnosis in clinical practice, new methods for discovering novel diagnostic markers are still needed. We sought new diagnostic markers for malignant pleural mesothelioma (MPM) using a reverse translational approach with limited archival tissues from a very rare case. Total RNA extracted from formalin-fixed paraffin-embedded (FFPE) tissues of a synchronous collision tumor consisting of MPM and pulmonary adenocarcinoma (PAC) was employed for gene expression profiling (GEP) analysis. Among the 54 genes selected by GEP analysis, we finally identified the following two candidate MPM marker genes: PHGDH and TRIM29. Immunohistochemical analysis of 48 MM and 20 PAC cases showed that both PHGDH and TRIM29 had sensitivity and specificity almost equivalent to those of calretinin (sensitivity 50% and 46% vs. 63%, and specificity 95% and 100% vs. 100%, respectively). Importantly, of the 23 epithelioid MMs, all 3 calretinin-negative cases were positive for TRIM29. These two markers may be diagnostically useful for immunohistochemical distinction between MPMs and PACs. This successful reverse translational approach based on FFPE samples from one very rare case encourages the further use of such samples for the development of novel diagnostic markers.

Gastric-type cervical adenocarcinoma with squamous differentiation: buried in adenosquamous carcinomas?

Gastric-type adenocarcinoma (GAS) of the cervix is a human papilloma virus (HPV)-independent, aggressive, and chemo-resistant adenocarcinoma. However, although the histopathological features of GAS have been extensively investigated, squamous differentiation has not been mentioned. This study aimed to elucidate the frequency of GAS with squamous differentiation and describe their clinicopathological characteristics. We retrospectively evaluated 78 patients with GAS (n = 13) and adenosquamous carcinoma (n = 65) diagnosed between 2000 and 2020. Two patients with GAS with squamous differentiation were identified. Both tumors showed advanced stage (pT2bN1) and had predominant GAS and merged squamous cell carcinoma components without p16-block positivity and HPV DNA. Gastric-type adenocarcinoma in situ was confirmed in both cases. Some cases of GAS could show squamous differentiation mimicking the usual, HPV-associated, adenosquamous carcinoma. GAS with squamous differentiation is recognized as an HPV-independent cancer.

APC mutations are common in adenomas but infrequent in adenocarcinomas of the non-ampullary duodenum.

BACKGROUND: Recent studies highlighted the clinicopathological heterogeneity of non-ampullary duodenal adenomas and adenocarcinomas, but the detailed process of the malignant transformation remains unclear. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Clear Cell Carcinoma of the Cervix With OHVIRA Syndrome: A Rare Case Report.

Obstructed hemivagina and ipsilateral renal agenesis (OHVIRA) syndrome is a rare Mullerian duct anomaly characterized by an obstructed hemivagina, ipsilateral renal agenesis, and uterine didelphys. There are only a few published case reports of OHVIRA syndrome, and cases of OHVIRA syndrome associated with cancer have rarely been reported. In fact, there is only one published report of a case with clear cell carcinoma (CCC) of the cervix. Here, we report a case of CCC of the cervix with OHVIRA syndrome that underwent abdominal radical hysterectomy; we also provide a short literature review of this topic. A 52-year-old woman presented with abnormal vaginal bleeding for 1 month 2 years after menopause. A pelvic examination and preoperative imaging showed uterine didelphys, an obstructed hemivagina with a mass measuring approximately 2 cm located in her left cervix, and an absence of her left kidney. A colposcopy biopsy reported CCC of the cervix. Clinical staging classified her with stage IB1 disease. Abdominal radical hysterectomy was performed. Her left ectopic ureter led to the left cervix and opened in the endometrium, resulting in a so-called ectopic ureter. Macroscopic examination of the excised specimens showed two cervixes, two corpora of the uterus, and a tumor measuring 1.0 × 2.0 cm on the left cervix. In addition to typical OHVIRA symptoms including uterine didelphys, obstructed hemivagina, and renal agenesis, several anatomical variants were present. The current case included those variants as well as an atrophic kidney with an ectopic ureter to the obstructed hemivagina. Based on the results of our case, clinicians should be aware of the risks of cancer and anatomical variants associated with OHVIRA syndrome.

Clinicopathologic and Molecular Characteristics of Familial Adenomatous Polyposis-associated Traditional Serrated Adenoma.

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.

Loss of nivolumab binding to T cell PD-1 predicts relapse of Hodgkin lymphoma.

Nivolumab is effective in the treatment of classical Hodgkin lymphoma that relapsed after allogeneic hematopoietic stem cell transplantation (SCT) with the risk of graft-versus-host disease; however, the optimal time and dose of nivolumab administration remain to be investigated. Nivolumab binding to PD-1 masks flowcytometric detection of PD-1 by the anti-PD-1 monoclonal antibody EH12.1. Using this method, we monitored nivolumab binding on T cells after nivolumab treatment in a patient with classical Hodgkin lymphoma relapsed after allogeneic SCT. Nivolumab was effective while prolonged nivolumab binding was evident, but restoration of PD-1 staining predicted tumor relapse. Flowcytometric monitoring of nivolumab binding on T cells could be a promising biomarker for predicting tumor relapse and determining the timing of nivolumab administration.

Familial multifocal micronodular pneumocyte hyperplasia with a novel splicing mutation in TSC1: Three cases in one family.

Multifocal micronodular pneumocyte hyperplasia (MMPH) is a rare pulmonary disease, generally manifesting as a tuberous sclerosis complex (TSC), characterised by multiple, small ground-glass nodular shadows on chest computed tomography (CT). Histological examination typically reveals multicentric, well-demarcated, nodular type II pneumocystic growth. Herein, we describe three cases of this rare pulmonary disease occurring within one family. Using reverse transcription polymerase chain reaction (RT-PCR) and direct DNA sequencing, we identified a novel germline mutation, a point mutation in TSC1 intron 5, which yielded a splice variant and loss of function of TSC1. Furthermore, immunohistochemical staining indicated the expression of phospho-p70S6K and phospho-4E-BP1, suggesting that TSC1 function was impaired by the novel gene mutation in MMPH cells.

Hepatocellular carcinoma producing granulocyte colony-stimulating factor: diagnosis and treatment.

Granulocyte colony-stimulating factor (G-CSF) is a naturally occurring glycoprotein that is synthesized by stromal cells in bone marrow. Several cases of G-CSF-producing malignant tumors in various organs have been reported, but it is extremely rare in hepatocellular carcinoma (HCC). Here, we report a rare case of HCC producing G-CSF. The patient presented with a continuous fever and had a huge liver mass in the right lobe with portal vein tumor thrombus (PVTT) in the right first branch. He had marked granulocytosis, and his serum level of G-CSF was elevated. A complete curative liver resection was performed after preoperative radiotherapy to PVTT. The pathological findings of the resected specimen revealed poorly/moderately differentiated HCC, and immunohistochemical staining of G-CSF was negative the first time it was tested, but the second time, it was positive in the cytoplasm of other tumor cells of HCC. Only a few cases of G-CSF-producing HCC have been reported, and they resulted in rapid tumor growth, metastases, and poor prognosis. In our case with PVTT, there was no liver recurrence, although multiple lung metastases occurred at 8 months after curative resection. We should consider G-CSF-producing HCC and diagnose promptly when encountering liver tumor patients with leukocytosis, and we should perform multimodal treatment including radiation, radical surgery, and chemotherapy.