Evolutionary histories of breast cancer and related clones.

Recent studies have documented frequent evolution of clones carrying common cancer mutations in apparently normal tissues, which are implicated in cancer development1-3. However, our knowledge is still missing with regard to what additional driver events take place in what order, before one or more of these clones in normal tissues ultimately evolve to cancer. Here, using phylogenetic analyses of multiple microdissected samples from both cancer and non-cancer lesions, we show unique evolutionary histories of breast cancers harbouring der(1;16), a common driver alteration found in roughly 20% of breast cancers. The approximate timing of early evolutionary events was estimated from the mutation rate measured in normal epithelial cells. In der(1;16)(+) cancers, the derivative chromosome was acquired from early puberty to late adolescence, followed by the emergence of a common ancestor by the patient's early 30s, from which both cancer and non-cancer clones evolved. Replacing the pre-existing mammary epithelium in the following years, these clones occupied a large area within the premenopausal breast tissues by the time of cancer diagnosis. Evolution of multiple independent cancer founders from the non-cancer ancestors was common, contributing to intratumour heterogeneity. The number of driver events did not correlate with histology, suggesting the role of local microenvironments and/or epigenetic driver events. A similar evolutionary pattern was also observed in another case evolving from an AKT1-mutated founder. Taken together, our findings provide new insight into how breast cancer evolves.

Frequent mutations that converge on the NFKBIZ pathway in ulcerative colitis.

Chronic inflammation is accompanied by recurring cycles of tissue destruction and repair and is associated with an increased risk of cancer1-3. However, how such cycles affect the clonal composition of tissues, particularly in terms of cancer development, remains unknown. Here we show that in patients with ulcerative colitis, the inflamed intestine undergoes widespread remodelling by pervasive clones, many of which are positively selected by acquiring mutations that commonly involve the NFKBIZ, TRAF3IP2, ZC3H12A, PIGR and HNRNPF genes and are implicated in the downregulation of IL-17 and other pro-inflammatory signals. Mutational profiles vary substantially between colitis-associated cancer and non-dysplastic tissues in ulcerative colitis, which indicates that there are distinct mechanisms of positive selection in both tissues. In particular, mutations in NFKBIZ are highly prevalent in the epithelium of patients with ulcerative colitis but rarely found in both sporadic and colitis-associated cancer, indicating that NFKBIZ-mutant cells are selected against during colorectal carcinogenesis. In further support of this negative selection, we found that tumour formation was significantly attenuated in Nfkbiz-mutant mice and cell competition was compromised by disruption of NFKBIZ in human colorectal cancer cells. Our results highlight common and discrete mechanisms of clonal selection in inflammatory tissues, which reveal unexpected cancer vulnerabilities that could potentially be exploited for therapeutics in colorectal cancer.

Age-related remodelling of oesophageal epithelia by mutated cancer drivers.

Clonal expansion in aged normal tissues has been implicated in the development of cancer. However, the chronology and risk dependence of the expansion are poorly understood. Here we intensively sequence 682 micro-scale oesophageal samples and show, in physiologically normal oesophageal epithelia, the progressive age-related expansion of clones that carry mutations in driver genes (predominantly NOTCH1), which is substantially accelerated by alcohol consumption and by smoking. Driver-mutated clones emerge multifocally from early childhood and increase their number and size with ageing, and ultimately replace almost the entire oesophageal epithelium in the extremely elderly. Compared with mutations in oesophageal cancer, there is a marked overrepresentation of NOTCH1 and PPM1D mutations in physiologically normal oesophageal epithelia; these mutations can be acquired before late adolescence (as early as early infancy) and significantly increase in number with heavy smoking and drinking. The remodelling of the oesophageal epithelium by driver-mutated clones is an inevitable consequence of normal ageing, which-depending on lifestyle risks-may affect cancer development.

On the origin of gastric tumours: analysis of a case with intramucosal gastric carcinoma and oxyntic gland adenoma.

Most gastric cancers develop in inflamed gastric mucosa due to Helicobacter pylori infection, typically with metaplastic changes. However, the origins of gastric cancer remain unknown. Here, we present a case of intramucosal gastric carcinoma (IGC) and oxyntic gland adenoma (OGA) derived from spasmolytic polypeptide-expressing metaplasia (SPEM). Early gastric cancer adjacent to a polyp was found in the upper corpus of a 71-year-old woman without H. pylori infection and was endoscopically resected. Histological examination showed IGC and OGA, both of which had predominant MUC6 expression. Interestingly, gastric glands with enriched MUC6-positive mucous cells, referred to as SPEM, expanded between them. Whole-exome sequencing analysis revealed a truncating KRAS(G12D) mutation in IGC, OGA, and SPEM. In addition, TP53 and CDKN2A mutations and a loss of chromosome 17p were found in the IGC, whereas a GNAS mutation was observed in the OGA. These results indicated that IGC and OGA originated from the KRAS-mutated SPEM. © 2023 The Pathological Society of Great Britain and Ireland.

Clinical and imaging characteristics of supratentorial glioma with IDH2 mutation.

PURPOSE: The rarity of IDH2 mutations in supratentorial gliomas has led to gaps in understanding their radiological characteristics, potentially resulting in misdiagnosis based solely on negative IDH1 immunohistochemical staining. We aimed to investigate the clinical and imaging characteristics of IDH2-mutant gliomas. METHODS: We analyzed imaging data from adult patients with pathologically confirmed diffuse lower-grade gliomas and known IDH1/2 alteration and 1p/19q codeletion statuses obtained from the records of our institute (January 2011 to August 2022, Cohort 1) and The Cancer Imaging Archive (TCIA, Cohort 2). Two radiologists evaluated clinical information and radiological findings using standardized methods. Furthermore, we compared the data for IDH2-mutant and IDH-wildtype gliomas. Multivariate logistic regression was used to identify the predictors of IDH2 mutation status, and receiver operating characteristic curve analysis was employed to assess the predictive performance of the model. RESULTS: Of the 20 IDH2-mutant supratentorial gliomas, 95% were in the frontal lobes, with 75% classified as oligodendrogliomas. Age and the T2-FLAIR discordance were independent predictors of IDH2 mutations. Receiver operating characteristic curve analysis for the model using age and T2-FLAIR discordance demonstrated a strong potential for discriminating between IDH2-mutant and IDH-wildtype gliomas, with an area under the curve of 0.96 (95% CI, 0.91-0.98, P = .02). CONCLUSION: A high frequency of oligodendrogliomas with 1p/19q codeletion was observed in IDH2-mutated gliomas. Younger age and the presence of the T2-FLAIR discordance were associated with IDH2 mutations and these findings may help with precise diagnoses and treatment decisions in clinical practice.

An exploratory study for tuft cells in the breast and their relevance in triple-negative breast cancer: the possible relationship of SOX9.

BACKGROUND: Breast cancer is highly heterogeneous, suggesting that small but relevant subsets have been under-recognized. Rare and mainly triple-negative breast cancers (TNBCs) were recently found to exhibit tuft cell-like expression profiles, including POU2F3, the tuft cell master regulator. In addition, immunohistochemistry (IHC) has identified POU2F3-positive cells in the normal human breast, suggesting the presence of tuft cells in this organ. METHODS: Here, we (i) reviewed previously identified POU2F3-positive invasive breast cancers (n = 4) for POU2F3 expression in intraductal cancer components, (ii) investigated a new cohort of invasive breast cancers (n = 1853) by POU2F3-IHC, (iii) explored POU2F3-expressing cells in non-neoplastic breast tissues obtained from women with or without BRCA1 mutations (n = 15), and (iv) reanalyzed publicly available single-cell RNA sequencing (scRNA-seq) data from normal breast cells. RESULTS: Two TNBCs of the four previously reported invasive POU2F3-positive breast cancers contained POU2F3-positive ductal carcinoma in situ (DCIS). In the new cohort of invasive breast cancers, IHC revealed four POU2F3-positive cases, two of which were triple-negative, one luminal-type, and one triple-positive. In addition, another new POU2F3-positive tumor with a triple-negative phenotype was found in daily practice. All non-neoplastic breast tissues contained POU2F3-positive cells, irrespective of BRCA1 status. The scRNA-seq reanalysis confirmed POU2F3-expressing epithelial cells (3.3% of all epithelial cells) and the 17% that co-expressed the other two tuft cell-related markers (SOX9/AVIL or SOX9/GFI1B), which suggested they were bona fide tuft cells. Of note, SOX9 is also known as the "master regulator" of TNBCs. CONCLUSIONS: POU2F3 expression defines small subsets in various breast cancer subtypes, which can be accompanied by DCIS. The mechanistic relationship between POU2F3 and SOX9 in the breast warrants further analysis to enhance our understanding of normal breast physiology and to clarify the significance of the tuft cell-like phenotype for TNBCs.

The landscape of genetic aberrations in myxofibrosarcoma.

Myxofibrosarcoma (MFS) is a rare subtype of sarcoma, whose genetic basis is poorly understood. We analyzed 69 MFS cases using whole-genome (WGS), whole-exome (WES) and/or targeted-sequencing (TS). Newly sequenced genomic data were combined with additional deposited 116 MFS samples. WGS identified a high number of structural variations (SVs) per tumor most frequently affecting the TP53 and RB1 loci, 40% of tumors showed a BRCAness-associated mutation signature, and evidence of chromothripsis was found in all cases. Most frequently mutated/copy number altered genes affected known disease drivers such as TP53 (56.2%), CDKN2A/B (29.7%), RB1 (27.0%), ATRX (19.5%) and HDLBP (18.9%). Several previously unappreciated genetic aberrations including MUC17, FLG and ZNF780A were identified in more than 20% of patients. Longitudinal analysis of paired diagnosis and relapse time points revealed a 1.2-fold mutation number increase accompanied with substantial changes in clonal composition over time. Our study highlights the genetic complexity underlying sarcomagenesis of MFS.

A novel SREBF1::NACC1 gene fusion in an unclassifiable intracranial tumour.

A 39-year-old man had an intracranial tumour without infiltration into the surrounding cerebral tissue. The tumour recurred seven times in 11 years but maintained a well-demarcated character. Histopathological examination of the 4th surgical specimens showed nests of tumour cells surrounding small blood vessels. The tumour cells harboured amphophilic cytoplasm and small round nuclei with fine chromatin, and perinuclear haloes and clear borders were frequently observed, which was unclassifiable histology. By the Deutsches Krebsforschungszentrum methylation classifier, the tumour was not classified into any of the methylation classes. mRNA sequencing identified a novel SREBF1::NACC1 gene fusion. This intracranial tumour could be a novel tumour entity with NACC1 rearrangement showing characteristic histological and diagnostic imaging findings.

Intra-cerebellar schwannoma with various degenerative changes: a case report and a systematic review.

BACKGROUND: Intra-cranial schwannomas account for less than 8% of brain tumors, among which more than 80% arise from the vestibular nerve. Intra-cerebellar schwannomas are extremely rare. Several cases have been previously reported but without remarkable degenerative changes on histology. CASE PRESENTATION: A 61-year-old man presented with worsening disorientation, and an imaging study revealed a cystic lesion (6.5 cm in the largest diameter) in the left hemisphere of the cerebellum accompanied by a mural nodule (2.5 cm) located just inside the skull with enhancement and focal calcification, in addition to hydrocephalus. The lesion was more than 5 mm from the left acoustic nerve. The patient underwent gross total resection. Pathological examination revealed remarkable degenerative changes with various morphological features. Tumor cells were pleomorphic with rich cytoplasm containing numerous eosinophilic granules. Blood vessels and extracellular matrix showed remarkable hyalinization. Immunohistochemical staining revealed that the tumor cells were positive for S-100 protein and negative for Olig2. The tumor was diagnosed as a schwannoma with marked degenerative changes. CONCLUSIONS: The present case is discussed with reference to a systematic review of previous reports of intra-cerebellar schwannoma. Intra-cerebellar schwannoma should be included in the differential diagnosis of cystic lesions with heterogeneous histopathological morphology in the cerebellum.

Maturing papillomatous nevoid melanoma in the scalp mimicking recurrent melanocytic nevus: A case report of previously undescribed subtype of nevoid melanoma.

Nevoid melanoma is a subtype of melanoma that histologically resembles a melanocytic nevus. Two subtypes have been proposed for nevoid melanoma, namely papillomatous and maturing. Here, we report the case of a 67-year-old woman who developed two nevoid melanomas on her scalp with composite histological features of papillomatous and maturing subtypes after electrocautery of a nearby solitary scalp papule. The histology of both lesions was very similar, papillary in shape, and both comprised two melanocyte populations, including large atypical melanocytes and small non-atypical melanocytes. Whole-exome sequencing was performed in one of the two lesions, which revealed a high mutation burden (17 mutations/megabase) with co-deletion of CDKN2A. Additional immunohistochemistry revealed that the large and small melanocytes in both lesions were completely negative for p16 and MTAP. A final diagnosis of nevoid melanoma was made. To our knowledge, this is the first report of a nevoid melanoma with both features of papillomatous and maturing subtypes. Pathologists should be aware of this subtype of melanoma to avoid misdiagnosis as a mitotically active melanocytic nevus. In this case, immunohistochemistry for p16 and MTAP, in addition to molecular analysis, helped in the final diagnosis.

Indolent feature of Helicobacter pylori-uninfected intramucosal signet ring cell carcinomas with CDH1 mutations.

BACKGROUND: In Helicobacter pylori (Hp)-uninfected individuals, diffuse-type gastric cancer (DGC) was reported as the most common type of cancer. However, the carcinogenic mechanism of Hp-uninfected sporadic DGC is largely unknown. METHODS: We performed whole-exome sequencing of Hp-uninfected DGCs and Hp-uninfected normal gastric mucosa. For advanced DGCs, external datasets were also analyzed. RESULTS: Eighteen patients (aged 29-78 years) with DGCs and nine normal subjects (28-77 years) were examined. The mutation burden in intramucosal DGCs (10-66 mutations per exome) from individuals aged 29-73 years was not very different from that in the normal gastric glands, which showed a constant mutation accumulation rate (0.33 mutations/exome/year). Unbiased dN/dS analysis showed that CDH1 somatic mutation was a driver mutation for intramucosal DGC. CDH1 mutation was more frequent in intramucosal DGCs (67%) than in advanced DGCs (27%). In contrast, TP53 mutation was more frequent in advanced DGCs (52%) than in intramucosal DGCs (0%). This discrepancy in mutations suggests that CDH1-mutated intramucosal DGCs make a relatively small contribution to advanced DGC formation. Among the 16 intramucosal DGCs (median size, 6.5 mm), 15 DGCs were pure signet ring cell carcinoma (SRCC) with reduced E-cadherin expression and a low proliferative capacity (median Ki-67 index, 2.4%). Five SRCCs reviewed endoscopically over 2-5 years showed no progression. CONCLUSIONS: Impaired E-cadherin function due to CDH1 mutation was considered as an early carcinogenic event of Hp-uninfected intramucosal SRCC. Genetic and clinical analyses suggest that Hp-uninfected intramucosal SRCCs may be less likely to develop into advanced DGCs.

Neonatal Fc receptor induces intravenous immunoglobulin growth suppression in Langerhans cell histiocytosis.

The neonatal Fc receptor (FcRn) plays a role in trafficking IgG and albumin and is thought to mediate intravenous immunoglobulin (IVIG) therapy for certain diseases. IVIG can be used for the treatment of human Langerhans cell histiocytosis (LCH); however, the mechanism remains unclear. The expression and function of FcRn protein have not been studied in LCH, though the expression of FcRn messenger RNA (mRNA) have been reported. In this report, we confirmed the expression of FcRn in 26 of 30 pathological cases (86.7%) diagnosed immunohistochemically as LCH. The expression was independent of age, gender, location, multi- or single-system, and the status of BRAFV600E immunostaining. We also confirmed the expression of FcRn mRNA and protein in the human LCH-like cell line, ELD-1. FcRn suppressed albumin consumption and growth of IVIG preparation-treated ELD-1 cells, but not of IVIG preparation-untreated or FcRn-knockdown ELD-1 cells. In addition, FITC-conjugated albumin was taken into Rab11-positive recycle vesicles in mock ELD-1 cells but not in FcRn-knockdown ELD-1 cells. IVIG preparation prolonged this status in mock ELD-1 cells. Therefore, ELD-1 recycled albumin via FcRn and albumin was not used for metabolism. Our results increase our understanding of the molecular mechanism of IVIG treatment of LCH.

Post-radiation fibrosarcoma of the cerebrum associated with a prominent, lace-like, perivascular, desmoplastic change.

An intra-axial tumor measuring about 4 cm was excised from the right temporal lobe of a 35-year-old woman, who had a past history of resection of craniopharyngioma and postoperative radiation 21 years earlier. The tumor involved both the cortex and white matter, but was not attached to the dura mater. It consisted of a dense, interlacing, fascicular proliferation of atypical fibroblastic cells and was associated with an extensive, lace-like, desmoplastic change mainly involving the perivascular region around the tumor and overlying the subarachnoid space. The histopathological features of the desmoplastic change resembled meningioangiomatosis, but no proliferation of meningothelial cells was noted. The patient has been free from recurrence for 12 months since the operation. The association of primary cerebral fibrosarcoma with an extensive, lace-like, perivascular, desmoplastic change has not been documented in the literature. The radiation administered 21 years previously may have played some pathogenetic role in the perivascular desmoplastic change, and a malignant transformation of fibroblasts within the perivascular collagenous tissue is considered the most likely origin of the fibrosarcoma.

Pleuroparenchymal fibroelastosis and non-specific interstitial pneumonia: frequent pulmonary sequelae of haematopoietic stem cell transplantation.

AIMS: Pulmonary sequelae, reported as chronic graft-versus-host disease (cGVHD), of haematopoietic stem cell transplantation (HSCT) include constrictive bronchiolitis obliterans (CBO), lymphocytic bronchiolitis (LB), and veno-occlusive disease (VOD); recently, pleuroparenchymal fibroelastosis (PPFE) has also been described in bone marrow transplant recipients. The histological features of pulmonary HSCT sequelae have not been described systematically. The aim of the study was to review and identify the histological features of PPFE after bone marrow transplant. METHODS AND RESULTS: A retrospective review of 20 patients who underwent lung transplantation for pulmonary disease following HSCT between 2004 and 2013 was conducted. The patient age at transplantation ranged from 8 years to 57 years (median, 27.5 years). Fifteen patients had cGVHD in other organs (skin, nine; liver, six; salivary gland, six). Lung transplantation was performed at a median of 4.6 years (range, 1.2-14.8 years) post-HSCT. Histologically, all cases had CBO, with concurrent LB in 10, and VOD in three. PPFE was identified in 15 cases (75%), with subpleural (15), paraseptal (11) and centrilobular (13) distributions; and non-specific interstitial pneumonia (NSIP) was identified in 15 cases (75%), with fibrotic (nine) and cellular (six) patterns. PPFE was distributed in all lobes, with a predominance in the upper lobe. NSIP was mostly focal, with two cases having diffuse involvement. CONCLUSIONS: PPFE and NSIP were frequently seen in HSCT patients. Possible causes may include reactions to drugs or radiation, or cGVHD.

Adenoma mimicking intraductal papillary neoplasm of the bile duct arising in an intrahepatic biliary duplication cyst.

We report a case of a cystic liver tumour in a 47-year-old man with Peutz-Jeghers syndrome (PJS) who had undergone sclerotherapy at another hospital for a cyst in hepatic segment IV (S4) 7 years earlier. Based on the preoperative imaging findings, the patient was diagnosed with an intraductal papillary neoplasm of the bile duct. Percutaneous transhepatic portal vein embolization was performed to increase the residual liver volume, followed by resection of the three right hepatic lobes and the caudate lobe, biliary reconstruction, and portal vein reconstruction. Pathological examination revealed an adenoma arising in an intrahepatic biliary duplication cyst. Retrospectively, the preoperative diagnosis was difficult, but it aligned with previous reports of biliary duplication cysts due to its continuity with the bile duct. Additionally, intrahepatic biliary duplication cysts with tumour lesions or cases in which 18F-fluorodeoxyglucose positron emission tomography was performed have not been previously reported. Therefore, preoperatively listing this disease as a differential diagnosis was difficult. PJS and chronic inflammation associated with cyst sclerotherapy may have contributed to tumour development in the intrahepatic biliary duplication cyst.

Successful Management of Malignant Pericarditis Using Nivolumab for Metastatic Esophageal Squamous Cell Carcinoma.

Esophageal cancer is a malignant disease with a poor prognosis and is one of the most common causes of cardiac metastasis. Malignant pericarditis may cause the repetitive accumulation of pericardial effusion, which can occasionally pose a clinical challenge. We herein report a case of malignant pericarditis in a patient with metastatic esophageal squamous cell carcinoma with cardiac tamponade, which was successfully managed with single pericardial drainage and systemic nivolumab monotherapy. This is the first case report to suggest that systemic therapy with nivolumab is a promising option for the management of malignant pericarditis.

Response to capmatinib in a patient with neuroendocrine carcinoma of the gallbladder origin harboring MET amplification.

Neuroendocrine carcinoma (NEC) of the gallbladder origin is particularly rare, accounting for only 0.38% of primary malignancies of the gallbladder, and standard therapies are limited. The MET gene encodes the tyrosine kinase receptor, c-Met. Pathogenic variants of MET, such as MET exon 14 skipping and MET amplification, result in excessive downstream signaling that promotes tumor progression. A MET inhibitor, capmatinib, blocks signaling of c-Met and has been approved by the Food and Drug Administration for non-small cell lung cancer with MET exon 14 skipping. The effectiveness of capmatinib has been reported in other cancers with MET amplification, but NEC with MET variants has not been reported. Here, we present a case of a 72-year-old woman with NEC of the gallbladder with multiple liver and lymph node metastases, who was resistant to conventional chemotherapy including carboplatin plus etoposide as first-line treatment and irinotecan as second-line treatment, but she responded to capmatinib. After 6 weeks of treatment, CT scan showed a partial response (80% reduction in size), but after 13 weeks, regrowth of liver metastasis was observed. Herein, we report a meaningful efficacy of capmatinib to the patient of NEC of the gallbladder origin with MET amplification.

Expression of FOXI1 and POU2F3 varies among different salivary gland neoplasms and is higher in Warthin tumor.

PURPOSE: Salivary gland tumors are histologically diverse. Ionocytes and tuft cells, rare epithelial cells found in normal salivary glands, might be associated with salivary tumors. Here, we explored the expression of FOXI1 and POU2F3, master regulators of ionocytes and tuft cells, respectively, for common salivary neoplasms using immunohistochemistry. METHODS: We analyzed normal salivary tissues and nine salivary gland tumors; Warthin tumors (WT), pleomorphic adenomas (PA), basal cell adenomas, and oncocytomas were benign, whereas mucoepidermoid, adenoid cystic, acinic cell, salivary duct carcinomas, and polymorphous adenocarcinomas were malignant. RESULTS: Normal salivary glands contained a few FOXI1- and POU2F3-positive cells in the ducts instead of the acini, consistent with ionocytes and tuft cells, respectively. Among the benign tumors, only WTs and PAs consistently expressed FOXI1 (10/10 and 9/10, respectively). The median H-score of WTs was significantly higher than that of PAs (17.5 vs. 4, P = 0.01). While WTs and PAs harbored POU2F3-positive cells (10/10 and 9/10, respectively), the median H-score was higher in WTs than in PAs (10.5 vs 4, respectively). Furthermore, WTs exhibited a unique staining pattern of FOXI1- and POU2F3-positive cells, which were present in luminal and abluminal locations, respectively. Whereas none of the malignant tumors expressed FOXI1, only adenoid cystic carcinoma consistently expressed POU2F3 (5/5), with a median H-score of 4. CONCLUSION: The expression patterns of the characteristic transcription factors found in ionocytes and tuft cells vary among salivary gland tumor types and are higher in WT, which might be relevant for understanding and diagnosing salivary gland neoplasms.