Loss-of-function mutations in ATP6AP1 and ATP6AP2 in granular cell tumors

Oral Granular Cell Tumour on the Mandibular Gingiva in an Adult: A Rare Case Report

Introduction: Granular cell tumours are rare benign tumours. In the oral cavity, these tumours are predominantly found on the tongue. This report describes a rare case of a granular cell tumour arising on the gingiva. Case Presentation: A 75-year-old man was referred to the department with a mandibular gingival mass. Intraoral examination revealed a relatively firm mass in the lingual gingiva around the left mandibular premolar. Biopsy results led to a diagnosis of granular cell tumour. Conclusion: Oral granular cell tumours can, in rare cases, occur in areas other than the tongue, such as the gingiva.

Hybrid granular cell tumor/perineurioma: a report of two rare cases with PIK3CA mutations

Hybrid peripheral nerve sheath tumors (PNSTs) are rare mesenchymal neoplasms with dual differentiation, most often combining two of the three main PNST types: schwannoma, neurofibroma, and perineurioma. Recognized by the WHO since 2013, these tumors can also exhibit fewer common combinations, such as hybrid granular cell tumor/perineurioma. We herein report two rare cases of hybrid granular cell tumor perineurioma with molecular analysis. Both tumors presented as dermal to subcutaneous, well-circumscribed lesions composed of a combination of spindled and granular cell components. By immunohistochemistry, the granular cells were positive for S100, SOX10, and CD68, while the perineurial cells were highlighted by EMA and GLUT1 stains. Subsequent molecular testing revealed pathogenic mutations involving PIK3CA in both cases. Our study expands on the clinical and pathologic spectrum and provides the first molecular data on these unusual neoplasms. Further, we provide a comprehensive review of the literature of all previously reported cases and briefly discuss relevant differential diagnoses and their molecular features.

Benign granular cell tumor of the abdominal wall mimicking postpartum desmoid tumor

Granular cell tumors are uncommon soft tissue neoplasms derived from Schwann cells. It is extremely rare for granular cell tumors to be found in the anterior abdominal wall, with only 12 cases of benign abdominal wall granular cell tumors reported in the medical literature to date. We report a case of an upper abdominal wall granular cell tumor in a recently postpartum 35-year-old woman. Based on the patient's history, recent postpartum presentation, and imaging findings, the soft tissue tumor was initially suspected to be a desmoid tumor. Therefore, following biopsy and resection, the final histopathological diagnosis of benign granular cell tumor was quite unusual. Herein, we discuss a unique presentation of benign granular cell tumor and its diagnostic workup, including imaging and histopathologic findings, to highlight the possibility of this rare entity in the differential diagnosis of certain abdominal wall soft tissue masses.

ATP6AP1 promotes cell proliferation and tamoxifen resistance in luminal breast cancer by inducing autophagy

Autophagy is a highly conserved cellular process essential for maintaining cellular homeostasis and influencing cancer development. Lysosomal acidification and autophagosome-lysosome fusion are two important steps of autophagy degradation that are tightly regulated. Although many key proteins that regulate these two events have been identified, the effector proteins that co-regulate both steps remain to be explored. ATP6AP1, an accessory subunit of V-ATPase, plays a critical role in the assembly and regulation of V-ATPase. However, the function of ATP6AP1 in autophagy remains unknown, and the role of ATP6AP1 in cancer is still poorly understood. In this study, we found that ATP6AP1 is overexpressed in luminal breast cancer tissues and promotes the proliferation and tamoxifen resistance of luminal breast cancer cells both in vitro and in vivo. We also observed that high ATP6AP1 expression correlates with poor overall patient survival. Our research further revealed that ATP6AP1 enhances tamoxifen resistance by activating autophagy. Mechanistically, ATP6AP1 promotes autophagy by regulating both lysosomal acidification and autophagosome-lysosome fusion. Remarkably, ATP6AP1 induces lysosomal acidification through the regulation of V-ATPase assembly and facilitates autophagosome-lysosome fusion by enhancing the interaction between Rab7 and the HOPS complex. Together, our studies identify ATP6AP1 as a crucial regulator of autophagy, potentially serving as a valuable prognostic marker or therapeutic target in human luminal breast cancer.

Mesenchymal Tumors of the Tubular Gastrointestinal Tract (Non-GIST): The GI Pathologist's Approach

Mesenchymal neoplasms of the gastrointestinal tract are rare compared with epithelial lesions. However, over the past few decades, the increasing volume of gastrointestinal endoscopy has expedited the recognition of several novel entities with varying clinical significance. Its spectrum extends from reactive changes and benign neoplasms to highly aggressive sarcomas. At the malignant end of the spectrum, the importance of correctly diagnosing these tumors is underscored by the specific therapeutic implications available for some tumor types (eg, tyrosine kinase inhibitors for gastrointestinal stromal tumors) that allow personalized treatments. Benign lesions frequently surface among routine polypectomy specimens, sometimes offering diagnostic challenges. However, precise classification is the only way to avoid prognostic uncertainty and overtreatment, and to recognize possible syndromic associations. Hereby, we offer a pragmatic review of the topic from the gastrointestinal pathologist's perspective, who, although more accustomed to epithelial neoplasms, can use an algorithmic approach to diagnose mesenchymal entities successfully.

A Granular Cell Tumor Arising in a Patient with Long-segment Barrett's Esophagus

Esophageal cell tumors are rare. Esophagogastroduodenoscopy performed on a 48-year-old woman revealed an elevated esophageal lesion and the presence of long-segment Barrett's esophagus. Endoscopic ultrasonography showed a 15 mm homogeneous hypoechoic tumor extending from the lamina propria mucosa to the submucosa. Pathological examination of the biopsy tissue revealed a sheet-like cluster of histiocytoid cells with an abundant eosinophilic granular cytoplasm. Immunohistochemical examination revealed S-100(+) and CD68(+), thus suggesting the diagnosis of a granular cell tumor. The tumor was resected by endoscopic submucosal dissection. Pathologically, the background mucosa was Barrett's mucosa. This is the first reported case of an esophageal granular cell tumor in long-segment Barrett's esophagus.

Lysosomal NKG7 restrains mTORC1 activity to promote CD8+ T cell durability and tumor control

During infection and cancer, mTORC1-mediated metabolic regulation impacts CD8+ T cell effector expansion and memory development. However, the mechanisms by which CD8+ T cells regulate mTORC1 to support their unique metabolic requirements remain unknown. Here we show that NKG7, a lysosomal protein whose expression is restricted to cytotoxic lymphocytes, negatively regulates mTORC1 recruitment and activation by inhibiting assembly and function of the lysosomal proton pump, vacuolar ATPase (v-ATPase). Human and mouse CD8+ T cells lacking NKG7 show more acidic lysosomes and increased activation of mTORC1 signaling, which could be reversed by inhibition of v-ATPase activity. In mice responding to LCMV infection, NKG7-deleted effector CD8+ T cells are less durable and generate fewer memory precursors, whereas induced expression of NKG7 in CD8+ T cells results in increased presence of intra-tumoral T cells. Overall, our work identifies NKG7 as a CD8+ T cell-specific regulator of mTORC1 activity, required for optimal immune responses.

Oral granular cell tumors: an analysis of the clinical and histopathologic features of 126 tumors

OBJECTIVE

To characterize the clinical and histologic features of oral granular cell tumors (GCTs).

STUDY DESIGN

A retrospective search of the archives of our diagnostic oral pathology service was performed for GCTs diagnosed between 1989 and 2023. A total of 126 tumors in 122 patients were retrieved.

RESULTS

There was a female predilection with a female-to-male ratio of 2.3:1. The age range was 5-73 years (mean = 33.3). The most commonly involved site was the tongue (81.0%), followed by the lips (7.9%). Most GCTs were pink, but many lesions appeared yellow or white. Histologically, most GCTs were sessile masses comprised of sheets or nodules of tumor cells. Uncommonly, GCTs were pedunculated (3.2%), papillary (2.4%), ulcerated (3.2%), or desmoplastic (11.1%). Pseudoepitheliomatous hyperplasia, histologically mimicking squamous cell carcinoma, was present in 25.4% of tumors. While 65.9% of GCTs demonstrated positive surgical margins, only 3 tumors recurred.

CONCLUSIONS

To the best of our knowledge, this is the largest series of oral GCTs with a comprehensive analysis of the clinical and histologic features. It is important for clinicians and pathologists to be aware of the spectrum of features observed in GCTs in order to avoid erroneous classification as malignancy.

Unveiling the structural proteome of an Alzheimer's disease rat brain model

Studying native protein structures at near-atomic resolution in a crowded environment presents challenges. Consequently, understanding the structural intricacies of proteins within pathologically affected tissues often relies on mass spectrometry and proteomic analysis. Here, we utilized cryoelectron microscopy (cryo-EM) and the Build and Retrieve (BaR) method to investigate protein complexes' structural characteristics such as post-translational modification, active site occupancy, and arrested conformational state in Alzheimer's disease (AD) using brain lysate from a rat model (TgF344-AD). Our findings reveal novel insights into the architecture of these complexes, corroborated through mass spectrometry analysis. Interestingly, it has been shown that the dysfunction of these protein complexes extends beyond AD, implicating them in cancer, as well as other neurodegenerative disorders such as Parkinson's disease, Huntington's disease, and schizophrenia. By elucidating these structural details, our work not only enhances our understanding of disease pathology but also suggests new avenues for future approaches in therapeutic intervention.

Lysosomal gene ATP6AP1 promotes doxorubicin resistance via up-regulating autophagic flux in breast cancer

BACKGROUND

Breast cancer remains the most prevalent malignancy in women. Chemotherapy is the primary systemic treatment modality, and the effectiveness of treatment is often hampered by chemoresistance. Autophagy has been implicated in promoting chemoresistance, as elevated autophagic flux supports tumor cell survival under therapeutic stress. Since lysosomes are essential for the completion of autophagy, their role in autophagy-related chemoresistance has been insufficiently studied. This study aims to elucidate the role of the lysosomal gene ATP6AP1 in promoting chemoresistance in breast cancer by upregulating autophagic flux.

METHODS

Doxorubicin-induced cell death was assessed by cytotoxicity, flow cytometry, lactate dehydrogenase (LDH) release assays in various breast cancer cell lines. Autophagic flux was assessed with western blot and the mRFP-GFP-LC3 fluorescence imaging. Breast cancer cells were infected with shRNA lentivirus targeting ATP6AP1, allowing investigation its tole in doxorubicin-induced cell death. ATP6AP1 expression and its association with prognosis were evaluated using public databases and immunohistochemistry.

RESULTS

Doxorubicin-induced cell death in breast cancer cells is negatively correlated with increased autophagic flux and lysosomal acidification. The lysosomal gene ATP6AP1, which plays a role in autophagic processes, is upregulated in breast cancer tissues. Knocking down ATP6AP1 reduces autophagy-mediated doxorubicin resistance by inhibiting autophagic flux and lysosomal acidification in breast cancer cells. Data analysis from public databases and our cohort indicate that elevated ATP6AP1 expression correlates with poor response to doxorubicin-based neoadjuvant chemotherapy (NAC) and worse prognosis.

CONCLUSIONS

Doxorubicin-induced cytotoxicity is associated with autophagy flux in breast cancer. The lysosomal gene ATP6AP1 facilitates autolysosome acidification and contributes to doxorubicin resistance in breast cancer.

Liver Transcriptome Analysis Reveals the Mechanisms of Metabolic Adaptation of Xizang Sheep to Seasonal Changes

Background/Objectives: The Xizang sheep is a unique breed of sheep in the highland regions of China that has gradually developed physiological characteristics adapted to the plate environment through long-term natural selection and artificial breeding. However, little is known about the molecular basis of metabolic adaptation to seasons in Xizang sheep. Methods: In this study, liver tissues from Xizang sheep in summer (SL) and autumn (AL) were selected for transcriptome sequencing to explore the metabolic adaptability of Xizang sheep to seasons. Results: The results showed that a total of 12,046 differentially expressed genes (DEGs) were identified, with 1123 genes significantly upregulated and 951 genes significantly downregulated in autumn. The top five pathways enriched for DEGs were Metabolic pathways, Phagosome, Valine, leucine and isoleucine degradation, Propanoate metabolism, and Fatty acid metabolism, which are involved in immune regulation, fat oxidation, and synthesis. The reduction in lipid synthesis, fatty acid oxidation, and fat breakdown metabolism promotes gluconeogenesis by inhibiting the Peroxisome proliferator-activated receptors (PPAR) and Phosphoinositide 3-kinase- Protein kinase B (PI3K-Akt) signaling pathways. Conclusions: This process helps to maintain the whole-body energy homeostasis of Xizang sheep, facilitating their adaptation to the seasonal changes in the extreme high-altitude environment. These findings provide foundational data for studying the molecular mechanisms of metabolic adaptation to seasons in ruminants.

Big1 is a newly identified autophagy regulator that is critical for a fully functional V-ATPase

The vacuolar-type H+-translocating ATPase (V-ATPase) is the major proton pump for intraorganellar acidification. Therefore, the integrity of the V-ATPase is closely associated with cellular homeostasis, and mutations in genes encoding V-ATPase components and assembly factors have been reported in certain types of diseases. For instance, the recurrent mutations of ATP6AP1, a gene encoding a V-ATPase accessory protein, have been associated with cancers and immunodeficiency. With the aim of studying V-ATPase-related mutations using the yeast model system, we report that Big1 is another homologue of ATP6AP1 in yeast cells, and we characterize the role of Big1 in maintaining a fully functional V-ATPase. In addition to its role in acidifying the vacuole or lysosome, our data support the concept that the V-ATPase may function as part of a signaling pathway to regulate macroautophagy/autophagy through a mechanism that is independent from Tor/MTOR.

ALK -rearranged Mesenchymal Neoplasms With Prominent Foamy/Pseudolipogenic Cell Morphology : Expanding the Phenotypic Spectrum of ALK Fusion Neoplasms and Report of Novel Fusion Partners

The category of ALK -rearranged mesenchymal neoplasms has been evolving rapidly, with reports of morphologically diverse lesions of cutaneous, soft tissue, and visceral origin. While some of these represent morphologically defined entities harboring recurrent ALK fusions (inflammatory myofibroblastic tumor and epithelioid fibrous histiocytoma), others are unclassified by morphology with variable overlap with the tyrosine kinase family of neoplasia and their underlying ALK fusions cannot be suspected based on morphology. We herein report 3 cases that expand the anatomic, morphologic, and genotypic spectrum of ALK -rearranged unclassified neoplasms. Patients were all adults aged 46 to 69 (median: 63) who presented with a mass located in the gingiva, subcutis of the back, and submucosal posterior pharyngeal wall. The tumor size ranged from 1 to 2.7 cm (median: 1.6). Conservative surgery was the treatment in all patients. Follow-up was available for one patient who remained disease-free at 14 months. Histologically, all tumors displayed large polygonal cells with foamy to granular and lipogenic-like microvacuolated copious cytoplasm and medium-sized round nuclei with 1 or 2 prominent nucleoli. Mitoses and necrosis were not seen. The initial diagnostic impression was PEComa, inflammatory rhabdomyoblastic tumor and unclassified pseudolipogenic neoplasm. Strong cytoplasmic ALK was detected by immunohistochemistry in all cases. Other positive markers include Cathepsin K (2/2), desmin (1/3), focal MyoD1 (1/1), focal SMA (1/3), and focal EMA (1/2). Targeted RNA sequencing revealed ALK fusions with exon 20 (2 cases) and exon 19 (one case) of ALK fused to RND3 (exon 3), SQSTM1 (exon 6), and desmin (intron 6). Methylation profiling in the desmin-fused case (initially diagnosed as inflammatory rhabdomyoblastic tumor) revealed an inflammatory myofibroblastic tumor match with a low confidence score of 0.5 and a flat copy number variation (CNV) profile. No NF1 mutation was detected in this case, altogether excluding an inflammatory rhabdomyoblastic tumor. Our study highlights and expands the morphologic and anatomic diversity of ALK- fused neoplasms and documents novel fusion partners ( RND3 and desmin).

Atypical Multifocal Granular Cell Tumor with FLT3 Y842C Somatic Mutation: A case report and a review of the literature

INTRODUCTION

Granular cell tumors (GCT) are predominantly benign neoplasms composed by cells with abundant eosinophilic granular cytoplasm. Although the majority of GCTs exhibit a benign clinical course, a minority display cytological atypia and may exhibit aggressive, cancer-like behavior. Definitive evidence of malignancy in GCTs is reliably established only through the presence of metastasis. Addi- tionally, a subset of GCTs demonstrates a high rate of recurrence, underscoring the need for better prog- nostic markers. Therefore, it is crucial to identify molecular markers associated with aggressive behavior in GCTs. Molecular analysis may be particularly beneficial in cases exhibiting cytological atypia to in- form clinical outcome prognostication and guide therapeutic strategies.

OBSERVATION

In this case report, a 45-year-old female with multiple gastrointestinal GCTs is pre- sented. The patient did not have any genetic syndromes commonly associated with GCT, such as neu- rofibromatosis type 1, Noonan syndrome or LEOPARD syndrome. The tumors not only demonstrated nuclear atypia, but also harbored a unique FLT3 Y842C somatic alteration identified by next-genera- tion sequencing. The patient remains asymptomatic and under endoscopic surveillance two years after diagnosis and complete resection of the neoplasms.

CONCLUSION

We presented an exceedingly rare case of multifocal atypical GCT in an adult without any previously known genetic syndrome. A tumoral FLT3 Y842C point mutation not previously reported in GCT was discovered. Although the precise significance of this finding is uncertain, FLT3 Y842C has been cataloged as likely pathogenic in ClinVar. This report underscores the potential predictive utility of next-generation sequencing in the characterization and management of rare neoplasms.

Malignant granular cell tumor of chest wall: a case report

Background

Granular Cell Tumors (GCTs), also known as Abrikossoff tumors, are rare neoplasms that typically originate from Schwann cells. These tumors most commonly occur in the head and neck region, particularly the tongue. While GCTs are generally benign, less than 2% of cases exhibit aggressive biological features such as rapid growth, high recurrence rates, and metastasis. In this report, we present a rare case of a Malignant Granular Cell Tumor (MGCT) of the chest wall, which posed significant challenges in both characterization and management.

Case Presentation

A fifty-year-old man underwent an ultrasound examination for a nodular mass on his right chest wall. The ultrasound revealed a firm, hard mass measuring 2 cm x 2 cm with an uncertain diagnosis. A fine-needle aspiration biopsy (FNAB) guided by ultrasound was performed, resulting in a diagnosis of Abrikossoff tumor. The patient subsequently underwent radical excision of the mass, which confirmed the initial diagnosis. Nine months after surgery, a new mass with similar characteristics was detected during a physical examination. The patient underwent a second surgery, but this time the histopathological examination was negative for neoplastic cells. However, another mass appeared at the same site as the previous surgical excision. A CT scan and MRI of the right chest wall confirmed the presence of a 2 cm x 2 cm nodular mass. The patient then underwent a deeper excision. Histomorphological and immunohistochemical assessments confirmed the recurrence of MGCT.

Conclusion

This case highlights the malignant potential of GCTs. The numerous local recurrences necessitated three surgeries and additional procedures. The aggressive nature of this pathology underscores the complexity of managing these tumors, which are poorly understood and lack proven post-operative strategies for controlling local and distant disease.

Oral granular cell tumor: a collaborative clinicopathological study of 61 cases

BACKGROUND

Granular Cell Tumor (GCT) is an uncommon benign lesion in the oral cavity whose pathogenesis remains poorly understood. Due to their infrequent occurrence and similarity to other oral lesions, they are often forgotten during the initial clinical diagnosis. Therefore, understanding its prevalence, clinical and pathological characteristics is crucial for an accurate diagnosis and adequate management.

METHODS

All cases diagnosed as GCTs in six Brazilian and Argentinian oral diagnostic centers were re-evaluated by HE staining, and clinical, demographic, and histopathological data were collected and evaluated.

RESULTS

The series comprised 45 female (73.8%) and 16 male (26.2%), with a 2.8:1 female-to-male ratio and a mean age of 35.3 ± 16.9 years (range: 7-77 years). Most cases occurred on the tongue (n = 49; 81.6%) and presented clinically as asymptomatic papules or nodules (n = 50; 89.3%) with a normochromic (n = 25; 45.5%) or yellowish (n = 11; 20.0%) coloration and sizes ranging from 0.2 to 3.0 cm (mean ± SD: 1.40 ± 0.75 cm). Morphologically, most tumors were characterized by a poorly delimited proliferation (n = 52; 88.1%) of cells typically rounded to polygonal containing abundant, eosinophilic, finely granular cytoplasm. Pustulo-ovoid bodies of Milian were identified in all lesions (n = 61; 100%). Entrapment of skeletal striated muscle (n = 44; 72.1%) and nerve fibers (n = 42; 68.9%) were common findings. Pseudoepitheliomatous hyperplasia (PEH) was observed in 23 cases (39.0%). In only 27.7% of cases (n = 13) there was agreement between the clinical and histopathological diagnosis. Outcome information was available from 16 patients (26.2%), with clinical follow-up ranging from 4 to 36 months (mean 13.3 months), and none developed local recurrence.

CONCLUSIONS

The clinical and histopathological features of GCTs were consistent with those described in previous studies. In general, these lesions have a predilection for the lateral region of the tongue in adult women. It is essential to consider GCTs in the differential diagnosis of yellow or normochromic papules and nodules in the oral cavity. Histopathological evaluation is essential for the definitive diagnosis and the prognosis is excellent.

Gastric granular cell tumor: A case report and literature review

Granular cell tumors (GCTs) are neoplasms of uncertain histopathological etiology and therefore there are no universally accepted treatment strategies. GCTs are characterized by abundant eosinophilic granules. Since they are predominantly located in the skin and subcutaneous tissues, gastric GCTs are exceedingly rare. The present study documents the case of a 52-year-old man who visited the Gastroenterology Clinic of the People's Hospital of Putuo District (Zhoushan, China) due to upper abdominal fullness. Endoscopic ultrasonography revealed a well-defined hypoechoic nodule in the submucosal layer of the stomach body. The lesion was completely excised using endoscopic submucosal dissection and the patient made a full postoperative recovery. Immunohistochemistry showed positivity for S100 and CD68, with CD34 expression surrounding the tumor cells. At telephone follow-up until May 2024, the patient's fullness and discomfort were noted to be relieved. The characteristics of the CD34 expression pattern may serve as a novel basis for the pathological diagnosis of gastric GCTs. Endoscopic resection is a feasible option for gastric GCTs smaller than 2 cm.

Gastrointestinal Tract Granular Cell Tumor in the Pediatric Population: A Multicenter Experience

BACKGROUND

Pediatric granular cell tumors (GCT) involving the gastrointestinal tract (GIT) are rare with limited case report/series reported to date.

METHODS

Multicenter retrospective study of pediatric GIT GCT.

RESULTS

A total of 10 cases were included in the study with a median age of 13.5 years (range: 7-18 years) and were predominantly female patients (60%). In half of the patients no significant medical history was present with the remaining 5 having Crohn disease (10%), eosinophilic esophagitis (EoE) (10%), Crohn disease and EoE (10%), growth hormone deficiency (10%), and aplasia cutis congenita (10%). The GCT median size was 1.3 cm (range: 1-1.6 cm) and were more commonly located in the esophagus (70%) followed by the stomach (20%) and rectum (10%). Most of the cases showed round/polygonal tumor cells with abundant granular cytoplasm, and none of the cases had nuclear atypia, increased mitotic activity, or tumor cell necrosis. None of our cases received specific therapy for GCT other than clinical follow-up, and none of the patients had evidence of local recurrence or metastatic disease.

CONCLUSION

We present our multicenter experience with GIT GCT, all cases had a benign course. Interestingly, 4 of the esophageal GCT cases (including 2 patients with EoE) showed an eosinophil-rich esophagitis in the underlying mucosa.

Non-gastrointestinal stromal tumor, mesenchymal neoplasms of the gastrointestinal tract: a review of tumor genetics, pathology, and cross-sectional imaging findings

There is a diverse group of non-gastrointestinal stromal tumor (GIST), mesenchymal neoplasms of the gastrointestinal (GI) tract that demonstrate characteristic pathology and histogenesis as well as variable imaging findings and biological behavior. Recent advancements in tumor genetics have unveiled specific abnormalities associated with certain tumors, influencing their molecular pathogenesis, biology, response to treatment, and prognosis. Notably, giant fibrovascular polyps of the esophagus, identified through MDM2 gene amplifications, are now classified as liposarcomas. Some tumors exhibit distinctive patterns of disease distribution. Glomus tumors and plexiform fibromyxomas exhibit a pronounced affinity for the gastric antrum. In contrast, smooth muscle tumors within the GI tract are predominantly found in the esophagus and colorectum, surpassing the incidence of GISTs in these locations. Surgical resection suffices for symptomatic benign tumors; multimodality treatment may be necessary for frank sarcomas. This article aims to elucidate the cross-sectional imaging findings associated with a wide spectrum of these tumors, providing insights that align with their histopathological features.

Converging and evolving immuno-genomic routes toward immune escape in breast cancer

The interactions between tumor and immune cells along the course of breast cancer progression remain largely unknown. Here, we extensively characterize multiple sequential and parallel multiregion tumor and blood specimens of an index patient and a cohort of metastatic triple-negative breast cancers. We demonstrate that a continuous increase in tumor genomic heterogeneity and distinct molecular clocks correlated with resistance to treatment, eventually allowing tumors to escape from immune control. TCR repertoire loses diversity over time, leading to convergent evolution as breast cancer progresses. Although mixed populations of effector memory and cytotoxic single T cells coexist in the peripheral blood, defects in the antigen presentation machinery coupled with subdued T cell recruitment into metastases are observed, indicating a potent immune avoidance microenvironment not compatible with an effective antitumor response in lethal metastatic disease. Our results demonstrate that the immune responses against cancer are not static, but rather follow dynamic processes that match cancer genomic progression, illustrating the complex nature of tumor and immune cell interactions.

Genomic and epigenomic basis of breast invasive lobular carcinomas lacking CDH1 genetic alterations

CDH1 (E-cadherin) bi-allelic inactivation is the hallmark alteration of breast invasive lobular carcinoma (ILC), resulting in its discohesive phenotype. A subset of ILCs, however, lack CDH1 genetic/epigenetic inactivation, and their genetic underpinning is unknown. Through clinical targeted sequencing data reanalysis of 364 primary ILCs, we identified 25 ILCs lacking CDH1 bi-allelic genetic alterations. CDH1 promoter methylation was frequent (63%) in these cases. Targeted sequencing reanalysis revealed 3 ILCs harboring AXIN2 deleterious fusions (n = 2) or loss-of-function mutation (n = 1). Whole-genome sequencing of 3 cases lacking bi-allelic CDH1 genetic/epigenetic inactivation confirmed the AXIN2 mutation and no other cell-cell adhesion genetic alterations but revealed a new CTNND1 (p120) deleterious fusion. AXIN2 knock-out in MCF7 cells resulted in lobular-like features, including increased cellular migration and resistance to anoikis. Taken together, ILCs lacking CDH1 genetic/epigenetic alterations are driven by inactivating alterations in other cell adhesion genes (CTNND1 or AXIN2), endorsing a convergent phenotype in ILC.

Expression of Melan-A in cutaneous granular cell tumours: a diagnostic pitfall

Morphological overlap exists between cutaneous granular cell tumours (GCT) and malignant melanoma, with the melanocyte-specific markers HMB45 and Melan-A commonly used to support the diagnosis of melanoma. We recently encountered several cases of GCT in our practice showing strong expression of Melan-A. The aim of this study was to establish the prevalence of positive immunohistochemical staining for Melan-A and HMB45 in a series of unequivocal GCTs. We also aimed to assess the prevalence of staining for PRAME (PReferentially expressed Antigen in MElanoma), a marker expressed in >80% of primary melanomas as well as many non-melanocytic tumours. A total of 20 cutaneous/subcutaneous GCTs were evaluated using Melan-A, HMB45 and PRAME immunohistochemistry. Staining for Melan-A and HMB45 was scored using a semiquantitative scale from 0 (absent) to 3+ (staining present in >50% of tumour cells). PRAME expression was recorded as either positive (>75% of cell nuclei staining) or negative. Melan-A expression was observed in four GCTs (20%), with strong and diffuse (3+) staining seen in two cases (10%), both from anogenital areas. Weak patchy nuclear PRAME expression was seen in every case, interpreted to be negative. HMB45 was also negative in all cases (100%). Our study demonstrates that Melan-A expression can be strong and diffuse in a subset of otherwise unequivocal cutaneous GCTs, which may cause diagnostic confusion with malignant melanoma. HMB45 and PRAME did not stain any of the GCTs in our series.

Aberrant Expressions of PSMD14 in Tumor Tissue are the Potential Prognostic Biomarkers for Hepatocellular Carcinoma after Curative Resection

Introduction

Hepatocellular carcinoma (HCC) has a high mortality rate, with curative resection being the primary treatment. However, HCC patients have a large possibility of recurrence within 5 years after curative resection.

Methods

Thus, identifying biomarkers to predict recurrence is crucial. In our study, we analyzed data from CCLE, GEO, and TCGA, identifying eight oncogenes associated with HCC. Subsequently, the expression of 8 genes was tested in 5 cases of tumor tissues and the adjacent non-tumor tissues. Then ATP6AP1, PSMD14 and HSP90AB1 were selected to verify the expression in 63 cases of tumor tissues and the adjacent non-tumor tissues. The results showed that ATP6AP1, PSMD14, HSP90AB1 were generally highly expressed in tumor tissues. A five-year follow-up of the 63 clinical cases, combined with Kaplan-Meier Plotter's relapse-free survival (RFS) analysis, found a significant correlation between PSMD14 expression and recurrence in HCC patients. Subsequently, we analyzed the PSMD14 mutations and found that the PSMD14 gene mutations can lead to a shorter disease-free survival time for HCC patients.

Results

The results of enrichment analysis indicated that the differentially expressed genes related to PSMD14 are mainly enriched in the signal release pathway.

Conclusion

In conclusion, our research showed that PSMD14 might be related to recurrence in HCC patients, and the expression of PSMD14 in tumor tissue might be a potential prognostic biomarker after tumor resection in HCC patients.

Lip Granular Cell Tumor (GCT) in a Pediatric Patient: Critical Literature Review on Pediatric Intraoral GCT and Acquired and Congenital Intraoral Non-Neural GCT

Granular cell tumor (GCT) is an uncommon benign neoplasm derived from Schwann cells, frequently affecting the oral cavity, skin, and gastrointestinal tract. On microscopy, pseudocarcinomatous squamous hyperplasia (PSH) and perineural involvement are potential diagnostic pitfalls. GCT should be differentiated from non-neural GCT (NN-GCT). A 13-year-old male patient was referred presenting a nodular lesion on the upper lip several months ago. After excisional biopsy, microscopy revealed GCT without PSH but presenting multifocal perineural involvement. By immunohistochemistry, ALK was negative, whereas Rb and INI1 expression was intact. Moreover, with few intraoral NN-GCTs being assessed, recent studies suggest that acquired dermal NN-GCT subgroup seems to correspond to ALK-rearranged variants of epithelioid fibrous histiocytoma. Accordingly, further research on this topic is strongly encouraged.

Antiangiogenics in Malignant Granular Cell Tumors: Review of the Literature

Granular cell tumors (GCT) represent 0.5% of all soft tissue sarcomas (STS), and when metastatic, they exhibit aggressive behavior and determine limited survival. Metastatic GCTs are relatively chemo-resistant; however, there is growing evidence of the benefit of using pazopanib and other targeted therapies in this histology. This is a review of the role of pazopanib and other targeted therapies in the treatment of GCTs, along with some insights on pathology and molecular biology described in GCTs. From 256 articles found in our search, 10 case-report articles met the inclusion criteria. Pazopanib was the most employed systemic therapy. The median reported time on therapy with pazopanib was seven months. Eight out of ten patients (80%) experienced disease control with pazopanib, while four out of ten (40%) patients achieved an objective RECIST response. Molecular studies suggested that antitumoral effects of pazopanib in GCT might be due to a loss-of-function of ATP6AP1/2 genes which consequently enhance signaling through several molecular pathways, such as SFKs, STAT5a/b, and PDGFR-β. Other reported targeted therapies for malignant GCTs included pazopanib in combination with crizotinib, which showed disease control for four months in one patient, and a PI3K inhibitor which achieved disease control for nine months in another patient. Dasatinib and megestrol were ineffective in two other different patients. Pazopanib has been demonstrated to be active in advanced GCTs and may be considered as a preferable treatment option.

Expression of Connexin 43 in Granular Cell Tumors of the Skin, Tongue and Esophagus

BACKGROUND

Granular cell tumors (GCT) are rare neoplasms of Schwann cell origin occurring in the skin and in other organs. The etiopathogenesis of GCT is yet poorly understood. Connexin 43 (Cx43) is the most broadly expressed gap junction protein in humans, the tumoral role of which has been investigated in several types of tumors. Its role in GCT of the skin, oral cavity and gastrointestinal tract is as yet unknown.

METHODS

Herein, we present a study on the immunohistochemical expression of Cx43 in GCT of the skin (n = 15), tongue (n = 4) and esophagus (n = 3). Immunolabeling was scored positive (weak (+), moderate (++) or strong (+++)).

RESULTS

Cx43 was expressed by all cases of GCT of the skin, tongue and esophagus (22/22), showing moderate to strong staining. All tissue sections of GCT were characterized by a diffuse, cytoplasmic staining pattern of the tumor cells. None of those showed membranous or nuclear staining.

CONCLUSION

Our results suggest that Cx43 probably plays an important role in the development of this rare tumor entity.

Gene fusions in superficial mesenchymal neoplasms: Emerging entities and useful diagnostic adjuncts

Cutaneous mesenchymal neoplasms are diagnostically challenging because of their overlapping morphology, and, often, the limited tissue in skin biopsy specimens. Molecular and cytogenetic techniques have identified characteristic gene fusions in many of these tumor types, findings that have expanded our understanding of disease pathogenesis and motivated development of useful ancillary diagnostic tools. Here, we provide an update of new findings in tumor types that can occur in the skin and superficial subcutis, including dermatofibrosarcoma protuberans, benign fibrous histiocytoma, epithelioid fibrous histiocytoma, angiomatoid fibrous histiocytoma, glomus tumor, myopericytoma/myofibroma, non-neural granular cell tumor, CIC-rearranged sarcoma, hybrid schwannoma/perineurioma, and clear cell sarcoma. We also discuss recently described and emerging tumor types that can occur in superficial locations and that harbor gene fusions, including nested glomoid neoplasm with GLI1 alterations, clear cell tumor with melanocytic differentiation and ACTIN::MITF translocation, melanocytic tumor with CRTC1::TRIM11 fusion, EWSR1::SMAD3-rearranged fibroblastic tumor, PLAG1-rearranged fibroblastic tumor, and superficial ALK-rearranged myxoid spindle cell neoplasm. When possible, we discuss how fusion events mediate the pathogenesis of these tumor types, and we also discuss the related diagnostic and therapeutic implications of these events.

Mesenchymal Tumors of the Breast: Fibroblastic/Myofibroblastic Lesions and Other Lesions

Mesenchymal breast tumors are a rare and diverse group of tumors that present some of the most challenging cases for multidisciplinary breast cancer teams. As a result of overlapping morphologies and a lack of large-scale studies on these tumors, practices are often heterogeneous and slow to evolve. Herein, we present a non-systematic review that focuses on progress, or lack thereof, in the field of mesenchymal breast tumors. We focus on tumors originating from fibroblastic/myofibroblastic cells and tumors originating from less common cellular origins (smooth muscle, neural tissue, adipose tissue, vascular tissue, etc.).

Molecular Characterization of Multifocal Granular Cell Tumors

Granular cell tumors (GrCT) were recently found to be driven by inactivating mutations in vacuolar H + -ATPase (V-ATPase) genes, most frequently ATP6AP1 and ATP6AP2 . Multifocal presentation is present in ~10% of cases; however, the relationship between multifocal tumors in a given patient has not been elucidated. We hypothesized that benign-appearing multifocal GrCT are molecularly distinct whereas paired primary and metastatic malignant GrCT share identical mutations. To test this, we conducted targeted next-generation sequencing of the V-ATPase genes in multifocal GrCT and whole exome and Sanger sequencing in paired primary and metastatic malignant GrCT. Thirteen patients with≥2 GrCT were identified (total of 43 tumors). Forty-two tumors were successfully sequenced. Tumors showed somatic mutations in 3 of the 10 targeted genes in 32 of 42 samples (76%). Twenty tumors showed mutations in ATP6AP1 (48%), 10 tumors had mutations in ATP6AP2 (24%), and 2 tumors showed mutations in ATP6V0A4 (5%). Predicted loss-of-function mutations were found in ATP6AP1 in 17 tumors (40%), in ATP6AP2 in 10 tumors (24%), and in ATP6V0A4 in 1 tumor (2%). In 8 patients, mutually exclusive mutations were detected in at least 2 tumors per patient. Two patients were identified with malignant GrCT with material available from both primary and metastatic sites. Identical frameshift insertions were found in ATP6AP1 in 1 case and the second case showed identical nonsense mutations in ATP6AP1 . In conclusion, multifocal GrCT within an individual patient are molecularly distinct, while paired primary and metastatic GrCT share identical mutations.

Granular cell tumour of the pancreas: a case report and systematic review

PURPOSE

Granular cell tumours (GCTs) of the pancreas are mostly benign and exceptionally rare, with no unique identifying radiological features. Following a case discussion of a patient with GCT, a comprehensive review of available literature was conducted to identify the common diagnostic features associated with GCT.

METHODS

Following a case report identified in our institution, a systematic review was conducted by two authors in accordance with Preferred Reporting Items for Systematic review and Meta-Analysis protocols (PRISMA) guidelines. Databases MEDLINE, EMBASE, Scopus, World of Science, and grey literature were searched on August 2021. Inclusion criteria were histopathology diagnosed granular cell tumour of the pancreas.

RESULTS

A 37-year-old male presented with 1 month of abdominal pain and an MRI demonstrating a dilated main pancreatic duct, distal parenchymal atrophy, but no focal lesion. Repeat MRI at 6 months re-demonstrated similar findings and subsequent endoscopic ultrasound was suspicious for main duct IPMN. Following multidisciplinary team discussion, a spleen-preserving distal pancreatectomy was performed. Histopathology demonstrated granular cell tumour with cells diffusely positive for S100 and no malignant transformation. 11 case reports were identified in the literature with diagnosis confirmed on tissue histopathology based on positive immunohistochemical staining for S-100 protein. Eight patients presented with gastrointestinal symptoms with abdominal pain the main presenting complaint (50%). 10 patients underwent CT with portal venous contrast and all underwent endoscopic examination. Imaging findings were similar in five studies for EUS which demonstrated a hypoechoic lesion with homogenous appearance. On non-contrast CT GCT was iso-enhancing, and with portal venous contrast demonstrated hypo-enhancement that gradually enhanced on late phases. Pre-operative diagnosis of pancreatic carcinoma was described in six cases based on imaging and biopsy, resulting in progression to surgical resection. Nine patients were managed surgically and no complications identified on follow-up (6-52 months).

CONCLUSION

The currently proposed management pathway includes EUS with biopsy and CT, and surgical resection recommended due to malignancy risk. Improved sample collection with EUS-FNA and microscopic assessment utilising S-100 immunohistochemistry may improve pre-operative diagnosis. Limitations include rare numbers in reported literature and short follow-up not allowing an assessment of GCT's natural history and malignancy risk. Additional cases would expand the current dataset of GCTs of the pancreas, so that surgical resection may be avoided in the future.

The (Pro)renin Receptor - A Regulatory Nodal Point in Disease Networks

Experimental inhibition of the (pro)renin receptor [(P)RR] is a promising therapeutic strategy in different disease models ranging from cardiorenal to oncological entities. Here, we briefly review the direct protein-protein interaction partners of the (P)RR and the plethora of distinct diseases in which the (P)RR is involved. The first structural work on the (P)RR using AlphaFold, which was recently published by Ebihara et al., is the center of this mini-review since it can mechanistically link the protein-protein interaction level with the pathophysiological level. More detailed insights into the 3D structure of the (P)RR and its interaction domains might guide drug discovery on this novel target. Finally, antibody- and small molecule-based approaches to inhibit the (P)RR are shortly discussed.

Recurrent WWTR1 S89W mutations and Hippo pathway deregulation in clear cell carcinomas of the cervix

Clear cell carcinoma (CCC) of the cervix (cCCC) is a rare and aggressive type of human papillomavirus (HPV)-negative cervical cancer with limited effective treatment options for recurrent or metastatic disease. Historically, CCCs of the lower genital tract were associated with in utero diethylstilbestrol exposure; however, the genetic landscape of sporadic cCCCs remains unknown. Here we sought to define the molecular underpinning of cCCCs. Using a combination of whole-exome, targeted capture, and RNA-sequencing, we identified pathogenic genetic alterations in the Hippo signaling pathway in 50% (10/20) of cCCCs, including recurrent WWTR1 S89W somatic mutations in 40% (4/10) of the cases harboring mutations in the Hippo pathway. Irrespective of the presence or absence of Hippo pathway genetic alterations, however, all primary cCCCs analyzed in this study (n = 20) harbored features of Hippo pathway deregulation at the transcriptomic and protein levels. In vitro functional analysis revealed that expression of the WWTR1 S89W mutation leads to reduced binding of TAZ to 14-3-3, promoting constitutive nuclear translocation of TAZ and Hippo pathway repression. WWTR1 S89W expression was found to lead to acquisition of oncogenic behavior, including increased proliferation, migration, and colony formation in vitro as well as increased tumorigenesis in vivo, which could be reversed by targeted inhibition of the TAZ/YAP1 complex with verteporfin. Finally, xenografts expressing WWTR1 S89W displayed a shift in tumor phenotype, becoming more infiltrative as well as less differentiated, and were found to be composed of cells with conspicuous cytoplasmic clearing as compared to controls. Our results demonstrate that Hippo pathway alterations are likely drivers of cCCCs and likely contribute to the clear cell phenotype. Therapies targeting this pathway may constitute a new class of treatment for these rare, aggressive tumors. © 2022 The Pathological Society of Great Britain and Ireland.

Mitonuclear genotype remodels the metabolic and microenvironmental landscape of Hürthle cell carcinoma

Hürthle cell carcinomas (HCCs) display two exceptional genotypes: near-homoplasmic mutation of mitochondrial DNA (mtDNA) and genome-wide loss of heterozygosity (gLOH). To understand the phenotypic consequences of these genetic alterations, we analyzed genomic, metabolomic, and immunophenotypic data of HCC and other thyroid cancers. Both mtDNA mutations and profound depletion of citrate pools are common in HCC and other thyroid malignancies, suggesting that thyroid cancers are broadly equipped to survive tricarboxylic acid cycle impairment, whereas metabolites in the reduced form of NADH-dependent lysine degradation pathway were elevated exclusively in HCC. The presence of gLOH was not associated with metabolic phenotypes but rather with reduced immune infiltration, indicating that gLOH confers a selective advantage partially through immunosuppression. Unsupervised multimodal clustering revealed four clusters of HCC with distinct clinical, metabolomic, and microenvironmental phenotypes but overlapping genotypes. These findings chart the metabolic and microenvironmental landscape of HCC and shed light on the interaction between genotype, metabolism, and the microenvironment in cancer.

An Update on Cutaneous Granular Cell tumours for Dermatologists and Dermatopathologists

Granular cell tumours are rare soft tissue neoplasms which occur at a wide variety of sites and commonly involve the skin. Distinction between benign and malignant granular cell tumours is important because benign tumours are commonly cured by complete excision and malignant tumours commonly recur and cause fatal metastatic disease. Communication between the dermatologist and pathologist is also important, as the pathologist may provide false reassurance by evaluating a benign appearing part of a clinically malignant tumour. The following review summarises the current literature on the epidemiology, clinical presentation, pathology, radiology, treatment and prognosis of cutaneous granular cell tumours, with a focus on improving diagnosis and management for dermatologists and dermatopathologists.

Hyperthermic intraperitoneal chemotherapy (HIPEC) with carboplatin induces distinct transcriptomic changes in ovarian tumor and normal tissues

OBJECTIVE

To determine the effect of hyperthermic intraperitoneal chemotherapy (HIPEC) with carboplatin on the transcriptomic profiles of normal and ovarian cancer (OC) tissues.

METHODS

Normal and tumor samples from four OCs were prospectively collected pre- and immediately post-HIPEC treatment and subjected to RNA-sequencing. Differential gene expression, gene ontology enrichment and pathway analyses were performed. Heat shock protein and immune-response protein expression was assessed using protein arrays and western blotting.

RESULTS

RNA-sequencing revealed 4231 and 322 genes significantly differentially expressed between pre- and post-treatment normal and OC tissues, respectively (both adjusted p-value <0.05). Gene enrichment analyses demonstrated that the most significantly upregulated genes in normal tissues played a role in immune as well as heat shock response (both adjusted p < 0.001). In contrast, HIPEC induced an increased expression of primarily heat shock response and protein folding-related genes in tumor tissues (both adjusted p < 0.001). HIPEC-induced heat shock protein (HSP) expression changes, including in HSP90, HSP40, HSP60, and HSP70, were also observed at the protein level in both normal and tumor tissues.

CONCLUSIONS

HIPEC with carboplatin resulted in an upregulation of heat shock-related genes in both normal and tumor tissue, with an additional immune response gene induction in normal and protein folding in tumor tissue. The findings of our exploratory study provide evidence to suggest that HIPEC administration may suffice to induce gene expression changes in residual tumor cells and raises a biological basis for the consideration of combinatorial treatments with HSP inhibitors.

Granular cell tumor of thyroid: a case series with molecular characterization highlighting unique pitfalls

Primary granular cell tumors (GCTs) of the thyroid are exceptionally rare. We report the clinicopathologic and molecular features of three cases and review the literature. Two patients (20-year-old, Case 1, and 26-year-old, Case 2, black American females) presented with painless masses with a preoperative fine-needle aspiration biopsy (FNAB) diagnosis of "Hürthle cell neoplasm," while one additional patient, 51-year-old white American female (Case 3), presented as an incidental finding within a background of chronic lymphocytic thyroiditis. On resection, morphologic, histochemical and immunohistochemical features were typical of GCT in all cases. Cases 1 and 2 had adequate material for molecular testing and demonstrated a clonal ATP6AP1 p.G381Vfs*15 frameshift mutation (Case 1) and a clonal ATP6AP2 p.L182Pfs*22 frameshift mutation along with a PIK3CA H1047R hotspot mutation (Case 2). All patients showed no evidence of GCT following resection (Cases 1, 3: 96-month follow-up; Case 2: 48-month follow-up). A literature review demonstrates similar clinicopathologic features and indolent course with only rare histologically or clinically aggressive outcomes. On FNAB, lesional cells are frequently miscategorized as Hürthle cells or oncocytes. In summary, GCT of the thyroid is rare but shows similar clinical, morphologic, immunophenotypic and genetic characteristics of GCT of other sites. This unusual site poses unique differential diagnostic pitfalls by mimicking other oncocytic head and neck lesions, particularly thyroid Hürthle cell neoplasms. We confirm that thyroid GCT also harbor V-ATPase component inactivating mutations that characterize these tumors, and that additional PI3K pathway alterations may not necessarily predict aggressive behavior.

Malignant granular cell tumors: Combining cytological and pathological findings for a definitive diagnosis

Malignant granular cell tumors (GCTs) account for less than 2% of all GCTs and mainly occur in the deep soft tissue of the thigh or trunk. Malignant GCTs are highly aggressive tumors with high rates of recurrence and metastasis. In this brief report, we describe a rare case of malignant GCT in a 64-year-old Japanese man who presented with a 14 × 20 cm mass in the left inguinal region. The cytologic findings of fine-needle aspiration (FNA) revealed atypical epithelial-like granular cells with granular substance in the background, which was difficult to differentiate from apocrine carcinoma or melanoma. The immunohistochemistry (IHC) findings of the needle biopsy revealed that the tumor cells were positive for S-100 and lysosomal marker CD68 which was suggestive of a GCT. However, the presence of crush artifacts made it challenging to identify cellular atypia, which is a characteristic of malignant tumor. Taken together, the FNA and needle biopsy results were suggestive of malignant GCT. The importance of preoperative diagnosis of malignant GCT is well known, but few reports have described its cytological findings. In our brief report, we show that combining cytological FNA and biopsy findings with IHC findings achieves an accurate diagnosis of malignant GCT.

Identification of a five-gene signature deriving from the vacuolar ATPase (V-ATPase) sub-classifies gliomas and decides prognoses and immune microenvironment alterations

Aberrant expression of coding genes of the V-ATPase subunits has been reported in glioma patients that can activate oncogenic pathways and result in worse prognosis. However, the predictive effect of a single gene is not specific or sensitive enough. In this study, by using a series of bioinformatics analyses, we identified five coding genes (ATP6V1C2, ATP6V1G2, TCIRG1, ATP6AP1 and ATP6AP2) of the V-ATPase that were related to glioma patient prognosis. Based on the expression of these genes, glioma patients were sub-classified into different prognosis clusters, of which C1 cluster performed better prognosis; however, C2 cluster showed more malignant phenotypes with oncogenic and immune-related pathway activation. The single-cell RNA-seq data revealed that ATP6AP1, ATP6AP2, ATP6V1G2 and TCIRG1 might be cell-type potential markers. Copy number variation and DNA promoter methylation potentially regulate these five gene expressions. A risk score model consisted of these five genes effectively predicted glioma prognosis and was fully validated by six independent datasets. The risk scores also showed a positive correlation with immune checkpoint expression. Importantly, glioma patients with high-risk scores presented resistance to traditional treatment. We also revealed that more inhibitory immune cells infiltration and higher rates of “non-response” to immune checkpoint blockade (ICB) treatment in the high-risk score group. In conclusion, our study identified a five-gene signature from the V-ATPase that could sub-classify gliomas into different phenotypes and their abnormal expression was regulated by distinct mechanisms and accompanied with immune microenvironment alterations potentially act as a biomarker for ICB treatment.

Investigation of the Molecular Profile of Granular Cell Tumours and Schwannomas of the Oral Cavity

Granular cell tumours (GCTs) are rare submucosal lesions, thought to develop from Schwann cells, characterised by large polygonal cells with abundant lysosomes. The objectives of this study are to investigate whether GCTs have an antigen-presenting cell (APC) phenotype or a neural crest phenotype using immunohistochemistry and to compare expression profiles with Schwannomas. Immunoreactivity to CD68, HLA-DR, CD163, CD40 and CD11c (APC phenotype) and markers of neural crest cell (NCC) origin S100, SOX10, NSE and GAP43 in 23 cases of GCTs and 10 cases of Schwannomas were evaluated. RT-qPCR was used to identify a possible NCC developmental phenotype in 6 cases of GCTs. GAP43 was identified as a new NCC marker for GCTs, and some evidence was found for an APC phenotype from CD68 and HLA-DR immunoreactivity. RT-qPCR failed to identify an NCC developmental phenotype of GCTs, likely due to technical issues.

Update from the 5th Edition of the World Health Organization Classification of Head and Neck Tumors: Soft Tissue Tumors

The fifth (5th) edition of the World Health Organization (WHO) Classification of Head and Neck Tumors introduces a new chapter dedicated to soft tissue neoplasms commonly affecting the head and neck. While the diversity, rarity, and wide anatomic range of soft tissue tumors precludes a discussion of all entities that may be found in the head and neck, the addition of this new chapter to the head and neck "blue book" aims to provide a more comprehensive and uniform reference text, including updated diagnostic criteria, of mesenchymal tumor types frequently (or exclusively) arising at head and neck sites. Since publication of the previous edition in 2017, there have been numerous advances in our understanding of the pathogenesis of many soft tissue tumors which have facilitated refinements in tumor classification, identification of novel entities, development of diagnostic markers, and improved prognostication. This review will provide a focused discussion of the soft tissue tumors included in the 5th edition WHO Head and Neck classification, with an emphasis on updates.

Update from the 5th Edition of the World Health Organization Classification of Head and Neck Tumors: Tumours of the Oral Cavity and Mobile Tongue

The fifth chapter of the upcoming fifth edition of the 2022 World Health Organization Classification of Tumours of the Head and Neck titled Tumours of the oral cavity and mobile tongue, has had some modifications from the 2017 fourth edition. A new section "Non-neoplastic Lesions", introduces two new entries: necrotizing sialometaplasia and melanoacanthoma. The combined Oral potentially malignant disorders and Oral epithelial dysplasia section in the 2015 WHO has now been separated and submucous fibrosis and HPV-associated dysplasia are also discussed in separate sections. Carcinoma cuniculatum and verrucous carcinoma are described in dedicated sections, reflecting that the oral cavity is the most common location in the head and neck for both these entities which have distinct clinical and histologic features from conventional squamous cell carcinoma. This review summarizes the changes in Chapter 5 with special reference to new additions, deletions, and sections that reflect current clinical, histological, and molecular advances.

Recurrent driver mutations in benign tumors

The understanding of the molecular pathogenesis of benign tumors may bring essential information to clarify the process of tumorigenesis, and ultimately improve the understanding of events such as malignant transformation. The definition of benign neoplasia is not always straightforward and herein the issues surrounding this concept are discussed. Benign neoplasms share all cancer hallmarks with malignancies, except for metastatic potential. Recently, next-generation sequencing has provided unprecedented opportunities to unravel the genetic basis of benign neoplasms and, so far, we have learned that benign neoplasms are indeed characterized by the presence of genetic mutations, including genes rearrangements. Driver mutations in advanced cancer are those that confer growth advantage, and which have been positively selected during cancer evolution. Herein, some discussion will be brought about this concept in the context of cancer prevention, involving precursor lesions and benign neoplasms. When considering early detection and cancer prevention, a driver mutation should not only be advantageous (i.e., confer survival advantage), but predisposing (i.e., promoting a cancer phenotype). By including the benign counterparts of malignant neoplasms in tumor biology studies, it is possible to evaluate the risk posed by a given mutation and to differentiate advantageous from predisposing mutations, further refining the concept of driver mutations. Therefore, the study of benign neoplasms should be encouraged because it provides valuable information on tumorigenesis central for understanding the progression from initiation to malignant transformation.

Neuroendocrine tumours of the breast: a genomic comparison with mucinous breast cancers and neuroendocrine tumours of other anatomic sites

AIMS

Breast neuroendocrine tumours (NETs) constitute a rare histologic subtype of oestrogen receptor (ER)-positive breast cancer, and their definition according to the WHO classification was revised in 2019. Breast NETs display histologic and transcriptomic similarities with mucinous breast carcinomas (MuBCs). Here, we sought to compare the repertoire of genetic alterations in breast NETs with MuBCs and NETs from other anatomic origins.

METHODS

On histologic review applying the new WHO criteria, 18 breast tumours with neuroendocrine differentiation were reclassified as breast NETs (n=10) or other breast cancers with neuroendocrine differentiation (n=8). We reanalysed targeted sequencing or whole-exome sequencing data of breast NETs (n=10), MuBCs type A (n=12) and type B (n=11).

RESULTS

Breast NETs and MuBCs were found to be genetically similar, harbouring a lower frequency of PIK3CA mutations, 1q gains and 16q losses than ER-positive/HER2-negative breast cancers. 3/10 breast NETs harboured the hallmark features of ER-positive disease (ie, PIK3CA mutations and concurrent 1q gains/16q losses). Breast NETs showed an enrichment of oncogenic/likely oncogenic mutations affecting transcription factors compared with common forms of ER-positive breast cancer and with pancreatic and pulmonary NETs.

CONCLUSIONS

Breast NETs are heterogeneous and are characterised by an enrichment of mutations in transcription factors and likely constitute a spectrum of entities histologically and genomically related to MuBCs. While most breast NETs are distinct from ER-positive/HER2-negative IDC-NSTs, a subset of breast NETs appears to be genetically similar to common forms of ER-positive breast cancer, suggesting that some breast cancers may acquire neuroendocrine differentiation later in tumour evolution.

A perspective on the role of autophagy in cancer

Autophagy refers to a ubiquitous set of catabolic pathways required to achieve proper cellular homeostasis. Aberrant autophagy has been implicated in a multitude of diseases including cancer. In this review, we highlight pioneering and groundbreaking research that centers on delineating the role of autophagy in cancer initiation, proliferation and metastasis. First, we discuss the autophagy-related (ATG) proteins and their respective roles in the de novo formation of autophagosomes and the subsequent delivery of cargo to the lysosome for recycling. Next, we touch upon the history of cancer research that centers upon ATG proteins and regulatory mechanisms that control an appropriate autophagic response and how these are altered in the diseased state. Then, we discuss the various discoveries that led to the idea of autophagy as a double-edged sword when it comes to cancer therapy. This review also briefly narrates how different types of autophagy-selective macroautophagy and chaperone-mediated autophagy, have been linked to different cancers. Overall, these studies build upon a steadfast trajectory that aims to solve the monumentally daunting challenge of finding a cure for many types of cancer by modulating autophagy either through inhibition or induction.

Update on MR Imaging of Soft Tissue Tumors of Head and Neck

This article reviews soft tissue tumors of the head and neck following the 2020 revision of WHO Classification of Soft Tissue and Bone Tumours. Common soft tissue tumors in the head and neck and tumors are discussed, along with newly added entities to the classification system. Salient clinical and imaging features that may allow for improved diagnostic accuracy or to narrow the imaging differential diagnosis are covered. Advanced imaging techniques are discussed, with a focus on diffusion-weighted and dynamic contrast imaging and their potential to help characterize soft tissue tumors and aid in distinguishing malignant from benign tumors.

Uncommon Tumors and Uncommon Presentations of Cancer in the Breast

Purpose of review

The purpose is to present a case series of rare diagnoses and unusual presentations of breast lesions with radiologic-pathologic correlation from a major cancer center, and to review the recent literature on each entity with a focus on radiology-pathology concordance. We present our findings and experience from cases of metastatic small cell lung carcinoma to the breast, IgG-4 related breast disease, breast implant associated anaplastic large cell lymphoma, granular cell tumor, pleomorphic sarcoma, adenomyoepithelioma, post-radiation angiosarcoma, and breast carcinoma after risk-reducing total mastectomy.

Recent findings

It is essential for physicians to have knowledge of rare breast diagnoses and unusual breast disease presentations to formulate a complete differential diagnosis, recognize radiological-pathological concordance of these entities and provide appropriate patient care.

Summary

Current literature on these rare described entities exists mainly as case reports, case series and small-scale studies. By sharing our findings, we hope to educate trainees in radiology, pathology and other fields across the continuum of care in radiologic-pathologic correlation, while also augmenting the existing literature on these rare entities.