BBT-877, a Novel Autotaxin Inhibitor, Abrogates Drug Resistance in Epithelial Ovarian Cancer Stem Cells.

BACKGROUND/AIM: Cancer stem cells (CSCs) contribute significantly to the poor prognosis of patients with epithelial ovarian cancer (EOC) due to their roles in drug resistance and tumor metastasis. Autotaxin (ATX) plays a pivotal role in the maintenance of the CSC-like properties of EOC tumors. BBT-877 is a novel ATX inhibitor used in clinical treatment of idiopathic pulmonary fibrosis. However, the effects of BBT-877 on drug resistance and metastasis in ovarian CSCs remain unknown. In this study, we aimed to investigate the effects of BBT-877 on drug resistance and intraperitoneal metastasis of EOC. MATERIALS AND METHODS: Spheroid-forming CSCs, which were isolated from two EOC cell lines, A2780 and SKOV3, were investigated by cell viability, western blot, PCR, Spheroid-forming assay, and in vivo experiments. RESULTS: Spheroid-forming CSCs exhibited increased CSC-like properties and paclitaxel (PTX) resistance. BBT-877 treatment inhibited the viability of spheroid-forming CSCs more potently than that of adherent ovarian cancer cell lines. Combinatorial treatment with BBT-877 and PTX significantly attenuated the viability of spheroid-forming CSCs. In a SKOV3 cells-derived intraperitoneal metastasis model, BBT-877 treatment reduced the number of metastatic tumor nodes, while combinatorial treatment with BBT-877 and PTX more potently attenuated the formation of metastatic nodes and accumulation of ascitic fluid. CONCLUSION: These results suggest that BBT-877 can be combined with conventional anticancer drugs for the treatment of patients with recurrent or drug-resistant EOC.

Pulmonary cryptococcosis masquerading as lung metastasis in gynecologic cancers: Two case reports.

RATIONALE: Pulmonary cryptococcal infections occur mainly in immunocompromised individuals, such as those with malignancies. Preoperative diagnosis of pulmonary cryptococcosis (PC) can be challenging for both clinicians and radiologists because of nonspecific clinical manifestations and variable radiologic features, as it is easily misdiagnosed as metastatic lung cancer. PATIENT CONCERNS: In case 1, a 76-year-old woman with a history of cervical cancer presented with lung nodules detected on chest computed tomography (CT) 13 months after completing concurrent chemoradiotherapy. In case 2, a 56-year-old woman with a history of ovarian cancer presented with pulmonary nodules on chest CT 19 months after completing chemotherapy. Both patients were clinically asymptomatic, and tumor markers were not elevated. DIAGNOSES: In case 1, chest CT revealed multiple enhanced nodules with lobulated margins in the left lower lobe, and positron emission tomography (PET)-CT showed uptake in the nodule with a standardized uptake value of 3.7. In case 2, chest CT revealed several nodules in the right upper lobe abutting the right major fissure, and PET-CT revealed fluorodeoxyglucose uptake in the nodules. Pathology revealed granulomatous inflammation with cryptococcal infection, and mucicarmine and periodic acid-Schiff staining confirmed cryptococcal infection in both cases. INTERVENTIONS: Presumptive diagnoses of lung metastases were made in both cases and thoracoscopic lobectomy was performed. Postoperatively, the patients received antifungal therapy with fluconazole. OUTCOMES: PC was differentially diagnosed and effectively managed. The patients remained disease-free for both PC and gynecological cancers during subsequent follow-ups. LESSONS: Recognition that PC can mimic lung metastasis is important for managing gynecological cancers. PC should be considered in the differential diagnosis when single or multiple nodules are detected on chest radiography without elevation of tumor markers in patients with gynecological cancer.

Preoperative Haematologic Markers for the Differentiation of Endometrial Cancer from Benign Endometrial Lesions in Postmenopausal Patients with Endometrial Masses.

Purpose: The diagnostic value of preoperative hematological changes in endometrial cancer (EC) remains unclear. This study aimed to assess the role of preoperative hematologic parameters in differentiating EC from benign endometrial lesions in postmenopausal women with endometrial masses. Methods: Preoperative laboratory variables were retrospectively reviewed in patients with malignant or benign endometrial lesions, and the significance of intergroup differences was assessed. Receiver operating characteristic curves were used to analyze the optimal cut-off values for each variable. Logistic regression analysis was used to identify the variables predicting the presence of endometrial malignancy. Results: Preoperative laboratory variables of 176 patients (84 EC and 92 benign lesions) with endometrial masses were analyzed. Significant differences were observed between malignant and benign lesions in terms of WBC count, ANC, MCV, MPV, PDW, CA125, NLR, PMR, LMR, and SII (P < 0.05). Multivariate analyses showed that a high WBC count, high ANC, low MCV, low MPV, low PDW, high CA125, high NLR, high PMR, high LMR, and high SII independently predicted the presence of endometrial malignancy. Conclusion: The combination markers, MPV+PDW+NLR, had good discriminatory power for the presence of malignancy (AUC 0.797). Our results suggest that hematologic markers could be useful for the differentiation of malignant and benign endometrial lesions.

Learning potential and visuospatial memory could predict amyloid-beta positron emission tomography positivity in amnestic mild cognitive impairment.

We investigate the role of neuropsychological tests, including the learning potential, in predicting amyloid-beta positron emission tomography (Aß-PET) status in amnestic mild cognitive impairment (aMCI). This cross-sectional study included 64 patients with aMCI (31 Aß-PET (-) and 33 (+)) who visited a memory impairment clinic at Pusan National University Hospital between 2014 and 2019. Patients underwent Aß-PET scans using 18F-florbetaben and the Seoul Neuropsychological Screening Battery. Learning potential was determined based on the difference in scores between the first and third trials of the Seoul Verbal Learning test (SVLT). Binary logistic regression was used to demonstrate the association between Aß-PET status and cognitive tests. Predictive ability of cognitive tests for Aß deposition was investigated using receiver operating characteristic curves analysis. From logistic regression models, the SVLT learning potential and Rey-Osterrieth Complex Figure Test (RCFT) delayed recall were found to predict Aß-PET positivity. The areas under the curve (AUC) of the SVLT learning potential and RCFT delayed recall were significantly different from 0.5. Our findings of an association between Aß deposition status and learning potential and visuospatial memory suggest that these cognitive tests could be used to screen patients with aMCI for Aß deposition status.

Tumor budding as a predictor of disease-free survival in patients with cholangiocarcinoma.

Background: Tumor budding is considered a prognostic factor in several solid cancer types. However, we lack comprehensive information on the importance of tumor budding in cholangiocarcinoma. Therefore, we aimed to assess the prognostic value of tumor budding in intrahepatic and extrahepatic cholangiocarcinomas and to evaluate its correlations with other clinicopathological parameters. Methods: We monitored 219 patients who underwent surgery for intrahepatic or extrahepatic cholangiocarcinoma at the Pusan National University Hospital between 2012 and 2021. Tumor budding was evaluated using the International Tumor Budding Consensus Conference scoring system. Tumor budding was classified into low (0-4), intermediate (5-9), and high (≥10). For statistical analysis, tumor budding was divided into two groups based on the cut-off value of 10 (lower: 0-9 vs. higher: ≥10). The correlations between clinicopathological parameters were examined using the chi-square and Fisher's exact test. The prognostic values of the variables were analyzed using the log-rank test and Cox regression analysis. Results: Low, intermediate, and high tumor buddings were identified in 135 (61.6%), 63 (28.8), and 21 (9.6%), patients, respectively. Higher tumor budding was related to the presence of lymphatic invasion (p = 0.017), higher tumor grade (p = 0.001), higher N category (p = 0.034). In the univariable and multivariable analyses, higher tumor budding was associated with shorter disease-free survival in 97 (44.3%) patients who underwent R0 resection (p < 0.001 and p = 0.011). Tumor budding did not significantly correlate with disease-specific survival in entire patients. Conclusion: Tumor budding may serve as a prognostic factor for intrahepatic and extrahepatic cholangiocarcinomas treated with R0 resection.

CD109 Promotes Drug Resistance in A2780 Ovarian Cancer Cells by Regulating the STAT3-NOTCH1 Signaling Axis.

Epithelial ovarian cancer (EOC) is the most lethal gynecological malignancy owing to relapse caused by resistance to chemotherapy. We previously reported that cluster of differentiation 109 (CD109) expression is positively correlated with poor prognosis and chemoresistance in patients with EOC. To further explore the role of CD109 in EOC, we explored the signaling mechanism of CD109-induced drug resistance. We found that CD109 expression was upregulated in doxorubicin-resistant EOC cells (A2780-R) compared with that in their parental cells. In EOC cells (A2780 and A2780-R), the expression level of CD109 was positively correlated with the expression level of ATP-binding cassette (ABC) transporters, such as ABCB1 and ABCG2, and paclitaxel (PTX) resistance. Using a xenograft mouse model, it was confirmed that PTX administration in xenografts of CD109-silenced A2780-R cells significantly attenuated in vivo tumor growth. The treatment of CD109-overexpressed A2780 cells with cryptotanshinone (CPT), a signal transducer and activator of transcription 3 (STAT3) inhibitor, inhibited the CD109 overexpression-induced activation of STAT3 and neurogenic locus notch homolog protein 1 (NOTCH1), suggesting a STAT3-NOTCH1 signaling axis. The combined treatment of CD109-overexpressed A2780 cells with CPT and N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT), a NOTCH inhibitor, markedly abrogated PTX resistance. These results suggest that CD109 plays a key role in the acquisition of drug resistance by activating the STAT3-NOTCH1 signaling axis in patients with EOC.

Neuropsychological, neuroimaging and autopsy findings of butane encephalopathy.

BACKGROUND: Butane is an aliphatic hydrocarbon used in various commercial products. While numerous reports of sudden cardiac-related deaths from butane inhalation have been described, butane-associated acute encephalopathy has rarely been reported. CASE PRESENTATION: A 38-year-old man presented with cognitive dysfunction after butane gas inhalation. Neuropsychological test results showed impairments in verbal and visual memory, and frontal executive function. Diffusion weighted MRI revealed symmetric high-signal changes in the bilateral hippocampus and globus pallidus. FDG-PET demonstrated decreased glucose metabolism in the bilateral precuneus and occipital areas and the left temporal region. At the 8-month follow-up, he showed still significant deficits in memory and frontal functions. Diffuse cortical atrophy with white matter hyperintensities and extensive glucose hypometabolism were detected on follow-up MRI and FDG-PET, respectively. Brain autopsy demonstrated necrosis and cavitary lesions in the globus pallidus. CONCLUSIONS: Only a few cases of butane encephalopathy have been reported to date. Brain lesions associated with butane encephalopathy include lesions in the bilateral thalamus, insula, putamen, and cerebellum. To the best of our knowledge, this is the first report on bilateral hippocampal and globus pallidal involvement in acute butane encephalopathy. The pathophysiology of central nervous system complications induced by butane intoxication is not yet fully understood. However, the direct toxic effects of butane or anoxic injury secondary to cardiac arrest or respiratory depression have been suggested as possible mechanisms of edematous changes in the brain after butane intoxication.

TRRAP Enhances Cancer Stem Cell Characteristics by Regulating NANOG Protein Stability in Colon Cancer Cells.

NANOG, a stemness-associated transcription factor, is highly expressed in many cancers and plays a critical role in regulating tumorigenicity. Transformation/transcription domain-associated protein (TRRAP) has been reported to stimulate the tumorigenic potential of cancer cells and induce the gene transcription of NANOG. This study aimed to investigate the role of the TRRAP-NANOG signaling pathway in the tumorigenicity of cancer stem cells. We found that TRRAP overexpression specifically increases NANOG protein stability by interfering with NANOG ubiquitination mediated by FBXW8, an E3 ubiquitin ligase. Mapping of NANOG-binding sites using deletion mutants of TRRAP revealed that a domain of TRRAP (amino acids 1898-2400) is responsible for binding to NANOG and that the overexpression of this TRRAP domain abrogated the FBXW8-mediated ubiquitination of NANOG. TRRAP knockdown decreased the expression of CD44, a cancer stem cell marker, and increased the expression of P53, a tumor suppressor gene, in HCT-15 colon cancer cells. TRRAP depletion attenuated spheroid-forming ability and cisplatin resistance in HCT-15 cells, which could be rescued by NANOG overexpression. Furthermore, TRRAP knockdown significantly reduced tumor growth in a murine xenograft transplantation model, which could be reversed by NANOG overexpression. Together, these results suggest that TRRAP plays a pivotal role in the regulation of the tumorigenic potential of colon cancer cells by modulating NANOG protein stability.

The stromal tumor-infiltrating lymphocytes, cancer stemness, epithelial-mesenchymal transition, and B7-H4 expression in ovarian serous carcinoma.

BACKGROUND: B7-H4 is expressed in various types of cancers and its expression inversely correlates with the degree of tumor-infiltrating lymphocytes (TILs). Studies have shown the relationship between B7-H4, cancer stem cell (CSC) properties, and epithelial-mesenchymal transition (EMT) in various cancers. However, very few studies have investigated the relationship between B7-H4, TILs, cancer stemness, and EMT in epithelial ovarian cancer (EOC). The present study aimed to elucidate whether B7-H4 is involved in immune evasion and examine whether B7-H4 is associated with cancer stemness or EMT in ovarian serous carcinoma, the most common type of EOC. The clinical significance of B7-H4 was also investigated to evaluate its potential as a therapeutic target. METHODS: A total of 145 patients included in this study. The degree of stromal TILs was evaluated using hematoxylin and eosin (H&E)-stained slides. Immunohistochemical analysis of B7-H4, CSC-related biomarkers (CD24, CD44s, CD133, and ALDH1), and EMT-related biomarkers (E-cadherin, N-cadherin, and vimentin) was performed using tissue microarray. qRT-PCR for VTCN1, CD24, CD44, PROM1, ALDH1, CDH1, CDH2, and VIM genes was performed on 38 frozen tissue samples. The mRNA expression levels were analyzed using Gene Expression Profiling Interactive Analysis (GEPIA) online analysis tool. RESULTS: B7-H4 protein expression positively correlated with the degree of stromal TILs. CD24, CD44s, and CD133 expression showed a positive correlation with B7-H4 expression at both the protein and mRNA levels, but ALDH1 correlated only at the protein level. E-cadherin expression was positively correlated with B7-H4 expression at both the protein and mRNA levels. N-cadherin and vimentin expression was inversely related to B7-H4 expression only at the mRNA level. B7-H4 positive patients were associated with higher tumor grade and lower overall survival rate than B7-H4 negative patients, especially in ovarian serous carcinoma with low stromal TILs. CONCLUSIONS: The present study demonstrates that B7-H4 may not be involved in the immune evasion mechanism, but is involved in cancer stemness and mesenchymal-epithelial transition. In addition, B7-H4 may be a therapeutic target for the treatment of ovarian serous carcinoma, especially with low stromal TILs.

Successful Treatment of Optic Neuropathy Associated with Sphenoid Sinus Aspergillosis.

PURPOSE: We report a case of optic neuropathy related to sphenoid sinus aspergillosis which showed good visual recovery with surgery and medical antifungal treatment. METHODS: Observational case study Case Presentation A 62-year-old man presented with decreased visual acuity in the right eye for 3 weeks. His visual acuity was counting fingers in the right eye and 20/20 in the left eye. Relative afferent pupillary defects were detected in the right eye. Optic neuropathy related to invasive fungal sphenoid sinusitis was suspected via radiologic evaluation. Endoscopic sinus surgery was performed and histopathological examination revealed aspergillosis. Amphotericin B combined with ceftriaxone and metronidazole was started. After the fungal culture results were positive for the Aspergillus species, amphotericin B was changed to voriconazole. At 1 month after surgery, visual acuity improved to 20/25. CONCLUSION: Appropriate radiologic evaluation can be helpful when optic neuropathy associated with a fungal infection is suspected, and timely surgical and medial treatment should be considered.

Eccrine Hidradenoma of the Nasal Vestibule: A Rare Clinical Entity.

Eccrine hidradenoma is a relatively rare benign tumor of sweat gland origin but with possible malignant transformation. It usually consists of solitary, well-demarcated papules or nodules covered with normal skin. Common sites of involvement are the scalp, face, limbs, and anterior trunk. Although the lining of the nasal vestibule includes hair follicles, sebaceous glands, and sweat glands, an eccrine hidradenoma originating in the nasal vestibule has yet to be reported. Herein, we describe a rare clinical presentation of nasal eccrine hidradenoma, treated successfully using a transnasal endoscopic approach.

A fertility-sparing surgery in lymphoepithelioma-like carcinomas of the uterine cervix: A case report.

INTRODUCTION: A poorly differentiated lymphoepithelioma-like carcinoma (LELC) of the cervix is an extremely rare presentation. We herein present an unusual case of LELC of the cervix, which was treated with radical trachelectomy for fertility preservation. PATIENT CONCERNS: A 28-year-old female patient presented with a 1-month-history of post-coital vaginal bleeding, and a 2 cm tumor was found on gynecological sonography and magnetic resonance imaging. DIAGNOSIS: The final pathological examination established a conclusive diagnosis of LELC of the cervix. After surgery, the patient was finally diagnosed as The International Federation of Gynecology and Obstetrics (FIGO) stage IB1 with no vaginal wall or parametrium infiltration. INTERVENTIONS: Subsequently, a surgery was scheduled, and intraoperatively, we performed resection twice because of a frozen biopsy result that was resection margin-positive initially. As a result, further resection was performed, which was a 5mm thickness for each. Cisplatin adjuvant chemotherapy was administered 3 weeks after the operation to prevent recurrence. OUTCOMES: The patient has been followed for 1 year postoperatively, with an adjuvant treatment, with no evidence of tumor recurrence or metastasis. CONCLUSION: Based on this case, we highly recommend that operators should consider a deeper resection margin range than that visible on magnetic resonance imaging. More attention is needed to better understand the treatment method for LELC of the cervix. We also plan to closely monitor the patient's prognosis and fertility, and to conduct additional studies.

Malignant Tenosynovial Giant Cell Tumor Presenting as an Extra-Articular Superficial Soft-Tissue Mass in a Knee.

Malignant tenosynovial giant cell tumor (TsGCT) is a rare disease that can arise as a recurrent lesion or co-exist with a benign TsGCT lesion. Here we report a rare case of malignant TsGCT in a 73-year-old male with a history of lymphoma. The tumor appeared as a superficial soft-tissue mass in the subcutaneous fat tissue of the left knee.

Myositis Ossificans with Aneurysmal Bone Cystic Changes at the Thoracic Paraspinal Region: A Case Report.

Myositis ossificans (MO) is a benign heterotopic bone formation in muscle or soft tissue. It is a self-limiting disease that is usually initiated by trauma and often occurs in the extremities of the body. Here we report a rare case of traumatic myositis ossificans caused by unusual trauma (extracorporeal shock wave therapy) at thoracic paraspinal muscles. After a needle biopsy, the lesion increased in size, and the patient's symptoms worsened. Malignant soft tissue tumors such as osteosarcoma should be differentiated, so excision of the mass was performed. The final diagnosis was MO with aneurysmal bone cystic change. This case is a very rare form of MO that showed an unusual cause, location, clinical course, and pathologic result on follow-up. This can be an instructive case for radiologists as it is a common disease entity with unusual manifestations.

Malignant melanotic nerve sheath tumors in the spinal canal of psammomatous and non-psammomatous type: Two case reports.

BACKGROUND: A malignant melanotic nerve sheath tumor (MMNST), previously known as a melanotic schwannoma, is a rare variant of a peripheral nerve sheath tumor composed of Schwann cells with melanotic differentiation. Only a few reports of spinal MMNST have been reported. CASE SUMMARY: In the first case, a 58-year-old woman presented with a history of low back pain and paresthesia. Magnetic resonance imaging (MRI) and computed tomography (CT) of the lumbar spine revealed an intradural extramedullary mass lesion with amorphous linear calcification. Complete tumor resection was performed and histological examination revealed a psammomatous melanotic schwannoma. In the second case, a 72-year-old man presented with low back pain and paresthesia. MRI of the thoracolumbar spine revealed an intramedullary mass lesion at the T11 vertebral body level. The mass lesion was hypointense on T2WI and hyperintense on T1WI. Tumor resection was performed and the histologic result was melanotic schwannoma. CONCLUSION: MMNST should be considered in the differential diagnosis when calcification or melanin is seen in an intradural spinal tumor.

MicroRNA-dependent inhibition of WEE1 controls cancer stem-like characteristics and malignant behavior in ovarian cancer.

Cancer stem-like cells (CSCs) have been suggested to be responsible for chemoresistance and tumor recurrence owing to their self-renewal capacity and differentiation potential. Although WEE1 is a strong candidate target for anticancer therapies, its role in ovarian CSCs is yet to be elucidated. Here, we show that WEE1 plays a key role in regulating CSC properties and tumor resistance to carboplatin via a microRNA-dependent mechanism. We found that WEE1 expression is upregulated in ovarian cancer spheroids because of the decreased expression of miR-424 and miR-503, which directly target WEE1. The overexpression of miR-424/503 suppressed CSC activity by inhibiting WEE1 expression, but this effect was reversed on the restoration of WEE1 expression. Furthermore, we demonstrated that NANOG modulates the miR-424/503-WEE1 axis that regulates the properties of CSCs. We also demonstrated the pharmacological restoration of the NANOG-miR-424/503-WEE1 axis and attenuation of ovarian CSC characteristics in response to atorvastatin treatment. Lastly, miR-424/503-mediated WEE1 inhibition re-sensitized chemoresistant ovarian cancer cells to carboplatin. Additionally, combined treatment with atorvastatin and carboplatin synergistically reduced tumor growth, chemoresistance, and peritoneal seeding in the intraperitoneal mouse models of ovarian cancer. We identified a novel NANOG-miR-424/503-WEE1 pathway for regulating ovarian CSCs, which has potential therapeutic utility in ovarian cancer treatment.

Inhibition of MEK-ERK pathway enhances oncolytic vaccinia virus replication in doxorubicin-resistant ovarian cancer.

Oncolytic vaccinia virus (OVV) has been reported to induce cell death in various types of cancer; however, the oncolytic activity of OVV in drug-resistant ovarian cancer remains limited. In the present study, we established doxorubicin-resistant ovarian cancer cells (A2780-R) from the A2780 human ovarian cancer cell line. Both A2780 and A2780-R cells were infected with OVV to explore its anticancer effects. Interestingly, OVV-infected A2780-R cells showed reduced viral replication and cell death compared with A2780 cells, suggesting their resistance against OVV-induced oncolysis; to understand the mechanism underlying this resistance, we explored the involvement of protein kinases. Among protein kinase inhibitors, PD0325901, an MEK inhibitor, significantly augmented OVV replication and cell death in A2780-R cells. PD0325901 treatment increased the phosphorylation of STAT3 in A2780-R cells. Moreover, cryptotanshinone, a STAT3 inhibitor, abrogated PD0325901-stimulated OVV replication. Furthermore, trametinib, a clinically approved MEK inhibitor, increased OVV replication in A2780-R cells. Transcriptomic analysis showed that the MEK inhibitor promoted OVV replication via increasing STAT3 activation and downregulating the cytosolic DNA-sensing pathway. Combined treatment with OVV and trametinib attenuated A2780-R xenograft tumor growth. These results suggest that pharmacological inhibition of MEK reinforces the oncolytic efficacy of OVV in drug-resistant ovarian cancer.

Distant migration of gel filler: imaging findings following breast augmentation.

Recently, many attempts have been made to use injectable materials in the subcutaneous fat layer anywhere in the body, including the breast and face, for cosmetic purposes. A 56-year-old woman presented with multiple palpable lumps without tenderness or skin color changes on the anterior and lateral chest and the abdominal walls. Magnetic resonance imaging showed fluid-like collections without surrounding soft tissue inflammatory changes in the chest wall, abdominal wall, and deeper within the abdomen. The lesions penetrated the peritoneum and were observed adjacent to the liver dome. Ultrasonography also showed hypoechogenicity suggestive of fluid collection in the left axilla and trunk. The differential diagnosis based on radiologic findings included parasite manifestation, non-specific inflammatory conditions, and chronic granulomatous infections such as tuberculosis or non-tuberculous mycobacterial infections. However, these conditions are usually accompanied by changes in the adjacent subcutaneous fat layers, but our patient did not show any other abnormalities in the adjacent soft tissue. After biopsy and aspiration analysis, the patient was found to have a history of filler injection for breast augmentation approximately 17 years prior. It is often difficult to make a differential diagnosis without detailed knowledge of the patient's medical history. Here we describe a rare case of distant migration of the filler to the axilla, chest wall, abdominal wall, and peritoneum following breast augmentation with filler injection. Knowledge of the radiologic characteristics and migration patterns of gel fillers and their related complications is useful for making an accurate diagnosis.

ACE2 and TMPRSS2 immunolocalization and oral manifestations of COVID-19.

OBJECTIVES: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry into the host cells depends on the expression of angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2). We investigated the distribution of ACE2- and TMPRSS2-expressing cells in various oral tissues to identify the underlying mechanism of oral manifestations in patients with coronavirus disease 2019. SUBJECTS: We analyzed the expression patterns of ACE2 and TMPRSS2 in the oral mucosa (tongue, palate, and buccal mucosa), trigeminal ganglion, vessels, and salivary glands of 9 Sprague-Dawley rats using immunohistochemistry and immunofluorescence. RESULTS: ACE2 and TMPRSS2 were strongly expressed in the intermediate layer of the squamous epithelia of tongue papillae and buccal mucosa. ACE2- and TMPRSS2-positive cells were observed in the taste buds of the tongue. Additionally, ACE2 and TMPRSS2 were co-expressed in the ductal epithelium and acinar cells of salivary glands. Furthermore, both ACE2 and TMPRSS2 were stained in the neuronal cell body of trigeminal ganglia, but not in Schwann cells. Moreover, ACE2 and TMPRSS2 were expressed in capillaries, but not in venules/arterioles. CONCLUSIONS: SARS-CoV-2 can spread the suprabasal area of squamous epithelia of the oral mucosa, invades taste bud, trigeminal nerve, parotid gland, and microvessel, resulting in oral manifestations.