Background/Objectives: Fibrous dysplasia (FD) is a benign fibro-osseous disorder characterized by the replacement of normal bone with fibrous tissue and immature woven bone, most commonly involving the craniofacial skeleton. It typically presents as an intraosseous lesion in children and young adults. Fibrous dysplasia may rarely present with predominant gingival involvement and minimal radiographic evidence of intraosseous disease. We report an unusual case of craniofacial fibrous dysplasia that clinically mimicked an exophytic gingival mass in the anterior maxilla of a middle-aged patient. Methods: A middle-aged patient presented with a slowly enlarging gingival mass extending from the right canine to the left central incisor region. After being lost to follow-up for approximately 4.5 years, the patient returned with increased swelling, pain, spacing of the anterior teeth, and functional impairment affecting mastication and speech. Clinical, radiographic, surgical, and histopathologic findings were evaluated. Surgical management included excision of the lesion, extraction of non-restorable teeth, and bone grafting under general anesthesia. Results: Radiographic examination demonstrated minimal osseous involvement without a clearly defined intraosseous expansile lesion. Histopathologic analysis revealed irregular curvilinear trabeculae of woven bone within a fibrous stroma containing bland spindle cell proliferation, consistent with FD. At the six-month follow-up, the patient remained asymptomatic without complications and was undergoing prosthetic rehabilitation with plans for future implant placement. Conclusions: FD may rarely present as a predominantly gingival lesion with minimal radiographic evidence of bone involvement, posing a diagnostic challenge. Recognition of this atypical presentation is important to avoid misdiagnosis and to facilitate appropriate management through comprehensive clinicoradiologic and histopathologic correlation.

Aberrant repair/regeneration of alveolar epithelial stem cells is a key driver of pulmonary fibrosis (PF). While βPAK-interacting exchange factor (βPIX) is connected to stem cell signaling, its role in pulmonary fibrosis (PF) remains unknown. Here, we generated conditional βPIX knockout mice to investigate its contribution to PF pathogenesis. Selectively depleting βPIX in alveolar type 2 (AT2) cells led to progressive PF in mice, recapitulating the key features observed in human idiopathic pulmonary fibrosis (IPF), where AT2 cells exhibit significantly reduced βPIX levels. Single-nucleus RNA sequencing of the lungs of βPIX-deficient mice revealed the emergence of progenitor cells in a transitional stem cell state with senescent attributes, along with active, collagen-producing myofibroblasts. Mechanistically, the loss of βPIX impaired AT2 cell stemness by downregulating Wnt/β-catenin signaling. AT2 cells from IPF patients also presented reduced levels of β-catenin and Axin2, confirming the downregulation of Wnt/β-catenin signaling. Treatment with a glycogen synthase kinase-3β inhibitor reactivated Wnt/β-catenin signaling and attenuated fibrosis in βPIX-deficient mice. Our results establish a direct causal link between βPIX deficiency and PF, highlighting βPIX and its downstream pathway as promising therapeutic targets for this devastating disease.

Background: The molecular changes associated with the progression of intraductal papillary mucinous neoplasm (IPMN) to pancreatic ductal adenocarcinoma (PDAC) and distant metastasis remain incompletely understood. Case Presentation: A man in his late 70s underwent pancreaticoduodenectomy and partial hepatectomy for a pancreatic head tumor with synchronous liver metastasis. Histology showed a 4.5 cm moderately differentiated PDAC arising in an IPMN with high-grade dysplasia (pT3N1M1). Genomic analysis of the IPMN, PDAC, and liver metastasis identified KRAS p.G12D, CDKN2A deletion, and GNAS p.R201H in the IPMN; additional SMAD4 p.R361C in the PDAC; and KRAS p.G12D, CDKN2A deletion, SMAD4 p.R361C, and APC p.R1450Ter in the liver metastasis. The APC alteration was confirmed by targeted sequencing and was accompanied by loss of heterozygosity at the APC locus. β-Catenin showed membranous expression in the IPMN and PDAC, but nuclear accumulation in the liver metastasis. Discussion: The shared KRAS, CDKN2A, and SMAD4 alterations support a common clonal origin of the PDAC and metastatic tumors. The absence of a detectable GNAS alteration in the liver metastasis and the presence of a metastasis-specific APC alteration are compatible with, but do not prove, branching evolution and selection of a metastatic subclone. Conclusions: This case shows a metastasis-specific heterozygous APC truncating alteration with loss of heterozygosity, accompanied by nuclear β-catenin accumulation, in an IPMN-associated PDAC.

PURPOSE:Immunotherapy combined with chemotherapy is the standard palliative treatment for gastric cancer. However, peritoneal metastases are often resistant to immunotherapy, underscoring the need to better understand the tumor immune microenvironment (TIME). In this study, we aimed to comprehensively analyze the TIME in peritoneal metastases of gastric cancer. MATERIALS AND METHODS:Paired single-cell suspensions from malignant ascites and peripheral blood mononuclear cells (PBMCs) were obtained from 27 patients with gastric cancer for multicolor fluorescence-activated cell sorting (FACS) analysis. Cell-free fluids from malignant ascites and plasma of 15 patients with gastric cancer, along with benign ascites from 15 patients with liver cirrhosis, were analyzed using multiplex enzyme-linked immunosorbent assay (ELISA). Paired samples of primary gastric tumors and metastatic peritoneal tumors from 12 patients were evaluated using multiplex immunohistochemistry (IHC). RESULTS:FACS analysis revealed that T cells in malignant ascites expressed higher levels of immune checkpoint receptors (programmed death-1, T-cell immunoglobulin and mucin-domain containing-3, T-cell immunoglobulin and ITIM domain, lymphocyte activation gene-3, and cytotoxic T-lymphocyte antigen 4), and that CD8⁺ T cells exhibited terminal exhaustion (EomeshighT-betlow). Multiplex ELISA showed that soluble immunosuppressive factors (matrix metalloproteinase [MMP]-1, MMP-2, MMP-7, transforming growth factor-beta 1, hepatocyte growth factor, E-cadherin, vascular endothelial growth factor, and angiopoietin-2) were elevated in malignant ascites. Multiplex IHC showed lower CD4⁺ and CD8⁺ T cell densities in metastatic peritoneal tumors, which predominantly exhibited immunosuppressive TIME subtypes (immune-desert and intrinsic induction). CONCLUSIONS:Our results revealed distinct peritoneal immunosuppressive TIMEs in patients with gastric cancer with peritoneal metastasis.

BACKGROUND:Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal malignancies. Tumor-infiltrating neutrophils (TINs) have been implicated in tumor progression and poor prognosis; however, their roles in PDAC remain unclear. TINs have been shown to granulocytic myeloid-derived suppressor cells (G-MDSCs) which inhibit adaptive immune responses and share morphological and functional features with classical neutrophils. G-MDSCs, unlike classical neutrophils, express myeloperoxidase (MPO). We evaluated the significance of TINs and MPO expression as a marker for prognosis in the PDAC. METHODS:We retrospectively analyzed 128 patients with surgically resected PDAC. The presence of TIN was assessed on hematoxylin and eosin-stained slides and immunohistochemistry was performed for MPO. RESULTS:TINs were identified in 61.7% of patients with PDAC. Their presence was significantly associated with worse overall survival and recurrence-free survival. After adjusting for clinicopathological variables, TIN remained an independent predictor of a poor prognosis. MPO was expressed in all TIN within PDAC, but was absent in neutrophils within benign inflammatory conditions. CONCLUSIONS:TIN in PDAC represents an independent adverse prognostic factor and is likely to be G-MDSCs based on MPO expression. Assessing TIN and MPO status in preoperative biopsy specimens may offer valuable prognostic information and guide future therapeutic strategies for PDAC.

Cellular senescence, a hallmark of aging, is pathogenically linked to the development of aging-related diseases. This study demonstrates that FRMD6, an upstream component of the Hippo/YAP signaling cascade, is a key regulator of senescence. Proteomic analysis revealed that FRMD6 is upregulated in senescent IMR90 fibroblasts under various senescence-inducing conditions. Silencing FRMD6 mitigated the senescence of IMR90 cells, suggesting its requirement in senescence. Conversely, the overexpression of FRMD6 alone induced senescence in cells and in lung tissue, establishing a causal link. The elevated FRMD6 levels correlated well with increased levels of the inhibitory phosphorylated YAP/TAZ. We identified cellular communication network factor 3 (CCN3), a key component of the senescence-associated secretory phenotype regulated by YAP, whose administration attenuated FRMD6-induced senescence in a dose-dependent manner. Mechanistically, FRMD6 interacted with and activated MST kinase, which led to YAP/TAZ inactivation. The expression of FRMD6 was regulated by the p53 and SMAD transcription factors in senescent cells. Accordingly, the expression of FRMD6 was upregulated by TGF-β treatment that activates those transcription factors. In TGF-β-treated IMR90 cells, FRMD6 mainly segregated with p21, a senescence marker, but rarely segregated with α-SMA, a myofibroblast marker, which suggests that FRMD6 has a role in directing cells towards senescence. Similarly, in TGF-β-enriched environments, such as fibroblastic foci (FF) from patients with idiopathic pulmonary fibrosis, FRMD6 co-localized with p16 in FF lining cells, while it was rarely detected in α-SMA-positive myofibroblasts that are abundant in FF. In sum, this study identifies FRMD6 as a novel regulator of senescence and elucidates the contribution of the FRMD6-Hippo/YAP-CCN3 axis to senescence.

BACKGROUND:Cytology has long been a major screening method for cervical cancer prevention. Human papillomavirus (HPV) testing has recently been introduced for cervical cancer screening, and HPV tests become a major screening method in some countries. To seek the optimal strategy considering the cost-effectiveness for cervical cancer screening, we compared the performance of primary LBC, primary HPV test, and LBC plus HPV co-test in real practice. METHODS:From March 2016 to June 2018, 3742 patients were included in this study. Liquid-based cytology (LBC), HPV test, and histopathological assessment were performed in 3727, 1063, and 508 cases, respectively. The sensitivity, specificity, and cost-benefit effects of primary HPV, primary LBC, and co-test algorithms were simulated for 317 cases with LBC, HPV, and histopathological results. RESULTS:On the LBC, 13.0% of the cases were diagnosed with atypical squamous cells of undetermined significance or higher grade lesions. In the HPV test, high-risk HPV was found in 43.5%, and 11.9% was positive for HPV type 16 or 18. Among the three simulated algorithms, the co-test demonstrated the best sensitivity (97.5%) and the lowest specificity (50.3%). The primary LBC demonstrated the best specificity (53.5%) and a slightly better sensitivity, compare with the primary HPV (95.1% vs. 93.8%). Using the primary LBC algorithm, 82.0% can be determined without additional HPV test, whereas 50.1% could be determined without additional LBC using the primary HPV algorithm. CONCLUSIONS:The primary LBC algorithm for uterine cervical cancer (UCC) screening is comparable to the primary HPV algorithm and has the best cost-benefit effect among the three algorithms.

Rationale:Myofibromas are rare benign spindle cell tumors of the soft tissue, bone, or internal organs that occur at any age. Here, we report a post-surgical thyroid bed myofibroma that mimicked a papillary thyroid carcinoma.Patient concerns:A 56-year-old male presented with a mass in the thyroid surgical bed, detected 3 years post thyroidectomy following papillary carcinoma.Diagnosis:Thyroid ultrasonography revealed a well-defined, lobulated, hypoechoic, solid nodule, with large rod-like echogenic foci in the thyroid surgical bed. The development of a postoperative suture granuloma was considered. However, ultrasonography performed 12 months later showed a marked increase in the lesion size. Two fine needle aspiration cytology yielded nondiagnostic results.Intervention:Considering the possibility of local tumor recurrence, surgical resection was performed.Outcome:The diagnosis of a myofibroma was confirmed, and no additional treatment was administered.Lessons:It is challenging to differentiate lesions occurring on the thyroid surgical bed after surgery, from recurrent thyroid cancer. A lesion measuring 6 mm, with a degree of punctate echogenicity, suggests tumor recurrence. Moreover, myofibromas are extremely rare. This case highlights that it is advisable to perform a core needle biopsy in cases of nondiagnostic fine needle aspiration results.

Background Epithelioid angiomyolipoma (EAML) is a rare variant of angiomyolipoma that predominantly consists of epithelioid cells and belongs to the perivascular epithelioid cell neoplasm (PEComa) family. The majority of EAMLs arise in the kidneys, and primary hepatic EAML appears to be much less common than renal EAML. Most PEComas arise sporadically, but may be associated with tuberous sclerosis complex (TSC), an autosomal dominant genetic disorder characterized by germline mutations in the TSC1 or TSC2 genes. However, PEComas have previously been reported in five patients with Li-Fraumeni syndrome (LFS), which is an inherited cancer susceptibility disorder resulting from germline mutations in the TP53 tumor suppressor gene. Case presentation We report a 49-year-old female patient with hepatic EAML and pancreatic cancer. Because she had previously been diagnosed with bilateral breast cancer at the age of 30, we performed a comprehensive genetic analysis to identify genetic alterations associated with any cancer predisposition syndrome. Whole-exome sequencing of a blood sample identified a heterozygous germline variant of TP53 (NM_000546.5):c.708C>A, and targeted next-generation sequencing of liver EAML and pancreatic cancer tissue samples demonstrated the same TP53 (NM_000546.5):c.708C>A variant in both. This, plus the patient’s history of early-onset breast cancer, met the 2015 version of the Chompret criteria for diagnosis of LFS. Conclusions There have been very few case reports regarding the presence of PEComa in LFS, and to the best of our knowledge, this is the first report of EAML of the liver in a patient with LFS.

Rationale:Primary pulmonary synovial sarcoma is a rare malignant pulmonary tumor accompanied by calcifications in approximately 15% of cases. These calcifications usually have a fine, stippled appearance; coarse shapes have seldom been reported. Moreover, the presence of coarse calcifications often suggests benign tumors, which vastly differ in treatment. We present a rare case of primary pulmonary sarcoma with coarse intratumoral calcifications, the diagnosis of which was delayed because of its radiologic appearance.Patient concerns:A computed tomography (CT) scan of a 69-year-old man with right upper quadrant (RUQ) pain revealed an incidental mass at the base of the right lower lobe, the margin of which was not well described with respect to the liver, and intratumoral coarse calcification was noted. Initially, the lesion was believed to be hepatic, and magnetic resonance imaging (MRI) was performed. Based on its imaging features, the mass was thought to be a pulmonary lesion, and a preliminary diagnosis of a benign lesion, such as a hamartoma or granuloma, was made. Four months after the initial CT scan, the patient's RUQ pain had aggravated; however, no change in the mass was observed on follow-up CT.Diagnosis:The final diagnosis was primary pulmonary sarcoma, proven by surgical biopsy.Interventions:Wedge resection of the right lower lobe was performed, and the patient received adjuvant chemotherapy.Outcomes:The patient's RUQ pain improved, and no recurrence or metastasis has been reported to date.Lessons:This case describes a rare presentation of a primary pulmonary synovial sarcoma with coarse intratumoral calcifications and the MRI features of the lesion. Intratumoral coarse calcifications often suggest benign lesions, such as hamartomas or post-inflammatory granulomas; however, as malignant lesions cannot be completely excluded, other radiologic and clinical features should be considered carefully. Focal areas of enhancement and eccentric calcification distribution might suggest malignant lesions such as primary pulmonary synovial sarcoma. Furthermore, despite not being used routinely, MRI scans might be helpful because advanced MRI techniques, such as diffusion-weighted imaging, can help distinguish malignant lesions from benign lesions. If the clinical course of a patient suggests malignancy, a more aggressive biopsy strategy should be considered.

Background Non-coding microRNAs (miRNAs) play critical roles in tumor progression and hold great promise as therapeutic agents for multiple cancers. MicroRNA 29a (miR-29a) is a tumor suppressor miRNA that inhibits cancer cell growth and tumor progression in non-small cell lung cancer. Carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6), which plays an important role in lung cancer progression, has been identified as a target of miR-29a. Here, we evaluated the therapeutic efficacy of a peptide vector capable of delivering miR-29a intracellularly using the acidic tumor microenvironment in a lung adenocarcinoma xenograft mouse model. Methods A miRNA delivery vector was constructed by tethering the peptide nucleic acid form of miR-29a to a peptide with a low pH-induced transmembrane structure (pHLIP) to enable transport of the miRNAs across the plasma membrane. Tumor suppressive effects of pHLIP-miR29a on lung adenocarcinoma development in vivo were assessed using a BALB/c xenograft model injected with A549 cells. Results Incubation of A549 cells with pHLIP-miR-29a at an acidic pH downregulated endogenous CEACAM6 expression and reduced cell viability. Intravenous injection of the mice with pHLIP-miR-29a inhibited tumor growth by up to 18.1%. Intraperitoneal injection of cisplatin reduced tumor volume by 29.9%. Combined pHLIP-miR-29a + cisplatin treatment had an additive effect, reducing tumor volume up to 39.7%. Conclusions Delivery of miR-29a to lung adenocarcinoma cells using a pHLIP-mediated method has therapeutic potential as a unique cancer treatment approach.

Primary retroperitoneal mucinous cystic neoplasms are rare retroperitoneal tumors, which are histologically similar to mucinous cystic neoplasms of the ovaries. Only 31 cases of primary retroperitoneal mucinous cystic neoplasm with borderline malignancy (PRMCN-BM) have been reported (26 in women and five in men). We describe an additional male patient with PRMCN-BM. A 39-year-old man presented to our hospital with back pain. Twelve years earlier, he had undergone an orchiectomy for a germ cell tumor. Computed tomography showed a 6.9- × 4.4-cm cystic mass in the left pararenal space. Laparoscopic mass excision was performed, and a unilocular cystic mass was found in the pararenal space near the lower pole of the left kidney. A histopathological examination showed a cyst lined by atypical mucinous intestinal epithelium without stromal invasion. Targeted next-generation sequencing identified two hotspot mutations, with one each in the KRAS and GNAS genes. Outpatient follow-up 10 months after surgery showed no evidence of tumor recurrence. PRMCNs are extremely rare retroperitoneal neoplasms, especially in men. These neoplasms are rarely considered in the differential diagnosis of retroperitoneal masses, and their preoperative diagnosis is difficult. Evaluation of additional patients is required to better determine the prognosis of PRMCNs and the optimal postoperative follow-up.

Oncogenic K-RAS mutations occur in approximately 25% of human lung cancers and are most frequently found in codon 12 (G12C, G12V, and G12D). Mutated K-RAS inhibitors have shown beneficial results in many patients; however, the inhibitors specifically target K-RASG12C and acquired resistance is a common occurrence. Therefore, new treatments targeting all kinds of oncogenic K-RAS mutations with a durable response are needed. RUNX3 acts as a pioneer factor of the restriction (R)-point, which is critical for the life and death of cells. RUNX3 is inactivated in most K-RAS-activated mouse and human lung cancers. Deletion of mouse lung Runx3 induces adenomas (ADs) and facilitates the development of K-Ras-activated adenocarcinomas (ADCs). In this study, conditional restoration of Runx3 in an established K-Ras-activated mouse lung cancer model regressed both ADs and ADCs and suppressed cancer recurrence, markedly increasing mouse survival. Runx3 restoration suppressed K-Ras-activated lung cancer mainly through Arf-p53 pathway-mediated apoptosis and partly through p53-independent inhibition of proliferation. This study provides in vivo evidence supporting RUNX3 as a therapeutic tool for the treatment of K-RAS-activated lung cancers with a durable response.

Inflammatory myofibroblastic tumors (IMTs), which are rare tumors, exhibit myofibroblastic differentiation, often with anaplastic lymphoma kinase (ALK) gene rearrangements. A subset of IMTs identified in the urinary tract have been shown to harbor a fibronectin 1 (FN1)-ALK gene fusion. In this case report, a case of an IMT with FN1-ALK fusion in the urinary bladder was presented, and its clinicopathological characteristics were reviewed. A 45-year-old female was referred to Chungbuk National University Hospital with gross hematuria. Cystoscopy revealed a solid mass in the bladder. The patient subsequently underwent transurethral resection of the lesion. The mass comprised stellate and spindled myofibroblastic cells that were arranged in loose fascicles, with a myxoid background and a mixed inflammatory infiltrate. Immunohistochemical analysis revealed that the tumor cells were positive for vimentin, cytokeratin AE1/AE3 and ALK, and focal-positive for desmin. Targeted next-generation sequencing was subsequently employed to identify the FN1-ALK fusion. To date, the patient has undergone outpatient follow-up for 18 months, with no signs of tumor recurrence. To conclude, in total, FN1 has been identified as an ALK fusion partner almost exclusively in cases of genitourinary IMTs [13 bladder IMTs (including the present case) and two uterine IMTs]. In the present case, the FN1-ALK fusion was found to involve ALK exon 19 and FN1 exon 23. By contrast, the majority of the other IMTs with an ALK fusion have involved ALK exon 20, whereas ALK fusion involving ALK exon 18 or 19 has been reported only in genitourinary IMTs. Therefore, the FN1-ALK fusion involving ALK exon 18 or 19 may be specific to a subset of IMTs arising in the urinary bladder.

Snail family transcriptional repressor 2 (SNAI2, Slug) is a transcription factor that belong to the Slug/Snail superfamily. Site specific phosphorylation of slug (pSlugS158) is detected during the M phase, and thus, this phosphorylated protein is considered a novel marker for detecting mitotic figures. Herein, we investigated whether the detection of mitosis using pSlugS158 expression can be used in the histological grading of meningioma. We performed immunohistochemistry for pSlugS158 and PHH3 in tissue samples of 61 patients with meningioma and examined the association between mitotic counts using pSlugS158 and recurrence-free survival (RFS). The nuclear expression of pSlugS158 was observed in the cell with mitotic figures. Tumor grading based on pSlugS158 was significantly associated with the RFS (p < .001). It can be concluded that pSlugS158 is a useful and practical marker to detect mitosis and seems to be reliable for the counting of mitoses in histological grading of meningioma.

While the seroprevalence of SARS-CoV-2 in healthy people does not differ significantly among age groups, those aged 65 years or older exhibit strikingly higher COVID-19 mortality compared to younger individuals. To further understand differing COVID-19 manifestations in patients of different ages, three age groups of ferrets are infected with SARS-CoV-2. Although SARS-CoV-2 is isolated from all ferrets regardless of age, aged ferrets (≥3 years old) show higher viral loads, longer nasal virus shedding, and more severe lung inflammatory cell infiltration, and clinical symptoms compared to juvenile (≤6 months) and young adult (1–2 years) groups. Furthermore, direct contact ferrets co-housed with the virus-infected aged group shed more virus than direct-contact ferrets co-housed with virus-infected juvenile or young adult ferrets. Transcriptome analysis of aged ferret lungs reveals strong enrichment of gene sets related to type I interferon, activated T cells, and M1 macrophage responses, mimicking the gene expression profile of severe COVID-19 patients. Thus, SARS-CoV-2-infected aged ferrets highly recapitulate COVID-19 patients with severe symptoms and are useful for understanding age-associated infection, transmission, and pathogenesis of SARS-CoV-2.

Rationale: Nilotinib is a second line tyrosine kinase inhibitor to treat patients with chronic myeloid leukemia after imatinib resistance or intolerance. Drug related pulmonary complication is known to be rare. We discuss a case of nilotinib-induced interstitial lung disease presenting with nonspecific interstitial pneumonia on the unilateral lung. Patient concerns: A 46-year-old man with chronic-phase chronic myeloid leukemia presented with cough and weight loss for 2 months. He had been treated with nilotinib for 52 months. Diagnosis: Computed tomography scan showed right lung dominant consolidations, ground glass opacities and traction bronchiectasis. Bronchoalveolar lavage fluid analysis revealed no evidence of infection or malignancy. Surgical lung biopsy specimen was consistent with fibrosing nonspecific interstitial pneumonia. The patient was diagnosed with nilotinib induced interstitial lung disease. Interventions: Corticosteroid treatment was initiated with prednisolone (50 mg daily) and slowly tapered down for 2 months. Outcomes: Cough improved after the course of corticosteroid treatment. However, fibrotic lung lesions persisted. Reinitiation of nilotinib resulted in the worsening of lung lesions. Lessons: We report a case of irreversible interstitial lung disease that caused by nilotinib. Clinicians should have suspicion of this potential pulmonary complication in patients with respiratory symptoms and abnormal radiologic findings during nilotinib treatment, albeit rarely.

As the SARS-CoV-2 pandemic remains uncontrolled owing to the continuous emergence of variants of concern, there is an immediate need to implement the most effective antiviral treatment strategies, especially for risk groups. Here, we evaluated the therapeutic potency of nirmatrelvir, remdesivir and molnupiravir, and their combinations in SARS-CoV-2 infected K18-hACE2 transgenic mice. Systemic treatment of mice with each drug (20 mg/kg) resulted in slightly enhanced antiviral efficacy and yielded an increased life expectancy of only about 20-40% survival. However, combination therapy with nirmatrelvir (20 mg/kg) and molnupiravir (20 mg/kg) in lethally infected mice showed profound inhibition of SARS-CoV-2 replication in both the lung and brain and synergistically improved survival rates up to 80% compared to those with nirmatrelvir (36%, P < 0.001) and molnupiravir (43%, P < 0.001) administered alone. This combination therapy effectively reduced clinical severity score, virus-induced tissue damage, and viral distribution compared to those in animals treated with these monotherapies. Furthermore, all these assessments associated with this combination were also significantly higher than that of mice receiving remdesivir monotherapy (P < 0.001) and the nirmatrelvir (20 mg/kg) and remdesivir (20 mg/kg) combination (P < 0.001), underscored the clinical significance of this combination. By contrast, the nirmatrelvir and remdesivir combination showed less antiviral efficacy, with lower survival compared to nirmatrelvir monotherapy due to the insufficient plasma exposure of the remdesivir, demonstrating the inefficient therapeutic effect of this combination in the mouse model. The combination therapy with nir-matrelvir and molnupiravir contributes to alleviated morbidity and mortality, which can serve as a basis for the design of clinical studies of this combination in the treatment of COVID-19 patients.

Background This study aimed to develop and validate five machine learning models designed to predict actinomycotic osteomyelitis of the jaw. Furthermore, this study determined the relative importance of the predictive variables for actinomycotic osteomyelitis of the jaw, which are crucial for clinical decision-making. Methods A total of 222 patients with osteomyelitis of the jaw were analyzed, and Actinomyces were identified in 70 cases (31.5%). Logistic regression, random forest, support vector machine, artificial neural network, and extreme gradient boosting machine learning methods were used to train the models. The models were subsequently validated using testing datasets. These models were compared with each other and also with single predictors, such as age, using area under the receiver operating characteristic (ROC) curve (AUC). Results The AUC of the machine learning models ranged from 0.81 to 0.88. The performance of the machine learning models, such as random forest, support vector machine and extreme gradient boosting was significantly superior to that of single predictors. Presumed causes, antiresorptive agents, age, malignancy, hypertension, and rheumatoid arthritis were the six features that were identified as relevant predictors. Conclusions This prediction model would improve the overall patient care by enhancing prognosis counseling and informing treatment decisions for high-risk groups of actinomycotic osteomyelitis of the jaw.