Single-Cell Sequencing Illuminates Thymic Development: An Updated Framework for Understanding Thymic Epithelial Tumors.

Thymic epithelial tumors (TETs) are rare tumors for which treatment options are limited. The ongoing need for improved systemic therapies reflects a limited understanding of tumor biology as well as the normal thymus. The essential role of the thymus in adaptive immunity is largely effected by its epithelial compartment, which directs thymocyte (T-cell) differentiation and immunologic self-tolerance. With aging, the thymus undergoes involution whereby epithelial tissue is replaced by adipose and other connective tissue, decreasing immature T-cell production. Against this natural drive toward involution, a fraction of thymuses will instead undergo oncologic transformation, leading to the formation of TETs, including thymoma and thymic carcinoma. The rarity of these tumors restricts investigation of the mechanisms of tumorigenesis and development of rational treatment options. To this end, the development of technologies which allow deep molecular profiling of individual tumor cells permits a new window through which to view normal thymic development and contrast the malignant changes that result in oncogenic transformation. In this review, we describe the findings of recent illuminating studies on the diversity of cell types within the epithelial compartment through thymic differentiation and aging. We contextualize these findings around important unanswered questions regarding the spectrum of known somatic tumor alterations, cell of origin, and tumor heterogeneity. The perspectives informed by single-cell molecular profiling offer new approaches to clinical and basic investigation of thymic epithelial tumors, with the potential to accelerate development of improved therapeutic strategies to address ongoing unmet needs in these rare tumors.

COVID-19 in patients with thymic epithelial tumors with or without Good's syndrome: a single-center retrospective study.

INTRODUCTION: Thymic epithelial tumors (TETs) are rare neoplasms often associated with immune-related disorders. Patients with Good's syndrome (GS), an adult-acquired TET-related immunodeficiency, are at a high risk of mortality due to infectious diseases. This study aims to examine COVID-19 occurrence and severity in TET patients, with or without GS. METHODS: Clinical records of TET patients referred to the Regional Coordinating Center for Rare Tumors of Campania Region were retrospectively collected. During the observation period, elapsing from March 2020 to April 2023, the following data were collected: occurrence of SARS-CoV-2 infection; COVID-19 severity, according to the National Institute of Health (NIH) illness categories; COVID-19 treatment. COVID-19 occurrence and severity were assessed in the overall population and correlated with the presence of GS and/or other immune-related dysregulations. RESULTS: Overall, 47 TET patients were included in the study; 27 of these (57.4%) had GS. All participants had received a full cycle of mRNA vaccine for SARS-CoV2., Thirty-one patients (66.0%) experienced COVID-19, of whom 18 (58.0%) had previously received a diagnosis of GS. No significant association of GS and/or other immune-related dysregulations with SARS-CoV-2 infection occurrence was detected (Fisher's exact test p = 1 and p = 0.3587, respectively). Among patients with GS, 8 (45.0%) reported a COVID-19 severity score of ≥ 3; whereas, only 1 of the 13 patients without GS (7.7%) had a severity score of ≥ 3. The correlation between presence of GS and COVID-19 severity (score 1 or 2 vs. ≥ 3) was statistically significant (p = 0.0448). No statistically significant association between COVID-19 severity and other immune-related syndromes were found (p = 1). Of note, all the hospitalized patients for NIH 4 and 5 COVID-19 had GS. CONCLUSIONS: Our data suggest that TET patients, especially those with GS, require a careful multidisciplinary monitoring for SARS-CoV-2 infection, in order to establish tailored treatments and prophylactic protocols.

Serum biomarkers of inflammation and vascular damage upon SARS-Cov-2 mRNA vaccine in patients with thymic epithelial tumors.

OBJECTIVES: Thymic epithelial tumors (TET) patients are at high risk of autoimmune and hypoimmune complications. Limited evidence is available on the potential risk of immune-related and inflammatory reactions induced by SARS-Cov-2 vaccine in this patient population. METHODS: In order to identify subjects at higher risk for vaccine complications, we prospectively evaluated a panel of serum biomarkers related to inflammation (TNF-α, IL-1ß, -6, -10, -12, and -17A, IFN-α, ß and γ, MPO, MMP-9), and vascular damage (E- and P-selectin, VEGF-A, P-ANCA and MCP-1) in 44 TET patients and in 30 healthy controls along the whole SARS-Cov-2 vaccine cycle. RESULTS: About 50 % of subjects (either TET and controls) showed an increase of serum biochemical markers of inflammation and endothelial damage with a large heterogeneity of values. Such increase appeared early, after the first dose in control subjects and later, after the second dose in TET patients (in which we observed mainly an increase of inflammatory biomarkers). The values normalized after about 3 months and did not increase after the third, booster dose. No autoimmune or vascular complications were observed in the study subjects and no difference was observed in terms of vaccine response among subjects showing serum biomarkers increase and those who experienced no changes. CONCLUSIONS: Our data highlight the relevance of Sars-Cov-2 vaccine in TET patients, as it resulted safe and prevented severe COVID-19. However, further studies are awaited to explore the mechanisms and the potential consequences of the observed increase of serum inflammatory and vascular damage biomarkers.

The Molecular Landscape of Thymic Epithelial Tumors: A Comprehensive Review.

Thymic epithelial tumors (TETs) are characterized by their extreme rarity and variable clinical presentation, with the inadequacy of the use of histological classification alone to distinguish biologically indolent from aggressive cases. The utilization of Next Generation Sequencing (NGS) to unravel the intricate genetic landscape of TETs could offer us a comprehensive understanding that is crucial for precise diagnoses, prognoses, and potential therapeutic strategies. Despite the low tumor mutational burden of TETS, NGS allows for exploration of specific genetic signatures contributing to TET onset and progression. Thymomas exhibit a limited mutational load, with prevalent GTF2I and HRAS mutations. On the other hand, thymic carcinomas (TCs) exhibit an elevated mutational burden, marked by frequent mutations in TP53 and genes associated with epigenetic regulation. Moreover, signaling pathway analyses highlight dysregulation in crucial cellular functions and pathways. Targeted therapies, and ongoing clinical trials show promising results, addressing challenges rooted in the scarcity of actionable mutations and limited genomic understanding. International collaborations and data-sharing initiatives are crucial for breakthroughs in TETs research.

Immunotherapy of thymic epithelial tumors: molecular understandings and clinical perspectives.

Immunotherapy has emerged to play a rapidly expanding role in the treatment of cancers. Currently, many clinical trials of therapeutic agents are on ongoing with majority of immune checkpoint inhibitors (ICIs) especially programmed death receptor 1 (PD-1) and its ligand 1 (PD-L1) inhibitors. PD-1 and PD-L1, two main immune checkpoints, are expressed at high levels in thymic epithelial tumors (TETs) and could be predictors of the progression and immunotherapeutic efficacy of TETs. However, despite inspiring efficacy reported in clinical trials and clinical practice, significantly higher incidence of immune-related adverse events (irAEs) than other tumors bring challenges to the administration of ICIs in TETs. To develop safe and effective immunotherapeutic patterns in TETs, understanding the clinical properties of patients, the cellular and molecular mechanisms of immunotherapy and irAEs occurrence are crucial. In this review, the progress of both basic and clinical research on immune checkpoints in TETs, the evidence of therapeutic efficacy and irAEs based on PD-1 /PD-L1 inhibitors in TETs treatment are discussed. Additionally, we highlighted the possible mechanisms underlying irAEs, prevention and management strategies, the insufficiency of current research and some worthy research insights. High PD-1/PD-L1 expression in TETs provides a rationale for ICI use. Completed clinical trials have shown an encouraging efficacy of ICIs, despite the high rate of irAEs. A deeper mechanism understanding at molecular level how ICIs function in TETs and why irAEs occur will help maximize the immunotherapeutic efficacy while minimizing irAEs risks in TET treatment to improve patient prognosis.

Prognosis of Concurrent Versus Sequential Chemo-Radiotherapy Induction Followed by Surgical Resection in Patients with Advanced Thymic Epithelial Tumors: A Retrospective Study.

BACKGROUND: This study aimed to evaluate the prognosis of concurrent chemo-radiotherapy (CCRT) versus sequential chemo-radiotherapy (SCRT) induction followed by surgical resection in patients with advanced thymic epithelial tumors (TETs). METHODS: This retrospective study included patients with advanced TETs who underwent CCRT or SCRT induction followed by surgical resection at the Second General Hospital of Guangdong Province between January 2008 and December 2019. The primary outcomes were induction response rate and surgical complete resection rate. The secondary outcomes were surgery combined resection, post-induction T staging, postoperative TNM staging, postoperative pathological tumor regression grade, progression-free survival (PFS) and overall survival (OS), and adverse events (AEs). RESULTS: A total of 31 patients were included, 15 of whom received CCRT and the other 16 SCRT. The induction response rates were 80.0 and 62.5%, respectively, the post-induction step-down rates were 46.7 and 31.3%, respectively, and the post-induction R0 resection rates were 80.0 and 68.8%, respectively, without significant differences between CCRT and SCRT groups (all P > 0.05). The 5-year OS rate was 64.2 and 51.6%, respectively, and PFS was 42.3 and 21.4%, respectively, without significant differences between CCRT and SCRT groups (both P > 0.05). AEs in the hematologic system were significantly higher with CCRT compared with SCRT (P = 0.009). CONCLUSIONS: Patients with advanced TETs might have a good prognosis with both CCRT and SCRT induction therapy, while SCRT induction may result in a lower probability of AEs in the hematologic system.

Genomic characterization of thymic epithelial tumors reveals critical genes underlying tumorigenesis and poor prognosis.

Thymic epithelial tumors (TETs) are rare mediastinal tumors whose tumorigenesis mechanism is poorly understood. Characterization of molecular alterations in TETs may contribute to a better understanding of tumorigenesis and prognosis. Hybrid capture-based next-generation sequencing was performed on tumor tissues from 47 TETs (39 thymomas and 8 thymic carcinomas) to detect mutations in 315 tumor-associated genes. In total, 178 nonsynonymous mutations were identified, with a median of 3.79 per tumor in 47 TETs. Higher tumor mutation burden (TMB) level was more common in older TET patients, and significantly associated with the more advanced pathological type, especially in thymic carcinomas (TC) patients. The gene mutation profiles of B1-3, A/AB, and TC patients varied greatly. In the actionable mutations analysis, we found 32 actionable mutations in 24 genes. Among them, NFKBIA and TP53 mutations was the most frequently, which were only identified in TCs. Additionally, TCGA database analysis found that the expression of NFKBIA mRNA in the TCs were significantly higher than thymomas. TET patients with high NFKBIA expression had shorter overall survival compared with patients with low/medium NFKBIA expression, thus providing insights to consider NFKBIA as a potential prognosis biomarker and therapeutic target in TETs.

Chemoradiotherapy for untreated Masaoka-Koga stage IVB thymic carcinoma: a single-center retrospective study.

BACKGROUND: Thymic carcinoma (TC) is a rare type of a malignant tumor. The optimal treatment for Masaoka-Koga stage IVB TC patients is controversial due to the rarity of the disease. Chemotherapy is still the preferred option, but the outcomes are unsatisfactory. Whether radiotherapy combined with chemotherapy could improve prognosis remains unclear. METHODS: Untreated stage IVB TC patients who have received first-line chemotherapy were included in the present study. The patients who have undergone surgery were excluded. The primary outcomes were objective response rate (ORR) and progression-free survival (PFS). RESULTS: Sixty-seven patients were included in the study. A total of 31 patients received chemoradiotherapy (ChemoRT cohort), and the remaining 36 patients only received chemotherapy (Chemo cohort). The median follow-up period was 40.3 months. The ORR for the ChemoRT and Chemo cohorts was 61.3 and 27.8%, respectively (P = 0.006). Furthermore, PFS (P = 0.003) and OS (P = 0.046) were significantly superior in the ChemoRT cohort. Radiotherapy maintained a significant favorable effect on PFS in multivariate analysis (P = 0.014), but the effect on OS was insignificant (P = 0.249). There was no advantage in PFS (P = 0.302) in the ChemoRT cohort in patients who received < 4 cycles of chemotherapy. In contrast, radiotherapy significantly improved PFS (P = 0.005) in patients who received ≥ 4 cycles of chemotherapy. CONCLUSIONS: Chemoradiotherapy used as the first-line treatment improved ORR and PFS in Masaoka-Koga stage IVB TC patients. Patients receiving more cycles of chemotherapy may have a better chance to benefit from chemoradiotherapy.

Histogenetic and disease-relevant phenotypes in thymic epithelial tumors (TETs): The potential significance for future TET classification.

Thymic epithelial tumors (TETs) encompass morphologically various subtypes. Thus, it would be meaningful to explore the expression phenotypes that delineate each TET subtype or overarching multiple subtypes. If these profiles are related to thymic physiology, they will improve our biological understanding of TETs and may contribute to the establishment of a more rational TET classification. Against this background, pathologists have attempted to identify histogenetic features in TETs for a long time. As part of this work, our group has reported several TET expression profiles that are histotype-dependent and related to the nature of thymic epithelial cells (TECs). For example, we found that beta5t, a constituent of thymoproteasome unique to cortical TECs, is expressed mainly in type B thymomas, for which the nomenclature of cortical thymoma was once considered. Another example is the discovery that most thymic carcinomas, especially thymic squamous cell carcinomas, exhibit expression profiles similar to tuft cells, a recently discovered special type of medullary TEC. This review outlines the currently reported histogenetic phenotypes of TETs, including those related to thymoma-associated myasthenia gravis, summarizes their genetic signatures, and provides a perspective for the future direction of TET classification.

Tumor size exceeding 5 cm as a valid prognostic factor in all stages of thymic epithelial tumors.

PURPOSE: This study investigated the prognostic factors of thymic epithelial tumors (TETs) to identify patients who require multidisciplinary treatment and improve the TET prognosis. METHODS: We retrospectively reviewed the data of 268 TET patients. Prognostic variables for the overall survival (OS) were analyzed in all TET stages (n = 268), and the recurrence-free survival (RFS) was analyzed in patients who achieved complete resection (n = 164). RESULTS: The median follow-up period was 7 years; thymic carcinomas (TCs) and advanced stages of tumor, node, and metastasis (TNM) classification had the worse prognosis according to a Kaplan-Meier analysis. The cut-off value of the tumor size to predict the OS and RFS was determined using modified Harrell's c-index calculated by a Cox regression analysis of the OS. Regarding the OS, a multivariate analysis revealed that age > 70 years old (p = 0.011), tumor size > 5 cm (p < 0.001), and TCs (p = 0.002) were significant prognostic factors aside from the TNM stage (p < 0.001). Regarding the RFS, tumor size > 5 cm was the only significant prognostic factor in the multivariate analysis (p = 0.002) aside from the TNM stage (p = 0.008). CONCLUSIONS: Tumor size > 5 cm was shown to be a prognostic predictor in addition to the WHO and TNM classifications. Therefore, multidisciplinary treatment should be developed for TET patients with poor prognostic factors, specifically tumor size.

Robot versus video-assisted thoracoscopic thymectomy for large thymic epithelial tumors: a propensity-matched analysis.

BACKGROUND: Both video-assisted thoracoscopic surgery (VATS) thymectomy and robot-assisted thoracoscopic surgery (RATS) thymectomy have been suggested as technically sound approaches for early-stage thymic epithelial tumors. However, the choice of VATS or RATS thymectomy for large and advanced thymic epithelial tumors remains controversial. In this study, the perioperative outcomes of VATS and RATS thymectomy were compared in patients with large thymic epithelial tumors (size ≥5.0 cm). METHODS: A total of 113 patients with large thymic epithelial tumors who underwent minimally invasive surgery were included. Sixty-three patients underwent RATS, and 50 patients underwent VATS. Patient characteristics and perioperative variables were compared. RESULTS: Compared with the VATS group, the RATS group experienced a shorter operation time (median: 110 min vs.130 min; P < 0.001) and less blood loss (30.00 ml vs. 100.00 ml, P < 0.001). No patients in the RATS group needed conversion to open surgery, but in the VATS series, five patients required conversion to open procedures (0% vs. 14.29%, P = 0.054). The rate of concomitant resection in the RATS group was similar to that in the VATS group (11.43% vs. 5.71%; P = 0.673). There was no significant difference between the two groups in the duration of chest tube (P = 0.587), postoperative complications (P = 1.000), and the duration of postoperative hospital stay (P = 0.141). CONCLUSION: For large thymic epithelial tumors, RATS thymectomy can be performed safely and effectively in a radical fashion. Due to the advanced optics and precise instrument control, concomitant resections can be easily achieved in larger thymic epithelial tumors using the robotic approach.

An Overview of the Use of Anti-Angiogenic Agents in the Treatment of Thymic Epithelial Tumors.

Angiogenesis significantly influences the carcinogenesis of thymic epithelial tumors (TET). Both thymomas and thymic carcinoma (TC) overexpress VEGF-A and VEGFR-1 and -2. This review aims to provide an appraisal of the use of anti-angiogenics in the treatment of TET. The literature research identified 16 studies that were deemed eligible for further analysis. Seven studies assessed the clinical efficacy of sunitinib and five studies the use of apatinib and/or anlotinib. The multicenter Japanese phase II REMORA trial investigated the efficacy of lenvatinib, which is a multi-targeted inhibitor of VEGFR, FGFR, RET, c-Kit, and other kinases. The objective response rate was 38% (25.6-52%), which is the highest documented in TET that progressed after first-line chemotherapy. Anti-angiogenic agents may be useful in the treatment of TET, which are not amenable to curative treatment. Their toxicity profile seems to be acceptable. However, angiogenesis inhibitors do not appear to have a major influence on either thymomas or TC, although multikinase inhibitors may have some effect on TC. The current evidence suggests that the most active agent is lenvatinib, whereas sunitinib could be proposed as an acceptable second-line therapy for TC. Further research concerning the combination of immune checkpoint inhibitors with anti-angiogenic drugs is warranted.

Histone Deacetylases (HDACs): Promising Biomarkers and Potential Therapeutic Targets in Thymic Epithelial Tumors.

Histone deacetylases (HDACs) are core epigenetic factors, with pivotal roles in the regulation of various cellular procedures, and their deregulation is a major trait in the acquisition of malignancy properties. In this study we attempt the first comprehensive evaluation of six class I (HDAC1, HDAC2, HDAC3) and II HDACs (HDAC4, HDAC5, HDAC6) expression patterns in thymic epithelial tumors (TETs), with the aim of identifying their possible association with a number of clinicopathological parameters. Our study revealed higher positivity rates and expression levels of class I enzymes compared to class II. Sub-cellular localization and level of staining varied among the six isoforms. HDAC1 was almost exclusively restricted to the nucleus, while HDAC3 demonstrated both nuclear and cytoplasmic reactivity in the majority of examined specimens. HDAC2 expression was higher in more advanced Masaoka-Koga stages, and displayed a positive correlation with dismal prognoses. The three class II HDACs (HDAC4, HDAC5, HDAC6) exhibited similar expression patterns, with predominantly cytoplasmic staining, that was higher in epithelial rich TETs (B3, C) and more advanced tumor stages, while it was also associated with disease recurrence. Our findings could provide useful insights for the effective implementation of HDACs as biomarkers and therapeutic targets for TETs, in the setting of precision medicine.

Thymic epithelial tumors: examining the GTF2I mutation and developing a novel prognostic signature with LncRNA pairs to predict tumor recurrence.

BACKGROUND: General transcription factor IIi (GTF2I) mutations are very common in thymic epithelial tumors (TETs) and are related to a more favorable prognosis in TET patients. However, limited research has been conducted on the role of GTF2I in the tumor immune microenvironment (TIME). Further, long non-coding RNAs (lncRNAs) have been associated with the survival of patients with TETs. Therefore, this study aimed to explore the relationship between GTF2I mutations and TIME and build a new potential signature for predicting tumor recurrence in the TETs. Research data was downloaded from The Cancer Genome Atlas database and the CIBERSORT algorithm was used to evaluate TIME differences between GTF2I mutant and wild-type TETs. Relevant differentially expressed lncRNAs based on differentially expressed immune-related genes were identified to establish lncRNA pairs. We constructed a signature using univariate and multivariate Cox regression analyses. RESULTS: GTF2I is the most commonly mutated gene in TETs, and is associated with an increased number of early-stage pathological types, as well as no history of myasthenia gravis or radiotherapy treatment. In the GTF2I wild-type group, immune score and immune cell infiltrations with M2 macrophages, activated mast cells, neutrophils, plasma, T helper follicular cells, and activated memory CD4 T cells were higher than the GTF2I mutant group. A risk model was built using five lncRNA pairs, and the 1-, 3-, and 5-year area under the curves were 0.782, 0.873, and 0.895, respectively. A higher risk score was related to more advanced histologic type. CONCLUSION: We can define the GTF2I mutant-type TET as an immune stable type and the GTF2I wild-type as an immune stressed type. A signature based on lncRNA pairs was also constructed to effectively predict tumor recurrence.

Resound Trial: A phase 2 study of regorafenib in patients with thymoma (type B2-B3) and thymic carcinoma previously treated with chemotherapy.

BACKGROUND: Angiogenesis has an important role in thymic epithelial tumors (TETs). Regorafenib inhibits vascular endothelial growth factor receptors (VEGFRs), platelet-derived growth factor receptor ß (PDGFR-ß), and fibroblast growth factor receptors (FGFRs). This study explored the activity of regorafenib as monotherapy in patients with advanced or recurrent B2-B3 thymoma (T) and thymic carcinoma (TC) previously treated with platinum-containing chemotherapy. METHODS: A Fleming single-arm, single-stage, phase 2 trial to evaluate the activity of regorafenib (160 mg once a day by mouth for 3 weeks on/1 week off) was planned. The study was designed to reject the null hypothesis of an 8-week progression-free survival (PFS) rate ≤25% with a type I error of 0.10 and a statistical power of 80% at the alternative hypothesis of an 8-week PFS rate of ≥50% (≥8 of 19 evaluable patients progression-free at 2 months). RESULTS: From June 2016 to November 2017, 19 patients were enrolled (11T/8TC). We observed partial response (PR) in 1 patient (1T) (5.3%), stable disease (SD) in 14 patients (9T/5TC) (73.7%), and progressive disease in 2 patients (1T/1TC) (10.5%), with a disease control rate of 78.9%. According to Choi-criteria, 13 patients (68.4%) achieved PR, and 2 patients SD (10.5%). The median PFS was 9.6 months whereas median overall survival was 33.8 months. The 8-week PFS rate was 78.9% (15 of 19 patients). Grade 3-4 treatment-related adverse events were observed in 10 patients (52.6%). CONCLUSIONS: The primary end point of this study was reached. The high rate of PR (Choi-criteria) suggests antitumor activity of regorafenib in TETs. On the basis of survival outcomes, the efficacy of regorafenib should be further evaluated in larger studies.

Joint-Predominant Rheumatic Complications of Immune Checkpoint Inhibitor Therapy in Patients with Thymic Epithelial Tumors.

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of advanced cancers. However, activation of the immune system can occasionally cause life-threatening toxicity involving critical organs. Induction of immune-mediated toxicity is a significant concern for patients with thymic epithelial tumors (TETs) due to defects in immune tolerance. An increased risk of skeletal and cardiac muscle inflammation following treatment with ICIs is well recognized in patients with advanced TETs. However, uncommon musculoskeletal and rheumatic complications can also occur. The cases presented in this report highlight the spectrum of presentation of immune-mediated, joint-predominant musculoskeletal adverse events in patients with advanced TETs treated with ICIs, including polymyalgia rheumatica-like illness and inflammatory arthritis.

Apatinib in patients with recurrent or metastatic thymic epithelial tumor: a single-arm, multicenter, open-label, phase II trial.

BACKGROUND: Thymic epithelial tumors (TETs) are rare malignancies and the treatment options are limited. We aimed to evaluate the efficacy and safety of apatinib, an angiogenesis inhibitor, in advanced TETs. METHODS: This was an open-label, single-arm, phase II trial at three centers in China. Patients with TET who had progressed after failure of at least one line of platinum-based chemotherapy were enrolled. Patients received apatinib 500 mg orally per day. The primary endpoint was objective response rate (ORR). Secondary endpoints were progression-free survival (PFS), overall survival (OS), disease control rate (DCR), and safety. RESULTS: From June 29, 2017, to April 18, 2019, 25 patients were enrolled. At data cut off (September 30, 2021), one patient achieved complete response, nine achieved partial response, and 11 achieved stable disease, with an ORR of 40% (95% CI 21-61%) and DCR of 84% (95% CI 64-95%). The median PFS was 9.0 (95% CI 5.4-12.6) months. The median OS was 24.0 (95% CI 8.2-39.8) months. All patients reported treatment-related adverse events (TRAEs). Grade 3 TRAEs occurred 26 times in 15 patients. No grade 4 or 5 toxicities occurred. CONCLUSIONS: This is the first trial of apatinib for the treatment of TETs. Apatinib showed promising antitumor activity and the toxicities were tolerable and manageable.

Multiparameter diagnostic model based on 18F-FDG PET and clinical characteristics can differentiate thymic epithelial tumors from thymic lymphomas.

OBJECTIVE: To evaluate the diagnostic performance of combined multiparametric 18F-fluorodeoxyglucose positron emission tomography (18FDG PET) with clinical characteristics in differentiating thymic epithelial tumors (TETs) from thymic lymphomas. PATIENTS AND METHODS: A total of 173 patients with 80 TETs and 93 thymic lymphomas who underwent 18F-FDG PET/CT before treatment were enrolled in this retrospective study. All patients were confirmed by pathology, and baseline characteristics and clinical data were also collected. The semi-parameters of 18F-FDG PET/CT, including lesion size, SUVmax (maximum standard uptake value), SUVmean (mean standard uptake value), TLG (total lesion glycolysis), MTV (metabolic tumor volume) and SUVR (tumor-to-normal liver standard uptake value ratio) were evaluated. The differential diagnostic efficacy was evaluated using the receiver operating characteristic (ROC) curve. Integrated discriminatory improvement (IDI) and net reclassification improvement (NRI), and Delong test were used to evaluate the improvement in diagnostic efficacy. The clinical efficacy was evaluated by decision curve analysis (DCA). RESULTS: Age, clinical symptoms, and metabolic parameters differed significantly between patients with TETs and thymic lymphomas. The ROC curve analysis of SUVR showed the highest differentiating diagnostic value (sensitivity = 0.763; specificity = 0.888; area under the curve [AUC] = 0.881). The combined diagnostics model of age, clinical symptoms and SUVR resulted in the highest AUC of 0.964 (sensitivity = 0.882, specificity = 0.963). Compared with SUVR, the diagnostic efficiency of the model was improved significantly. The DCA also confirmed the clinical efficacy of the model. CONCLUSIONS: The multiparameter diagnosis model based on 18F-FDG PET and clinical characteristics had excellent value in the differential diagnosis of TETs and thymic lymphomas.

Prognostic value of preoperative C-reactive protein to albumin ratio in patients with thymic epithelial tumors: a retrospective study.

BACKGROUND: The C-reactive protein to albumin ratio (CAR) is associated with poor prognosis in various cancers. However, its value in thymic epithelial tumors remains to be elucidated, we aimed to evaluate the prognostic significance of preoperative CAR in patients with surgically resected thymic epithelial tumors (TETs). METHODS: We retrospectively collected data from 125 patients with TETs who underwent thymoma resection at our center. The best cutoff values ​​for the continuous variable, CAR, were obtained using X-tile software. Univariate and multivariate Cox regression analyses were used to evaluate CAR as an independent predictor of overall survival (OS) and recurrence-free survival (RFS). Kaplan-Meier analysis and log-rank tests were used to present risk stratification of patients based on CAR and the Glasgow-prognostic-score (GPS). The prognostic effect of CAR was assessed using a receiver operating characteristic curve. RESULTS: Patients were categorized into high (≥ 0.17) and low (< 0.17) CAR groups according to the optimal cutoff value of 0.17. Univariate and multivariate analyses showed that CAR was an independent predictor of prognosis. World health organization stage, CAR level, GPS score, and drinking history were important independent prognostic factors for OS (p < 0.05). T stage, CAR level, and drinking history were important independent prognostic factors for RFS (p < 0.05). The area under the curve value of CAR to predict prognosis was 0.734 for OS and 0.680 for RFS. CONCLUSIONS: Elevated preoperative CAR was independently associated with poor OS and RFS after thymectomy. Therefore, CAR may be a valuable biomarker for the postoperative prognosis of TETs.

Molecular landscape of thymic epithelial tumors.

Thymic epithelial tumors (TETs) are extremely rare and represent the most frequent tumors of the anterior mediastinum originating from epithelial cells in the thymus. Thymic epithelial tumors include thymomas (TM), thymic carcinomas (TC) and thymic neuroendocrine neoplasms (TNEN). Thymomas are the most predominant and are associated with autoimmune diseases. The available data suggests that the different histological subtypes have specific molecular alterations. Thymic carcinoma shows recurrent gene mutations, but further investigations are needed to understand the role of those mutations in the pathogenetic of the TETs. Some of the new emerging identified molecular alterations have the potential to offer new targeted therapies opening new possibilities for the treatment of thymic epithelial tumors.