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John N, Schlintl V, Sassmann T, Lindenmann J, Fediuk M, Wurm R, Douschan P, Zacharias M, Kalson L, Posch F, Absenger G, Brcic L, Jost PJ, Terbuch A. Longitudinal analysis of PD-L1 expression in patients with relapsed NSCLC. J Immunother Cancer 2024; 12:e008592. [PMID: 38604811 PMCID: PMC11015283 DOI: 10.1136/jitc-2023-008592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/18/2024] [Indexed: 04/13/2024] Open
Abstract
BACKGROUND The use and approval of immune checkpoint inhibitors for the treatment of non-small cell lung cancer (NSCLC) depends on PD-L1 expression in the tumor tissue. Nevertheless, PD-L1 often fails to predict response to treatment. One possible explanation could be a change in PD-L1 expression during the course of the disease and the neglect of reassessment. The purpose of this study was a longitudinal analysis of PD-L1 expression in patients with relapsed NSCLC. METHODS We retrospectively analyzed PD-L1 expression in patients with early-stage NSCLC and subsequent relapse in preoperative samples, matched surgical specimens and biopsy samples of disease recurrence. Ventana PD-L1 (SP263) immunohistochemistry assay was used for all samples. PD-L1 expression was scored based on clinically relevant groups (0%, 1%-49%, and ≥50%). The primary endpoint was the change in PD-L1 score group between preoperative samples, matched surgical specimens and relapsed tumor tissue. RESULTS 395 consecutive patients with stages I-III NSCLC and 136 (34%) patients with a subsequent relapse were identified. For 87 patients at least two specimens for comparison of PD-L1 expression between early stage and relapsed disease were available. In 72 cases, a longitudinal analysis between preoperative biopsy, the surgically resected specimen and biopsy of disease recurrence was feasible. When comparing preoperative and matched surgical specimens, a treatment-relevant conversion of PD-L1 expression group was found in 25 patients (34.7%). Neoadjuvant treatment showed no significant effect on PD-L1 alteration (p=0.39). In 32 (36.8%) out of 87 cases, a change in PD-L1 group was observed when biopsies of disease relapse were compared with early-stage disease. Adjuvant treatment was not significantly associated with a change in PD-L1 expression (p=0.53). 39 patients (54.2%) showed at least 1 change into a different PD-L1 score group during the course of disease. 14 patients (19.4%) changed the PD-L1 score group twice, 5 (6.9%) of them being found in all different score groups. CONCLUSION PD-L1 expression shows dynamic changes during the course of disease. There is an urgent need for consensus guidelines to define a PD-L1 testing strategy including time points of reassessment, the number of biopsies to be obtained and judgment of surgical specimens.
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Affiliation(s)
- Nikolaus John
- Division of Pulmonology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Verena Schlintl
- Division of Oncology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Teresa Sassmann
- Division of Pulmonology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Jörg Lindenmann
- Division of Thoracic Surgery, Department of Surgery, Medical University of Graz, Graz, Austria
| | - Melanie Fediuk
- Division of Thoracic Surgery, Department of Surgery, Medical University of Graz, Graz, Austria
| | - Robert Wurm
- Division of Pulmonology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Philipp Douschan
- Division of Pulmonology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
- Department of Internal Medicine, Marburg Lung Center, Giessen, Germany
| | - Martin Zacharias
- Diagnostic and Research Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Lipika Kalson
- Diagnostic and Research Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Florian Posch
- Division of Hematology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Gudrun Absenger
- Division of Oncology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Luka Brcic
- Diagnostic and Research Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Philipp J Jost
- Division of Oncology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
- BioTechMed-Graz Office, Graz, Austria
| | - Angelika Terbuch
- Division of Oncology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
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Stergiou IE, Palamaris K, Levidou G, Tzimou M, Papadakos SP, Mandrakis G, Masaoutis C, Rontogianni D, Theocharis S. PD-L1 Expression in Neoplastic and Immune Cells of Thymic Epithelial Tumors: Correlations with Disease Characteristics and HDAC Expression. Biomedicines 2024; 12:772. [PMID: 38672128 PMCID: PMC11048374 DOI: 10.3390/biomedicines12040772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 03/26/2024] [Accepted: 03/28/2024] [Indexed: 04/28/2024] Open
Abstract
BACKGROUND Programmed death-ligand 1 (PD-L1) expression in neoplastic and immune cells of the tumor microenvironment determines the efficacy of antitumor immunity, while it can be regulated at the epigenetic level by various factors, including HDACs. In this study, we aim to evaluate the expression patterns of PD-L1 in thymic epithelial tumors (TETs), while we attempt the first correlation analysis between PD-L1 and histone deacetylases (HDACs) expression. METHODS Immunohistochemistry was used to evaluate the expression of PD-L1 in tumor and immune cells of 91 TETs with SP263 and SP142 antibody clones, as well as the expressions of HDCA1, -2, -3, -4, -5, and -6. RESULTS The PD-L1 tumor proportion score (TPS) was higher, while the immune cell score (IC-score) was lower in the more aggressive TET subtypes and in more advanced Masaoka-Koga stages. A positive correlation between PD-L1 and HDAC-3, -4, and -5 cytoplasmic expression was identified. CONCLUSIONS Higher PD-L1 expression in neoplastic cells and lower PD-L1 expression in immune cells of TETs characterizes more aggressive and advanced neoplasms. Correlations between PD-L1 and HDAC expression unravel the impact of epigenetic regulation on the expression of immune checkpoint molecules in TETs, with possible future applications in combined therapeutic targeting.
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Affiliation(s)
- Ioanna E. Stergiou
- Department of Pathophysiology, School of Medicine, National and Kapodistrian University of Athens, 11527 Athens, Greece;
- First Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, 10679 Athens, Greece; (K.P.); (M.T.); (S.P.P.); (G.M.); (C.M.)
| | - Kostas Palamaris
- First Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, 10679 Athens, Greece; (K.P.); (M.T.); (S.P.P.); (G.M.); (C.M.)
| | - Georgia Levidou
- Second Department of Pathology, Paracelsus Medical University, 90419 Nurenberg, Germany
| | - Maria Tzimou
- First Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, 10679 Athens, Greece; (K.P.); (M.T.); (S.P.P.); (G.M.); (C.M.)
| | - Stavros P. Papadakos
- First Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, 10679 Athens, Greece; (K.P.); (M.T.); (S.P.P.); (G.M.); (C.M.)
| | - Georgios Mandrakis
- First Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, 10679 Athens, Greece; (K.P.); (M.T.); (S.P.P.); (G.M.); (C.M.)
| | - Christos Masaoutis
- First Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, 10679 Athens, Greece; (K.P.); (M.T.); (S.P.P.); (G.M.); (C.M.)
| | - Dimitra Rontogianni
- Department of Pathology, Evangelismos General Hospital of Athens, 10676 Athens, Greece;
| | - Stamatios Theocharis
- First Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, 10679 Athens, Greece; (K.P.); (M.T.); (S.P.P.); (G.M.); (C.M.)
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Ao YQ, Gao J, Wang S, Jiang JH, Deng J, Wang HK, Xu B, Ding JY. Immunotherapy of thymic epithelial tumors: molecular understandings and clinical perspectives. Mol Cancer 2023; 22:70. [PMID: 37055838 PMCID: PMC10099901 DOI: 10.1186/s12943-023-01772-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 04/03/2023] [Indexed: 04/15/2023] Open
Abstract
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.
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Affiliation(s)
- Yong-Qiang Ao
- Department of Thoracic Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, 200032, Shanghai, China
- Cancer Center, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jian Gao
- Department of Thoracic Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, 200032, Shanghai, China
- Cancer Center, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Shuai Wang
- Department of Thoracic Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, 200032, Shanghai, China
- Cancer Center, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jia-Hao Jiang
- Department of Thoracic Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, 200032, Shanghai, China
- Cancer Center, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jie Deng
- Institute of Vascular Disease, Shanghai TCM-Integrated Hospital, Shanghai, China
| | - Hai-Kun Wang
- CAS Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Bei Xu
- Department of Oncology, Zhongshan Hospital, Fudan University, Shanghai, China.
| | - Jian-Yong Ding
- Department of Thoracic Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, 200032, Shanghai, China.
- Cancer Center, Zhongshan Hospital, Fudan University, Shanghai, China.
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Roden AC, Rakshit S, Johnson GB, Jenkins SM, Mansfield AS. Correlation of Somatostatin Receptor 2 Expression, 68Ga-DOTATATE PET Scan and Octreotide Treatment in Thymic Epithelial Tumors. Front Oncol 2022; 12:823667. [PMID: 35198446 PMCID: PMC8859934 DOI: 10.3389/fonc.2022.823667] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Accepted: 01/10/2022] [Indexed: 12/14/2022] Open
Abstract
Somatostatin receptor 2 (SSTR2) has been shown to be expressed in a subset of neuroendocrine tumors and carcinomas and plays a role in imaging studies and guiding therapy. Patients with tumors expressing SSTR2 may be successfully treated with somatostatin inhibitors or radiolabeled somatostatin analogues. We studied SSTR2 expression in TET and correlated it with 68Ga-DOTATATE PET/CT or 68Ga-DOTATATE PET/MR results and treatment outcome. An institutional database of TET was searched for thymoma, thymic carcinoma, and thymic neuroendocrine tumor (TNET) with available resection specimens. Cases were subtyped (2021 WHO classification) and staged (8th AJCC/UICC staging). A section was stained with anti-SSTR2 antibody (clone UMB1). Percent tumor cells with membranous staining was recorded if present in ≥1% of tumor cells. Medical records were searched for 68Ga-DOTATATE PET scans and treatment. Statistical analysis was performed. Eighty patients (1969-2021) with a median age of 61.3 years (range, 19.1-87.3) (37 males, 46.3%) had thymic carcinoma (N=33), TNET (N=7), or thymoma (N=40). SSTR2 expression was identified in 29 (of 80, 36.3%) TET including 2/2 (100%) small cell carcinomas, 2/5 (40.0%) atypical carcinoid tumors, 16/23 (69.6%) squamous cell carcinomas, 2/2 (100%) lymphoepithelial carcinomas, 1/1 (100%) adenosquamous carcinoma, and 6/40 (15.0%) thymomas. SSTR2 expression in ≥50% of tumor cells (vs 1-49%) was associated with younger age (p=0.023) and shorter recurrence/metastasis-free survival (p=0.007). 68Ga-DOTATATE PET scans (N=9) revealed a Krenning score of 3 in patients with atypical carcinoid tumor, small cell carcinoma, and squamous cell carcinoma (N=1 each) with SSTR2 expression in 95, 100, and 5% of tumor cells, respectively. Scans with Krenning scores of ≤2 (N=5) were seen in tumors with no SSTR2 expression in 80% of cases and a single atypical carcinoid tumor with SSTR2 expression in 10% of tumor cells. One scan resulted as "increased uptake" was in a patient with no SSTR2 expression. In conclusion, 68Ga-DOTATATE PET scans correlated with SSTR2 expression in TET in most patients and appeared to be useful to identify patients with TET who may be amenable to treatment with somatostatin analogues. Larger studies including more patients with 68Ga-DOTATATE PET scans are necessary to independently and prospectively validate our findings.
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Affiliation(s)
- Anja C. Roden
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States,*Correspondence: Anja C. Roden,
| | - Sagar Rakshit
- Division of Medical Oncology, Mayo Clinic, Rochester, MN, United States
| | - Geoffrey B. Johnson
- Department of Radiology, Mayo Clinic, Rochester, MN, United States,Department of Immunology, Mayo Clinic, Rochester, MN, United States
| | - Sarah M. Jenkins
- Department of Immunology, Mayo Clinic, Rochester, MN, United States,Division of Clinical Trials and Biostatistics, Mayo Clinic, Rochester, MN, United States
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Hazim A, Majithia N, Murphy SJ, Wigle D, Aubry MC, Mansfield AS. Heterogeneity of PD-L1 expression between invasive and lepidic components of lung adenocarcinomas. Cancer Immunol Immunother 2021; 70:2651-2656. [PMID: 33599823 PMCID: PMC10991100 DOI: 10.1007/s00262-021-02883-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 02/01/2021] [Indexed: 10/22/2022]
Abstract
The dynamics of PD-L1 expression are poorly understood over the development of lung adenocarcinomas from pre-invasive lesions to fully invasive carcinomas. Given the importance of PD-L1 expression for the selection of patients to receive immunotherapy in the metastatic setting and possibly in the neoadjuvant setting, we sought to evaluate the agreement of PD-L1 expression in invasive and lepidic components of resected tumor specimens. We stained 86 adenocarcinomas for PD-L1 using the SP263 clone. We assessed the agreement of PD-L1 expression by tumor cells and immune cells between lepidic and invasive components. When both lepidic and invasive components were considered, PD-L1 positive immune cells and tumor cells were observed in 50 (58.1%) and 18 (20.9%) samples, respectively, using a ≥ 1% PD-L1 expression cutoff. Using a ≥ 1% cutoff for PD-L1 expression, positively stained tumor cells were observed in 11 (13%) lepidic and 15 (17%) invasive patterns, with agreement in 76 (88%) specimens and disagreement in 10 (12%) specimens (ĸ = 0.549). At ≥ 1% PD-L1 expression cutoff, PD-L1 positive immune cells were observed in 31 (35%) lepidic and 32 (37%) invasive patterns with an agreement of PD-L1 expression in 49 (57%) specimens and disagreement in 37 (43%) specimens (ĸ = 0.073). In our study of early stage adenocarcinomas of the lung, there was poor agreement in PD-L1 expression between paired invasive and lepidic components of tumors. Our data suggest that the non-invasive tumor components may not be as immunostimulatory as the invasive components, resulting in less adaptive expression of PD-L1.
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Affiliation(s)
- Antonious Hazim
- Department of Internal Medicine, Mayo Clinic, Rochester, MN, USA
| | - Neil Majithia
- Division of Oncology, Mayo Clinic, 200 First St SW, Rochester, MN, 55905, USA
| | - Stephen J Murphy
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
| | - Dennis Wigle
- Division of General Thoracic Surgery, Department of Surgery, Rochester, MN, USA
| | | | - Aaron S Mansfield
- Division of Oncology, Mayo Clinic, 200 First St SW, Rochester, MN, 55905, USA.
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Roden AC, Szolkowska M. Common and rare carcinomas of the thymus. Virchows Arch 2021; 478:111-128. [PMID: 33389148 DOI: 10.1007/s00428-020-03000-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 12/04/2020] [Accepted: 12/14/2020] [Indexed: 12/15/2022]
Abstract
Thymic carcinoma encompasses a diverse group of rare tumors that occur almost exclusively in the prevascular (anterior) mediastinum. Thymic carcinomas have a worse outcome than thymomas with a median time to death of under 3 years. These tumors lack the typical lobulation of thymomas, exhibit commonly more cytologic atypia, are associated with a desmoplastic stromal reaction, and lack thymocytes, features that distinguish them from thymomas. The most common thymic carcinoma is squamous cell carcinoma; other subtypes include mucoepidermoid carcinoma, NUT carcinoma, and adenocarcinoma, among others. Largely due to multi-institutional and global efforts and meta-analysis of case reports and series, some of the thymic carcinoma subtypes have been studied in more detail and molecular studies have also been performed. Morphology and immunophenotype for the vast majority of thymic carcinoma subtypes are similar to their counterparts in other organs. Therefore, the distinction between thymic carcinoma and metastatic disease, which is relatively common in the prevascular mediastinum, can be challenging and in general requires clinical and radiologic correlation. Although surgical resection is the treatment of choice, only 46 to 68% of patients with thymic carcinoma can undergo resection as many other tumors present at high stage with infiltration into vital neighboring organs. These patients are usually treated with chemotherapy and/or radiation. The search for better biomarkers for prognosis and treatment of thymic carcinomas is important for improved management of these patients and possible targeted therapy.
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Affiliation(s)
- Anja C Roden
- Department of Laboratory Medicine & Pathology, Mayo Clinic Rochester, Hilton 11, 200 First St SW, Rochester, MN, 55905, USA.
| | - Malgorzata Szolkowska
- Department of Pathology, The National Tuberculosis and Lung Diseases Research Institute, Warsaw, Poland
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Yokoyama S, Miyoshi H. Comparison of PD-L1 immunohistochemical assays and the significance of PD-L1 expression in thymoma. J Thorac Dis 2020; 12:7553-7560. [PMID: 33447446 PMCID: PMC7797863 DOI: 10.21037/jtd-19-3703] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Thymoma is a relatively rare malignancy, which is categorized as thymic epithelial tumor but known as the most common pathology that is developed in the anterior mediastinum. Complete resection is recommended for localized tumors and usually favorable prognosis can be obtained. However, poor survival period has been reported in unresectable cases exhibiting extensive invasion or distant metastasis, as effective chemotherapeutic regimens are restrained. We previously assessed expression of programmed death ligand 1 (PD-L1) and programmed death 1 (PD-1) and discussed their prospective application in the immunotherapy of thymic epithelial tumors. After our publication, additional studies using reliable PD-L1 antibodies, which are currently administered to predict efficacy of PD-1/PD-L1 blockade therapy were performed and further characterized PD-L1 in thymoma. Herein, recent knowledge in relation to the significance of PD-L1 expression in thymoma is reviewed based on recent findings using qualified PD-L1 clones. Most studies coherently found high expression of PD-L1 on the cell membrane and cytoplasm of tumor epithelial cells in accordance with previous reports, which is a predictive marker for effectiveness of anti-PD-1/PD-L1 drugs, even when approved PD-L1 antibodies were employed. On the other hand, PD-L1 expression on tumor infiltrating immune cells remains to be sufficiently determined. High PD-L1 expression can be expected in cases with high grade histological subtypes, such as type B2/B3 thymomas, or those with advanced stages III or IV of the disease. Interestingly, the level of PD-L1 expression was found to be upregulated after chemotherapy compared with that before, which could be explained by immunogenic cell death. The prognostic impact of PD-L1 expression in thymoma might be found only when thymic carcinoma patients were excluded. Furthermore, it also could be identified when we analyzed thymomas completely resected, distinct from biopsy and incompletely resected cases.
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Affiliation(s)
- Shintaro Yokoyama
- Department of Surgery, Kurume University School of Medicine, Kurume, Japan
| | - Hiroaki Miyoshi
- Department of Pathology, Kurume University School of Medicine, Kurume, Japan
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Abstract
Thymic malignancies are rare mediastinal cancers, classified according to the World Health Organization's histopathologic classification which distinguishes thymomas from thymic carcinomas. One key consideration when discussing immunotherapy for thymic epithelial tumors is that one-third of patients diagnosed with thymomas present at the time of diagnosis with autoimmune disorders, the most common being myasthenia gravis. The first step in the understanding of autoimmunity in thymic epithelial tumors is to distinguish true autoimmune disorders from paraneoplastic syndromes; besides pathophysiology, clinical correlates, impact on oncological management and survival may differ strongly. Autoimmune disorders are related to a deregulation in the physiological role of the thymus (i.e. to induce central tolerance to tissue self-antigens) through control of differentiation and subsequent positive and negative selection of immature T cells; from a clinical standpoint, in thymomas, once autoimmune disorders are present, they may not regress significantly after thymectomy. PD-L1 expression, while observed in more than 90% of epithelial cells of the normal thymus with a medullar tropism respecting Hassall's corpuscles, has also been identified in thymomas and thymic carcinomas using various immunohistochemistry protocols. Immune checkpoint inhibitors of the PD-1/PD-L1 axis have been assessed in advanced and metastatic thymic epithelial tumors, mainly thymic carcinomas. Several case reports have been published, and four trials have assessed the efficacy and safety of these inhibitors. Immunotherapy is not standard given the frequent occurrence of severe autoimmune disorders, and clinical trials are ongoing. Thymic malignancies are rare tumors. Advanced, metastatic and refractory thymic tumors may be treated with chemotherapy. Autoimmune disorders, such as myasthenia gravis, are observed in 30% of cases. PD-L1 expression is a hallmark of thymic epithelial cells. Immunotherapy is not standard, given the occurrence of autoimmune disorders.
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Affiliation(s)
- Nicolas Girard
- Correspondence to: Nicolas Girard, Institut Curie, 26 rue d’Ulm, 75248 Paris Cedex 05, France.
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