Case Report: Durvalumab-Associated Encephalitis in Extensive-Stage Small Cell Lung Carcinoma.

In recent years, the clinical importance of immunotherapy has been demonstrated in the treatment of extensive-stage small-cell lung cancer (ES-SCLC). However, immune checkpoint inhibitors (ICIs) have been shown to cause immune-related adverse events (irAEs), including autoimmune encephalitis. Here, we describe th treatment of a patient with ES-SCLC who developed immune-related encephalitis. A 68-year-old Japanese woman with ES-SCLC treated with carboplatin plus etoposide plus durvalumab 20 days earlier was admitted to our hospital with a high fever and anorexia. Her symptoms gradually worsened over time, and she had a headache daily and showed reduced levels of consciousness. An electroencephalogram showed diffuse slow waves, and there was a slight increase in cell counts and an increase in protein levels in the cerebrospinal fluid. The patient was diagnosed with durvalumab-associated encephalitis. Her symptoms improved immediately after steroid pulse therapy. Following steroid pulse therapy, oral prednisolone (1 mg/kg) was administered, and then, the dose was gradually reduced. Subsequently, treatment with carboplatin plus etoposide without durvalumab was restarted. In conclusion, this study shows the efficacy of steroid therapy in the treatment of durvalumab-induced encephalitis in ES-SCLC.

Possible Pseudo-progression of Non-small Cell Lung Carcinoma in a Patient With Clinical Hyper-progression Associated With Trousseau Syndrome Who Was Treated With Pembrolizumab: A Case Report.

BACKGROUND/AIM: Immune checkpoint inhibitors (ICIs), including nivolumab and pembrolizumab, have recently been shown to have clinical benefits in patients with advanced non-small cell lung cancer (NSCLC). The novel tumour responses to these agents are changing the management of patients with cancer. Pseudo-progression of disease (pseudo-PD), that is, an initial flare followed by shrinkage of the tumour, has been described as a distinctive response to ICIs. However, pseudo-PD manifest initial progression and is difficult to segregate with hyper progressive disease (HPD). We, therefore, analysed a case with pseudo-PD histologically. PATIENTS AND METHODS: A 68-year-old Japanese man with stage IV non-small cell lung carcinoma (NSCLC) was treated by anti-PD-1 antibody (pembrolizumab). Four weeks later after second time treatment with pembrolizumab, the patient showed severe melena followed by Trousseau syndrome and died at day 174 after first treatment by pembrolizumab, suggesting HPD clinically. Primary lesion and metastatic lesions were analysed histologically. RESULTS: Histological analysis revealed that NSCLC cells expressed PD-L1, and CD8+ tumor-infiltrated lymphocytes (TILs) were observed. CD8+ TILs showed higher rates of PD-1 indicating that lesions were of the inflamed type and the case was pseudo-PD. Furthermore, it was found that cancer cells expressed MUC1. CONCLUSION: The clinical appearance of the case was aggressive after treatment by pembrolizumab, and the case seemed to be HPD; however, histological analysis revealed that the case was likely pseudo-PD. Therefore, careful histological evaluation is important when investigating the clinical response to an ICI and mucin expression might be a predictive marker for Trousseau syndrome.

Resected thymic large cell neuroendocrine carcinoma: report of a case.

BACKGROUND: Thymic large cell neuroendocrine carcinoma (LCNEC) is extremely rare. The detailed clinical features of thymic LNCECs remain unknown. CASE PRESENTATION: A 90-year-old man with a history of diabetes mellitus, chronic renal failure, and an abdominal aortic aneurysm underwent computed tomography for follow-up, which showed an anterior mediastinal tumor, measuring 31 mm × 28 mm in diameter. Magnetic resonance imaging showed an iso-intensity mass on T1-weighted images and high intensity on T2-weighted images. 18F-Fluorodeoxyglucose-positron emission tomography showed marked uptake in the mass, which was diagnosed as invasive thymoma or thymic carcinoma. Video-assisted thoracic surgery through the left thoracic cavity was converted to median sternotomy due to severe adhesions between the left lung and the chest wall. Partial thymectomy and combined partial resection of left upper lobectomy and the first and the second costal cartilages were performed. The pathologic diagnosis was thymic LCNEC, Masaoka stage III. The patient developed pleural dissemination and left lung metastases in 5 months and died 12 months after surgery. CONCLUSIONS: Thymic LCNEC has high malignant potential. More cases need to be studied.

HLA-A24 ligandome analysis of colon and lung cancer cells identifies a novel cancer-testis antigen and a neoantigen that elicits specific and strong CTL responses.

This study focused on HLA-A24 and comprehensively analyzed the ligandome of colon and lung cancer cells without the use of MHC-binding in silico prediction algorithms. Affinity purification using the antibody specific to HLA-A24 followed by LC-MS/MS sequencing was used to detect peptides, which harbored the known characteristics of HLA-A24 peptides in terms of length and anchor motifs. Ligandome analysis demonstrated the natural presentation of two different types of novel tumor-associated antigens. The ligandome contained a peptide derived from SUV39H2, a gene found to be expressed in a variety of cancers but not in normal tissues (except for the testis). The SUV39H2 peptide is immunogenic and elicits cytotoxic CD8+ T-cell (CTL) responses against cancer cells and is thus a novel cancer-testis antigen. Moreover, we found that microsatellite instability (MSI)-colon cancer cells displayed a neoepitope with an amino-acid substitution, while microsatellite stable (MSS)-colon and lung cancer cells displayed its counterpart peptide without the substitution. Structure modeling of peptide-HLA-A24 complexes predicted that the mutated residue at P8 was accessible to T-cell receptors. The neoepitope readily elicited CTL responses, which discriminated it from its wild-type counterpart, and the CTLs exhibited considerably high cytotoxicity against MSS-colon cancer cells carrying the responsible gene mutation. The specific and strong CTL lysis observed in this study fosters our understanding of immune surveillance against neoantigens.

Brother of the regulator of the imprinted site (BORIS) variant subfamily 6 is a novel target of lung cancer stem-like cell immunotherapy.

Lung cancer is one of the most common malignancies with a high rate of mortality. Lung cancer stem-like cells (CSCs)/ cancer-initiating cells (CICs) play major role in resistance to treatments, recurrence and distant metastasis and eradication of CSCs/CICs is crucial to improve recent therapy. Cytotoxic T lymphocytes (CTLs) are major effectors of cancer immunotherapy, and CTLs recognize antigenic peptides derived from antigens that are presented by major histocompatibility complex (MHC) class I molecules. In this study, we analyzed the potency of a cancer-testis (CT) antigen, brother of the regulator of the imprinted site variant subfamily 6 (BORIS sf6), in lung CSC/CIC immunotherapy. BORIS sf6 mRNA was expressed in lung carcinoma cells (9/19), especially in sphere-cultured lung cancer stem-like cells, and in primary lung carcinoma tissues (4/9) by RT-PCR. Immunohistochemical staining using BORIS sf6-specific antibody revealed that high expression of BORIS sf6 is related to poorer prognosis. CTLs could be induced by using a human leukocyte antigen, (HLA)-A2 restricted antigenic peptide (BORIS C34_24(9)), from all of 3 HLA-A2-positive individuals, and CTL clone cells specific for BORIS C34_24(9) peptide could recognize BORIS sf6-positive, HLA-A2-positive lung carcinoma cells. These results indicate that BORIS sf6 is a novel target of lung cancer immunotherapy that might be useful for targeting treatment-resistant lung cancer stem-like cells.

Loss of tapasin in human lung and colon cancer cells and escape from tumor-associated antigen-specific CTL recognition.

Cytotoxic T-lymphocytes (CTLs) lyse target cells after recognizing the complexes of peptides and MHC class I molecules (pMHC I) on cell surfaces. Tapasin is an essential component of the peptide-loading complex (PLC) and its absence influences the surface repertoire of MHC class I peptides. In the present study, we assessed tapasin expression in 85 primary tumor lesions of non-small cell lung cancer (NSCLC) patients, demonstrating that tapasin expression positively correlated with patient survival. CD8+ T-cell infiltration of tumor lesions was synergistically observed with tapasin expression and correlated positively with survival. To establish a direct link between loss of tapasin and CTL recognition in human cancer models, we targeted the tapasin gene by CRISPR/Cas9 system and generated tapasin-deficient variants of human lung as well as colon cancer cells. We induced the CTLs recognizing endogenous tumor-associated antigens (TAA), survivin or cep55, and they responded to each tapasin-proficient wild type. In contrast, both CTL lines ignored the tapasin-deficient variants despite their antigen expression. Moreover, the adoptive transfer of the cep55-specific CTL line failed to prevent tumor growth in mice bearing the tapasin-deficient variant. Loss of tapasin most likely limited antigen processing of TAAs and led to escape from TAA-specific CTL recognition. Tapasin expression is thus a key for CTL surveillance against human cancers.

Plasticity of lung cancer stem-like cells is regulated by the transcription factor HOXA5 that is induced by oxidative stress.

Cancer stem-like cells (CSCs)/cancer-initiating cells (CICs) are reasonable targets for cancer therapy. However, recent studies have revealed that some non-CSCs/CICs have plastic ability and can dedifferentiate into CSCs/CICs. Therefore, an understanding of the molecular mechanisms that control the plasticity is essential to achieve CSC/CIC-targeting therapy. In this study, we analyzed the plasticity of lung cancer cells and found that lung non-CSCs/CICs can dedifferentiate into CSCs/CICs in accordance with the expression of stem cell transcription factor SOX2. SOX2 expression was induced by the transcription factor HOXA5. Oxidative stress repressed the expression of HDAC8 and then induced histone 3 acetylation and increased the expression of HOXA5 and SOX2. These findings indicate that lung cancer cells have plasticity under a condition of oxidative stress and that HOAX5 has a critical role in dedifferentiation.

Microenvironmental stresses induce HLA-E/Qa-1 surface expression and thereby reduce CD8(+) T-cell recognition of stressed cells.

Hypoxia and glucose deprivation are often observed in the microenvironment surrounding solid tumors in vivo. However, how they interfere with MHC class I antigen processing and CD8(+) T-cell responses remains unclear. In this study, we analyzed the production of antigenic peptides presented by classical MHC class I in mice, and showed that it is quantitatively decreased in the cells exposed to either hypoxia or glucose deprivation. In addition, we unexpectedly found increased surface expression of HLA-E in human and Qa-1 in mouse tumor cells exposed to combined oxygen and glucose deprivation. The induced Qa-1 on the stressed tumor model interacted with an inhibitory NKG2/CD94 receptor on activated CD8(+) T cells and attenuated their specific response to the antigen. Our results thus suggest that microenvironmental stresses modulate not only classical but also nonclassical MHC class I presentation, and confer the stressed cells the capability to escape from the CD8(+) T-cell recognition.