Primary hepatic chronic expanding hematoma: a case report and literature review.

Chronic expanding hematoma (CEH), first reported in 1968, is a hematoma that gradually enlarges over a long course of time after an initial period of bleeding. It can occur anywhere in the body; however, there are many reports of its occurrence in the thoracic cavity. Primary hepatic CEH is extremely rare. In this current study, we report on a case of primary hepatic CEH diagnosed preoperatively, with a review of the literature. A 68-year-old man presented with liver dysfunction. Abdominal computed tomography revealed a giant cystic tumor in the left lobe of the liver, with a longer axis of approximately 12 cm. Magnetic resonance imaging revealed a mosaic pattern with a mixture of high and low signals within the tumor on T1-weighted images and a high signal at the tumor margin on T2-weighted images. Based on these findings, primary hepatic CEH was suspected. However, other malignant tumors could not be excluded owing to tumor compression resulting in bile duct dilatation. Left trisectionectomy was performed, followed by bile duct drainage and percutaneous transhepatic portal vein embolization. Intraoperative hemorrhage was controlled by the Pringle maneuver and with temporary clamping of the inferior vena cava. Pathological examination revealed a pseudocyst containing a clot, consistent with CEH. In conclusions, the case report illustrates the potential to enhance preoperative diagnosis, inform surgical approaches, and minimize associated risks. Furthermore, it highlights the importance of increasing awareness and research on this condition for improved clinical decision-making and patient care.

Development of T cell receptor-engineered T cells targeting the sarcoma-associated antigen papillomavirus binding factor.

We previously identified papillomavirus binding factor (PBF) as an osteosarcoma antigen recognized by an autologous cytotoxic T lymphocyte clone. Vaccination with PBF-derived peptide presented by HLA-A24 (PBF peptide) elicited strong immune responses. In the present study, we generated T cell receptor-engineered T cells (TCR-T cells) directed against the PBF peptide (PBF TCR-T cells). PBF TCR was successfully transduced into T cells and detected using HLA-A*24:02/PBF peptide tetramer. PBF TCR-T cells generated from a healthy donor were highly expanded and recognized T2-A24 cells pulsed with PBF peptide, HLA-A24+ 293T cells transfected with PBF cDNA, and sarcoma cell lines. To establish an adoptive cell therapy model, we modified the PBF TCR by replacing both α and ß constant regions with those of mice (hybrid PBF TCR). Hybrid PBF TCR-T cells also showed reactivity against T2-A24 cells pulsed with PBF peptide and to HLA-A24+ 293T cells transfected with various lengths of PBF cDNA including the PBF peptide sequence. Subsequently, we generated target cell lines highly expressing PBF (MFH03-PBF [short] epitope [+]) containing PBF peptide with in vivo tumorigenicity. Hybrid PBF TCR-T cells exhibited antitumor effects compared with mock T cells in NSG mice xenografted with MFH03-PBF (short) epitope (+) cells. CD45+ T cells significantly infiltrated xenografted tumors only in the hybrid PBF TCR T cell group and most of these cells were CD8-positive. CD8+ T cells also showed Ki-67 expression and surrounded the CD8-negative tumor cells expressing Ki-67. These findings suggest that PBF TCR-T cell therapy might be a candidate immunotherapy for sarcoma highly expressing PBF.

Eribulin is an immune potentiator in breast cancer that upregulates human leukocyte antigen class I expression via the induction of NOD-like receptor family CARD domain-containing 5.

Eribulin inhibits microtubule polymerization and improves the overall survival of patients with recurrent metastatic breast cancer. A subgroup analysis revealed a low neutrophil to lymphocyte ratio (NLR) (<3) to be a prognostic factor of eribulin treatment. We thus hypothesized that eribulin might be related to the immune response for breast cancer cells and we analyzed the effects of eribulin on the immune system. Immunohistochemical staining revealed that human leukocyte antigen (HLA) class I expression was increased in clinical samples after eribulin treatment. In vitro assays revealed that eribulin treatment increased HLA class I expression in breast cancer line cells. RNA-sequencing demonstrated that eribulin treatment increased the expression of the NOD-like family CARD domain-containing 5 (NLRC5), a master regulator of HLA class I expression. Eribulin treatment increased the NY-ESO-1-specific T-cell receptor (TCR) transduced T (TCR-T) cell response for New York oesophageal squamous cell carcinoma 1 (NY-ESO-1) overexpressed breast cancer cells. The eribulin and TCR-T combined therapy model revealed that eribulin and immunotherapy using TCR-T cells has a synergistic effect. In summary, eribulin increases the expression of HLA class 1 via HLA class 1 transactivatior NLRC5 and eribulin combination with immunotherapy can be effective for the treatment of breast cancer.

Primary Lung Adenocarcinoma With ALK Gene Rearrangement Mostly Occupied by the Signet-Ring Cell Carcinoma Component: A Case Report.

Primary lung carcinoma tumors possessing a signet-ring cell carcinoma (SRCC) component at varying proportions are rare, while those primarily composed of an SRCC component are much rarer. Reported here is a case of primary lung adenocarcinoma primarily composed of an SRCC component with a scant acinar component that developed in an 81-year-old male. Approximately 95% of the adenocarcinoma was occupied by an SRCC component that was shown to be diastase-resistant based on positive periodic acid-Schiff staining. Immunostaining for ALK and fluorescence in situ hybridization analysis (break-apart assay) showed the presence of an ALK gene rearrangement. Findings in this case indicated a primary lung adenocarcinoma with ALK gene rearrangement, in which an SRCC component accounted for approximately 95% of the tumor.

One-step embedding method for maintaining orientation of pathological tissue specimens using agar thin films.

Pathological histology examination involves handling a variety of specimens that are cut according to regulations and placed in cassettes. Tissue fragments in the cassettes are then diagnosed after processing, embedding, thin sectioning, staining and other procedures using a processing machine. Maintaining tissue fragment order and orientation during these processes is important for accurate diagnosis. In this study, we present a method of maintaining tissue fragment order and orientation using a thin film of ultra-high-strength agar and evaluate its usefulness during tissue sectioning.Cassettes were prepared, each containing three pieces of porcine liver, and compared embedding time with and without agar thin films (ATFs). Embedding was performed by three medical laboratory scientists with different levels of experience.To enable one-step tissue sample embedding, ATFs were integrated with samples in the cassettes. This resulted in an average reduction of 6.22 s of embedding time per cassette compared with traditional embedding methods.Through the use of ATFs, tissue fragment order and orientation is maintained, and embedding process time shortened. Additionally, ATFs are easily prepared and stored in 10% neutral buffered formalin over extended periods, allowing for immediate use during sectioning. This method is ideal to implement in busy pathology laboratories.

Myxofibrosarcoma of the Breast: A Case Report.

Development of a myxofibrosarcoma in the breast tissue is extremely rare. Reported here is a case of myxofibrosarcoma found in the left breast tissue of a male in his late fifties. The patient first underwent tumor resection, followed by a left mastectomy with the reconstruction of the vastus lateralis valve. The tumor comprised atypical spindle-shaped cells in a myxoid matrix with elongated blood vessels. Myxofibrosarcoma was diagnosed based on histology and immunohistochemical examination results performed for differential diagnosis. At two years and two months after the mastectomy, no local occurrence or metastasis had occurred.

Fusion with type 2 macrophages induces melanoma cell heterogeneity that potentiates immunological escape from cytotoxic T lymphocytes.

Evasion from immunity is a major obstacle to the achievement of successful cancer immunotherapy. Hybrids derived from cell-cell fusion are theoretically associated with tumor heterogeneity and progression by conferring novel properties on tumor cells, including drug resistance and metastatic capacity; however, their impact on immune evasion remains unknown. Here, we investigated the potency of tumor-macrophage hybrids in immune evasion. Hybrids were established by co-culture of a melanoma cell line (A375 cells) and type 2 macrophages. The hybrids showed greater migration ability and greater tumorigenicity than the parental melanoma cells. The hybrids showed heterogeneous sensitivity to New York esophageal squamous cell carcinoma-1 (NY-ESO-1)-specific T-cell receptor-transduced T (TCR-T) cells and two out of four hybrid clones showed less sensitivity to TCR-T compared with the parental cells. An in vitro tumor heterogeneity model revealed that the TCR-T cells preferentially killed the parental cells compared with the hybrids and the survival rate of the hybrids was higher than that of the parental cells, indicating that the hybrids evade killing by TCR-T cells efficiently. Analysis of a single-cell RNA sequencing dataset of patients with melanoma revealed that a few macrophages expressed RNA encoding melanoma differentiation antigens including melan A, tyrosinase, and premelanosome protein, which indicated the presence of hybrids in primary melanoma. In addition, the number of potential hybrids was correlated with a poorer response to immune checkpoint blockade. These results provide evidence that melanoma-macrophage fusion has a role in tumor heterogeneity and immune evasion. © 2023 The Pathological Society of Great Britain and Ireland.

Identification of antigenic epitopes recognized by tumor infiltrating lymphocytes in high grade serous ovarian cancer by multi-omics profiling of the auto-antigen repertoire.

Immunotherapeutic strategies aimed at enhancing tumor cell killing by tumor-specific T cells hold great potential for reducing tumor burden and prolonging survival of cancer patients. Although many potential tumor antigens have been described, identifying relevant targets when designing anti-cancer vaccines or targeted cell therapies remains a challenge. To identify novel, potentially immunogenic candidate tumor antigens, we performed integrated tumor transcriptomic, seromic, and proteomic analyses of high grade serous ovarian cancer (HGSC) patient tumor samples. We identified tumor neo-antigens and over-expressed antigens using whole exome and RNA sequencing and examined these in relation to patient-matched auto-antibody repertoires. Focusing on MHC class I epitopes recognized by CD8+ T cells, HLA-binding epitopes were identified or predicted from the highly expressed, mutated, or auto-antibody target antigen, or MHC-associated peptides (MAPs). Recognition of candidate antigenic peptides was assessed within the tumor-infiltrating T lymphocyte (TIL) population expanded from each patient. Known tumor-associated antigens (TAA) and cancer/testis antigens (CTA) were commonly found in the auto-antibody and MAP repertoires and CD8+ TILs recognizing epitopes from these antigens were detected, although neither expression level nor the presence of auto-antibodies correlated with TIL recognition. Auto-antibodies against tumor-mutated antigens were found in most patients, however, no TIL recognition of the highest predicted affinity neo-epitopes was detected. Using high expression level, auto-antibody recognition, and epitope prediction algorithms, we identified epitopes in 5 novel antigens (MOB1A, SOCS3, TUBB, PRKAR1A, CCDC6) recognized by HGSC patient TILs. Furthermore, selection of epitopes from the MAP repertoire identified 5 additional targets commonly recognized by multiple patient TILs. We find that the repertoire of TIL specificities includes recognition of highly expressed and immunogenic self-antigens that are processed and presented by tumors. These results indicate an ongoing autoimmune response against a range of self-antigens targeted by HGSC TILs.

SOX10 Inhibits T Cell Recognition by Inducing Expression of the Immune Checkpoint Molecule PD-L1 in A375 Melanoma Cells.

BACKGROUND/AIM: Malignant melanoma is a fatal skin cancer and is among the most immunogenic malignancies expressing melanoma-differentiation antigens and neoantigens. SRY-related HMG-box 10 (SOX10) is a transcription factor and a neural-crest differentiation marker that is used as a diagnostic marker for melanoma whilst playing a role in melanoma initiation through activation of the SOX10-MITF axis. SOX10 was shown to play a role in melanoma initiation by inducing expression of immune checkpoint molecules (e.g., HVEM and CEACAM1). In this study, we aimed to investigate the relationship between SOX10 and the expression an immune checkpoint molecule, programmed death-1 ligand 1 (PD-L1). MATERIALS AND METHODS: SOX10 overexpression and knockdown was performed using SOX10 gene transfection and SOX10 siRNA transfection into A375 melanoma cells. PD-L1 expression was assessed by flow cytometry and western blotting. T cell response was evaluated using NY-ESO-1 specific TCR-transduced T (TCR-T) cells by IFNγ ELISPOT assay. RESULTS: SOX10 overexpression increased the expression of PD-L1, whereas SOX10 knockdown, using siRNA, decreased its expression. IFNγ ELISPOT assay revealed that overexpression of SOX10 decreased the susceptibility of cells to NY-ESO-1-specific TCR-T cells. CONCLUSION: SOX10 has a role in the intrinsic immune suppressive mechanisms of melanoma through expression of PD-L1.

Efficacy of CT Value Along Portal Vein for Preoperative Prediction of Portal Vein Resection in Pancreatic Head Cancer.

BACKGROUND: It is important for surgeons to determine whether combined portal vein (PV) resection (PVR) is necessary before surgery. The present study aimed to determine the ability of computed tomography (CT) value along the PV in predicting the necessity for concomitant PVR. METHODS: A total of 107 consecutive patients who underwent pancreaticoduodenectomy (PD) for invasive ductal carcinoma of the pancreatic head at our institute between September 2007 and September 2020 were reviewed retrospectively. Univariate analysis to predict PVR was performed with preoperative radiological valuables acquired by Synapse Vincent. The resected specimen near the PV or the PV notch was analyzed by histopathological findings. RESULTS: Only the CT value of the PV was independently associated with PVR (Mann-Whitney U test; P = .045, logistic regression test; P = .039). The outer boundary of the PV was unclear in the cases without pathological PV invasion and PVR due to the development of smooth muscle in the outer membrane of the PV and the proliferation of collagen fibers. The elastic fibers were arranged regularly in the notch portion of the PV in cases wherein PVR was not performed. DISCUSSION: The CT value along the PV was independently associated with PVR and is the only predictor of PVR. These results were very useful in predicting PVR preoperatively and were histopathologically supportive.

Cisplatin resistance driver claspin is a target for immunotherapy in urothelial carcinoma.

Bladder cancer is a major and fatal urological disease. Cisplatin is a key drug for the treatment of bladder cancer, especially in muscle-invasive cases. In most cases of bladder cancer, cisplatin is effective; however, resistance to cisplatin has a significant negative impact on prognosis. Thus, a treatment strategy for cisplatin-resistant bladder cancer is essential to improve the prognosis. In this study, we established a cisplatin-resistant (CR) bladder cancer cell line using an urothelial carcinoma cell lines (UM-UC-3 and J82). We screened for potential targets in CR cells and found that claspin (CLSPN) was overexpressed. CLSPN mRNA knockdown revealed that CLSPN had a role in cisplatin resistance in CR cells. In our previous study, we identified human leukocyte antigen (HLA)-A*02:01-restricted CLSPN peptide by HLA ligandome analysis. Thus, we generated a CLSPN peptide-specific cytotoxic T lymphocyte clone that recognized CR cells at a higher level than wild-type UM-UC-3 cells. These findings indicate that CLSPN is a driver of cisplatin resistance and CLSPN peptide-specific immunotherapy may be effective for cisplatin-resistant cases.

Development of CAR-T cells specifically targeting cancer stem cell antigen DNAJB8 against solid tumours.

BACKGROUND: As therapy for solid tumours, various tumour antigens have been selected as targets, but CAR-T cells targeting these antigens have shown limited efficacy, in contrast to the effectiveness of CAR-T cells targeting haematological malignancies. In a previous report, we identified a cancer-testis antigen, DNAJB8. DNAJB8 plays a major role in tumorigenicity in cancer stem-like cells/cancer-initiating cells (CSCs/CICs). Here, we report a DNAJB8-reactive CAR yielding anti-tumour effects against renal cell carcinoma (RCC) and osteosarcoma. METHODS: We constructed a second-generation chimeric antigen receptor (CAR) against HLA-A*24:02/DNAJB8-derived peptide (DNAJB_143) complex (B10 CAR). The reactivity of B10-CAR T cells against T2-A24 cells pulsed with the cognate peptide and an RCC and osteosarcoma cell lines were quantified. The effects of adoptive cell transfer (ACT) therapy were assessed using in vivo xenografted mice models. RESULTS: B10 CAR-T cells recognised DNAJB8_143-pulsed T2-A24 cells and HLA-A*24:02(+)/DNAJB8(+) renal cell carcinoma and osteosarcoma cell lines. Moreover, ACT using B10 CAR-T cells showed anti-tumour effects against RCC and osteosarcoma cells. CONCLUSION: B10 CAR-T cells could show specific cytotoxicity against RCC and osteosarcoma cells in vitro and in vivo. B10 CAR-T cells targeting the CSC/CIC antigen DNAJB8 might be a candidate immunotherapy for carcinoma and sarcoma.

[A case of giant cell arteritis after prednisolone dose reduction during treatment of polymyalgia rheumatica].

Giant cell arteritis (GCA) is closely associated with polymyalgia rheumatica (PMR). We herein report an 82-year-old woman who developed GCA during PMR treatment. She initially presented with shoulder pain and was diagnosed with PMR based on elevated serum C-reactive protein (CRP) levels and bursitis detected in both shoulders on ultrasonography (US). Treatment was initiated with a daily dose of 15 mg prednisolone (PSL), which led to rapid symptom alleviation, and the dosage was tapered to 1 mg/day. One month later, she developed myalgia extending from the lumbar region to the thigh and tenderness in the left temporal region. However, no abnormalities in the temporal artery were observed on US. Although the PSL dose was increased to 2 mg for relapse of PMR, the symptoms did not improve. One week later, she developed occipital pain with an increased CRP level of 9 mg/dL. She was diagnosed with GCA based on the 1990 ACR Classification Criteria. Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) detected anomalous accumulations in the bilateral superficial temporal and vertebral arteries, but not in the larger vessels. We therefore diagnosed her with cranial-type GCA. At this time point, we repeated US and found a halo sign in the temporal artery. Although epithelioid and giant cells were not observed in the temporal artery biopsy, vascular inflammatory findings such as disruption of the internal elastic lamina and chronic inflammatory cell infiltration were noted. Symptoms improved immediately and CRP levels decreased after the PSL dose was increased to 30 mg daily. To mitigate the risk of steroid-induced diabetes, tocilizumab was introduced, and gradual tapering of PSL was implemented. In conclusion, we encountered a case of GCA that developed after PSL reduction during the course of PMR. PET/CT confirmed intracranial artery inflammation and facilitated a definitive diagnosis. Although PET/CT cannot be routinely performed for diagnose in Japan, we consider it useful as an adjunctive diagnostic tool.

Characterization of Proteasome-Generated Spliced Peptides Detected by Mass Spectrometry.

CD8+ T cells recognize peptides displayed by HLA class I molecules and monitor intracellular peptide pools. It is known that the proteasome splices two short peptide fragments. Recent studies using mass spectrometry (MS) and bioinformatics analysis have suggested that proteasome-generated spliced peptides (PSPs) may account for a substantial proportion of HLA class I ligands. However, the authenticity of the PSPs identified using bioinformatics approaches remain ambiguous. In this study, we employed MS-based de novo sequencing to directly capture cryptic HLA ligands that were not templated in the genome. We identified two PSPs originating from the same protein in a human colorectal cancer line with microsatellite instability. Healthy donor-derived CD8+ T cells readily responded to the two PSPs, showing their natural HLA presentation and antigenicity. Experiments using minigene constructs demonstrated proteasome-dependent processing of two PSPs generated by standard and reverse cis splicing, respectively. Our results suggest a broader diversity of HLA class I Ag repertoires generated by proteasomal splicing, supporting the advantage of MS-based approaches for the comprehensive identification of PSPs.

Tracheobronchial chondritis as an immune-related adverse event occurring during the administration of nivolumab for recurrent hypopharyngeal squamous cell carcinoma.

Tracheobronchial chondritis is a rare immune-related adverse event (irAE) associated with immune checkpoint inhibitors. We report a case wherein tracheobronchial chondritis occurred while administering nivolumab for recurrent hypopharyngeal squamous cell carcinoma (SCC) in a man diagnosed with T2N3bM0 stage IVB hypopharyngeal SCC. After treatment with cisplatin and radiotherapy followed by left and right neck dissection, local recurrence was observed in the hypopharynx. Because of the difficulty of salvage surgery, we administered 240 mg/body of nivolumab. After 9 cycles of nivolumab, the patient was judged to have complete response. After 10 cycles, he had cough and sputum, for which prompting us to perform imaging tests. Computed tomography (CT) showed edematous thickening around the trachea and bilateral bronchi and elevated amounts of adjacent subcutaneous fat tissue. Positron emission tomography-CT showed diffuse fluorodeoxyglucose uptake in the trachea and bilateral bronchi, bronchial endoscopy showed redness and swelling throughout the bronchi, and biopsy showed partial mucosal erosion, inflammatory cell (lymphocyte) infiltration, interstitial edema, and desmoplasia. The patient was diagnosed with tracheobronchial chondritis as an irAE resulting from administering anti-programmed death-1 monoclonal antibody. After four-day prednisolone treatment, his cough and sputum disappeared; after two weeks, tracheobronchial chondritis no longer appeared on CT.

Minocycline-induced black thyroid with black pigmentation of the thyroid cartilage, cricoid cartilage, and trachea found during reconstructive surgery for hypopharyngeal cancer.

Black thyroid is characterized by a rare pigment change observed almost exclusively in patients taking minocycline. We present the case of a 72-year-old man diagnosed with T3N3bM0 stage IVB hypopharyngeal squamous cell carcinoma who had been taking minocycline for approximately 18 months as a treatment for prurigo chronica multiformis. Initial treatment consisted of total pharyngolaryngoesophagectomy, bilateral neck dissection, total thyroidectomy, pharyngeal reconstruction using a free jejunal autograft, and creation of a permanent tracheostoma. During surgery, black discoloration of the thyroid and trachea was observed. Postoperative histological findings confirmed the black discoloration, with deposits of dark-brown, melanin-like granules observed in the thyroid, trachea, thyroid cartilage, and cricoid cartilage. Therefore, the black discoloration of the thyroid associated with the use of minocycline can extend to the thyroid cartilage, cricoid cartilage, and trachea. This information is important for surgeons to recognize in order to prevent unnecessary resection due to misdiagnosis.

Nivolumab for recurrent/metastatic hypopharyngeal squamous cell carcinoma in a liver transplant recipient.

Nivolumab administration to patients with organ transplantation history requires careful management. Herein, we report the case of a living-donor liver-transplant recipient, a 52-year-old man, with recurrent and metastatic hypopharyngeal cancer treated with nivolumab. He was diagnosed with T2N2bM0 stage IVA hypopharyngeal squamous cell carcinoma. While using oral immunosuppressants (cyclosporine and mycophenolate mofetil), the patient underwent right neck dissection followed by radiotherapy as an initial treatment. Three months after radiotherapy, positron emission tomography scans revealed multiple bone metastases. We administered two courses of the EXTREME regimen, comprising cisplatin, 5-fluorouracil, and cetuximab, as the first-line treatment for distal metastasis, but the patient presented with progressive disease. The patient was administered nivolumab as the second-line treatment. The programmed death-ligand 1 (PD-L1) expression level in a biopsy specimen of the primary hypopharyngeal tumor and resected specimen of the cervical lymph node metastasis was 40% and 10%, respectively. PD-L1 expression was not detected in hepatocytes of the liver biopsy sample obtained before nivolumab introduction. The patient received four courses of nivolumab 240 mg. Although liver dysfunction was alleviated by adjusting the dose of the hepatoprotective agent and cyclosporine, the progressive disease status persisted after completing nivolumab courses. The patient died of hypopharyngeal cancer progression.

Tumor-infiltrating CD8+ T cells recognize a heterogeneously expressed functional neoantigen in clear cell renal cell carcinoma.

Immune checkpoint inhibitors (ICIs) are used in cancer immunotherapy to block programmed death-1 and cytotoxic T-lymphocyte antigen 4, but the response rate for ICIs is still low and tumor cell heterogeneity is considered to be responsible for resistance to immunotherapy. Tumor-infiltrating lymphocytes (TILs) have an essential role in the anti-tumor effect of cancer immunotherapy; however, the specificity of TILs in renal cell carcinoma (RCC) is elusive. In this study, we analyzed a 58-year-old case with clear cell RCC (ccRCC) with the tumor showing macroscopic and microscopic heterogeneity. The tumor was composed of low-grade and high-grade ccRCC. A tumor cell line (1226 RCC cells) and TILs were isolated from the high-grade ccRCC lesion, and a TIL clone recognized a novel neoantigen peptide (YVVPGSPCL) encoded by a missense mutation of the tensin 1 (TNS1) gene in a human leukocyte antigen-C*03:03-restricted fashion. The TNS1 gene mutation was not detected in the low-grade ccRCC lesion and the TIL clone did not recognized low-grade ccRCC cells. The missense mutation of TNS1 encoding the S1309Y mutation was found to be related to cell migration by gene over-expression. These findings suggest that macroscopically and microscopically heterogenous tumors might show heterogenous gene mutations and reactivity to TILs.

CD8+ T-cell Immune Surveillance against a Tumor Antigen Encoded by the Oncogenic Long Noncoding RNA PVT1.

CD8+ T cells recognize peptides displayed by HLA class I molecules on cell surfaces, monitoring pathologic conditions such as cancer. Advances in proteogenomic analysis of HLA ligandomes have demonstrated that cells present a subset of cryptic peptides derived from noncoding regions of the genome; however, the roles of cryptic HLA ligands in tumor immunity remain unknown. In the current study, we comprehensively and quantitatively investigated the HLA class I ligandome of a set of human colorectal cancer and matched normal tissues, showing that cryptic translation products accounted for approximately 5% of the HLA class I ligandome. We also found that a peptide encoded by the long noncoding RNA (lncRNA) PVT1 was predominantly enriched in multiple colorectal cancer tissues. The PVT1 gene is located downstream of the MYC gene in the genome and is aberrantly overexpressed across a variety of cancers, reflecting its oncogenic property. The PVT1 peptide was recognized by patient CD8+ tumor-infiltrating lymphocytes, as well as peripheral blood mononuclear cells, suggesting the presence of patient immune surveillance. Our findings show that peptides can be translated from lncRNAs and presented by HLA class I and that cancer patient T cells are capable of sensing aberrations in noncoding regions of the genome.