Morphological basis of the lung adenocarcinoma subtypes.

Lung adenocarcinoma (LUAD), which accounts for a large proportion of lung cancers, is divided into five major subtypes based on histologic characteristics. The clinical characteristics, prognosis, and responses to treatments vary among subtypes. Here, we demonstrate that the variations of cell-cell contact energy result in the LUAD subtype-specific morphogenesis. We reproduced the morphologies of the papillary LUAD subtypes with the cellular Potts Model (CPM). Simulations and experimental validations revealed modifications of cell-cell contact energy changed the morphology from a papillary-like structure to micropapillary or solid subtype-like structures. Remarkably, differential gene expression analysis revealed subtype-specific expressions of genes relating to cell adhesion. Knockdown experiments of the micropapillary upregulated ITGA11 gene resulted in the morphological changes of the spheroids produced from an LUAD cell line PC9. This work shows the consequences of gene mutations and gene expressions on patient prognosis through differences in tissue composing physical forces among LUAD subtypes.

Alveolar adenoma with a single cyst: A case report.

Alveolar adenoma is a rare and benign pulmonary tumor, which originates from type II pneumocytes and is often incidentally identified on radiographic images. Alveolar adenoma presents as a peripleural, solitary and cystic nodule in the lung and may mimic other types of lung tumors, thus rendering its differential diagnosis difficult. Alveolar adenoma is diagnosed based on histopathological and immunohistochemical analyses. The present study describes the case of a 50-year-old male patient with alveolar adenoma. He visited a local doctor ~3 years prior due to left chest pain. A chest computed tomography scan revealed a cystic lesion in segment 8 of the left lung. A nodular shadow appeared in the cyst and gradually increased in size; the patient was thus referred to the authors' hospital. The nodule was well-defined, solitary and solid; thus, lung cancer or aspergilloma were suspected. Thoracoscopic wedge resection was performed as diagnostic therapy. The frozen sections were non-diagnostic, and a pathological examination revealed an alveolar adenoma with no evidence of malignancy and a negative culture. The patient had a good post-operative course, with no sign of recurrence at the follow-up evaluation 46 months later. On the whole, alveolar adenoma is a rare, benign pulmonary tumor that is difficult to diagnose pre-operatively.

Downregulated expression of PBRM1 in sarcomatoid hepatocellular carcinoma.

Sarcomatoid hepatocellular carcinoma (SHCC) is a rare and highly lethal subtype of HCC. The present study aimed to explore the unique markers of SHCC using whole gene expression analysis. Subsequently, gene expression analysis was performed using five sarcomatoid and seven carcinomatoid components of seven tissues from patients with SHCC. The results demonstrated a significant downregulation of polybromo 1 (PBRM1) gene expression in the sarcomatoid components. Immunohistochemical staining also indicated a decreased expression of PBRM1 in the sarcomatoid components. Moreover, gene ontology enrichment analysis revealed that most of the 336 differentially expressed genes between the sarcomatoid and carcinomatoid components were involved in functions associated with DNA replication and histone methylation, which was consistent with the loss of function of PBRM1 which encodes Switch/sucrose-non-fermentable chromatin remodeling complex protein. Therefore, the results of the present study suggested that PBRM1 may be a candidate biomarker for the evaluation of SHCC.

Giant cell glioblastoma with lipogenic differentiation in a patient with neurofibromatosis type 1: A case report.

A 45-year-old woman with neurofibromatosis type 1 (NF1) developed a tumor in the left frontal lobe that showed features of giant cell glioblastoma (GC-GB). In addition to the typical GC-GB features, the tumor showed lipogenic differentiation, with many atypical lipoblasts and mature adipocytes. Tumor cells, including the lipogenic cells, were immunoreactive for GFAP, S-100 protein, ATRX, and p53. They were negative for IDH1-R132H, BRAF V600E, synaptophysin, NeuN, p16, mismatch repair proteins, and CD34. The patient is free from recurrence at approximately two years postoperatively. This is the fifth reported case of NF1-associated GC-GB (the second adult case). NF1 gene mutation might have played a role in the pathogenesis of lipogenic differentiation of GC-GB. The differential diagnosis of lipidized GC-GB from gliosarcoma or anaplastic pleomorphic xanthoastrocytoma is briefly discussed.

Successful endoscopic resection for well-differentiated neuroendocrine tumor, Grade 1, in the hypopharynx.

Well-differentiated neuroendocrine tumor, Grade 1 (NET, G1), in the hypopharynx is extremely rare. A 62-year-old woman was referred to our clinic with a tumor in the postcricoid area. The tumor was diagnosed NET on biopsy and there were no metastatic findings on CT, therefore we performed endoscopic resection. Histologic examination revealed well-differentiated neuroendocrine tumor, Grade 1. This case was an extremely rare and valuable case in which endoscopic images can be observed in detail. Endoscopic resection was performed and successful endoscopic and histological resection was achieved.

Direct specimen collection during routine operation improves nucleic acid quality in genetic analysis samples for head and neck tumors: A retrospective study.

The nucleic acid integrity of head and neck squamous cell carcinoma (HNSCC) samples is poor, and the material available for genetic analysis is limited. Therefore, to expand the effectiveness of personalized medicine in patients with HNSCC, a new sampling method is needed. In total, 128 samples from 44 patients with HNSCC were studied: 32 genetic analysis samples (GASs) collected as 5 × 5 × 5 mm tissue fragments from resected large tumors and immediately embedded in a small formalin bottle within 10 min (i.e., the ischemic time), 43 primary tumor components (primary), 14 decalcified tumor (DC) samples, 32 metastatic tumors in lymph nodes (LNs), and 7 parakeratinized components (PKCs). The nucleic acid quality in the GAS, primary, DC, LN, and PKC groups was compared and next-generation sequencing (NGS) was performed. DNA integrity number and percentage of RNA fragments with > 200 nucleotides were significantly higher in the GAS group than those in the other groups. RNA integrity number decreased first in LN, followed by GAS, primary, and DC. No significant differences were observed in DIN, RIN and DV200 among the PKC, primary and LN. Following methyl green-pyronin staining, preserved DNA and RNA were not visualized in DC samples. Most NGS metrics did not differ significantly among primary, LN, and PKC samples. In conclusion, GASs should be collected during routine hospital activities. When the volume of viable materials is limited, PKCs should be considered for genetic analysis.

Adult cerebral high-grade glioneuronal tumor with perivascular or pseudopapillary growth co-existing with low-grade tumor: a case report.

An unusual, small cell-predominant, high-grade glioneuronal tumor in the occipital lobe of a 49-year-old man that co-existed with a low-grade tumor is reported. The tumor consisted of two distinct components: the major component was a dense proliferation of primitive small cells showing bidirectional neuronal and glial differentiation; and the minor component consisted of a proliferation of well-differentiated astrocytes intermingled with mature neuronal cells. In the former component, perivascular pseudorosette-like or pseudopapillary growth reminiscent of ependymoma or papillary glioneuronal tumor (PGNT), respectively, was prominent, and hypertrophic astrocytic cells were located just outside the central blood vessels. Small cells were immunoreactive for Olig2, synaptophysin, and, less frequently, for glial fibrillary acidic protein. The low-grade component included Rosenthal fibers, hemosiderin deposition, and perivascular lymphocytic infiltration, thus closely resembling ganglioglioma. Cytogenetic studies did not demonstrate any mutations or rearrangements of the genes IDH1, IDH2, H3F3A, BRAF, FGFR1, or TERT promoter. The tumor recurred and spread along the ventricular surface three years after total removal. The small cell-predominant, high-grade component was considered to have evolved from the ganglioglioma-like, low-grade component. The histopathologic resemblance of the high-grade component to PGNT was a special feature.

Hypoxia-inducible factor 2α protein and mRNA expression correlate with histomorphological features in clear cell renal cell carcinoma.

Hypoxia-inducible factor 2α (HIF2α) has been identified as a potential biomarker and novel target for systemic therapy in clear cell renal cell carcinoma (ccRCC). The present study aims to evaluate the association of HIF2α protein and HIF2A mRNA expression with clinicopathological factors and histomorphological features related to vasculature and inflammation of ccRCC using a localized ccRCC cohort (n = 428) and The Cancer Genome Atlas (TCGA)-KIRC cohort (n = 433). HIF2α protein expression was immunohistochemically assessed using tissue microarrays and HIF2A mRNA expression was assessed using the TCGA RNA-sequencing data. Positive HIF2α protein and high HIF2A mRNA expression were observed in 145 (33.9 %) and 142 (32.8 %) patients, respectively. Positive nuclear HIF2α protein expression was significantly associated with the clear histological phenotype and architectural patterns related to rich vascular networks (p < 0.001), and no tumor-associated immune cells status (p < 0.05) in addition to favorable prognostic factors such as lower TNM stage, lower WHO/ISUP grade, or the absence of necrosis (p < 0.001). The HIF2A mRNA expression profile by the TCGA cohort showed similar trends as the HIF2α protein profile. In addition, positive HIF2α protein and high HIF2A mRNA expression were associated with higher recurrence-free survival and overall survival, respectively (both p < 0.001). In conclusion, we comprehensively demonstrated the association of HIF2α profiles with clinicopathological factors and histomorphological features related to vasculature and inflammation at both protein and mRNA levels. Histomorphological features expressing HIF2α may provide information on HIF2α targeted therapeutic response as well as prognosis in ccRCC patients.

Cell Block-Based Two-Dimensional and Immunocytochemical Analyses Could Reduce Atypical/Indeterminate Case Frequency in Breast Fine-Needle Aspiration Cytology: A Retrospective Analysis.

INTRODUCTION: In fine-needle aspiration of the breast (FNAB), the "atypical" category encompasses both benign and malignant lesions, particularly papillary proliferative lesions, as per the latest WHO classification. We aimed to reduce atypical cases and improve diagnostic accuracy by investigating the utility of cell block (CB) analysis. METHODS: FNAB CB samples (2018-2022) were reviewed using smear only or CBs. CB-based diagnosis was performed with 2D morphological analysis and immunocytochemistry using ER, CK5/6, p63, SMA, and CD56. Samples were reclassified as "benign," "atypical," "suspicious of malignancy," "malignant," or "insufficient/inadequate." Atypical cases were reexamined. Diagnoses were validated histologically. RESULTS: On examining the FNAB samples (n = 149; 32 atypical), 2D CB sectioning achieved a clearer definition of myoepithelial cells and fibrovascular cores than Papanicolaou staining. Immunocytochemistry was evaluated for 36 cases: estrogen receptor (ER)- and CK5/6+ tumors were reclassified as benign; ER+ and CK5/6- tumors as malignant; p63- tumors as invasive; papillary malignant tumors with a smooth muscle actin (SMA)+ fibrovascular core and p63- myoepithelial cells as encapsulated papillary carcinoma; and CD56+ carcinomas as neuroendocrine carcinoma. Diagnostic rates were as follows: benign (44% FNAB, 51% CB), atypical (21% FNAB, 3% CB), suspicious of malignancy and malignant (28% FNAB, 40% CB), and insufficient/inadequate (7% FNAB, 6% CB). CB achieved >85% sensitivity, specificity, and positive and negative predictive values. CONCLUSION: CBs represent 3D FNA cell morphology using 2D sections, enabling adaption of pathology criteria to the cytological material. Immunocytochemical staining of CBs can predict low nuclear grade papillary tumors and reduce atypical case frequency, improving diagnostic accuracy.

[Radiofrequency Ablation for Pulmonary Metastasis of Ovarian Cancer Caused Iatrogenic Pneumothorax, Leading to Empyema].

A female patient in her 40s who underwent surgery for recurrent right lung metastasis from resected ovarian cancer was referred to our department because of the right pneumothorax due to radiofrequency ablation for multiple lung metastases. Methicillin-resistant Staphylococcus epidermidis( MRSE) was detected from the tip of the drainage catheter indicated persistent pulmonary fistula with right empyema, and surgical treatment was performed. A white coat of the whole lung surface and air leakage were observed at radiofrequency ablation (RFA) treated lesion and partial resection of the right lung, debridement, and irrigation were performed. A pathological examination revealed residual viable ovarian cancer cells and pleural fistula.

Primary Gastric Rhabdomyosarcoma.

Primary gastric rhabdomyosarcoma is extremely rare. An 87-year-old man visited our clinic with a chief complaint of abdominal pain. Computed tomography (CT) and 18F-fluorodeoxyglucose positron emission tomography-CT revealed a massive tumor originating from the muscularis propria of the stomach along with splenic vein tumor thrombosis. We diagnosed the patient with primary gastric rhabdomyosarcoma by an endoscopic ultrasound-guided fine-needle aspiration/biopsy.

Adenoid Ameloblastoma with BRAF p.V600E Mutation Revealing Ameloblastomatous Origin: A First Case Report.

BACKGROUND: Adenoid ameloblastoma (AdAM) is a frequently recurrent tumor that shows hybrid histological features of both ameloblastoma and adenomatoid odontogenic tumor (AOT). AdAM is expected to be classified as a new subtype of ameloblastoma in the next revision of the World Health Organization (WHO) odontogenic tumor classification. However, whether AdAM is a histologic variant of ameloblastoma or AOT remains unclear. To establish a new category, genetic evidence indicating the tumor category is necessary. METHODS: We present a case of a 23-year-old Japanese woman with AdAM who underwent genetic/DNA analysis for ameloblastoma-related mutation using immunohistochemical staining, Sanger sequencing, and next-generation sequencing (NGS) analyses with reliable clinicopathological evidence. RESULTS: Immunohistochemical expression of BRAF p.V600E was diffusely positive for both ameloblastoma- and AOT-like components. Sanger sequencing and NGS analyses showed missense mutations in BRAF p.V600E (c.1799T > A), a gene that is commonly altered in ameloblastomas but not in KRAS, another gene associated with AOT. CONCLUSION: This case report is the first to provide genetic evidence on the ameloblastomatous origin of AdAM with a BRAF p.V600E mutation. A larger series of AdAM groups' molecular testing is needed to aptly classify them and prognosticate the best treatment.

Mucous Gland Adenoma of the Lung: A Neoplastic Counterpart of Mucinous Bronchial Glands.

Mucous gland adenoma (MGA) is a rare benign tumor that usually arises in the proximal airway and consists of mucus-secreting cells resembling bronchial glands. Here, we report 2 cases of MGAs and describe their morphologic, immunohistochemical, and molecular profiles in comparison with 19 pulmonary tumors of 5 other histologic types with mucinous cells (invasive mucinous adenocarcinoma, mucoepidermoid carcinoma, mixed squamous cell and glandular papilloma, bronchiolar adenoma/ciliated muconodular papillary tumor, and sialadenoma papilliferum). Two MGAs were found in 1 male patient and 1 female patient, located in the bronchus and trachea, respectively. One MGA was examined by RNA sequencing, and no putative driver mutations (including BRAF, KRAS, and AKT1 mutations) or gene fusions were identified. In another case of MGA, V600E mutations of BRAF and E17K mutations of AKT1 were not detected by allele-specific real-time PCR or digital PCR, respectively. However, a gene expression analysis revealed that the MGA presented a specific RNA expression profile with multiple genes enriched in the salivary gland. The gene expression of NKX3.1 was significantly higher in the MGA case in comparison to normal control lungs (P < .001). We then examined NKX3.1 immunohistochemistry for 2 MGAs and 19 tumors of 5 other histologic types. NKX3.1 was positive in MGA (2/2, 100%), whereas all constituent cells, including mucinous cells, were negative for NKX3.1 in other histologic types (0%, 0/19). In normal lung tissue, NKX3.1 was positive for mucinous acinar cells of the bronchial glands. In conclusion, the gene expression profile, taken together with the histologic similarity between MGA and bronchial glands, and the preferred location of the tumors (proximal airways with submucosal glands) suggest that MGA is a neoplastic counterpart of mucinous bronchial glands. NKX3.1 immunohistochemistry can be a sensitive and specific ancillary marker that distinguishes MGA from other histologic mimics.

[Giant Bullae Misdiagnosed as Pneumothorax:Report of a Case].

A 46-year-old man was taken to a hospital by ambulance because of sudden onset of dyspnea, and was inserted chest drainage tube with a diagnosis of right-sided tension pneumothorax on chest X-ray. Since the chest drainage was not effective, he was transferred to our institute. Based on chest computed tomography (CT) findings, a diagnosis of giant bullae of the right lung was made, and surgical treatment was performed. Postoperatively, the improvement of respiratory function was confirmed.

Areas of Crush Nuclear Streaming Should Be Included as Tumor Content in the Era of Molecular Diagnostics.

Degenerated tissues are frequently observed in malignant tumors, but are not analyzed. We investigated whether nuclear streaming and necrosis samples could be used for genetic analysis to expand the sample pool. A total of 81 samples were extracted from small cell carcinoma and lymphoma FFPE tissue blocks and classified into three histological cohorts: 33 materials with well-preserved tumor morphology, 31 nuclear streaming samples, and 17 necrosis samples. DNA and RNA integrity numbers, percentage of RNA fragments with >200 nucleotides, and next-generation sequencing quality metrics were compared among the cohorts. DNA quality did not significantly differ between nuclear streaming materials and materials with well-preserved morphology, whereas that of the necrosis samples was inferior. RNA quality decreased in the following order: materials with well-preserved morphology > nuclear streaming > necrosis. The sequencing metrics did not differ significantly between the nuclear streaming samples and materials with well-preserved morphology, and reliable variants were detected. The necrosis samples extracted from resections exhibited sequencing failure and showed significantly fewer on-target aligned reads and variants. However, variant allele frequency did not differ among the cohorts. We revelated that DNA in nuclear streaming samples, especially within biopsies, could be used for genetic analysis. Moreover, degenerated non-tumor cells should be counted when evaluating tumor content to avoid misinterpreting the variant allele frequency.

MMP14 expression levels accurately predict the presence of extranodal extensions in oral squamous cell carcinoma: a retrospective cohort study.

BACKGROUND: Extranodal extension (ENE) is an adverse prognostic factor for oral squamous cell carcinoma (OSCC), and patients with OSCC along with ENE require neck dissection. In this study, we developed a novel ENE histology-based pathological predictor using MMP14 expression patterns in small biopsy specimens. METHODS: A total of 71 surgically resected tissue, 64 dissected lymph node (LN), and 46 biopsy specimens were collected from 71 patients with OSCC. Immunohistochemical analyses of total MMP14 expression in the tumour nest and cancer-associated fibroblasts (CAFs) were performed using the MMP14 co-scoring system (high- or low-risk). The association analysis of MMP14 expression in metastatic LNs was performed with respect to the presence and absence of ENE. Clinicopathological analyses and multivariate examinations were performed to assess the risks of metastasis and ENE presence. The predictive value of ENE and the impact of ENE and MMP14 expression on 5-year overall survival were examined. RESULTS: High-risk MMP14 expression was detected in metastatic LN specimens with ENE. MMP14 expression in tumour nests and CAFs and its overexpression at the tumour-stromal interface significantly correlated with the presence of ENE. The MMP14 co-scoring system was an independent risk predictor for ENE, with sensitivity, specificity, and accuracy of over 80% in biopsy samples; patients with a high risk in the MMP14 co-scoring system had significantly worse prognoses in both resections and biopsies. CONCLUSION: The MMP14 co-scoring system accurately predicted ENE presence and poor prognosis via immunohistochemical evaluation of small biopsies. This system is a simple, accurate, and inexpensive immunohistochemical approach that can be used in routine pathological diagnosis for effective treatment planning.

Gastric hamartomatous inverted polyp: Report of three cases with a review of the endoscopic and clinicopathological features.

Objectives: A gastric hamartomatous inverted polyp (GHIP) is a rare submucosal tumor characterized histopathologically by a submucosal inverted proliferation of cystically dilated hyperplastic gastric glands. Only 42 GHIPs have been reported in English literature. Few GHIPs have been reported to accompany adenocarcinomas. We reported on three patients with a GHIP and reviewed the clinicopathological and endoscopic features of GHIPs. Methods: This study included two men and one woman with a GHIP. The endoscopic, histopathological, and immunohistochemical features of the endoscopically resected specimens were analyzed. A gene mutation analysis was also performed. Results: All the tumors were located in the body of the stomach, with a median size of 20 mm. Two tumors were sessile, and the remaining tumor had a pedunculated appearance. The overlying mucosa mainly appeared normal but was reddish in one tumor. The histopathological examination of the tumors revealed a well-circumscribed and lobular submucosal proliferation of cystically dilated hyperplastic glands. The immunohistochemical analysis revealed that the MUC5AC-positive foveolar epithelium was located in the center, and MUC6-positive pseudo-pyloric or pepsinogen-I and H+/K+ ATPase-positive fundic-type glands were located at the periphery of two tumors. No carcinomatous components were noted in any of the tumors. Moreover, no significant mutations in oncogenes or tumor suppressor genes were noted. Conclusions: Our review revealed that approximately three fourths of GHIP cases showed an submucosal tumor-like feature, whereas endoscopic features, including the endoscopic ultrasonography findings, were not characteristic. Because an endoscopic diagnosis of a GHIP may be difficult, complete endoscopic resection may be required for a pathological diagnosis.

Deep learning-based predictions of clear and eosinophilic phenotypes in clear cell renal cell carcinoma.

We have recently shown that histological phenotypes focusing on clear and eosinophilic cytoplasm in clear cell renal cell carcinoma (ccRCC) correlated with prognosis and the response to angiogenesis inhibition and checkpoint blockade. This study aims to objectively show the diagnostic utility of clear or eosinophilic phenotypes of ccRCC by developing an artificial intelligence (AI) model using the TCGA-ccRCC dataset and to demonstrate if the clear or eosinophilic predicted phenotypes correlate with pathological factors and gene signatures associated with angiogenesis and cancer immunity. Before the development of the AI model, histological evaluation using hematoxylin and eosin whole-slide images of the TCGA-ccRCC cohort (n = 435) was performed by a urologic pathologist. The AI model was developed as follows. First, the highest-grade area on each whole slide image was captured for image processing. Second, the selected regions were cropped into tiles. Third, the AI model was trained using transfer learning on a deep convolutional neural network, and clear or eosinophilic predictions were scaled as AI scores. Next, we verified the AI model using a validation cohort (n = 95). Finally, we evaluated the accuracy of the prognostic predictions of the AI model and revealed that the AI model detected clear and eosinophilic phenotypes with high accuracy. The AI model stratified the patients' outcomes, and the predicted eosinophilic phenotypes correlated with adverse clinicopathological characteristics and high immune-related gene signatures. In conclusion, the AI-based histologic subclassification accurately predicted clear or eosinophilic phenotypes of ccRCC, allowing for consistently reproducible stratification for prognostic and therapeutic stratification.

Significance of placental CD200 expression in patients with preeclampsia: Comparison between early­ and late­onset patients.

Preeclampsia, characterized by high blood pressure and proteinuria during pregnancy, causes serious complications in both the mother and the fetus. Although there have been several studies on the causes of preeclampsia, the detailed mechanism of this disease remains unclear. Moreover, a few reports have focused on the causes of preeclampsia in number of weeks at onset. The present study aimed to elucidate the differences between early­ and late­onset preeclampsia. This study enrolled patients with preeclampsia from January 2014 to December 2020. They were classified into early­ (<34 weeks) and late­onset (≥34 weeks) preeclampsia groups. The expression profiles of 770 immune­related genes were studied in the placental tissue from five patients each in the early­ and late­onset groups. The expression of CD200 in the trophoblasts of the placenta of 26 and 27 patients in early­ and late­onset groups, respectively, was also analyzed using immunostaining. Analysis of extracted RNA indicated that CD200 was significantly upregulated in the early­onset group compared with late­onset group and normal control. Immunostaining for CD200 demonstrated a significantly increased expression in the early­onset group compared with the late­onset group. The present study demonstrated that upregulation of CD200, which belongs to the immunoglobulin superfamily and is recognized as a molecule that acts in immune tolerance via inhibition of classical macrophage activation, may be associated with early­onset preeclampsia, although it remains unknown whether upregulation of CD200 expression is a cause or effect of the development of early­onset preeclampsia. Early­onset preeclampsia might have a different mechanism from that of late­onset; thus, further studies are needed to clarify the mechanism of these conditions for adequate treatment.

CD155 immunohistochemical expression in upper tract urothelial carcinoma predicts poor prognosis.

A novel immune checkpoint, CD155/T-cell immunoreceptor with Ig and ITIM domains, has been recognized as a new therapeutic target in addition to conventional immune checkpoints, such as anti-programmed cell death protein 1/programmed cell death ligand 1 (PD-L1), for urothelial carcinoma (UC). Fibroblast growth factor receptor (FGFR) is considered another new therapeutic target for UC. As FGFR3-mutant UC may be associated with decreased T-cell infiltration, FGFR3 inhibition may facilitate lymphocyte invasion into the tumor microenvironment. Although a combined effect of immune checkpoint inhibitors and FGFR inhibition is expected, the combined expression profiles of CD155, PD-L1 and FGFR3 have not been evaluated in upper tract UC (UTUC). The present study aimed to investigate the association between CD155 expression and clinicopathological factors in 208 patients with UTUC undergoing radical nephroureterectomy. Furthermore, the expression profiles of CD155, PD-L1 and FGFR3 were compared. Immunohistochemical analysis was performed using tissue microarray specimens and survival analyses were performed using the Kaplan-Meier method and the Cox proportional hazards model. High immunohistochemical expression of CD155 was observed in 177 patients (85.1%) and it was associated with advanced pathological stage and lymphovascular invasion. The survival rate was lower among patients with tumors exhibiting high CD155 expression than among those with tumors with low CD155 expression. In addition, multivariate survival analysis revealed that high CD155 expression was an independent prognostic factor for recurrence (hazard ratio=7.32, 95% CI=1.01-53.35, P=0.049). FGFR3 and immune checkpoint signaling molecules, such as CD155 and PD-L1, had a weak negative correlation. The present results indicated that the expression of CD155 is a useful marker for predicting the recurrence of UTUC. In addition, the immunohistochemical expression profiles of CD155, PD-L1 and FGFR3 may further the understanding of the role of FGFR-targeted therapies in immunotherapy for UTUC.