Japanese Case of Enzalutamide-Resistant Prostate Cancer Harboring a SPOP Mutation With Scattered Allelic Imbalance: Response to Platinum-Based Therapy

Prognostic impact and landscape of cellular CXCR5 chemokine receptor expression in clear-cell renal cell carcinoma

CXCR5 is a chemokine receptor that promotes B cell follicular formation and antibody production. Indeed, CXCR5 has been found to be expressed in a variety of cancers; however, the role of CXCR5 expression in clear-cell renal cell carcinoma (ccRCC) remains unclear. We aimed to determine the impact of cellular CXCR5 expression on cancer outcomes, the PD-1/PD-L1 axis, and genetic states in patients with ccRCC. First, multiplex immunofluorescence staining for CXCR5, CD4, CD8, and AE1/AE3, along with automated single-cell counting, was performed to assess cellular CXCR5 expression in ccRCC and its association with prognosis. Second, the tumour microenvironment (TME) was analysed, with a focus on the relationship between the PD-1/PD-L1 axis and CXCR5 expression. Finally, an integrated analysis of CXCR5 expression and genomic mutation information was conducted to reveal the genetic background underlying CXCR5 expression. A total of 105 ccRCC patients were included. Among the 696,964 cells analysed, the distribution of CXCR5-expressing cells was as follows: 30% CXCR5+CD4+ cells, 9% CXCR5+CD8+ cells, and 26% CXCR5+AE1/AE3+ cells. Survival analysis revealed that tumours with low-CXCR5+CD8+ cells had a poor prognosis; TME analysis revealed a relationship between low-CXCR5+CD8+ status and a highly suppressive PD-L1-positive immune environment. Genomic analysis revealed a correlation between low-CXCR5+CD8+ status and high rates of alterations in chromatin remodelling genes, including PBRM1. This study highlights the significance of CXCR5+CD8+ cells in ccRCC, demonstrating their clinical implications and revealing the immunogenomic landscape underlying CXCR5 expression.

An Overview of Altered Pathways Associated with Sensitivity to Platinum-Based Chemotherapy in Neuroendocrine Tumors: Strengths and Prospects

Neuroendocrine neoplasms (NENs) are a diverse group of malignancies with a shared phenotype but varying prognosis and response to current treatments. Based on their morphological features and rate of proliferation, NENs can be classified into two main groups with a distinct clinical behavior and response to treatment: (i) well-differentiated neuroendocrine tumors (NETs) or carcinoids (with a low proliferation rate), and (ii) poorly differentiated small- or large-cell neuroendocrine carcinomas (NECs) (with a high proliferation rate). For certain NENs (such as pancreatic tumors, higher-grade tumors, and those with DNA damage repair defects), chemotherapy is the main therapeutic approach. Among the different chemotherapic agents, cisplatin and carboplatin, in combination with etoposide, have shown the greatest efficacy in treating NECs compared to NETs. The cytotoxic effects of cisplatin and carboplatin are primarily due to their binding to DNA, which interferes with normal DNA transcription and/or replication. Consistent with this, NECs, which often have mutations in pathways involved in DNA repair (such as Rb, MDM2, BRCA, and PTEN), have a high response to platinum-based chemotherapy. Identifying mutations that affect molecular pathways involved in the initiation and progression of NENs can be crucial in predicting the response to platinum chemotherapy. This review aims to highlight targetable mutations that could serve as predictors of therapeutic response to platinum-based chemotherapy in NENs.

G-protein signaling of oxytocin receptor as a potential target for cabazitaxel-resistant prostate cancer

Although the treatment armamentarium for patients with metastatic prostate cancer has improved recently, treatment options after progression on cabazitaxel (CBZ) are limited. To identify the mechanisms underlying CBZ resistance and therapeutic targets, we performed single-cell RNA sequencing of circulating tumor cells (CTCs) from patients with CBZ-resistant prostate cancer. Cells were clustered based on gene expression profiles. In silico screening was used to nominate candidate drugs for overcoming CBZ resistance in castration-resistant prostate cancer. CTCs were divided into three to four clusters, reflecting intrapatient tumor heterogeneity in refractory prostate cancer. Pathway analysis revealed that clusters in two cases showed up-regulation of the oxytocin (OXT) receptor-signaling pathway. Spatial gene expression analysis of CBZ-resistant prostate cancer tissues confirmed the heterogeneous expression of OXT-signaling molecules. Cloperastine (CLO) had significant antitumor activity against CBZ-resistant prostate cancer cells. Mass spectrometric phosphoproteome analysis revealed the suppression of OXT signaling specific to CBZ-resistant models. These results support the potential of CLO as a candidate drug for overcoming CBZ-resistant prostate cancer via the inhibition of OXT signaling.

Hybridisation chain reaction-based visualisation and screening for lncRNA profiles in clear-cell renal-cell carcinoma

BACKGROUND

Analysis of long noncoding RNA (lncRNA) localisation at both the tissue and subcellular levels can provide important insights into the cell types that are important for their function.

METHODS

By applying new fluorescent in situ hybridisation technique called hybridisation chain reaction (HCR), we achieved a high-throughput lncRNA visualisation and evaluation of clinical samples.

RESULTS

Assessing 1728 pairs of 16 lncRNAs and clear-cell renal-cell carcinoma (ccRCC) specimens, three lncRNAs (TUG1, HOTAIR and CDKN2B-AS1) were associated with ccRCC prognosis. Furthermore, we derived a new lncRNA risk group of ccRCC prognosis by combining the expression levels of these three lncRNAs. Examining genomic alterations underlying this classification revealed prominent features of tumours that could serve as potential biomarkers for targeting lncRNAs. We then derived combination of HCR with expansion microscopy and visualised nanoscale-resolution HCR signals in cell nuclei, uncovering intracellular colocalization of three lncRNA (TUG1, HOTAIR and CDKN2B-AS1) signals such as those located intra- or out of the nucleus or nucleolus in cancer cells.

CONCLUSION

LncRNAs are expected to be desirable noncoding targets for cancer diagnosis or treatments. HCR involves plural probes consisting of small DNA oligonucleotides, clinically enabling us to detect cancerous lncRNA signals simply and rapidly at a lower cost.

Landscape of prognostic signatures and immunogenomics of the AXL/GAS6 axis in renal cell carcinoma

BACKGROUND

Cabozantinib is an oral tyrosine kinase inhibitor in renal cell carcinoma (RCC), whose targets include oncogenic AXL and unique ligand GAS6. Critical gaps in basic knowledge need to be addressed to devise an exclusive biomarker and candidate when targeting the AXL/GAS6 axis.

METHODS

To clarify the effects of the AXL/GAS6 axis on RCC, we herein performed a large-scale immunogenomic analysis and single-cell counts including various metastatic organs and histological subtypes of RCC. We further applied genome-wide mutation analyses and methylation arrays.

RESULTS

Varying patterns of AXL and GAS6 expression were observed throughout primary RCC tumours and metastases. Scoring individual AXL/GAS6 levels in the tumour centre and invasive margin, namely, the AXL/GAS6 score, showed a good ability to predict the prognosis of clear cell RCC. Metastasis- and histological subtype-specific differences in the AXL/GAS6 score existed since lung metastasis and the papillary subtype were weakly related to the AXL/GAS6 axis. Cell-by-cell immunohistological assessments clarified an immunosuppressive environment in tumours with high AXL/GAS6 scores. Genomic alterations in the PI3K-mTOR pathway and DNA methylation profiling revealed distinct differences with the AXL/GAS6 score in ccRCC.

CONCLUSION

The AXL/GAS6 scoring system could predict the outcome of prognosis and work as a robust biomarker for the immunogenomic state in RCC.

Profiling the inhibitory receptors LAG-3, TIM-3, and TIGIT in renal cell carcinoma reveals malignancy

A cutting edge therapy for future immuno-oncology is targeting a new series of inhibitory receptors (IRs): LAG-3, TIM-3, and TIGIT. Both immunogenomic analyses and diagnostic platforms to distinguish candidates and predict good responders to these IR-related agents are vital in clinical pathology. By applying an automated single-cell count for immunolabelled LAG-3, TIM-3, and TIGIT, we reveal that individual IR levels with exclusive domination in each tumour can serve as valid biomarkers for profiling human renal cell carcinoma (RCC). We uncover the immunogenomic landscape associated with individual IR levels in human RCC tumours with metastases in various organs and histological subtypes. We then externally validate our results and devise a workflow with optimal biomarker cut-offs for discriminating the LAG-3, TIM-3, and TIGIT tumour profiles. The discrimination of LAG-3, TIM-3, and TIGIT profiles in tumours may have a broad impact on investigations of immunotherapy responses after targeting a new series of IRs.

Targeting the inhibitory receptors (IRs) LAG-3, TIM-3 and TIGIT is a promising immune-oncology approach and the identification of biomarkers of response is crucial. Here, the authors apply automated single-cell count for these IRs in human renal cell carcinoma and investigate the immunogenomic landscape of the disease.

Prominent response to platinum-based chemotherapy in a patient with BRCA2 mutant-neuroendocrine prostate cancer and MDM2 amplification

INTRODUCTION

Genomic profiling provides useful information for diagnosis, treatment, and prognosis, and detection of certain defects, such as DNA repair gene aberrations or microsatellite instability, can possibly lead to optimal treatment, but this testing has not been widely used to inform prostate cancer treatment.

CASE PRESENTATION

A 55-year-old man sequentially treated for prostate cancer was diagnosed as neuroendocrine prostate cancer from prostate specimens resected because of urinary retention. Subsequently, he received five cycles of platinum-based chemotherapy in total and responded well. We also performed next-generation sequencing of a sample from the prostate specimen and identified a breast cancer susceptibility gene mutation with Murine Double Minute 2 amplification and loss of heterozygosity in retinoblastoma 1.

CONCLUSION

We report a neuroendocrine prostate cancer patient with Murine Double Minute 2 amplification who experienced an aggressive course and for whom platinum-based chemotherapy was effective, and one of the reasons for the good response might be the breast cancer susceptibility gene mutation.

Pulmonary metastasis secondary to abiraterone-resistant prostate cancer with homozygous deletions of BRCA2: First Japanese case

INTRODUCTION

Most metastatic prostate cancers acquire the capacity for androgen-independent growth and become resistant to androgen deprivation therapy. A patient-focused treatment strategy is needed for aggressive castration-resistant prostate cancer.

CASE PRESENTATION

We report the case of a 62-year-old man who presented with prostatic adenocarcinoma who was treated by radiation and combined androgen blockade. After completion of first-line therapy, he was diagnosed with multiple metastatic castration-resistant prostate cancer in the lung. Second-line therapy with abiraterone acetate resulted in partial remission of the lung metastases. Thoracic surgery was performed to remove the single lung metastasis remaining. Next-generation sequencing of the specimens demonstrated homozygous loss of BRCA2. We note in this case a heterogeneous response to abiraterone acetate may be related to the somatic BRCA2 deletions.

CONCLUSIONS

We present the first Japanese case of a metastatic abiraterone acetate-resistant castration-resistant prostate cancer accompanied by BRCA2 mutation.

A first Japanese case of neuroendocrine prostate cancer accompanied by lung and brain metastasis with somatic and germline BRCA2 mutation

Germline mutations and copy number changes in DNA damage repair (DDR) genes such as BRCA2 are associated with aggressive forms of prostate cancer (PCa). Although the prevalence of BRCA2 variants in PCa is increasing in Japan, the genomic and biological implications in Japanese patients are unclear. An 81-year-old male presented with prostatic adenocarcinoma with neuroendocrine differentiation accompanied by metastatic lung nodule and brain metastases. Platinum-based doublet chemotherapy combined with etoposide resulted in partial and complete remissions of brain and lung metastases, respectively. Next-generation sequencing of biopsy and peripheral blood samples demonstrated a somatic BRCA2 mutation at c.7008-2A>C and a germline mutation at p.E2877*. The patient's son had been diagnosed with breast cancer 2.5 years ago and was found to have the same germline BRCA2 mutation. BRCA2 mutation increases the risks of aggressive PCa and other cancer types in Japanese males. These forms may be highly responsive to platinum-based chemotherapy.