PD-L1 expression is an unfavourable prognostic indicator in Asian renal cell carcinomas

PD1/PD-L1 blockade in clear cell renal cell carcinoma: mechanistic insights, clinical efficacy, and future perspectives

The advent of PD1/PD-L1 inhibitors has significantly transformed the therapeutic landscape for clear cell renal cell carcinoma (ccRCC). This review provides an in-depth analysis of the biological functions and regulatory mechanisms of PD1 and PD-L1 in ccRCC, emphasizing their role in tumor immune evasion. We comprehensively evaluate the clinical efficacy and safety profiles of PD1/PD-L1 inhibitors, such as Nivolumab and Pembrolizumab, through a critical examination of recent clinical trial data. Furthermore, we discuss the challenges posed by resistance mechanisms to these therapies and potential strategies to overcome them. We also explores the synergistic potential of combination therapies, integrating PD1/PD-L1 inhibitors with other immunotherapies, targeted therapies, and conventional modalities such as chemotherapy and radiotherapy. In addition, we examine emerging predictive biomarkers for response to PD1/PD-L1 blockade and biomarkers indicative of resistance, providing a foundation for personalized therapeutic approaches. Finally, we outline future research directions, highlighting the need for novel therapeutic strategies, deeper mechanistic insights, and the development of individualized treatment regimens. Our work summarizes the latest knowledge and progress in this field, aiming to provide a valuable reference for improving clinical efficacy and guiding future research on the application of PD1/PD-L1 inhibitors in ccRCC.

Comprehensive Genomic Characterization of Tumor Microenvironment and Relevant Signature in Clear Cell Renal Cell Carcinoma

Purpose

To systematically investigate the characterization of tumor microenvironment (TME) in clear cell renal cell carcinoma (ccRCC), we performed a comprehensive analysis incorporating genomic alterations, cellular interactions, infiltrating immune cells, and risk signature.

Patients and Methods

Multi-omics data including RNA-seq, single-nucleotide variant (SNV) data, copy number variation (CNV) data, miRNA, and corresponding prognostic data were obtained from The Cancer Genome Atlas (TCGA) and the International Cancer Genome Consortium (ICGC) database. The CIBERSORT algorithm was utilized to identify prognostic TME subclusters, and TMEscore was further quantified. Moreover, the mutational landscape of TCGA-KIRC was explored. Lastly, TIDE resource was applied to assess the significance of TMEscore in predicting immunotherapeutic benefits.

Results

We analyzed the TME infiltration patterns from 621 ccRCC patients and identified 5 specific TME subclusters associated with clinical outcomes. Then, we found that TMEcluster5 was significantly related to favorable prognosis and enriched memory B-cell infiltration. Accordingly, we depicted the clustering landscape of TMEclusters, TMEscore levels, tumor mutation burden (TMB), tumor grades, purity, and ploidy in all patients. Lastly, TIDE was used to assess the efficiency of immune checkpoint blockers (ICBs) and found that the TMEscore has superior predictive significance to TMB, making it an essential independent prognostic biomarker and drug indicator for clinical use.

Conclusions

Our study depicted the clustering landscape of TMEclusters, TMEscore levels, TMB, tumor grades, purity, and ploidy in total ccRCC patients. The TMEscore was proved to have promising significance for predicting prognosis and ICB responses, in accordance with the goal of developing rationally individualized therapeutic interventions.

Tumor cell PD-L1 expression is a strong predictor of unfavorable prognosis in immune checkpoint therapy-naive clear cell renal cell cancer

BACKGROUND

PD-L1 expression predicts response to immune checkpoint inhibitors in renal cell carcinomas (RCC), but has also been suggested to be linked to poor patient outcome.

METHODS

We analyzed PD-L1 in > 1400 RCC in a tissue microarray format by immunohistochemistry. Results were compared with histological tumor type, parameters of cancer aggressiveness, and intratumoral CD8⁺ cytotoxic cells.

RESULT

At a cut-off level of 5% PD-L1 positive tumor cells, PD-L1 positivity was seen in 6.3% of 633 clear cell RCC (ccRCC), 18.2% of 165 papillary RCC, 18.8% of 64 chromophobe RCC, and 41.7% of 103 oncocytomas. In ccRCC, PD-L1 positivity was significantly linked to high ISUP (p < 0.0001), Fuhrman (p < 0.0001), Thoenes grade (p < 0.0001), distant metastasis (p = 0.0042), short recurrence-free (p < 0.0001), and overall survival (p = 0.0002). Intratumoral CD8⁺ lymphocytes were more frequent in PD-L1 positive (1055 ± 109) than in PD-L1 negative ccRCC (407 ± 28; p < 0.0001). PD-L positive immune cells were seen in 8.2% of all RCC and 13.9% of papillary RCC. In ccRCC, PD-L1 positive immune cells were linked to high numbers of tumor-infiltrating CD8⁺ cells (p < 0.0001), high ISUP (p < 0.0001), Fuhrman (p = 0.0027), and Thoenes grade (p < 0.0001), and poor tumor-specific survival (p = 0.0280).

CONCLUSIONS

These data suggest that PD-L1 expression in highly immunogenic RCCs facilitates immune evasion and contributes to cancer aggressiveness.

Galectin-9 expression as a poor prognostic factor in patients with renal cell carcinoma

Recently, the effectiveness of anti-programmed death 1 (PD-1) antibody therapy in the treatment of renal cell carcinoma (RCC) has been established. Nevertheless, efficacy has been reported to be limited to only 10-30% of patients. To develop more effective immunotherapy for RCC, we analyzed the immunological characteristics in RCC tissues by immunohistochemistry (IHC). We prepared a tissue microarray that consisted of tumor tissue sections (1 mm in diameter) from 83 RCC patients in Kanagawa Cancer Center between 2006 and 2015. IHC analysis was performed with antibodies specific to immune-related (CD8 and Foxp3) and immune checkpoint (programmed death ligand 1 (PD-L1) and 2 (PD-L2), B7-H4 and galectin-9) molecules. The numbers and proportions of positively stained tumor cells or immune cells were determined in each section. From multivariate analysis of all 83 patients, higher galectin-9 expression was detected as a factor associated with worse overall survival (OS) (P = 0.029) and that higher stage and higher B7-H4 expression were associated with worse progression-free survival (PFS) (P < 0.001 and P = 0.021, respectively). Similarly, in multivariate analysis of 69 patients with clear cell RCC, though not statistically significant, there was a trend for association between higher galectin-9 expression and worse OS (P = 0.067), while higher stage was associated with worse PFS (P < 0.001). This study suggests that higher galectin-9 expression is an independent adverse prognostic factor of OS in RCC patients. Therefore, to develop more effective personalized immunotherapy to treat RCC, it may be important to target not only PD-1/PD-L1, but also other immune checkpoint molecules such as galectin-9.