Ueda K, et al. - Authors assessed the expression of programmed death 1 (PD-1) and PD-L1 and investigated their clinical and prognostic significance in patients with clear cell RCC (CCRCC) having received molecular targeted therapies. They also evaluated the association between the expression of PD-1 and PD-L1 and intratumoral tumor infiltrating lymphocytes (TILs). Findings suggested a significant association of PD-1 and PD-L1 expression with adverse clinicopathological features in CCRCC. Moreover, one of the biomarkers could be PD-1 expression, thereby suggesting poor outcome in patients with metastatic CCRCC receiving molecular targeted therapies.

Methods

• Researchers retrospectively reviewed and analyzed a total of 33 patients with metastatic CCRCC who underwent surgery and received molecular targeted therapies from March 2008 to April 2016.
• They analyzed the tissue specimens from the patients for PD-1 and PD-L1 expression by immunohistochemistry.

Results

• As per data, the median patient age was 64 years old (range=53-78) with the majority of patients being male (81.8%).
• Findings suggested that all Memorial Sloan Kettering Cancer Center risk groups were represented among the patients with 39.4% with favorable-, 51.5% with intermediate- and 9.1% with poor-risk.
• They observed the expression of PD-1 and PD-L1 in 16 (48.5%) and 9 (27.3%) patients, respectively.
• Authors noted an association of the expression of PD-1 and PD-L1 with a larger primary renal tumor size, higher nuclear grade and sarcomatoid feature.
• No significant difference in progression free survival of first line molecular targeted therapy was found for PD-1 (P=0.2396) and PD-L1 (P=0.5919) expression; as revealed by Kaplan-Meier analysis.
• Nonetheless, they noted a significant worse impact of PD-1 expression on overall survival (OS) (P=0.0385), while for PD-L1 expression only a trend is seen for OS (P=0.1542).
• A higher infiltration of CD4 (P < 0.0001 and P < 0.0001, respectively), CD8 (P=0.0328 and P=0.0044, respectively) and FOXP3 (P < 0.0001 and P=0.0033, respectively) positive TILs was demonstrated by the patients with PD-1 and PD-L1 expression.