J Cancer 2019; 10(5):1154-1161. doi:10.7150/jca.29052 This issue
1. Collaborative Innovation Center for Cancer Medicine, State Key Laboratory of Oncology in South China, Sun Yat-Sen University Cancer Center, Guangzhou, P. R. China
2. Department of Biotherapy, Sun Yat-Sen University Cancer Center, Guangzhou 510060, People's Republic of China
3. Department of Pathology, Sun Yat-Sen University Cancer Center, Guangzhou 510060, People's Republic of China
Purpose: To evaluate the tumour cell PD-L1 (TC-PD-L1) expression patterns in the local microenvironment of clear cell renal cell carcinoma (ccRCC).
Materials and Methods: 30 fresh primary ccRCC tissues were used to detect the association between TC-PD-L1 and CD8+TILs at mRNA level. The in vitro incubation experiment was used to confirm the association between extrinsic TC-PD-L1 expression and IFNγ. A cohort of 135 ccRCC patients treated between January 2009 and August 2013 was included for survival analysis.
Results: Our results confirmed that ccRCC cell lines were capable of expressing PD-L1. The incubation experiment in vitro demonstrated the positive correlation of TC-PD-L1 expression with interferon-gamma (IFNγ). Additionally, survival analysis was investigated in 135 ccRCC patients and found no independent correlation of TC-PD-L1 expression in multivariate analysis, whereas more distinct prognostic differences were detected when TC-PD-L1-positive ccRCC were sub-classified as with or without CD8+ T cell infiltration.
Conclusion: The intrinsic and extrinsic expression patterns are both detected in ccRCC. High positive rate of TC-PD-L1 correlated closely to the strong infiltration of CD8+ TILs. TC-PD-L1-positive ccRCC patients with abundant CD8+ TILs infiltration confer the high risk of death and disease relapse.
Keywords: PD-L1, local microenvironment, intrinsic expression, extrinsic expression, clear cell renal cell carcinoma