616 Background: To evaluate the differential expressions of PD-1, PD-L1 and PD-L2 between the primary and metastatic sites of renal cell carcinoma (RCC), and to find potential factors influencing expression difference. Methods: We included cases of RCC histologically diagnosed at West China Hospital between January 2009 and November 2016. Clinicopathological data were retrospectively extracted. SPPS 22.0 and GraphPad Prism 6 statistical software were used for data analysis. Kaplan-Meier was used to analyze PFS and OS. R software was used to calculate predictive accuracy (PA). Results: A total of 163 patients were included in this study. Immunohistochemistry results suggested significant differential expressions of PD-1, PD-L1 and PD-L2 between the primary and metastasis, with a higher detection rate of the primary than metastasis. Meanwhile, the concordance rate of PD-L1 between the primary and metastasis was only 32.5% (27/83), with a significant statistically difference (χ2 = 4.664, p = 0.031) and poor consistency (Kappa = 0.229, p = 0.031). PD-1 and PD-L1 were highly expressed in the lung/lymph node and PD-L2 was highly expressed in visceral metastases. Survival analysis suggested that PD-1 positive either in the primary or metastasis was a poor prognostic factor for OS (HR: 1.59, 95% CI 1.08-2.36, P = 0.0195). The expression of PD-L1 in the primary was a poor prognostic factor for OS (HR 2.55, 95% CI 1.06-6.15, P = 0.0373). Although the predictive effect of PD-L1 expression on OS was not statistically significant in TKI treated patients, the OS time was shorter in PD-L1-positive patients than those negative (median OS 19.0 vs 41.0 months). In the whole cohort, the PA value of COX regression analysis was 0.683 for PFS, and the addition of PD-1 expression in the primary increased the PA value to 0.699. Conclusions: The assessment of immunological checkpoint-related protein in primary tumor may not be able to provide adequate information for clinicians to evaluate or predict the patient's treatment-related efficacy and prognosis. Biopsy or resection of the metastases may provide a more accurate biological information for clinician's decision-making and the patient's prognosis.
Long non-coding RNA Lucat1 is a poor prognostic factor and demonstrates malignant biological behavior in clear cell renal cell carcinoma
