Elevated CD36 expression correlates with increased visceral adipose tissue and predicts poor prognosis in ccRCC patients.

Abstract

571 Background: Growing evidence has proved obesity one of the confirmed important etiologic indicators for renal cell carcinoma (RCC). CD36 is underpinned to be involved in adipose absorption, but its role in clear cell renal cell carcinoma (ccRCC) remains unclear. This study aimed to investigate the mRNA expression of CD36 in anthropometric measures of adipose tissue and defining its value in predicting prognosis in ccRCC patients. Methods: Real-Time qPCR was detected from 367 paired ccRCC and adjacent normal tissues. Distributions of categorical clinical-pathological data together with levels of CD36 expression were compared with χ2-test. Subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) were measured by MRI. Pearson’s correlation coefficient was utilized to quantify relations between body mass index (BMI), VAT%, SAT and CD36 expression respectively. Cox regression analysis were developed to address the influence of independent factors on prognostic value. Gene Set Enrichment Analysis (GSEA) was performed to select related genes and pathways from TCGA database. Results: In the current study, we demonstrated that CD36 mRNA was highly expressed in ccRCC tissues, and was found significantly increased in patients with advanced TNM stage ( p= 0.003, p< 0.001, p< 0.001), and high VAT% ( p= 0.004). Pearson’s correlation coefficient indicated CD36 amplification positively correlated with BMI ( r= 0.117, p= 0.025), VAT% ( r= 0.465, p< 0.001), while negatively with SAT ( r= -0.296, p= 0.002). Furthermore, ccRCC patients with elevated CD36 expression held shorter PFS and OS, with HR of 4.873 (3.300-7.196, p< 0.001) and 4.610 (2.956-7.189, p< 0.001). In 104 cases whose MRI scans were available, VAT was significantly correlated with poor PFS and OS. Significant genes were obtained from GSEA, and CD36 was found involved in the most significant pathways including fatty acid metabolism, angiogenesis and TGF-β signaling pathways. Conclusions: In conclusion, our study first reveal that elevated CD36 mRNA expression is positively correlated to distribution of abdominal adipose, particularly VAT%, which, in addition, notably predicts poor prognosis in ccRCC patients.