High XB130 expression in renal cell carcinoma is strongly associated with poor prognosis

The aim of this study was to assess the prognostic value of XB130 expression in three major RCC subtypes, and its association with clinical outcomes and adverse clinicopathologic features. A total of 101 nephrectomy samples at Srinagarind Hospital, Faculty of Medicine, Khon Kaen University, Thailand, from 2007 to 2017 were included in the study. XB130 immunohistochemistry was performed on slides from a tissue microarray comprised of 71 clear cell RCCs, 23 papillary RCCs, and 7 chromophobe RCCs, and were scored using a Histoscore system on a 0-300 scale. High XB130 expression in clear cell RCC and papillary RCC patients was associated with poor prognosis (log-rank test, P = 0.013, and P = 0.001, respectively). WHO/ISUP grade (P = 0.001) and XB130 high expression (P = 0.019) were found to be independent risk factors for mortality in clear cell RCC using multivariate analysis. The high expression of XB130 in clear cell RCC patients was also associated with high WHO/ISUP grade (P = 0.011), distant metastasis (P = 0.036), TNM stage (P = 0.007), sarcomatoid/rhabdoid differentiation (P = 0.061), and urinary collecting system invasion (P = 0.002). Similarly, high XB130 expression (P = 0.038) was associated with poor prognosis among papillary RCC patients as well as with lymphovascular invasion (P = 0.022), TNM stage (P = 0.030), and sarcomatoid/rhabdoid differentiation (P = 0.044). Overall, our findings showed that high XB130 expression in clear cell RCC and papillary RCC patients are associated with a worse prognosis.