Somatic mutations in renal cell carcinomas from Chinese patients revealed by targeted gene panel sequencing and their associations with prognosis and PD-L1 expression

Dear Editor, Renal cell carcinoma (RCC) is among the most common human cancers in the United States, with approximately 63,990 new patients and 14,400 deaths annually [1]. However, RCC is not among the top 10 malignancies in China in terms of incidence and mortality [2]. The clini-cal and molecular features of RCC differ among distinct pathological types, mainly clear cell renal cell carcinoma (ccRCC), papillary renal cell carcinoma (PRCC), and chromophobe renal cell carcinoma (ChRCC). The most common subtype of RCC is ccRCC worldwide. Accord-ing to The Cancer Genome Atlas (TCGA), the somatic mutation landscape of RCC has been revealed by whole- exome sequencing (WES) or whole-genome sequencing (WGS). In our previous WES study, we validated most of the significantly mutated genes reported by the TCGA and identified several novel somatically altered genes [3]. The TCGA study showed that only somatic mutations in BRCA1-associated protein 1 (BAP1) were associated with patients’ poor survival outcomes among all significantly mutated genes [4]. In our previous WES study, BAP1 was somatically mutated in 2 of 15 ccRCC samples [3]. Never-theless, all of these RCC patients lacked follow-up infor-mation. Hence, further analysis is needed to determine whether there are any somatically mutated genes associ-ated with the prognosis of Chinese patients with RCC. However, WES or WGS is time-consuming and costly. Furthermore, compared with targeted sequencing, WES was more likely to generate false positives and false nega-tives due to insufficient base coverage [5].