We performed hematoxylin staining in both healthy adjacent tissue and RCC subtypes of clear cell RCC (ccRCC), papillary RCC (pRCC) as well as chromophobe RCC (chRCC) that were included in our patient cohort (Figure S1A), and analyzed the CAIX mRNA expression, which was shown to be upregulated in more than 90% of RCC cases [32] (Figure S1B). Here, CA9 is linked to renal cell carcinoma.