ANGPT1 and hereditary clear cell renal cell carcinoma: In stark contrast to multiple studies cited above, Zeng et al. did not detect convincing changes in either Ang-1 or Ang-2 expression in HCC tissue and observed an Ang-2/Ang-1 mRNA ratio that was multiple times lower compared to renal cell carcinoma (RCC), one of the most highly angiogenic human cancers.