 The Human Protein Atlas project has created a comprehensive map of human proteins and their corresponding RNA levels in various tissues. This map provides insight into the regulation of gene expression and the relationship between RNA and protein levels. It also reveals that many proteins cannot be detected despite being highly expressed, suggesting that there may be other factors involved in determining protein production. Additionally, the map shows that protein expression levels vary significantly between different tissues, while RNA levels tend to remain relatively constant. Finally, only a small number of amino acid variants were identified as being present in proteins, highlighting the difficulty of detecting protein variations using current techniques. This article was authored by Dong Xiu Wang, Basik Erislan, Thomas Wieland, and others.