Next we compared the expression of genes encoding known growth factors, receptors, cytokines, proteins involved in the immune response, and signaling pathways, including angiogenesis and mTOR in AF-set A compared with AF-set B. The genes that were up-regulated 3-fold or more in AF-set B compared to AF-set A are listed in additional file 2. This evidence concerns the gene MTOR and atrial fibrillation.