To more closely delineate the effect of PKA in the COX-2 - PGE2 pathway active in colorectal cancer, we treated ApcMin/+ mice with the PKA antagonist Rp-8-Br-cAMPS for 6 weeks using earlier established doses (see Additional file 1, Supplementary information) and compared the result with that of treatment with the COX inhibitor indomethacin, previously shown to inhibit tumor development in the ApcMin/+model [20]. This evidence concerns the gene PTGS2 and colorectal cancer.