The prostanoid IP receptor antagonist RO1138452 (1 μM) shifted the CRC for anandamide to the right by a factor of 16 and reduced the maximal effect of anandamide at 100 μM by about 60 % (Fig. 4b; for pEC25 and Rmax values, see Table 1). The gene discussed is PTGIR; the disease is colorectal carcinoma.