ADRB2 and colorectal carcinoma: In addition to the direct activation of catecholamines, recent studies have reported that high-fat diet feeding and palmitic acid can increase the expression of β2AR via Sp1 in tumor tissues of CRC mice, and activation of cAMP/PKA increased the phosphorylation of hormone-sensitive lipase (HSL), a lipase that activates FFA, which is used as a fuel to provide energy for cancer growth, at S552 [179, 180].