B2M and acute pancreatitis: In studies of caerulein-induced murine acute pancreatitis, ACTB [22–28], GAPDH [18, 19, 28–30], 18sRNA [21, 31, 32], beta-2 microglobulin (B2M) [4, 33], and hypoxanthine phosphoribosyltransferase 1 (HPRT1) [34] have been frequently used as reference genes for comparison of mRNA transcription in pancreatic tissue.