HLA-B and pancreatic serous cystadenoma: However, DMRs in PsA probands vs. controls and PsC probands vs. controls were significantly enriched within the major histocompatibility complex on 6p21.3, a region which contains several loci associated with PsA and PsC, including HLA-B, HLA-C, MICA, HCP5, and TNFA [30].