These include well-known tumor markers (e.g., CA19-9, CEA, and CA125), as well as proteins more recently described as potential novel biomarkers for the detection of PC (e.g., Beta-2 microglobulin (B2M), TIMP-1, CRP, Galectin-3, uPA, and VEGF-A) (Figure 4). Here, B2M is linked to pachyonychia congenita.