HOXD13 and neoplasm: While sPD-1 showed no significant correlation with CA19-9 (r = 0.111, p = 0.056) or CEA (r = 0.085, p = 0.140), sPD-L1 was significantly correlated with both tumor markers; CA19-9 (r = 0.350, p < 0.001) and CEA (r = 0.331, p < 0.001).