To uncover the mechanism by which the preoperative serum CA125 level can distinguish the “surgical benefit” group of patients with pancreatic head cancer with LN16 metastasis, the expression of CA125 (mucin-16) and its related protein JAK2 was analyzed in primary pancreatic cancer tissues using immunohistochemistry assay. The gene discussed is JAK2; the disease is familial pancreatic carcinoma.