As shown in this report, NSC109555 significantly antagonizes the GEM-induced CHK2 phosphorylation (T68) and autophosphorylation (S516), partly suppressed GEM-induced phosphorylation of Cdc25A (S79), the true known substrate of CHK2 [27] and enhances the GEM-induced antitumour effects in pancreatic cancer cells. The gene discussed is CHEK2; the disease is familial pancreatic carcinoma.