-4D3 decreased HIF-1α expression in PDAC cells -4D3 increased intracellular concentration of 5-FU-Simultaneous treatment of 4D3 increased the antitumoral effect of the FFX regimen, i.e., oxaliplatin (L-OHP), irinotecan (CPT-11), and 5-FU-4D3 and FFX suppressed tumor growth in vivo and prolonged mice survival-A half dose of FFX is a significantly safer approach than a full dose of FFX with a similar anti-cancer effect. The gene discussed is HIF1A; the disease is neoplasm.