PTGS2 and cancer: Compared to the more conventional Cyclooxygenase-2 inhibition strategy, our novel strategy of inhibiting delta-5-desaturase and taking advantage of the high Cyclooxygenase-2 expression in cancer cells will lead to better anti-cancer effects in two ways: stimulating an anti-cancer effect from dihomo-γ-linolenic acid while decreasing the pro-cancer effect from arachidonic acid.