PTGS2 and breast cancer: Other researchers have found similar phenomena that FADS1 knockdown did not affect cell proliferation in CRC and breast cancer cells in general culture, however, with the addition of dihomo-γ-linolenic acid (DGLA, the precursor of AA), FADS1 knockdown only showed an inhibited cell proliferation only in tumor cells with a high-expression cyclooxygenase-2 (PTGS2, COX2)42,43.