HIF1A and cancer: Caulerpin’s IC50 values were recorded 20 μM against certain cancer cell lines (T47-D, MCF-7, MDA-MB-231, PC3 DU145, HMEC, HCT116, HT29, LOVO and SW480) but its mechanism of action disclosed that caulerpin obstructs hypoxia-inducible factor 1 (HIF-1) at 10 μM concentration and blocks the induction of HIF-1α protein, an essential oxygen-regulated subunit, under hypoxic circumstances.