HIF1A and cancer: In fact, the HIF-1α isoform is overexpressed inmany cancers, and its activation, along with oncogene activation andloss of tumor suppressor function, is associated with HIF-1 activation.A HIF-1 bacterial reverse two-hybrid system (RTHS) was developed andused to screen a plasmid-encoded SICLOPPS library of 6-mer cyclicpeptides to inhibit the dimerization of HIF-1.