HIF1A and cancer: New therapeutic strategies such as guanine-rich oligodeoxynucleotides (G-rich ODNs), chemical compounds and chemotherapeutic drugs that target HIF-1α and/or HIF-2α proteins and repress the expression of their target genes in various cancer cells have been shown to counteract primary cancer progression and metastases at distant sites, and reverse treatment resistance under normoxic and hypoxic conditions (Tables 1 and 2) [11, 39, 44, 54–66].