SP1 and cancer: In AA TNBC, this core set of AA-specific hypoxia response TFs includes six members of the large multigene family of Sp/Kruppel-like factor (KLF) TFs, all of which have been linked to altered cancer cell metabolism; further, three members of the Sp subfamily (SP1, SP2, SP3) have been shown to regulate hypoxia through direct interaction with HIF1a (50).