Sp1 upregulates multiple genes critical to tumor metabolism and pH regulation, with six genes related to malignancy with a crucial role in the pH-tome, including HIF-1α (hypoxia-inducible factor 1 alpha), CAIX (carbonic anhydrase 9), NHE1 (sodium/hydrogen exchanger 1), NaV1.5 (an isoform of voltage-gated sodium channel), and V-ATPase protein which act as proton pumps. Here, CA9 is linked to neoplasm.