Several studies reported that SP1 and SP3 regulated the expression of ABC family member genes in different types of cancer cells, and that inhibition of SP1 activity with MTM downregulated the expression of ABC family genes and CSC-associated genes, inhibited proliferation and tumorigenicity, suppressed CSC-associated properties and caused chemosensitization to anti-cancer drugs [28, 29, 39–41]. Here, SP3 is linked to cancer.