Indeed, knockdown of USP4 in the cancer cell lines D121, LLC, H1299, and HCC827 increased expression of the stemness genes Oct4, Sox2, Nanog, KLF4, ABCG2, and ALDH1 in different degree in different cell lines as measured by RT-qPCR (Figure 7A). The gene discussed is ABCG2; the disease is cancer.