The RT-qPCR and/or IHC analysis of tumor tissues revealed that ASO-circFOXK2 treatment restored the responses of CCND1 expression, RB phosphorylation, the expression of circFOXK2-regulated E2F target genes, and Ki67 expression to tamoxifen treatment (Fig. 6 H–J). The gene discussed is CCND1; the disease is neoplasm.