Key functional binding sites for CREB, AP1, AP2α, and SP1 transcription factors were identified in SMO promoter elements through luciferase reporter and electrophoretic mobility shift assay (EMSA), suggesting an important role of these transcription factors in SMO transcriptional activity and subsequent GLI2 activation in PC3 prostate cancer and MCF7 breast cancer cell lines [76]. Here, GLI2 is linked to breast cancer.