MYCN and neoplasm: Immunohistochemistry, (Figure 7C) clearly indicated that the combination of vismodegib and topotecan significantly decreased the expression of Smo, MYCN and Ki-67, and increased the levels of cleaved (activated) caspase 3, suggesting vismodegib combined with topotecan not only enhanced the reduction in tumor growth and increased survival, but also targeted the associated pathways and downstream molecules in xenograft tumors.