MMP9 and Patent ductus arteriosus: One study for example claimed that dexamethasone inhibited the invasiveness of a human pancreatic cancer cell line that was examined by in vitro invasion assay and expression of MMP-9.38 Another study found a dexamethasone-induced inhibition of in vitro invasion of the PDA cell line Panc-TuI and, after orthotopic transplantation to immunodeficient mice, reduced tumor growth and metastasis.39 We do not know the reason for these obvious discrepancies to our results, but suspect that it might be because of differences in cell lines, experimental conditions and data evaluation.