ZIC5 and cancer: Furthermore, ZIC5 overexpression has been found to promote cell proliferation and invasion in multiple cancer cell types.30,31 GFP is a protein derived from jellyfish that can naturally emit green fluorescence and is widely used for monitoring gene expression and evaluating cell viability.21 Studies have shown that when GFP is transfected into cells, its fluorescence intensity is closely correlated with cellular metabolic activity (e.g., ATP levels) and the activity of gene expression.21 In this study, ZIC5 expression in the A549 and H1299 cell lines was silenced using siRNA technology.