A reporter cell line is a cell line that has been engineered to express a reporter gene, which allows researchers to visualize and track protein expression. Reporter cell lines are used in many scientific studies, including: Drug discovery, Toxicity studies, In vivo imaging, Tumor evaluation, and Analyzing gene expression and regulation.

Reporter cell lines are created by inserting a reporter gene next to a gene promoter of interest within a vector and then transfecting the vector into a cell line. When the promoter is expressed, the reporter gene is also expressed. Common reporter genes include luciferase and fluorescent proteins like GFP and RFP.