The STAT3 Luciferase Reporter THP-1 cell line is designed for monitoring the STAT3 signal transduction pathway. It contains a firefly luciferase gene driven by STAT3 response elements located upstream of the minimal TATA promoter. After activation by cytokines or growth factors, endogenous STAT3 binds to the DNA response elements, inducing transcription of the luciferase reporter gene.