JUN and neoplasm: Trop2 has also been observed to regulate the activation of a number of important tumor-promoting growth factors, such as nuclear factor-κB, cyclic adenosine monophosphate response element-binding protein, Jun, retinoblastoma protein, signal transducer and activator of transcription 1 (STAT1) and STAT3, through the ERK/MAPK signaling pathway (14).