PTGER4 and cancer: Accumulating evidence indicated that deregulation and inter-collaboration of SP1 and NF-κB/p65 expression was implicated in the several pathological responses, such as growth and progression of many cancer types, by affecting the expression of other target genes [43–47] The critical roles of these transcription factors in influencing the PGE2/EP4 signaling and relevant connections-mediated functions were reported in other studies [22, 28, 48, 49].