Expression of the p38 MAPK, NF-κB and cyclin D1 in extramammary Paget's disease

Background: The p38 mitogen-activated protein kinase (MAPK)/nuclear factor κB (NF-κB)/cyclin D1 signaling pathway has recently been shown to play an important part in the pathogenesis of many human tumors. However, the role of this signal transduction pathway in extramammary Paget's disease (EMPD) remains unknown. Objective: This study was designed to investigate the expression of phosphorylated p38 MAP kinaseα (p-p38 MAPKα), phosphorylated NF-κ B p65 (p-NF-κB p65) and cyclin D1 proteins in EMPD and to evaluate the relationship among them. Methods: Thirty-five tissue samples from 30 primary EMPD cases were analyzed by immunohistochemical staining in formalin-fixed, paraffin-embedded tissue sections for p-p38 MAPKα, p-NF-κB p65 and cyclin D1. Results: Among the 35 specimens of EMPD, p-p38 MAPKα, p-NF-κB p65 and cyclin D1 were expressed in 30, 28 and 27, respectively. Moreover, in five metastatic lymph node specimens, all were positive for p-p38 MAPKα and p-NF-κB p65, four were positive for cyclin D1. There were significant correlations between expression of p-p38 MAPKα, p-NF-κB p65, and cyclin D1 in EMPD. Conclusion: This study provides evidence that p-p38 MAPKα, p-NF-κB p65, and cyclin D1 was overexpressed in EMPD, suggesting that the p38 MAPK/NF-κB/cyclin D1 signaling pathway might participate in the oncogenesis of EMPD.