Concordant over-expression of transcription factor Sp1 and vascular endothelial growth factor in extramammary Paget's disease

Background: Specificity protein 1 (Sp1) is a transcription factor and shown to be a sequence-specific DNA-binding protein that activate a broad and diverse spectrum of mammalian gene, such as vascular endothelial growth factor (VEGF) gene. But the expression of Sp1 and VEGF has not previously been investigated in extramammary Paget's disease (EMPD). Methods: To investigate the expression of Sp1 and VEGF proteins in EMPD and to assess their relationships and potential contribution to malignant transduction of EMPD, paraffin-embedded EMPD specimens (35 tissue samples from 33 patients with primary EMPD, including two samples of metastatic lymph nodes from two patients) were subjected to immunohistochemical staining for Sp1 and VEGF. Results: All of the 35 EMPD specimens, including all of six invasive EMPD and two metastatic lymph node specimens, showed strong nuclear positive staining for Sp1 and strong cytoplasmic positive staining for VEGF. The expression levels (% positive cells) of Sp1 and VEGF in EMPD were significantly higher than those of normal skin (NS). There was a significantly high correlation between expression levels of Sp1 and VEGF in EMPD. Conclusions: The present study reveals that the concordant over-expression of Sp1 and VEGF may play a pivotal role in the tumorigenesis and further malignant transduction of EMPD.