Expression of SOX18 in Mycosis Fungoides.

SOX18 is a transcription factor involved in the development of hair follicle, blood and lymphatic vessels, as well as regenerative processes. In addition, accumulated data indicate the role of SOX18 in tumourigenesis. So far, no studies on the role of SOX18 expression in mycosis fungoides (MF), the most common primary cutaneous T-cell lymphoma, have been performed. Therefore, we evaluated SOX18 expression in MF at the mRNA and protein level. SOX18 expression was observed predominantly on the blood and lymphatic vessels, in the intratumoural and peritumoural microenvironment of MF. The intra-tumoural, but not peritumoural, expression of SOX18 correlated positively with the advancement of the disease, cutaneous involvement and extracutaneous meta-stases at the protein level (p < 0.001, p < 0.001, p = 0.004; respectively). Significantly lower SOX18 mRNA expression was correlated with lymph node involvement (p = 0.01). In conclusion, we hypothesize that SOX18, as a marker of neovascularization, may be involved in the progression of MF.