Diagnostic value of Wilms tumor 1 and CD44 in Langerhans cell sarcoma: case series of 4 patients.

Langerhans cell sarcoma (LCS) is a rare tumor with markedly malignant cytological features originating from Langerhans cells. LCS diagnosis is difficult and requires differentiation from other malignant tumors and Langerhans cell histiocytosis (LCH). Immunochemical antibodies, such as langerin, S-100 protein, and CD1a, have been used to diagnose LCS, but the results are crossed with LCH. To determine more significant biomarkers of LCS, we studied the expression and distribution pattern of Wilms tumor 1 (WT1) and cluster of differentiation 44 (CD44) in LCS. A broad panel of antibodies was used for immunohistochemical technology. Simultaneously, dual immunofluorescence staining examination and fluorescence in situ hybridization staining methods were used to study the location of WT1 and CD44 in LCS tumor cells. The results showed that tumor cells expressed WT1, CD44, and other special Langerhans cell markers (langerin, CD1a, and S-100 protein). LCS cells in all the cases showed normal cytogenetic findings without overexpression of WT1 and CD44. The expression of WT1 and CD44 was observed on langerin tumor cells by dual immunofluorescence staining examination in LCS. Our results suggest that WT1 and CD44 are potential biomarkers for LCS diagnosis. Clear understanding of their functional roles may further explain the pathogenesis of this highly malignant tumor and develop some novel immunotherapy strategies.