Myeloid CD11c⁺ S100⁺ dendritic cells express indoleamine 2,3-dioxygenase at the inflammatory border to invasive lower lip squamous cell carcinoma

Melanie Alice Kuales, Jörg Wenzel, Monika-Hildegard Schmid-Wendtner, Thomas Bieber and Dagmar von Bubnoff

Department of Dermatology, Friedrich-Wilhelms-University, Bonn, Germany.

Offprint requests to: Dagmar von Bubnoff, Department of Dermatology, Friedrich-Wilhelms-University, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany. e-mail: d.bubnoff@uni-bonn.de


Summary. The prevalence of squamous cell carcinoma of the lower lip (SCC-LL) is increasing worlwide. The expression of the enzyme indoleamine 2,3-dioxygenase (IDO) by antigen-presenting cells and/or tumor cells leads to tumor escape by inhibiting T cell-mediated rejection responses. The aim of this study was to determine the expression of IDO in SCC-LL. IDO-expression was analyzed in 47 SCC-LL, together with the expression of markers of T-cells (CD3), myeloid DCs (S100, CD11c), macrophages (CD68, CD11c), Langerhans cells (CD1a, Langerin (CD207)), plasmacytoid DCs (CD123), and regulatory T cells (Foxp3) by immunohistochemistry and immunofluorescence analysis. Twelve specimens out of 47 LL-SCCs contained cells that expressed IDO. IDO-positivity was strongly associated with the intensity of the cancer-associated infiltrate (P=0.0007). IDO-positive cells are located right along the border between the developing tumor and the inflammatory infiltrate. Immunofluorescence stainings showed that CD11c⁺S100⁺CD68^- dendritic cells (DCs) express IDO in SCC-LL. IDO expression in LL-SCC may aid immune escape and chronic inflammation to promote cancer progression. Inhibition of IDO might be a therapeutic strategy to increase the anti-tumor immune response in SCC-LL. Histol Histopathol 26, 997-1006 (2011)

Key words: Indoleamine 2,3-dioxigenase, Squamous cell carcinoma, Cancer immunology

DOI: 10.14670/HH-26.997