The prognostic significance of indoleamine-2,3-dioxygenase and the receptors for transforming growth factor β and interferon γ in metastatic lymph nodes in malignant melanoma

We analyzed the prognostic significance of indoleamine-2,3-dioxygenase (IDO) and type 1 receptors for transforming growth factor beta (TGF-βR1) and interferon gamma (IFN-γR1) in resected nodal metastases of 48 malignant melanoma patients. In 32 cases the corresponding skin tumors were available. We used immunohistochemical (IHC) staining which was assessed by pathologists and by a computer-aided algorithm that yielded quantitative results, both absolute and relative. We correlated the results with the patient outcome. We identified absolute computer-assessed IDO levels as positively correlated with increased risk of death in a multivariate model (HR = 1.02; 95% CI: 1.002-1.04; p = 0.03). In univariate analysis, patients with IDO levels below the median had a better overall survival time (30.3 vs. 17.5 months; p = 0.03). TGF-βR1 and IFN-γR1 expression was modestly correlated (R = 0.34; p lt; 0.05) and TGF-βR1 expression was lower in lymph nodes than in matched primary skin tumors (Z = 2.87; p = 0.004). The pathologists' and computer-aided IHC assessment demonstrated high correlation levels (R = 0.61, R = 0.74 and R = 0.88 for IDO, TGF-βR1 and IFN-γR1, respectively). Indoleamine-2,3-dioxygenase is prognostic for the patient outcome in melanoma with nodal involvement and should be investigated prospectively for its predictive significance. IHC assessment by computer-aided methods is recommended as its gives IHC more objectivity and reproducibility. ecting mismatch repair deficiency. Association of CDX2 and PMS2 in the present study is necessary to conduct further genetic and pathological studies focusing on these two markers together.