S100A9 and pachyonychia congenita: In addition, the area under the curves of the receiver operating characteristic curves for serum levels of the 3 potential cachexigenic factors in differentiating between PC patients with and without cachexia were S100A8: 0.65 (95% CI: 0.56–0.75); S100A9: 0.68 (95% CI: 0.59–0.77), and S100A8/A9: 0.66 (95% CI: 0.57–0.75), respectively (Fig. 5d).