NPC1 and nasopharyngeal carcinoma: Macrophage migration inhibitory factor (MIF) NPC1 CSF levels (Fig. 2d) were elevated (188 ± 66 ng/ml) ~ 2.4-fold above non-NPC levels (80 ± 49 ng/ml, p < 0.0001) with a dynamic range of ~ 3.7-fold (65–310 ng/ml).