Expression of the drug targets PLK1, RRM1, and RRM2 in MPNST cell lines and prognostic relevance in patients with MPNST. Normalized RPPA protein expression of PLK1 in MPNST cell lines (median = 0 across 271 cancer‐relevant proteins) indicates an increased expression of PLK1 in seven MPNST cell lines as compared to the mean of duplicate runs of normal Schwann cell HSC1 (A). Regions of genomic gain (red) are not observed in the region on chromosome 16 harboring PLK1 (16p12.2) in the tested MPNST cell lines, while regions of loss (blue) are observed in the two cell lines S1507‐2 and ST8814 (B). Gene expression of PLK1 is significantly higher in MPNST tumor samples as compared to benign neurofibromas (C, left panel), and high expression in MPNST is associated with high tumor grade and large tumor size (C, right panel). MPNST patients with high expression of PLK1 in the tumor had worse outcome than patients with low expression, although not significantly at a 5% level (the P‐value and hazard ratio (HR) for PLK1 expression as a continuous variable in univariate Cox regression analysis for five‐year disease‐specific survival are shown) (D). The gene expression of gemcitabine target RRM1 and its activator RRM2 is significantly higher in MPNST tumor samples as compared to benign neurofibromas (E, left panel), and high expression of RRM2 in MPNST is associated with high tumor grade and large tumor size (E, right panel). MPNST patients with high expression of RRM2 in the tumor had significantly worse outcome than patients with low expression (P‐value and hazard ratio (HR) for gene expression as a continuous variable in univariate Cox regression analysis for 5‐year disease‐specific survival are shown) (F).