From the ROC curve, the area under the ROC curve is 0.715 (Fig. S7m, P = 0.01), and a sensitivity of 60% and specificity of 85.71% at a cut-off probability of 21.88 pg/mL, suggesting the serum VEGFA has a potential to be a biomarker for the diagnosis of OPLL. The gene discussed is VEGFA; the disease is ossification of the posterior longitudinal ligament of the spine.