CXCL12 and amyotrophic lateral sclerosis: To establish the best candidate for ALS biomarker, we compared the AUC values of candidates; the results showed that the most likely was CXCL12 the AUC value of which showed significant differences or tendencies when compared with AAAS (p = 0.08), S100A6 (p = 0.002), PAAF1 (p = 0.08) and STX12 (p = 0.08) AUC values (Figure 2F).