PLP1 and neoplasm: The myelin-specific proteolipid protein (PLP1) and glioma-specific mutated proteins EGFRvIII and IDH1R132H, have not been found in serum but are other highly tissue- or tumour-specific proteins (Moscatello et al., 1995; Klugmann et al., 1997; Yan et al., 2009; Uhlen et al., 2015).