EGFR and glioblastoma: By dichotomizing the abundance variables, we found an association between high pre-diagnostic EGFR concentration and risk of glioblastoma (P = 0.008; OR = 1.58, 95 % CI = 1.13–2.22), as well as associations between high pre-diagnostic ErbB2 concentration and overall risk for glioma (P = 0.049; OR = 1.39, 95 % CI = 1.00–1.93) and glioblastoma (P = 0.017, OR = 1.63, 95 % CI = 1.09–2.44).