RTN4 and brain neoplasm: We showed that: (1) with an increase in CSF Nogo-A by 100 pg/mL, the chances of brain tumour presence decrease by 15.03%; (2) with an increase in K + concentration by 1 mg/dL, the chances of brain tumour presence increase by more than 17-fold; (3) with an increase in urea concentrations by 1 mg/dL, the chances of brain tumour presence increase by 23.00%; (4) with an increase in creatinine concentration by 0.01 mg/dL, the chances of developing a brain tumour decrease by 6.76% (Table 2).