The predictive potential of hyponatremia for glioblastoma patient survival.

Glioblastoma is a devastating malignancy with a dismal survival rate. Currently, there are limited prognostic markers of glioblastoma including IDH1, ATRX, MGMT, PTEN, EGFRvIII, and others. Although these biomarkers for tumor prognosis are available, a surgical biopsy must be performed for these analyses, which has morbidity involved. A non-invasive and readily available biomarker is sought after which provides clinicians prognostic information. Sodium is an electrolyte that is easily and quickly obtained through analysis of a patient's serum. Hyponatremia has been shown to have a predictive and negative prognostic indication in multiple cancer types, but the role of glioblastoma patients' serum sodium at the time of diagnosis in predicting glioblastoma patient survival has not been determined. We assessed whether hyponatremia at the time of glioblastoma diagnosis correlates to patient survival and show that in our cohort of 200 glioblastoma patients, sodium, at any level, did not significantly correlate to glioblastoma survival, unlike what is seen in multiple other cancer types. We further demonstrate that inducing hyponatremia in an orthotopic murine model of glioblastoma has no effects on tumor progression and survival.