Obermannova R, et al. - Via this analysis, researchers examined patients with previously untreated advanced gastric cancer treated in the randomised controlled phase III Erbitux (cetuximab) in combination with Xeloda (capecitabine) and cisplatin in advanced esophago-gastric cancer (EXPAND) trial (NCT00678535) for their pretherapeutic circulating 25-OHD plasma levels. In addition, they investigated the association of low 25-OHD plasma levels with worse prognosis and if these levels compromise the clinical efficacy of cetuximab. Among 630 patients with available pretherapeutic 25-OHD plasma levels, the majority displayed severe deficiency of vitamin D. In the patient cohort, 25-OHD plasma levels were identified to have no prognostic value. In addition, 25-OHD plasma levels had no predictive impact on the efficacy of anti-EGFR targeted antibody treatment.