Viala M, et al. - Given vitamin D (VD) enhanced chemotherapy-induced cell death in pre-clinical studies and vitamin D deficiency was associated with not attaining a pathologic complete response (pCR) following neoadjuvant chemotherapy (NAC) for operable breast cancer, researchers explored the influence of VD on pCR and survival in an expanded cohort in Iowa and Montpellier registries. A total of 327 women who had serum VD level measured before or during NAC were included. They found that vitamin D deficiency was associated with the inability to reach pCR in breast cancer patients undergoing NAC. Findings revealed no significant correlation between VD level and overall survival but a trend was seen in progression-free-survival in the hormone receptor positive (HR+)/human epidermal receptor 2 (HER)- subgroup and in overall survival in the triple negative breast cancer subgroup.