EGFR and lung cancer: We surmised based on our in vitro observations that EGFR mutant lung cancers are vulnerable to the anti-cancer actions of vitamin D. A corollary to our hypothesis, which is supported by recent epidemiological studies, is that low 25D3 levels increase risk of developing or dying from EGFR mutant lung cancer: lower 25D3 levels are associated with a 2.4-fold increased risk of developing EGFR mutant adenocarcinoma of the lung [6].