ESR2 and colon adenocarcinoma: This study demonstrates, for the first time, that natural δ-Toc and semisynthetic δ-tocopheryl sulfide (δ-Toc)2S and disulfide (δ-Toc)2S2, similar to 17β-E2, are able to reduce proliferation and increase the ERβ expression in human colon adenocarcinoma HCT8 cells engineered to overexpress ERβ but not in HCT8-pSV2neo.