The T3-rich fraction of palm oil is comprised of all T3 forms (α- [25%], γ- [29%], δ-T3 [14%] relative to the total vitamin E amount) and inhibits the proliferation of the estrogen receptor‐negative human breast cancer cell line MDA-MB-435 with an IC50 of 180 μg/ml (Nesaretnam et al., 1995). The gene discussed is ESR1; the disease is breast cancer.