CCND1 and breast cancer: Strikingly, we also showed that MeJA‐treated Arabidopsis explants substantially reduced the levels of Cyclin D proteins in human breast cancer cell lines, in accordance with studies linking the downregulation of Cyclin D1 and Cyclin D3 levels to antitumour therapy in breast cancer patients (Ortiz et al., 2017; Wang et al., 2019), hereby providing mechanistic targets for MeJA‐induced plant bioactivities inhibiting breast cancer cells growth, and further ground for these cell cycle regulators as targets of anticancer compounds.