FH and breast cancer: Though the loss of fumarate hydratase (FH) and subsequent accumulation of fumarate marks the genetic cancer syndrome Hereditary leiomyomatosis and renal cell cancer (HLRCC) [39, 40, 41], it was reported that dimethyl fumarate, a fumaric acid ester, could effectively abrogate NF‐κB‐dependent mammosphere formation of breast cancer cells and inhibit xenograft tumor growth [15].