HDAC1 and breast cancer: Subsequently, the FPU of 6 d was introduced to the peptoid‐based scaffold of VK‐1 yielding the HDAC1/2 selective inhibitor 10 c (hereafter referred to as LSH‐A54) whose antiproliferative properties were superior to the late‐stage clinical candidate entinostat (HDAC1‐3 selective) and FDA‐approved HDACi vorinostat (pan‐HDACi) in a WST‐8 assay against three different breast cancer entities.