Further structural modification of N6 led La Motta and coworkers to identify MF7 (Figure 4), a fluoro derivative showing a micromolar IC50 (=22.8 ± 1.6 μM, Table 3) on recombinant human ALDH1A3 in enzymatic assays and antiproliferative activity in the breast cancer MDA-468 cell line in vitro [106]. Here, ALDH1A3 is linked to breast carcinoma.