In contrast, knockdown of SLC7A11 significantly enhanced the effect of VD on the size and number of tumour spheroids, Cys and GSH levels, ROS levels, and the levels of ferroptosis markers, such as SLC7A11 and COX2 (Figures 6(a), 6(b), and 6(d)–6(i), Additional file 4). This evidence concerns the gene SLC7A11 and neoplasm.