There is at least one report showing that rottlerin was able to upregulate HO-1 through reactive oxygen species (ROS) dependent and PKC-δ-independent pathway in human colon cancer HT29 cells, as its induction was abrogated by antioxidant NAC but not by suppression of PKC-δ expression by small interfering RNA technology [33]. Here, HMOX1 is linked to malignant colon neoplasm.