SMAD4 and malignant colon neoplasm: Agarwal et al. [34] reported that curcumin suppressed the cell proliferation ability and induced apoptosis by upregulating reactive oxygen species in a colon cancer cell line with mutations in SMAD4 and TP53; however, SMAD4 was not considered as a biomarker with the ability to predict the sensitivity of CRC cells to curcumin.