NOS2 and malignant colon neoplasm: Our group reported earlier that doxorubicin induces NF-κB activation and NO synthesis in human colon cancer HT29 cells, but fails to augment the levels of NO in the drug-resistant HT29-dx sub-clone, where the drug is pumped out of the cell before it can elicit any nuclear translocation of NF-kB and increase of iNOS expression [5,9].