The present invention provides a method of treating cancer with a proteasome inhibitor. The invention also provides a method of treating a patient with cancer based on elevated expression levels of NF&kgr;B, as measured by a H-score of the patients tumor sample using a NF&kgr;B p65 IHC assay. The invention also provides a method of determining whether to treat a patient with a proteasome inhibitor based on the level of NF&kgr;B p65 in the patient's tumor sample.