p65-/-Ras cells show delayed tumor formation in SCID mice. However, after prolonged latency, tumor formation was observed from these mice. To understand the changes of NF-kB regulated genes before and after tumor formation, RNA from p65+/+Ras, p65+/+RasTumor, p65-/-Ras, p65-/-RasTumor cells were isolated and microarray were performed. Overall design: p65+/+Ras and p65-/-Ras cells were injected into SCID mice. Tumors were removed and put back into tissue culture. RNA was isolated from these cells and microarrays were performed.