Our resultsprovide evidence that synergism between 17-AAG and MS-275 might be mediated bythe prosurvival NF-κB pathway.Evidence from microarray expression profiling has demonstrated that the NF-κB activator RIPK4 is highly upregulated in synovial sarcoma, and the datapresented here shows that the RelA subunit of NF-κB is found in the nucleus of untreated synovialsarcoma cells, suggesting baseline activation of NF-κB in this malignancy. Here, RIPK4 is linked to synovial sarcoma.