Comparative transcriptional and functional profiling of clear cell and papillary renal cell carcinoma

Renal cell carcinoma (RCC) is known to effectively prevent immune recognition. However, little is known about the mechanisms that underlie this phenomenon. Thus, the identification of immunogenic molecules associated with RCC and the elucidation of the corresponding signaling pathways are crucial to the development of effective treatments. We performed transcriptional and functional profiling with cDNA microarrays (1070 cDNA probes) on a total of 17 RCCs, 11 clear cell and 6 papillary, and on corresponding normal tissue. Samples were clustered based on their expression profiles. We found a total of 45 genes to be regulated equally by both tumor types compared to the normal tissue. A set of 13 differentially expressed genes was identified between the examined tumor subtypes. Functional analysis was performed for both gene sets and showed a significant enrichment of cell surface genes regulated in both tumor subtypes. Within these we found five surface marker genes to be upregulated (TNFRSF10B, CD70, TNFR1, PDGFRB, and BAFF) which are involved in immune responses via the regulation of lymphocytes and can also induce apoptosis. Their overexpression in both tumor subtypes suggests a possible involvement in the immune escape strategies of RCC. The combination of transcriptional and functional profiling revealed potential target molecules for novel therapy strategies that must be studied in more detail.