Diagnostic and Prognostic roles of YY1

Several investigators have observed YY1 deregulation in numerous tumor types. YY1 overexpression and its role in cancer were largely discussed during all of the workshop sessions. The results reported underlined the diagnostic and prognostic significance of YY1 in solid and hematologic malignancies. In particular, the reported inversion in the ratio between YY1 and Raf-1 kinase inhibitor protein (RKIP) expression in hepatocellular carcinoma, compared with the adjacent nontumoral tissues suggests a direct/indirect regulatory role of YY1 in hepatocyte transformation.1 RKIP was reported to antagonize the oncogenic activities of different kinases in the MAPK and NF-?B activation pathways. Furthermore, Seligson et al. reported that YY1 protein levels are higher in prostate metastatic tissues than primary tumors; intriguingly, low YY1 levels correlated with a poorer outcome, suggesting that decreased YY1 expression may enhance the survival of metastatic prostate cancer cells.2 Finally, Byers et al. showed that YY1, at mRNA levels, is overexpressed in follicular lymphomas and in diffuse large B-cell lymphoma.3 Moreover, the authors demonstrated that this overexpression is linked with a shorter survival. These data are in agreement with the findings reported, whereby the significance of YY1 deregulation in NHL was reported.4 In the reported in silico analysis, the YY1 association with prognosis was evaluated only in high-grade lymphomas and overexpression was statistically and significantly associated with poorer outcome. Confirmation data at the protein level are needed to better clarify the important findings mentioned above. © 2010 by Begell House, Inc.