Sézary syndrome (SS) is an incurable leukemic variant of cutaneous T-cell lymphoma and its pathogenesis is still unknown. Diagnosis/prognosis may strongly ameliorate the management of SS individuals. Here, we profiled the expression of 470 microRNAs (miRNAs) in a cohort of 22 SS patients, and we identified 45 miRNAs differentially expressed between SS and controls. Using predictive analysis, a list of 19 miRNAs, including miR-21, miR-214, miR-486, miR-18a, miR-342, miR-31 and let-7 members were also found. Moreover, we defined a signature of 14 miRNAs including again miR-21, potentially able to discriminate patients with unfavorable and favorable outcome. We validated our data for miR-21, miR-214 and miR-486 by qRT-PCR, including an additional set of array-independent SS cases. In addition, we also provide an in vitro evidence for a contribution of miR-214, miR-486 and miR-21 to apoptotic resistance of CTCL cell line.

Highlights d CD27 dull and CD27 bright MBCs share their VH repertoire but have different functions d CD27 dull MBCs are the long-lived substrate of selected and specific CD27 bright MBCs d The interplay between CD27 dull and CD27 bright MBCs preserves B cell memory d In pregnancy, MBCs decline, but persisting CD27 dull MBCs re-expand after delivery

In this study, we used single nucleotide polymorphism and comparative genomic hybridization array to study DNA copy number changes and loss of heterozygosity for 28 patients affected by Sézary syndrome (SS), a rare form of cutaneous Tcell lymphoma (CTCL). Our data identified, further confirming previous studies, recurrent losses of 17p13.2-p11.2 and 10p12.1-q26.3 occurring in 71% and 68% of cases, respectively; common gains were detected for 17p11.2-q25.3 (64%) and chromosome 8/8q (50%). Moreover, we identified novel genomic lesions recurring in >30% of tumors: loss of 9q13-q21.33 and gain of 10p15.3-10p12.2. Individual chromosomal aberrations did not show a significant correlation with prognosis; however, when more than three recurrent chromosomal alterations (gain or loss) were considered, a statistical association was observed using Kaplan-Meier survival analysis. Integrating mapping and transcriptional data, we were able to identify a total of 113 deregulated transcripts in aberrant chromosomal regions that included cancer-related genes such as members of the NF-κB pathway (BAG4, BTRC, NKIRAS2, PSMD3, and TRAF2) that might explain its constitutive activation in CTCL. Matching this list of genes with those discriminating patients with different survival times, we identify several common candidates that might exert critical roles in SS, such as BUB3 and PIP5K1B. Altogether, our study confirms and maps more precisely the regions of gain and loss and, combined to transcriptional profiles, suggests a novel set of genes of potential interest in SS. [Cancer Res 2009;69(21):8438-46]