Abstract
The TP73 gene is located at the chromosome 1p36 locus that is commonly disrupted or deleted in follicular lymphoma (FL) with poor prognosis. Therefore, we analyzed the expression of the pro-apoptotic TAp73 and anti-apoptotic Delta Np73 isoforms in cases of FL with normal or abnormal 1p36. We observed a significant increase in Delta Np73 expression and Delta Np73:TAp73 ratio, lower expression of cleaved caspase-3 and a higher frequency of Ki-67 and proliferating cell nuclear antigen (PCNA) positive cells in cases of FL with abnormal 1p36. A negative correlation between the Delta Np73:TAp73 ratio and cleaved caspase-3 expression, and a positive correlation between Delta Np73 expression and Ki-67 or PCNA, were observed. The expression of TAp73 and its pro-apoptotic transcriptional targets BIM. PUMA and NOXA were significantly lower in FL compared to reactive follicular hyperplasia. Together, our data demonstrate that 1p36 disruption is associated with increased Delta Np73 expression, decreased apoptosis and increased proliferation in FL.