PRAD1 GENE OVER-EXPRESSION IN MANTLE-CELL LYMPHOMA BUT NOT IN OTHER LOW-GRADE B-CELL LYMPHOMAS, INCLUDING EXTRANODAL LYMPHOMA

Employing Northern blot analysis and the polymerase chain reaction, we investigated PRAD1 gene overexpression in the tumour tissues of 58 pa tients with B-cell lymphoma. These findings were then examined in rela tion to the patients' clinical and immunohistological characteristics. The over-expression of this gene was detected in 6/8 patients with ma ntle cell lymphoma (MCL) and in only 1/50 other lymphomas, indicating its close association with MCL. The patients with MCL had common clini cal findings of advanced disease with generalized lymphadenopathy on a dmission, and they had a CD5+CD10-IgD+ phenotype. The patients with ch ronic lymphocytic leukaemia (CLL) also showed findings indicating a di stinctive disease entity: a CD5+CD10-IgD+ phenotype and lack of PRAD1 over-expression. In contrast, most patients with diffuse low-grade lym phoma other than MCL and CLL, had localized extranodal disease, expres sed a CD5-CD10-IgD- phenotype, and lacked PRAD1 over-expression. These findings suggest that extranodal low-grade lymphomas differ from noda l MCL and are not part of the spectrum of CLL.