Detection of cyclin D1 overexpression by real-time reverse-transcriptase-mediated quantitative polymerase chain reaction for the diagnosis of mantle cell lymphoma

The diagnosis of mantle cell lymphoma (MCL) is particularly important for c linical management because of a remarkable prognostic difference between MC L and other types of B-cell lymphoma. In addition to immunohistochemical an alysis, we have established a 5' exonuclease-based real-time reverse transc riptase-mediated quantitative polymerase chain reaction (RQ-PCR) method to detect cyclin DI overexpression for the diagnosis of MCL. The RQ-PCR could detect cyclin DI overexpression in all nine examined MCL cases, in contrast genomic PCR detected t(11;14) in only two of nine cases. By RQ-PCR the exp ression of G6PDH was significantly higher in myeloid leukemias than those i n B-cell lymphomas (P = 0.018). As a result, cyclin D1/G6PDH ratio ranged f rom 0.78 to 12.4 (mean, 1.83) in MCL, exclusively higher than those in othe r B-cell lymphoma. (0.00009 similar to 0.16) and myeloid leukemia (0.00011 similar to 0.085). The high expression of cyclin DI in certain myeloid leuk emias was identified to reflect their proliferative activity and not to rep resent the oncogenic overexpression. The 95% confidence interval of the cyc lin D1/G6PDH ratio was 0.29 similar to 11.1 for MCL, 0.014 similar to 0.25 for other B-cell lymphomas and 0.000014 similar to 0.083 for myeloid leukem ia, suggesting that a cutoff value can be set at 0.25. The RQ-PCR of cyclin D1 is convenient and especially useful for the diagnosis of MCL.