A highly sensitive and specific qPCR assay for quantification of the biomarker SOX11 in mantle cell lymphoma.

OBJECTIVES: Mantle cell lymphoma (MCL) is one of the most heterogeneous lymphoid neoplasms with a variable course of disease. Although t(11;14)(q13;q32) is the hallmark of MCL resulting in cyclin D1 (CCND1) overexpression in 90% of patients, this is difficult to validate by immunohistochemistry. We hypothesised that SOX11 could be a robust molecular biomarker for MCL.

METHODS: We have developed very sensitive and specific RT-qPCR assay employing a poly-A specific RT primer to circumvent contamination from gDNA caused by the intron-less nature of SOX11.

RESULTS: We found a significant difference between the expression levels of SOX11 in patients with MCL at diagnosis (n = 21) and in healthy donors (n = 18) (blood: P < 0.0001; marrow: P = 0.0001). SOX11 expression of very low levels close to the assay sensitivity was detected in only 2 of 18 healthy donors, while low levels of CCND1 expression was observed in all blood and 12 of 13 marrow samples within the defined detection limit of Cq = 40. In spiking experiments of the GRANTA-519 MCL cell line into mononuclear cells from normal donor, the sensitivity of the SOX11 assay was found to be 2 × 10(-4) , while the sensitivity of the CCND1 assay was estimated to 2 × 10(-3) because of the normal background expression. In longitudinal sampling from patients with MCL the minimal residual disease (MRD) values based on the SOX11 expression mirrored the clinical disease development.

CONCLUSION: This SOX11 RT-qPCR assay could be a useful tool for MRD monitoring in patients with MCL.