Expression and prognostic significance of TOSO in CD19+ B cells from Chinese CLL patients

Abstract

To investigate the expression and its prognostic significance of TOSO in CD19(+) B cells from Chinese chronic lymphocytic leukemia (CLL) patients. The expression of TOSO was detected by absolute quantitative reverse transcription-polymerase chain reaction (RT-PCR) in a cohort of 85 untreated CLL patients from March 2006 to September 2010. Their status of immunoglobulin heavy chain variable (IGVH) somatic mutation, ZAP70 and CD38 were analyzed. The expression of TOSO was significantly elevated in CLL patients versus the healthy population (8.30 ± 2.99 vs 6.63 ± 1.22, P = 0.036) and other B cell lymphoproliferative diseases (8.30 ± 2.99 vs 7.12 ± 1.13, P = 0.023). The expression of TOSO was elevated in the IGVH non-mutated group versus the mutated group (9.87 ± 1.08 vs 7.61 ± 3.03, P = 0.000). The expression of TOSO was significantly elevated in Binet stage C patients versus in Binet stage B and Binet stage A patients (9.91 ± 3.03 vs 8.73 ± 1.86 vs 7.27 ± 2.83, P = 0.000). The expression of TOSO rose to (9.37 ± 2.12) in the chemotherapy group. And it was significantly higher than that in the observation group (7.19 ± 3.23, P = 0.001). At the cut-off point of 55 years old, the younger patients had a higher expression of TOSO than the elders (9.10 ± 2.06 vs 7.95 ± 3.22, P = 0.049). The expression of TOSO in ZAP70 and CD38-positive groups had no difference with those in the negative groups. The over-expressed TOSO in CLL cells is associated with a progressive disease. It may be an important prognostic factor for CLL.