Objective: To investigate the expression and its prognostic significance of TOSO in CD19(+) B cells from Chinese chronic lymphocytic leukemia (CLL) patients.
Methods: 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.
Results: 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.
Conclusion: The over-expressed TOSO in CLL cells is associated with a progressive disease. It may be an important prognostic factor for CLL.