Overexpression of Fc mu receptor (FCMR, TOSO) gene in chronic lymphocytic leukemia patients

Abstract

Rai and Binet staging systems that have been used as a standard method for evaluating the prognosis of chronic lymphocytic leukemia (CLL) have some restrictions in distinguishing the early stage CLL patients that will progress rapidly. To solve this shortcoming, prognostic parameters other than staging have become important in the recent years. Intracellular upregulation of Fc mu receptor (FCMR, FAIM3/TOSO) gene in the leukemic lymphocytes of the patients with CLL may be an important parameter in predicting the progression of the disease. In this study, FCMR mRNA expression levels were evaluated in 50 CLL patients and in 50 healthy controls. FCMR mRNA expression was found to be significantly higher in CLL patients than in healthy controls. We, then, evaluated FCMR mRNA levels according to the stages of CLL. Rai stage 0, I, II cases were compared with stage III and IV, and Binet A was compared with Binet B and C according to FCMR mRNA levels. In cases with higher risks, Rai stage III, IV and Binet stage B and C, FCMR mRNA levels were also significantly higher. In addition, overexpression of the FCMR seems to be promoting the chromosomal abnormalities. As a result, we found that the mRNA levels of FCMR in the CLL patients are 23-fold higher than that of the control group and this may suggest that it can be associated with the disease progression and survival. For this reason and because of the simplicity of analyzing with Q-PCR, it can be a useful clinical parameter, after its importance has been shown in larger and multi-variate studies.