NF-κB1 -94del/del ATTG polymorphic variant maintains CLL at an early, mildest stage.

Abstract

NF-κB is an essential player in cancer biology, especially in tumor development, due to its constitutive activation, and because a four-base deletion (ATTG) in the NF-κB1 promoter region at site -94, alters mRNA stability and regulates translation efficiency. This polymorphism is a good candidate risk marker and modulator of clinical course in chronic lymphocytic leukemia (CLL). As the effect of this NF-κB1 gene polymorphism has not been studied in patients with CLL so far, the present study was undertaken to find out whether the NF-κB1 promoter -94 ins/del ATTG polymorphism might be an essential genetic risk factor and/or modulatory disease player associated with CLL. The NF-κB1 -94 ins/del ATTG (rs28362491) polymorphism was investigated as a potential CLL susceptibility and progression factor, along with demonstration of potential modulation of the stage of clinical disease based on Rai classification. The associations of NF-κB1 -94 ins/del ATTG polymorphism with CLL and its clinical manifestation in 282 Polish individuals, including 156 CLL patients, were analyzed using polymerase chain reaction (PCR) with primers including a labeled forward primer, followed by capillary electrophoresis. A higher occurrence of the del/del homozygosity was observed among patients when compared to controls, resulting in an increase in CLL risk of more than twofold in patients carrying this homozygous genotype (OR = 2.23, p = 0.02, 95% CI = 1.14-4.37). Moreover, the del/del-positive patients more frequently presented the less aggressive disease phenotype (Rai 0), suggesting a low probability of progression to more advanced disease. The NF-κB1 -94 del/del genetic variant, although associated with increased risk of CLL disease, may be associated with maintenance of disease severity in the early, mildest stage. The likelihood of disease progression may increase as the frequency of wild-type (insertion) alleles for this polymorphism increases.