Association of BTLA rs1982809 polymorphism with lung cancer risk in Tunisian population.

B and T lymphocyte attenuator (BTLA) is an immune-inhibitory receptor that negatively regulates the lymphocyte activation. A few studies have been devoted to the relationship between BTLA gene variations and cancer's risk. It has been essentially demonstrated to be involved in increasing cancer risk in chronic lymphocyte leukaemia, renal cell carcinoma, breast and colorectal cancer predispositions in Asian population. The aim of this study was to evaluate the association between BTLA gene polymorphisms and the risk of lung cancer in the Tunisian population. In a case-control study, three BTLA single-nucleotide polymorphism (SNP): rs1982809 (A > G), rs9288952 (G > A) and rs9288953(C > T) were genotyped with the use of TaqMan probes in 169 lung cancer patients and in 300 controls. The rs1982809 SNP was significantly associated with an increased risk of lung cancer compared with controls in codominant and dominant models. The heterozygous rs1982809-AG genotype carriers had a higher risk of developing lung cancer when compared to AA genotype carriers in Tunisian population (OR (95%CI) = 1.63 (1.09-2.42), p = .01]. The AG genotype is an important risk factor associated with lymphatic invasion (OR = 3.71) and large-sized lung tumour (OR = 1.80). It is also a risk factor for the development of an adenocarcinoma subtype (OR = 2.08). However, the BTLA rs9288953 and rs9288952 SNPs were not associated with susceptibility for lung cancer (p > .05). Haplotype comparison did not show any significant association in our research. For the survival analysis, there was no impact of BTLA SNPs on the mortality risk associated to lung cancer in Tunisian patients. The current study is the first to demonstrate an association between BTLA rs1982809 polymorphism and an increased lung cancer risk in the Tunisian population.