Evaluation of the genetic diversity of KIR genes in patients with endometrial cancer

Endometrial cancer (EC) constitutes more than half of all genital cancers in women, with an increasing incidence in different countries. Natural killer cells (NK cells) are kinds of innate immune cells that are controlled by sets of receptors, such as killer cell Ig-like receptors (KIRs), which can inhibit or activate NK cells. In this study, we evaluated the diversity and genetic association of KIRs in confirmed cases of endometrial cancer compared to healthy controls. A total of 151 women with EC and 167 age/race-matched healthy controls were analyzed for KIR genes. Demographic and histopathologic data were gathered in questionnaires, and 16 KIR genes along with two variants of KIR2DS4 (KIR2DS4fl and KIR2DS4del), were genotyped by usingsequence specific primers-polymerase chain reaction (SSP-PCR) method. A comparison between cases and controls revealed that although there were not any significant differences in A haplotype associated genes and also the variants of KIR2DS4 (p >0.05), B haplotype associated genes such as KIR2DS2 and KIR2DL2 decreased significantly in EC patients in comparison with healthy controls (p=0.03 and p=0.01, respectively). Furthermore, we found that EC mostly developed in cases with the AA genotype; however, the carriers of Bx and C4T4 genotypes were less frequent in patients with EC. Our results revealed that KIR2DS2 and KIR2DL2, along with Bx and C4T4 genotypes, have a protective impact against developing endometrial cancer in Iranians.

KIR-HLA gene diversities and susceptibility to lung cancer

Killer-cell immunoglobulin-like receptors (KIR) are essential for acquiring natural killer (NK) cell effector function, which is modulated by a balance between the net input of signals derived from inhibitory and activating receptors through engagement by human leukocyte antigen (HLA) class I ligands. KIR and HLA loci are polygenic and polymorphic and exhibit substantial variation between individuals and populations. We attempted to investigate the contribution of KIR complex and HLA class I ligands to the genetic predisposition to lung cancer in the native population of southern Iran. We genotyped 16 KIR genes for a total of 232 patients with lung cancer and 448 healthy controls (HC), among which 85 patients and 178 HCs were taken into account for evaluating combined KIR-HLA associations. KIR2DL2 and 2DS2 were increased significantly in patients than in controls, individually (OR 1.63, and OR 1.42, respectively) and in combination with HLA-C1 ligands (OR 1.99, and OR 1.93, respectively). KIR3DS1 (OR 0.67) and 2DS1 (OR 0.69) were more likely presented in controls in the absence of their relative ligands. The incidence of CxTx subset was increased in lung cancer patients (OR 1.83), and disease risk strikingly increased by more than fivefold among genotype ID19 carriers (a CxTx genotype that carries 2DL2 in the absence of 2DS2, OR 5.92). We found that genotypes with iKIRs > aKIRs (OR 1.67) were more frequently presented in lung cancer patients. Additionally, patients with lung cancer were more likely to carry the combination of CxTx/2DS2 compared to controls (OR 2.04), and iKIRs > aKIRs genotypes in the presence of 2DL2 (OR 2.05) increased the likelihood of lung cancer development. Here we report new susceptibility factors and the contribution of KIR and HLA-I encoding genes to lung cancer risk, highlighting an array of genetic effects and disease setting which regulates NK cell responsiveness. Our results suggest that inherited KIR genes and HLA-I ligands specifying the educational state of NK cells can modify lung cancer risk.