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Background: NK cells as a part of innate immune system, are controlled by a set of activating and inhibitory KIR receptors (aKIR, iKIR) which are implicated in tumor microenvironment immunity through a variety of activating and inhibitory immune signals. KIRs are multi gene family receptors that differ in the number and type of genes among individuals. In the current research we determined the KIRs genes and genotypes impact on predisposition to meningioma development in Iranians., Methods: Sequence-specific primers-polymerase chain reaction (SSP-PCR) was performed for genotyping of 16 KIRs in 159 meningioma cases and 362 age and sex matched healthy controls (CNs) at Shiraz Institute for Cancer Research., Results: Comparison of the KIR genotypes frequencies between cases and controls disclosed a highly significant increase in Bx genotype, CxTx subset and Cen AB and Tel AB in meningioma cases and a decrease in AA genotype, C4Tx subset and Cen AA, Tel AA, Tel BB in healthy controls. Among all 16 KIR genes, the carriers of KIR2DL5 and KIR2DS5 constituted a much greater proportion in meningioma than control group. Comparison of carrier frequencies of KIR2DS4 variants between case and controls revealed a higher frequency of KIR2DS4 full length (KIR2DS4fl) in meningioma cases and a lower frequency of KIR2DS4 deleted variant (KIR2DS4del) in controls. Furthermore, the simultaneous presence of 2DS5, 2DS4fl, CenAB, TelAB and absence of 2DS4del, CenAA, TelAA, TelBB, magnify the risk of developing meningioma substantially (OR ≈ 23). Altogether, 41 distinct KIR genotypes were characterized in 521 subjects. Among them, some individuals were characterized by seven peculiar genotypes that the linkage disequilibrium between KIR2DS2-KIR2DL2 and KIR2DL5-KIR2DS3-KIR2DS5 has not been detected. The carriers of certain genotypes with presence of as KIR2DL5 and absence of KIR2DS3, KIR2DS5 constituted a much higher proportion in meningioma than control group which increase the risk of meningioma up to 72 times., Conclusion: This case- control study suggests carriers of Bx genotype, KIR2DL5, KIR2DS5, 2DS4fl, ≥ 4 iKIR, CxTx subset as well as Cen AB and Tel AB are associated with an increased risk of developing meningioma whereas carrying KIR2DS4del, AA, C4TX genotypes and Cen AA, Tel AA, Tel BB reduce the genetic predisposition for meningioma., Competing Interests: Declaration of Competing Interest None., (Copyright © 2019 Elsevier GmbH. All rights reserved.)

Background: Activating and inhibitory KIR receptors (aKIR, iKIR) control the development and function of NK cells whose function alterations adjust the tumor microenvironment immunity. This research was conducted to determine the KIRs gene impact on genetic predisposition to Head and Neck Squamous Cell Carcinoma (HNSCC) in Iranians., Methods: KIR genotyping using sequence-specific primers-polymerase chain reaction (SSP-PCR) method was performed to identify the presence of all 16 KIR genes in 285 HNSCC patients, including laryngeal, oral cavity and pharyngeal SCC and 273 controls (CNs)., Results: Comparison of KIRs gene frequency between HNSCC and CNs revealed a highly significant increase in KIR2DL5, 2DS1, 2DS5, 3DS1 and CxT4 genotype and a decrease in KIR2DS4 deleted variant and AA genotype carriers. A significant increase was noted in individuals withhigher iKIRs than aKIRs in HNSCC compared with CNs. Individuals with ≥4 iKIR and those with ≥5 aKIRs were significantly more common in HNSCC than CNs. 68distinct KIR genotypes were identified in 558 individuals., Conclusion: Our findings determined the detrimental impact of KIR2DS1, 2DS5, 3DS1, 2DL5 and CxT4 genotype as well as the protective impact of KIR2DS4del and AA genotype on genetic predisposition to HNSCC in Iranians., (Copyright © 2018 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.)