Diversity of KIRs in invasive breast cancer patients and healthy controls along with the clinical significance in ER/PR/HER2+ patients

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.

The impact of killer cell immunoglobulin-like receptor (KIR) genes and human leukocyte antigen (HLA) class I ligands on predisposition or protection against prostate cancer

Natural killer (NK) cell development largely depends on killer cell immunoglobulin-like receptors (KIRs) and human leukocyte antigen (HLA) class I ligands. In the current study, we investigated the role of KIR genes, HLA ligands, and KIR-HLA combinations in vulnerability or protection against prostate cancer (PC). To analyze the frequency of 16 KIR genes and 5 HLA ligands, polymerase chain reaction with sequence-specific primers (PCR-SSP) was conducted in 150 PC patients and 200 healthy controls (CNs). KIR2DL5 (p = 0.0346, OR = 0.606, CI = 0.3916-0.9336), KIR2DS5 (p = 0.0227, OR = 0.587, CI = 0.3793-0.9139), HLA-B Bw4^Thr80 (p = 0.0401, OR = 0.3552, CI = 0.1466-0.9059), HLA Bw4 (p = 0.0190, OR = 0.4744, CI = 0.2656-0.8521), and T4 gene cluster (including KIR2DS5-2DL5-3DS1-2DS1 genes) (p = 0.0194, OR = 0.5575, CI = 0.3449-0.8938) had a lower frequency in the PC patients compared to the control group. Moreover, a lower frequency of the genotypes contacting activating KIR (aKIR) > inhibitory KIR (iKIR) (p = 0.0298, OR = 0.5291, CI = 0.3056-0.9174) and iKIR + HLA < aKIR + HLA (p = 0.0183, OR = 0.2197, CI = 0.0672-0.7001) in PC patients compared to the CNs implies a protective role for aKIR genes. In the case of KIR-HLA interactions, we detected a significant association between KIR3DS1⁺ + HLA-A Bw4⁺ (p = 0.0113, OR = 0.5093, CI = 0.3124-0.8416) and KIR3DL1^- + HLA-A Bw4⁺ (p = 0.0306, OR = 0.1153, CI = 0.0106-0.6537) combinations and resistance to prostate cancer. In contrast, the presence of KIR3DL1 in the absence of HLA-A Bw4 (p = 0.0040, OR = 2.00, CI = 1.264-3.111), HLA Bw4 (p = 0.0296, OR = 2.066, CI = 1.094-3.906), and HLA-Bw4^Thr80 (p = 0.0071, OR = 2.505, CI = 1.319-4.703) genes probably predisposes to prostate cancer. Carrying the CxT4 genotype in PC patients was positively associated with lower tumor grades (Gleason score ≤ 6) (p = 0.0331, OR = 3.290, and CI = 1.181-8.395). Altogether, our data suggest a protective role for aKIRs, HLA-B Bw4^Thr80, and HLA Bw4 ligands as well as a predisposing role for certain KIR-HLA combinations in prostate cancer. The findings of this study offer new insight into the population's risk assessment for prostate cancer in men. Additionally, predicting immunotherapy response based on KIR-HLA combinations aids in implementing the most effective therapeutic approach in the early stages of the disease.

Understanding the killer-cell immunoglobulin like receptor polymorphism in retinoblastoma

BACKGROUND

The KIR receptors present on the natural killer (NK) cells play a crucial role by exercising cytotoxicity to eliminate tumor cells. Both KIR and class-I HLA molecules exhibit extensive polymorphism. Although RB1 inactivation triggers the initiation of retinoblastoma; however additional immune alterations trigger tumor development. The aim was to explore the KIR/HLA polymorphism and its role in the pathogenesis of retinoblastoma.

METHODS

Patients with unilateral, non-familial retinoblastoma were enrolled as cases. Healthy individuals matched for ethnicity were enrolled as controls. KIR genotyping was performed by sequence-specific primer assay. The investigated KIR genes included: inhibitory (2DL1, 2DL2, 2DL3, 2DL4, 2DL5A, 2DL5B), activating (2DS1, 2DS2, 2DS3, 2DS4*FUL, 2DS4*DEL, 2DS5, 3DL1, 3DL2, 3DL3, 3DS1) and pseudogenes (2DP1, 3DP1*FUL, 3DP1*DEL). In addition, HLA ligands were investigated by sequence-specific oligonucleotide assay for HLA-A, B, and C locus.

RESULTS

KIR genotyping was performed in 48 cases and 107 controls. The mean age of cases was 2.9 ± 2.2 years (range: 0.25-10). Among the 19 KIR genes, the frequency of KIR2DS4*FUL (p = 0.0019) and 2DS5 (p = 0.0095) was increased among cases. HLA ligands were investigated in 25 cases and 50 controls. The frequency of HLA ligands (C1/C2, Bw4, A3/A11) was similar among cases and controls. However, the KIR/HLA combination frequency for KIR3DS1/HLA-Bw4 was decreased in cases (p = 0.006).

CONCLUSION

It is the pioneer study to report the association of killer cell immunoglobulin-like receptors in retinoblastoma. KIR2DS4*FUL and KIR2DS5 had a susceptible, and KIR3DS1/HLA-BW4 had a protective role in retinoblastoma. The results will aid in exploring the therapeutic potential of NK cell-based therapy for retinoblastoma.

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.

KIR-HLA Functional Repertoire Influences Trastuzumab Efficiency in Patients With HER2-Positive Breast Cancer

Trastuzumab induced a high rate of pathological Complete Response (pCR) in patients affected by locally advanced HER2-positive Breast Cancer (HER2-BC), by exploiting immune-mediated mechanisms as Antibody-Dependent Cell Cytotoxicity (ADCC) involving Natural Killer (NK) cells. Host's immune genetics could influence the response to therapy, through the expression of variants that characterize NK receptors involved in ADCC effectiveness. Killer cell immunoglobin-like receptors (KIRs) modulate NK cell activity through their binding to class-I Human Leukocyte Antigens (HLA). The impact of the KIR/HLA repertoire in HER2-BC is under study. We characterized KIR genotypes of 36 patients with locally advanced HER2-BC treated with neoadjuvant chemotherapy including trastuzumab. We monitored pCR achievement before surgery and Disease-Free Survival (DFS) and Overall Survival (OS) after adjuvant therapy. HLA, and Fc gamma receptor IIIa (FcγR3A) and IIa (FcγR2A) were genotyped through targeted PCR and Sanger sequencing in 35/36 patients. The KIR-HLA combinations were then described as functional haplotypes and divided in two main categories as inhibitory tel A and stimulatory tel B. Trastuzumab-dependent ADCC activity was monitored with an in vitro assay using a HER2-BC model and patients' NK cells.We observed a higher frequency of KIR activators in patients who achieved a pCR compared to partial responders. During the study of functional haplotypes, individuals carrying a tel B haplotype showed greater ADCC efficiency than tel A cases. In subjects with the tel A haplotype the presence of the favorite V allele in FcγR3A receptor improved their low ADCC levels. Regardless of the haplotypes detected, the presence of KIR3DL2/HLA-A03 or A11 was always associated with the FcγR3A V allele, and therefore correlated with greater ADCC efficiency. However, this particular KIR receptor appeared to harm DFS and OS. Indeed, patients with tel B haplotype without KIR3DL2/HLA-A03 or A11 showed a better outcome. Our data, although preliminary, suggested a potential predictive role for KIR haplotype tel B, in identifying patients who achieve a pCR after neoadjuvant treatment with trastuzumab, and supported a negative prognostic impact of KIR3DL2/HLA-A03 or A11 in the adjuvant setting.

Coexistence of inhibitory and activating killer-cell immunoglobulin-like receptors to the same cognate HLA-C2 and Bw4 ligands confer breast cancer risk

Human leukocyte antigen (HLA) class I-specific killer-cell immunoglobulin-like receptors (KIR) regulate natural killer (NK) cell function in eliminating malignancy. Breast cancer (BC) patients exhibit reduced NK-cytotoxicity in peripheral blood. To test the hypothesis that certain KIR-HLA combinations impairing NK-cytotoxicity predispose to BC risk, we analyzed KIR and HLA polymorphisms in 162 women with BC and 278 controls. KIR-Bx genotypes increased significantly in BC than controls (83.3% vs. 71.9%, OR 1.95), and the increase was more pronounced in advanced-cancer (OR 5.3). No difference was observed with inhibitory KIR (iKIR) and HLA-ligand combinations. The activating KIR (aKIR) and HLA-ligand combinations, 2DS1 + C2 (OR 2.98) and 3DS1 + Bw4 (OR 2.6), were significantly increased in advanced-BC. All patients with advanced-cancer carrying 2DS1 + C2 or 3DS1 + Bw4 also have their iKIR counterparts 2DL1 and 3DL1, respectively. Contrarily, the 2DL1 + C2 and 3DL1 + Bw4 pairs without their aKIR counterparts are significantly higher in controls. These data suggest that NK cells expressing iKIR to the cognate HLA-ligands in the absence of putative aKIR counterpart are instrumental in antitumor response. These data provide a new framework for improving the utility of genetic risk scores for individualized surveillance.