It has been hypothesized that polymorphisms expected to result in functional changes in cytokine genes may influence susceptibility to cancer, including malignant melanoma (MM). Here, we have screened 24 potentially functional polymorphisms in five cytokine genes by PCR-SBT and PCR-SSP methods in 122 MM cell lines derived from Caucasian patients. The polymorphic positions studied were: TNFA -1031, -863, -857, -851, -574, -376, -308, -238, +488; TGFB1 -988, -800, -509, +869, +915, +652, +673, +713, +788; IL10 -1082, -819, -592; IL6 -174; IFNG -333, +874. The frequencies of cytokine genotypes of melanoma tumours were compared with those published for healthy Caucasians. It was found that TNFA -238 GA, TGFB1 -509 CT, -800 GG, IFNG +874 AT, IL6 -174 GG, IL10 -1082 GA genotypes were significantly decreased, while TNFA -238 AA, -857 CC, TGFB1 -509 TT, IFNG +874 AA, IL6 -174 CC, IL10 -1082 AA, -819 TT, -592 AA genotypes were significantly increased, in MM. This suggests that genotypes provisionally associated with low expression of pro-inflammatory and immunomodulatory TNF-alpha, IFN-gamma and IL-6 and anti-inflammatory IL-10 and TGF-beta1 could be involved in the mechanisms of cancer progression and escape from immunosurveillance.

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Tumor growth and dissemination depend partly on the reactivity of natural killer (NK) cells and T cells expressing NK-associated receptors. Their effector functions are regulated by an array of activating and inhibitory cell surface receptors with MHC class I ligand specificity, such as the killer immunoglobulin-like receptors (KIRs). Given the extensive genomic diversity of KIRs and their HLA ligands, it is reasonable to speculate that HLA, KIR gene variations and specific KIR-ligand combinations will have an impact on disease susceptibility and/or progression. Here, we discuss how KIR genotypes and KIR/HLA immunogenetic profiles may be involved in tumorigenesis, especially in malignant melanoma (MM). A hypothetical model of the impact of KIR/ligand combinations on immune responses in MM is proposed.

The occurrence of multiple sclerosis (MS) in subjects clustering to a particular mitochondrial DNA (mtDNA) haplogroup/haplotype or carrying mtDNA mutations associated with Leber's hereditary optic neuropathy (LHON) has suggested that mitochondrial genome may contribute to susceptibility to MS. In the present study, 58 unrelated Bulgarian patients with relapsing remitting form of MS and 104 randomly selected healthy individuals were analysed for the presence of 14 mtDNA polymorphisms determining major European haplogroups as well as three (4216, 14 798, 13 708) secondary LHON mutations. Restriction enzyme analysis used to screen patients and controls for the common haplogroup-associated polymorphisms showed that each of these changes was present in MS patients at a similar frequency to control subjects. However, 21 of the 58 patients (36.2%) were positive for T4 216C mutation, while only 11.3% of the controls carried this secondary LHON base change (P < 0.01; OR = 4.38). Our finding indicated that 4216C base substitution could be considered as a predisposing marker for MS and supported the hypothesis that particular mtDNA variants could contribute to genetic susceptibility of MS, and merits further investigation.

Objective:Natural killers (NK) cell function is mainly controlled by the expression of killer immunoglobulin-like receptors (KIRs) and their ligation with the corresponding ligands. The objective of this study was to investigate the putative association of KIRs, HLA class I ligands, and KIR/ligand combinations with rates of development of acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), and chronic myeloid leukemia (CML).Materials and Methods:The KIR/HLA I genotypes of 82 patients with leukemia (ALL, n=52; AML, n=17; and CML, n=13) were determined by PCR-SSP method and compared with genotypes of healthy controls (n=126).Results:KIR genotype frequency differed significantly between myelogenous leukemia patients and healthy controls for KIR2DL5A (17.6% vs. 47.7%, p=0.02), KIR3DS1 (17.6% vs. 47.6%, p=0.02), and KIR2DS4*001 (36.6% vs. 20.2%, p=0.017). The incidence of homozygous HLA-BBw4 (31.0% vs. 12.5%, p=0.042) and HLA-Bw4Thr80 Thr80 (13.0% vs. 1.2%, p=0.01) was significantly elevated in myeloid leukemia patients compared to healthy controls. KIR/HLA class I ligand profile KIR3DS1(+)/L (-) was decreased and KIR3DL2(+)/HLA-A3/11(-) was increased among myeloid leukemia cases compared to controls.Conclusion:These data suggest that the activity of NK cells as determined by inherited KIR/HLA class I ligand polymorphisms influences the susceptibility to myelogenous leukemia, but not to lymphoblastic leukemia. Additionally, the KIR genotype characterized by the absence of the inhibitory KIR2DL2 and the activating KIR2DS2 and KIR2DS3 (ID2) was found at a lower frequency in patients compared to controls, which confirmed the need for complex analysis based on all possible KIR/HLA class I ligand polymorphism combinations.