| Objective:Non-Hodgkin’s lymphoma (NHL) is a cancer originated in lymphatic hematopoietic tissue. The incidence of NHL has increased during the last twenty years around the world, but etiological factors contributing to this phenomenon remain still largely unknown. There were66,120cases of newly diagnosed NHL in the United States, ranking as the sixth most common cancer. According to the published data from the2008Shanghai World Lymphoma Awareness Day, the incidence rate was3.5/100,000and the number of newly diagnosed cases was45,000every year, with more than20,000deaths, ranking from the10th to the9th in the malignant tumor incidence. Several large-scale studies have reported associations between family history of hematopoietic malignancy and lymphoma risk, it is likely that more common genetic variants may influence disease susceptibility. It also has been suggested that immune dysfunction may be the underlying basis of lymphomagenesis. Therefore, investigation of the inherited genetic variation background of immune-related genes is important for revealing and elucidating the pathogenesis of NHL. Based on the formation of large-scale Han people of NHL resources database, we detected12SNP loci of4immune-related genes using PCR-LDR technology, screened and identificated the immunity-related SNPs loci for NHL and its major subtypes (DLBCL, FL, PTL and NK/T lymphoma), we also made a functional analysis of the screened susceptibility SNP loci. Our study will lay a foundation for screening the NHL susceptibility genes in the genome-wide association studies and identify the NHL pathogenesis. The contents of this study includes three parts:(1)To investigate the clinical and pathological data of1248cases of NHL patients in Shandong Cancer Hospital from January2002to December2010.(2)To detect the association between four immune-related genes (Interleukin-10, tumour necrosis factor-a, lymphotoxin and cytotoxic T-lymphocyte antigen4) genetic variants and susceptibility to non-Hodgkin’s lymphoma in Shandong Chinese population.(3)To investigate the functional studies of LTA+252A>G SNP related to the susceptibility of NK/T cell lymphoma.Methods:(1)The clinical data of patients diagnosed with lymphoma in Shandong Cancer Hospital continuously from January2002to December2010were retrospectively analyzed. The clinical data of patients included gender, age, pathological type and immunohistochemistry, clinical stage, lesion location, date of diagnosis, family history, personal history. Significant differences between the proportions or the averages were analyzed using chi-square test or t test.(2) We genotyped12SNPs of the IL-10(-3575T>A,-1082A>G,-819T>C and-592A>C),TNF-α(-857C>T,-308G>A,-238G>A), LTA (+252A>G) and CTLA-4(-1661A>G,-318C>T,+49A>G, CT60A>G) using polymerase chain reaction-ligase detection reaction (PCR-LDR) analysis in947subjects with NHL and1044healthy controls. Odds ratio and95%confidence interval were determined by logistic regression for the associations between genotypes or haplotypes with the risk of NHL and subtypes (DLBCL, FL, PTL and NK/T)(3)The serum LTA protein expression level of patients with NK/T cell lymphoma and controls were detected using enzyme-linked immunosorbent assay (ELISA), the correlation between LTA+252polymorphism and plasma protein expression was analyzed.Results:(1)The pathological subtypes of the patients included in this study were classified according to the Revised European-American Lymphoma (REAL)/World Health Organization lymphoma classification scheme (2001).①There were807cases of B-cell lymphoma (64.7%);378cases of T-cell lymphoma (30.3%). Among them, the pathological types were mainly:diffuse large B cell lymphoma (DLBCL)(40.9%); extranodal NK/T-cell lymphoma, nasal type (NK/T)(10.0%); Peripheral T cell lymphoma, unspecified (PTL)(9.2%); follicular lymphoma (FL)(6.4%); extranodal marginal zone B cell lymphoma (MALT)(5.4%); precursor T lymphoblastic leukemia/lymphoma (T-LBL)(4.5%);②The male to female ratio of B-cell NHL patients (1.4:1) was significantly lower than that of T-cell NHL patients (2.0:1). ③The mean age of patients with B-cell NHL of50.7±15.2was significantly higher than that of the patients with T-cell NHL of42.0±17.1;④In this study,64.0%lesions were lymph nodes and36.0%were extranodal sites. The most common sites of Extranodal were digestive system, nasal cavity and Waldeyer’s ring.(2) No significant difference was seen between these12gene polymorphisms (SNPs) and total NHL. TNF-α-857TT genotype was associated with increased risk of B-NHL; IL-10-1082AG genotype and G allele, IL-10-819CC genotype and C allele, LTA+252AA genotype were associated with increased risk of T-NHL. When the main pathological subtypes of NHL was analyzed, IL-10-819CC genotype and C allele, IL-10-592CC genotype and C allele, TNF-α-857TT genotype was associated with FL; IL-10-1082AG genotype and G allele, CTLA-4-1661AG genotype and G allele, CTLA-4-318CT genotype and T allele, CTLA-4+49G allele was associated with PTL; the LTA+252GG genotype was associated with NK/T lymphoma.(3) The analysis of functional activity of LTA+252A>G SNP showed that the plasma LTA protein level was significantly elevated in NK/T cell lymphoma patients than in controls (P<0.05). In the NK/T cell lymphoma patients, the plasma LTA protein level of individuals with AA genotype was significantly higher than those with GG genotype(391.2±85.6pg/ml vs.197.3±31.5pg/ml, P<0.05); The LTA protein level of individuals with AG genotype was boardline higher than those with GG genotype (312.2±68.9pg/ml vs.197.3±31.5pg/ml, P=0.06)Conclusion:(1) This study suggests that the clinical and pathological distribution of NHL in Shandong province, China, is consistent with that for Asian populations, but significantly different from that in the Western countries, with higher proportion of NK/T lymphoma in this region. Overall, the B-cell lymphoma accounted for a high proportion worldwide, the T-cell lymphoma in China was however higher than that in European and American countries. DLBCL is the pathological subtype with the highest rate of incidence all around the world, accounting for25%-50%of NHL. The incidence proportions of FL and CLL/SLL in the United States, the Netherlands and Chinese-Americans were significantly higher than those in China. T-cell lymphoma (especially PTL, NK/T, and T-LBL) in European and American countries was significantly lower than that in China. Therefore NHL has its unique clinical and pathological features in Chinese Han population.(2)The inherited genetic variations in the immune-related genes IL-10, TNF-α, LTA and CTLA-4loci may influence risks of different subtypes of NHL in the Chinese population. The IL-10gene polymorphism was associated with FL, the IL-10and CTLA-4gene polymorphism was associated with PTL lymphoma and the LTA gene polymorphism was associated with NK/T cell lymphoma. Therefore, from the the breakthrough point that relationship between the immune related genes polymorphism and susceptibility of NHL, a large case-control study is very likely to discover the key genes of NHL pathogenesis and to determine the susceptibility genes of NHL.(3) The inherited LTA+252A>G site genetic polymorphisms is correlate with the LTA protein expression and may affect the NK/T cell lymphoma pathogenesis.Summary:Our results showed that genetic variation in the immune-related gene IL-10, TNF-α, LTA and CTLA-4has a certain correlation with the different risks of NHL subtypes.Significance:This study analyzed the clinical and pathological data of1248patients diagnosed with NHL in Shandong Cancer Hospital continuously from January2002to December2010, and proved that NHL has its unique clinical and pathological features in Chinese Han population. Then, based on the previous work, we genotyped12SNPs of the IL-10,TNF-α, LTA and CTLA-4genes using PCR-LDR method and analyzed the correlation between these genotypes and haplotypes and the risk of NHL and subtypes (DLBCL, FL, PTL and NK/T). Further, we made a functional analysis of LTA+252A>G SNP in NK/T cell lymphoma. Our study established a good foundation for the next step to research the genome-wide linkage studies screening susceptibility genes for NHL in Chinese population and to elaborate the pathogenesis of non-hodgkin’s lymphoma. |
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