结直肠癌患者循环肿瘤DNA定量KRAS基因突变的检测

目的建立结直肠癌KRAS基因G12D液体活检技术,并探讨其在结直肠癌诊疗中的应用价值。方法用微滴式数字PCR(ddPCR)技术定量检测52例结直肠癌患者和80名健康对照的血浆游离DNA的KRAS基因G12D突变率和突变浓度;以结直肠癌患者肿瘤组织KRAS基因测序结果为金标准评价ddPCR检测的准确性;分析结直肠癌患者KRAS基因G12D突变率、浓度与其临床表征的关系。结果结直肠癌患者血浆KRAS基因G12D突变型检出率(26.92%)和浓度中位数(81.5 copies/m L)显著高于健康对照(8.75%,16 copies/m L);结直肠患者组高分化腺癌的KRAS基因G12D突变浓度显著高于中分化和低分化腺癌(P<0.05),淋巴结转移N2的KRAS基因G12D突变浓度显著高于N0和N1(P<0.05);结直肠癌患者血浆KRAS基因G12D突变与肿瘤组织突变一致性达87.50%。结论ddPCR检测方法是一种快速、无创和准确的检测血浆循环肿瘤DNA(ctDNA)的方法,其检测结果可为临床用药指导和病程监控提供依据。     

Prognostic significance of alterations in KRAS isoforms KRAS‐4A/4B and KRAS mutations in colorectal carcinoma

Somatic KRAS mutation is an early well‐known event in colorectal carcinogenesis but a complete understanding of RAS function and dysfunction in colorectal cancer is still to come. Our aim was to study the incidence of KRAS mutation; KRAS splice variants: KRAS4A and KRAS4B; and their relationships with various clinico‐pathological characteristics in colorectal cancer (CRC).In this study, 285 CRC cases were analysed for KRAS mutation by direct DNA sequencing followed by immunohistochemical analysis after validation with real‐time PCR assay, to study the protein expression of KRAS4A and ‐4B isoforms. KRAS gene mutations were seen in 80/285 CRCs (28.1%) and of the mutated cases, the majority of the mutations were seen in codon 12 (81.2%) as opposed to codon 13 (18.8%). CRCs with KRAS mutations were associated with a poor overall survival (p = 0 . 0009). Furthermore, KRAS mutations at codon 12 were associated with a poor overall survival of 64.4% at 5 years compared with a 5‐year overall survival of 75.8% and 78.2% with codon 13 mutation and absence of KRAS mutations, respectively (p = 0 . 0025). KRAS4A protein expression was predominantly seen in the cytoplasm, while KRAS4B protein was nuclear. KRAS4A overexpression was significantly associated with left colon, histology subtype of adenocarcinoma, p27kip1, and cleaved caspase3 expression. Interestingly, KRAS4A overexpression was associated with a better overall survival (p = 0 . 0053). On the other hand, KRAS4B overexpression (33.2%) was significantly associated with larger tumour size (p = 0 . 0234) and inversely correlated with p27kip1 protein (p = 0 . 0159). Both KRAS mutation and KRAS4A were independent prognostic markers in a multivariate analysis with age, gender, stage, differentiation, and MSI status. Our results highlight the differential role of KRAS isoforms in CRC, their utility as a prognostic biomarker, and underline the importance of KRAS alterations as a potential therapeutic target for CRC. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

HOXD13 methylation status is a prognostic indicator in breast cancer

Homeobox protein Hox-D13 is encoded by HOXD13 gene which is frequently methylated in cancer and has been recognized as a tumor suppressor in pancreatic cancer. In this study, we examined HOXD13 mRNA expression in 40 pairs of breast cancers and corresponding normal breast tissues. Bisulfite sequencing of HOXD13 promoter was performed in 6 pairs of breast tumors and corresponding normal breast tissues to examine the potential HOXD13 CpG methylated sites. HOXD13 DNA methylation frequency analysis was performed using MethyLight in 196 pairs of breast cancers and corresponding normal breast samples. DNA methylation status and clinico-pathological features were investigated. Kaplan-Meier survival analysis and Cox proportional hazards models were utilized to assess the effect of methylation status on overall survival. We found that 60% (24/40) of breast cancers showed low HOXD13 mRNA expression when compared with corresponding normal breast tissue. The predicted CpG island was located in the -1325 bp to +675 bp region. Next, the -332 bp site in HOXD13 gene promoter was further examined and in 57.7% (113/196) samples methylation was detected at this site. HOXD13 methylation was correlated with larger tumor size (P = 0.004), but not with other clinico-pathological parameters. In addition, patients with methylated -HOXD13 promoter had worse overall survival (OS) (P = 0.005). Based on our results we conclude that HOXD13 methylation is a common event in primary breast cancer and is associated with poor survival of breast cancer patients. HOXD13 methylation could therefore potentially be used as a prognostic factor for breast cancer.     

Roles of genetic variants in the PI3K/PTEN pathways in susceptibility to colorectal carcinoma and clinical outcomes treated with FOLFOX regimen

The genetic or abnormal activation of PI3K/PTEN signaling pathway play an important role with regard to disease progression in variety of human malignancies. Experimental and epidemiologic studies indicated that the genetic polymorphisms in the PTEN, PI3K genes are associated with cancer risk, yet little evidence exists for those 2 genes and colorectal cancer (CRC) risk. To address this, we evaluated whether PTEN rs701848, PIK3CA rs2699887 variants are associated with CRC susceptibility, clinicopathological parameters and clinical outcomes in CRC patients treated with FOLFOX (Oxaliplatin, Leucovorin, 5-Fluorouracil) regimen. A case-control study was performed in 780 CRC patients and 764 healthy controls using the TaqMan assay method. A significant increased risk of CRC was observed in patients carrying PTEN rs701848 TC or CC genotype (adjusted OR=1.306, 95% CI=1.030-1.655, P=0.027; adjusted OR=1.543, 95% CI=1.148-2.075, P=0.004, respectively), TC/CC genotype (adjusted OR=1.367, 95% CI=1.090-1.714, P=0.043) in the dominant model, and C allele (adjusted OR=1.229, 95% CI=1.067-1.416, P=0.004). However, no association was detected between rs2699887 in the PIK3CA gene and CRC risk. A significant association was found between pathological grade (Dukes A and B vs. Dukes C and D) and PIK3CA rs2699887 genotypes. Furthermore, Kaplan-Meier analysis revealed that PTEN rs701848 genotypes were significantly associated with the overall survival (OS) of CRC patients treated with FOLFOX regimen (n=780). Individuals carrying PTEN rs701848 TC or TC/CC genotypes showed significantly longer median survival time (MST) than TT genotype and significant hazard ratio (TC: adjusted HR=0.523, 95% CI=0.325-0.840, P=0.007; TC/CC: adjusted HR=0.545, 95% CI=0.351-0.845, P=0.007). Therefore, rs701848 polymorphism in the PTEN gene is associated with susceptibility to CRC, and C allele of rs701848 showed significant independent better prognosis of CRC patients treated with FOLFOX regimen. These results indicate that rs701848 in the PTEN gene might be a candidate pharmacogenomic factor to assess the susceptibility and prognosis in CRC patients.     

p53 expression in colorectal carcinoma in relation to histopathological features in Ugandan patients

Background

It has been shown that colorectal carcinoma is increasing in incidence in African countries. This could be due to change in life style. Molecular pathogenesis of colorectal cancer commonly involves mutation in p53 gene which leads to expression of p53 protein in tumor cells. Expression of p53 protein has been associated with poor clinical outcome and reduced survival in patients.

Objective

This was a retrospective laboratory based study carried out in the Department of Pathology Makerere University, Kampala, Uganda. The aim of the study was to evaluate the expression of p53 protein in colorectal carcinoma in Ugandan patients, specifically its association with histological types, degree of differentiation, sites of the tumor and demographic characteristics of the patients.

Methods

Immunohistochemistry was carried out on 109 patient''s paraffin embedded tissue blocks of colorectal carcinoma diagnosed in the Pathology Department, Faculty of Medicine Makerere University Kampala during the period 1995 to 2005. The indirect immunoperoxidase method using monoclonal antibody p53 DO-7 and Envision ⁺ Dual link system-HRP to detect p53 expression was used. Haematoxylin and eosin stain was used for evaluation of histological types and degree of differentiation of the tumors. Topography of the tumors and demographic data were obtained from accompanying histological request forms.

Results

Out of 109 patient''s tissue blocks that were studied, 61 cases (56%) expressed p53 protein in the nucleus of malignant cells. Right sided colonic tumors were commoner (53.2%) than left sided colonic tumors (46.8%). p53 protein was expressed more in left sided colonic tumors with a significant difference (p<0.05), it was also expressed more in well differentiated tumors and non mucinous adenocarcinomas but with no significant difference (p>0.05). p53 expression was not affected by age or sex.

Conclusion

Frequency of p53 protein expression in Ugandan patients did not differ from that reported in the other parts of the world. It was expressed more in the left sided colonic tumors and this could support the hypothesis that right and left colonic tumors could have different pathogenesis and probably also responsible for difference in prognosis in these two topographic sites.     

Anti-epidermal growth factor receptor monoclonal antibody-based therapy for metastatic colorectal cancer: a meta-analysis of the effect of PIK3CA mutations in KRAS wild-type patients

Introduction

We conducted a meta-analysis to dissect the association between PIK3CA mutations (exon 9 and exon 20) and resistance to anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (MoAbs) in KRAS wild-type metastatic colorectal cancer (mCRC) patients.

Material and methods

In 11 previously published studies, 864 cancer patients were treated with cetuximab or panitumumab-based therapy. Primary outcomes included objective response (complete response + partial response vs. stable disease + progressive disease), progression-free survival (PFS), and overall survival (OS). We calculated the odds ratio (OR) or hazard ratio (HR) with 95% confidence intervals (CIs) to estimate the risk or hazard. We found consistent and clinically substantial risk or hazard for objective response, PFS, and OS in the cetuximab or panitumumab-treated mCRC patients.

Results

PIK3CA mutations as a whole were associated with reduced response and poor PFS and OS in KRAS wild-type mCRC patients (objective response: OR = 0.42 and 95% CI 0.23–0.75; PFS: HR = 1.54 and 95% CI 1.13–2.09; and OS: HR = 1.4 and 95% CI 1.02–1.91). PIK3CA exon 9 mutations had no effect, whereas exon 20 mutations were associated with a worse outcome compared with wild types, with an OR of 0.21 (95% CI 0.05–0.93).

Conclusions

PIK3CA mutations as a whole might be useful prognostic factors for assessing clinical outcomes of anti-EGFR MoAb-based chemotherapies in KRAS wild-type mCRC patients. In particular, PIK3CA exon 20 mutations were significantly associated with lack of response.     

Transition between morule-like and solid components may occur in solid-predominant adenocarcinoma of the lung: report of 2 cases with EGFR and KRAS mutations

A limited number of pulmonary adenocarcinoma cases with morule-like components have been described to date, and the most frequent histological subtype is papillary-predominant adenocarcinoma. Occasionally, this type of adenocarcinoma is associated with solid-predominant adenocarcinoma. EGFR mutations are predominant in adenocarcinoma with morule-like components, followed by ALK rearrangements. Herein, we present 2 cases of solid-predominant adenocarcinoma with morule-like components harboring either an EGFR or KRAS mutation. This KRAS-mutant case is the first to be associated with morule-like components, to the best of our knowledge. Both cases showed transition between micropapillary and morule-like components. Transition between morule-like and solid components was also observed in both cases. Although a few cases of solid-predominant adenocarcinoma have been shown to harbor morule-like components, this type of transition has not been previously well described. We surmised that the solid components of some EGFR-mutant adenocarcinomas might be derived from morule-like components.     

Integrated DNA-based/biochemical screening for early diagnosis of multiple endocrine neoplasia type 2A (MEN2A)

Multiple endocrine neoplasia type 2A (MEN2A), a subtype of MEN2, is characterized by medullary thyroid cancer, pheochromocytoma, and primary hyperparathyroidism. A Han Chinese pedigree with MEN2A was investigated following confirmation of the proband''s diagnosis by pathological findings and DNA/biochemical screening. DNA samples from 4 other family members were collected and exon 5, 8, 10, 11, 13, 16 and 18 of the RET proto-oncogene were sequenced and then analyzed. A missense mutation of TGG (Trp) to TGC (Cys) at codon 634 (the classic MEN2A mutation) in exon 11 of the RET gene was detected in 3 family members, including the proband. Sequencing data were compared with the human gene mutation database. Elevated serum calcitonin level was detected initially; medullary thyroid carcinoma was revealed in the 3 cases and adrenal pheochromocytoma was also found in the proband. Elective operations were successfully performed on the adrenal and thyroid glands because of pheochromocytoma and medullary thyroid carcinoma. Our case study confirms that integrated DNA-based/biochemical screening is crucial for early diagnosis of MEN2A and is helpful in the screening of their relatives. In addition, DNA-based screening may occasionally uncover a previously unknown RET sequence.     

Screening for EGFR and KRAS mutations in non-small cell lung carcinomas using DNA extraction by hydrothermal pressure coupled with PCR-based direct sequencing

EGFR and KRAS mutations correlate with response to tyrosine kinase inhibitors in patients with non-small cell lung carcinoma (NSCLC). We reported a hydrothermal pressure method of simultaneous deparaffinization and lysis of formalin-fixed paraffin embedded (FFPE) tissue followed by conventional chaotropic salt column purification to obtain high quality DNA for mutation analysis using PCR-base direct sequencing. This study assessed the feasibility of using this method to screen for exons 18-21 of EGFR and exon 2 of KRAS gene mutations in surgical resection and core needle biopsy specimens from 251 NSCLC patients. EGFR mutations were identified in 140 (55.8%) NSCLC patients (118 in adenocarcinoma, 11 in squamous cell carcinoma, 7 in adenocarcinoma and 4 in NSCLC-not otherwise specified), including four novel substitutions (L718M, A743V, L815P, V819E). EGFR mutations were frequently present in female patients (72 of 113, 63.7%) and NSCLC with adenocarcinoma component (125/204, 61.3%) with statistical significance. Twenty-one patients had multiple mutations at different exons of EGFR, in which seventeen patients had deletions in exon 19. KRAS mutations were found in 18 (7.2%) patients (15 in adenocarcinoma, 2 in squamous cell carcinoma and one in NSCLC-not otherwise specified), including an uncommon substitution G13C. Deparaffinization and lysis by hydrothermal pressure, coupled with purification and PCR-based sequencing, provides a robust screening approach for EGFR and KRAS mutation analysis of FFPE tissues from either surgical resection or core needle biopsy in clinical personalized management of lung cancer.     

Type A microsatellite instability in pediatric gliomas as an indicator of Turcot syndrome

Microsatellite instability (MSI) is present in hereditary conditions due to mismatch repair (MMR) gene mutations. Following MSI analysis, tumor samples are classified into MSS (stable), MSI-L (low instability), and MSI-H (high instability) based on the fraction of unstable loci. Another MSI-based classification takes into account the size difference between mutant alleles in tumor DNA compared to wild-type alleles; two types of MSI, A and B, are recognized using this approach, type A being characterized by smaller, more subtle allelic shifts compared to type B. Biallelic mutations of MMR genes are associated with pediatric cancers, including glial tumors, in Turcot syndrome type 1 (TS1). However, most TS1-associated gliomas so far analyzed did not display MSI. We investigated the frequency of MSI in a series of 34 pediatric gliomas of different grade using a panel of five mononucleotide quasimonomorphic markers. Subtle qualitative changes were observed for the majority of markers in two glioblastomas (5.9% of the total series and 33.3% of glioblastomas). In both cases, family histories were compatible with TS1, and mutations of the PMS2 and MLH1 genes were identified. In one family, the MSI patterns were compared between the glioblastoma and a colon cancer from an affected relative, showing a clear qualitative difference, with the former displaying type A and the latter type B instability, respectively. These results were confirmed using additional microsatellite markers, indicating that knowledge of the association between TS1-related glial tumors and subtle type A MSI is important for full ascertainment of TS1 patients and appropriate counselling.     

Identification of a novel in-frame deletion in KCNQ4 (DFNA2A) and evidence of multiple phenocopies of unknown origin in a family with ADSNHL

Autosomal dominant sensorineural hearing loss (ADSNHL) is extremely genetically heterogeneous, making it difficult to molecularly diagnose. We identified a multiplex (n=28 affected) family from the genetic isolate of Newfoundland, Canada with variable SNHL and used a targeted sequencing approach based on population-specific alleles in WFS1, TMPRSS3 and PCDH15; recurrent mutations in GJB2 and GJB6; and frequently mutated exons of KCNQ4, COCH and TECTA. We identified a novel, in-frame deletion (c.806_808delCCT: p.S269del) in the voltage-gated potassium channel KCNQ4 (DFNA2), which in silico modeling predicts to disrupt multimerization of KCNQ4 subunits. Surprisingly, 10/23 deaf relatives are non-carriers of p.S269del. Further molecular characterization of the DFNA2 locus in deletion carriers ruled out the possibility of a pathogenic mutation other than p.S269del at the DFNA2A/B locus and linkage analysis showed significant linkage to DFNA2 (maximum LOD=3.3). Further support of genetic heterogeneity in family 2071 was revealed by comparisons of audio profiles between p.S269del carriers and non-carriers suggesting additional and as yet unknown etiologies. We discuss the serious implications that genetic heterogeneity, in this case observed within a single family, has on molecular diagnostics and genetic counseling.     

Large copy number variations in combination with point mutations in the TYMP and SCO2 genes found in two patients with mitochondrial disorders

Mitochondrial disorders are caused by defects in mitochondrial or nuclear DNA. Although the existence of large deletions in mitochondrial DNA (mtDNA) is well known, deletions affecting whole genes are not commonly described in patients with mitochondrial disorders. Based on the results of whole-genome analyses, copy number variations (CNVs) occur frequently in the human genome and may overlap with many genes associated with clinical phenotypes. We report the discovery of two large heterozygous CNVs on 22q13.33 in two patients with mitochondrial disorders. The first patient harboured a novel point mutation c.667G>A (p.D223N) in the SCO2 gene in combination with a paternally inherited 87-kb deletion. As hypertrophic cardiomyopathy (HCMP) was not documented in the patient, this observation prompted us to compare his clinical features with all 44 reported SCO2 patients in the literature. Surprisingly, the review shows that HCMP was present in only about 50% of the SCO2 patients with non-neonatal onset. In the second patient, who had mitochondrial neurogastrointestinal encephalopathy (MNGIE), a maternally inherited 175-kb deletion and the paternally inherited point mutation c.261G>T (p.E87D) in the TYMP gene were identified.     

Discordant intracellular and plasma D-2-hydroxyglutarate levels in a patient with IDH2 mutated angioimmunoblastic T-cell lymphoma

Objectives: Angioimmunoblastic T-cell lymphoma (AITL) is an aggressive peripheral T-cell lymphoma with mutations in genes encoding isocitrate dehydrogenase1 and 2 (IDH1 and IDH2). Mutant IDH generates the oncometabolite D-2-hydroxyglutarate (D-2HG). We report the first case of discordant intracellular and plasma D-2HG levels in a patient with IDH2 R172S mutated AITL. Methods: An 87-year-old woman was diagnosed with AITL in the groin lymph node by morphologic and immunophenotypic analyses, and molecular studies by DNA sequencing. D-2HG was measured in both tumoral tissue and in pre-treatment plasma by liquid chromatography-tandem mass spectrometry. Results: While D-2HG was markedly elevated in the tissue sample, its level in plasma was normal. We discuss this discordant D-2HG result within the context of previously reported discordant 2HG results in other IDH mutated tumors, and its implication for using circulating D-2HG as a biomarker of IDH mutation. In addition, this case also harbored mutations in RHOA, TET2, and TP53. The molecular pathogenesis is briefly discussed. Conclusion: While our case suggests that circulating D-2HG is not a reliable marker of IDH mutation in AITL, more cases need to be studied to arrive at a definite conclusion.     

TAP1 and TAP2 gene polymorphisms in Korean patients with allergic rhinitis

Antigen peptides are actively transported across the endoplasmic reticulum by the transporters associated with antigen presentation (TAP). TAP genes polymorphism could influence the selection process that determines which antigen peptides play a role in the pathogenesis of allergic rhinitis. The aim of this study was to investigate the association of TAP genes polymorphism with allergic rhinitis. TAP1 and TAP2 genotyping were performed on 110 allergic rhinitis patients and 107 healthy controls. TAP1 polymorphic residues at codons 333 and 637, and TAP2 polymorphic residues at codons 379, 565, 651, and 665 were analyzed by the amplification refractory mutation system-polymerase chain reaction (ARMS-PCR). Analysis of TAP1 gene polymorphism demonstrated decreased frequencies of Ile/Val genotype at codon 333, Asp/Gly genotype at codon 637, and haplotype A and B in allergic rhinitis patients when compared to controls (p<0.05). However, there was no significant difference in the genotype, phenotype, or allele frequencies at four TAP2 codons between controls and allergic rhinitis patients. In conclusion, TAP1 gene polymorphism may be an important factor contributing to the genetic susceptibility in the development of allergic rhinitis in the Korean population.     

Comparison of neuroendocrine differentiation and KRAS/NRAS/BRAF/PIK3CA/TP53 mutation status in primary and metastatic colorectal cancer

Neuroendocrine differentiation of tumor tissue has been recognized as an important prerequisite for new targeted therapies. To evaluate the suitability of colorectal cancer (CRC) tissue for these treatment approaches and to find a possible link to pretherapeutic conditions of other targeted strategies, we compared neuroendocrine differentiation and KRAS/NRAS/BRAF/PIK3CA/TP53 mutational status in primary and metastatic CRC. Immunohistochemical expression analysis of neuroendocrine markers chromogranin A and synaptophysin was performed on archival CRC tissue, comprising 116 primary tumors, 258 lymph node metastases and 72 distant metastases from 115 patients. All CRC samples but 30 distant metastases were subjected to mutation analysis of KRAS, NRAS, BRAF, PIK3CA, and TP53. Neuroendocrine marker expression was found significantly less frequently in lymph node metastases compared to primary tumors and distant metastases (20%, 31%, 28%, respectively, P = 0.044). KRAS mutation rates increased significantly from primary tumors to lymph node metastases and distant metastases within the neuroendocrine negative CRC group (44%, 53%, 64%, respectively, P = 0.042). Neuroendocrine differentiation was significantly less concordant than KRAS/NRAS/BRAF/PIK3CA/TP53 mutational status in primary tumor/lymph node metastases pairs (65% versus 88%-99%; P < 0.0001) and primary tumor/distant metastases pairs (64% versus 83%-100%; P = 0.027 and P < 0.0001, respectively). According to these data, therapeutic targeting of neuroendocrine tumor cells can be considered only for a subset of CRC patients and biopsies from the metastatic site should be used to guide therapy. A possible importance of lacking neuroendocrine differentiation for progression of KRAS mutant CRC should be further investigated.     

PGD for hereditary breast and ovarian cancer: the route to universal tests for BRCA1 and BRCA2 mutation carriers

Preimplantation Genetic Diagnosis (PGD) is a method of testing in vitro embryos as an alternative to prenatal diagnosis with possible termination of pregnancy in case of an affected child. Recently, PGD for hereditary breast and ovarian cancer caused by BRCA1 and BRCA2 mutations has found its way in specialized labs. We describe the route to universal single-cell PGD tests for carriers of BRCA1/2 mutations. Originally, mutation-specific protocols with one or two markers were set up and changed when new couples were not informative. This route of changing protocols was finalized after 2 years with universal tests for both BRCA1 and BRCA2 mutation carriers based on haplotyping of, respectively, 6 (BRCA1) and 8 (BRCA2) microsatellite markers in a multiplex PCR. Using all protocols, 30 couples had a total of 47 PGD cycles performed. Eight cycles were cancelled upon IVF treatment due to hypostimulation. Of the remaining 39 cycles, a total of 261 embryos were biopsied and a genetic diagnosis was obtained in 244 (93%). In 34 of the 39 cycles (84.6%), an embryo transfer was possible and resulted in 8 pregnancies leading to a fetal heart beat per oocyte retrieval of 20.5% and a fetal heart beat per embryonic transfer of 23.5%. The preparation time and costs for set-up and validation of tests are minimized. The informativity of microsatellite markers used in the universal PGD-PCR tests is based on CEPH and deCODE pedigrees, making the tests applicable in 90% of couples coming from these populations.     

Polymorphisms in the IL2, IL2RA and IL2RB genes in multiple sclerosis risk

Interleukin (IL)-2/IL-2R signalling promotes proliferation and survival of activated T cells and has an essential non-redundant role in the production of regulatory T cells. Associations with different autoimmune diseases of polymorphisms in a linkage disequilibrium block in which the IL2/IL21 genes map (4q27), and also in genes encoding the IL2RA and IL2RB subunits (located in 10p15 and 22q13, respectively), were identified through genome-wide studies. Polymorphisms in these three genes were studied in 430 multiple sclerosis (MS) patients and in 550 ethnically matched controls from Madrid (Spain). Replication and meta-analysis with results from an independent cohort of 771 MS patients and 759 controls from Andalucía (Spain) confirmed the association of polymorphisms in the IL2RA gene (P_{Mantel–Haenszel,} odds ratio (OR)_M–H (95% confidence interval, CI) for rs2104286: 0.0001, 0.75 (0.65–0.87); for rs11594656/rs35285258: 0.004, 1.19 (1.06–1.34); for rs41295061: 0.03, 0.77 (0.60–0.98)); showed a trend for association of the IL2/IL21 rs6822844 (P_M–H=0.07, OR_M–H (95% CI)=0.86 (0.73–1.01)), but did not corroborate the association for IL2RB. Regression analyses of the combined Spanish cohort revealed the independence of two IL2RA association signals: rs2104286 and rs11594656/rs35285258. The relevant role of the IL2RA gene on MS susceptibility adds support to its common effect on autoimmune risk and the suggestive association of IL2/IL21 warrants further investigation.