Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and FOLFOX response in colorectal cancer patients

AIMS

To test prospectively the predictive value of germinal gene polymorphisms related to fluorouracil (FU) and oxaliplatin (Oxa) pharmacodynamics on toxicity and responsiveness of colorectal cancer (CRC) patients receiving FOLFOX therapy.

METHODS

Advanced CRC patients (n= 117) receiving FOLFOX 7 therapy were enrolled. Gene polymorphisms relevant for FU [thymidylate synthase (TYMS, 28 bp repeats including the G→C mutation + 6 bp deletion in 3''UTR), methylenetetrahydrofolate reductase (MTHFR, 677C→T, 1298A→C), dihydropyrimidine deshydrogenase (IVS14+1G→A) and Oxa: glutathione S-transferase (GST) π (105Ile→Val, 114Ala→Val), excision repair cross-complementing group 1 (ERCC1) (118AAT→AAC), ERCC2 (XPD, 751Lys→Gln) and XRCC1 (399Arg→Gln)] were determined (blood mononuclear cells).

RESULTS

None of the genotypes was predictive of toxicity. Response rate (54.7% complete response + partial response) was related to FU pharmacogenetics, with both 677C→T (P= 0.042) and 1298A→C (P= 0.004) MTHFR genotypes linked to clinical response. Importantly, the score of favourable MTHFR alleles (677T and 1298C) was positively linked to response, with response rates of 37.1, 53.3, 62.5 and 80.0% in patients bearing no, one, two or three favourable alleles, respectively (P= 0.040). Polymorphisms of genes related to Oxa pharmacodynamics showed an influence on progression-free survival, with a better outcome in patients bearing GSTπ 105 Val/Val genotype or XPD 751Lys-containing genotype (P= 0.054).

CONCLUSIONS

These results show that response to FOLFOX therapy in CRC patients may be driven by MTHFR germinal polymorphisms.     

Methylenetetrahydrofolate reductase (MTHFR) variants and fluorouracil-based treatments in colorectal cancer

5-fluorouracil (5FU)-based treatments remain the main chemotherapy for colorectal cancer. Optimal cytotoxicity of fluoropyrimidines requires elevated CH(2)FH(4) tumoral concentrations, controlled by the methylenetetrahydrofolate reductase (MTHFR) enzyme, which irreversibly converts CH(2)FH(4) into 5-methyltetrahydrofolate. The MTHFR gene is subject to several polymorphisms, of which the 677C>T and 1298A>C SNPs are the two most commonly linked with altered enzyme activity. Since a drop in MTHFR enzymatic activity may theoretically favor an increase in intracellular CH(2)FH(4) concentrations, it can be hypothesized that tumors exhibiting the rare MTHFR variants may be more sensitive to 5FU cytotoxicity. Accordingly, experimental data have shown that rare MTHFR variants in position 677 and 1298 are more sensitive to 5FU. However, results of clinical data do not concord regarding the influence of MTHFR genotype on tumoral CH(2)FH(4) concentration, 5FU responsiveness, patient survival and 5FU-related toxicity. These discrepancies may result from the interpatient variability arising from the individual folate status, as well as from the limited role of fluoropyrimidines in the current chemotherapy regimen administered in colorectal cancer.     

First-line treatment strategies to improve survival in patients with advanced colorectal cancer

Advanced colorectal cancer is a significant cause of worldwide cancer-related mortality. For the majority of patients, palliative chemotherapy can yield substantial improvements in survival. Fluorouracil has been the mainstay of treatment in this setting for the past few decades. The relatively recent availability of new combinations with active agents such as irinotecan and oxaliplatin makes this a promising and hopeful time for the treatment of metastatic colorectal cancer, with median survivals now approaching 18-21 months. For patients presenting with resectable metastases, the goal of therapy is surgery with a curative intent. There exists the potential for this approach to be extended also to a greater proportion of patients whose cancer may be rendered resectable following effective neoadjuvant chemotherapy. In addition, an improved understanding of molecular predictors for treatment response and toxicity may facilitate the future selection of individualised treatments for a given tumour profile. Further improvements in the management of advanced disease will continue to be pursued through the ongoing development of multimodality approaches and the incorporation of novel targeted agents with innovative chemotherapy combinations.     

亚甲基四氢叶酸还原酶C677T与A1298C基因多态性在卡培他滨治疗中晚期结直肠癌患者的临床意义

目的 探讨亚甲基四氢叶酸还原酶（MTHFR）C677T与A1298C基因多态性在卡培他滨治疗中晚期结直肠癌（CRC）患者的安全性及有效性,为临床诊治CRC提供理论依据。方法 收集经病理诊断确诊的中晚期结直肠癌患者50例,用实时荧光定量PCR仪进行MTHFR C677T与A1298C基因多态性检测,观察不同基因型之间安全性及有效性的差异。结果 MTHFR C677T的CC、CT、TT基因型频率分别为46%、40%、14%,TT基因型恶心呕吐的发生率及有效率高于CC与CT基因型,差别具有统计学意义（P<0.05）。MTHFR A1298C的AA、AC、CC基因型频率分别为60%、34%、6%,CC基因型腹泻发生率高于AA与AC基因型,差别具有统计学意义（P<0.05）,MTHFR A1298 C中各基因型有效率差异无统计学意义。结论 MTHFR C677T与MTHFR A1298C基因多态性在卡培他滨治疗CRC患者具有较好的临床意义,但MTHFR A1298C与药物治疗有效率无关。     

胸苷酸合成酶基因多态性预测氟尿嘧啶在晚期食管癌中的化疗疗效

目的研究胸苷酸合成酶（TS）和亚甲酰四氢叶酸还原酶（MTHFR）基因多态性与应用以氟尿嘧啶为基础的化疗方案治疗晚期食管癌疗效的相关性。方法收集经病理学确诊的晚期食管癌患者107例,并应用顺铂联合氟尿嘧啶三周方案化疗,最终98例患者按要求完成该研究。检测患者上述基因位点的多态性,分析基因多态性与反应率（response rate,RR）和无进展生存时间（progression free survival,PFS）的关系。结果TS-5′UTR端为2R2R或2R3C或3C3C型患者反应率和无进展生存时间优于2R3G或3C3G或3G3G（P=0.007和0.018）,其他位点基因多态性与反应率和无进展生存时间无显著相关性。结论TS-5＇UTR位点为2R2R或2R3C或3C3C型的晚期食管癌患者与氟尿嘧啶疗效存在相关性,有助于指导晚期食管癌选择氟尿嘧啶化疗。     

亚甲基四氢叶酸还原酶基因多态性及同型半胱氨酸水平与冠心病的关系

目的观察高同型半胱氨酸(HCY)是否是冠心病的一个独立危险因素,并探讨亚甲基四氢叶酸还原酶(MTHFR)基因多态性与冠心病(CHD)的联系。方法选择CHD患者80例,对照组70例。应用荧光偏振免疫分析法测定血浆HCY,以聚合酶链反应-限制性内切酶片段长度多态性(PCR-RELP)分析MTHFR基因多态性。结果CHD患者血浆HCY浓度显著高于对照组[分别为(17±11)μmol/L与(12±7)μmol/L,P<0.01]。MTHFR有3种基因型,即纯合子突变(TT)、杂合子突变(TC)及野生纯合型(CC)。CHD组TT型、TC型、CC型基因频率分布及T、C等位基因频率与对照组比较差异无统计学意义(χ2=3.213,P>0.05;χ2=1.836,P>0.05)。CHD组和对照组的TT型的血浆HCY水平明显高于TC型和CC型(P<0.01)。Logistic回归分析显示高HCY血症是CHD发病的独立危险因素,其OR值为3.108,95%可信区间1.426～6.775。结论高HCY血症是CHD发病的独立危险因素。MTHFR基因的C677T突变是高同型半胱氨酸血症的原因,但MTHFRC677T基因多态性与冠心病的发生无显著相关。     

西妥昔单抗联合化疗方案治疗晚期结直肠癌的临床疗效

目的评价西妥昔单抗联合化疗方案治疗晚期结直肠癌的疗效及不良反应。方法选择我院2007年1月-2010年6月单用或联合化疗使用西妥昔单抗治疗晚期或转移性结直肠癌患者35例,采用RF,cISr 1.1版实体肿瘤客观疗效评定标准进行临床疗效评价。并采用美国毒性反应评价标准(CIE 3.0)进行不良反应评价。结果共有31例纳入疗效评价。其中完全缓解l例,部分缓解9例,疾病稳定14例,疾病进展7例,有效率32.3%,疾病控制率75.O%;K-RAS基因野生型的患者有效率(40.0%)明显高于未检测组(18.2%)。33例发生了不良反应,发生率94.3%,主要为I～Ⅱ级(占74.1%)。结论西妥昔单抗联合放化疗方案治疗晚期结直肠癌可获得较高有效率,延长了疾病进展时间。     

贝伐珠单抗联合FOLFOX方案治疗晚期结肠癌患者的临床效果观察

目的 研究贝伐珠单抗联合FOLFOX方案治疗晚期结肠癌患者的临床效果.方法 将2014年7月至2016年7月于本院接受治疗的148例晚期结肠癌患者作为研究对象,用数字法随机将其分成观察组(74例)和对照组(74例).对照组接受FOLFOX治疗.观察组接受贝伐珠单抗联合FOLFOX方案治疗.治疗4周期后,利用x2检验对比两组客观缓解率及不良反应.结果 观察组总体客观缓解率优于对照组(41.89％比14.86％),差异具有统计学意义(x2=13.297,P=0.000).两组治疗后高血压(22.97％比36.49％)、胃肠道反应(22.97％比33.78％)以及白细胞减少(18.92％比28.38％)等不良反应发生率差异均无统计学意义(x2=3.234、1.834、2.128,P=0.072、0.176、0.145).结论 贝伐珠单抗联合FOLFOX方案治疗晚期结肠癌患者有较好的临床效果,且安全性高,值得临床推广.     

XRCC1基因多态与晚期胃癌化疗敏感性的关系

目的观察DNA修复酶XRCC1基因密码子399和194多态与晚期胃癌患者对5-氟尿嘧啶（5-FU）和铂类药物化敏感性的关系。方法 91例晚期胃癌患者给予5-FU和铂类药物方案治疗,化疗前检测XRCC1基因型。观察化疗疗效及其与XRCC1基因多态性的关系。结果本组化疗有效率为37.4%。XRCC1399和XRCC11943种基因型化疗有效率比较差异均无统计学意义（P〉0.05）。XRCC1399杂合子Arg/Gln基因型骨髓抑制发生率为25.7%低于纯合子基因型（Gln/Gln和Arg/Arg）的50.0%和47.8%;XRCC1399Gln等位基因携带型（Gln/Gln和Arg/Gln）呕吐反应发生率为30.0%和31.4%低于Arg/Arg基因型的54.4%;XRCC1194Trp/Trp基因型骨髓抑制发生率为0低于Arg等位基因携带型（Arg/Trp和Arg/Arg）的41.5%和45.2%,差异均有统计学意义（P〈0.05）。结论 XRCC1基因多态性与晚期胃癌患者对5-FU为基础的含铂类药物方案化疗疗效的关系不确切,但与晚期胃癌对5-FU和铂类药物化疗的Ⅱ度以上严重不良反应发生有关,检测XRCC1基因型可以为晚期胃癌化疗药物的选择、避免严重毒副反应的发生提供参考依据。     

Skin rash secondary to bevacizumab in a patient with advanced colorectal cancer and relation to response

Bevacizumab (Avastin) in combination with intravenous 5-fluorouracil-based chemotherapy as first-line as well as second-line treatment of metastatic colorectal cancer improves survival. Although skin rash (type unspecified) has been described in some patients following infusion of bevacizumab, it is not a common toxicity of bevacizumab, while acneiform rash occurs in more than 90% of patients who receive cetuximab (Erbitux), the severity of which appears to be predictive of response. We report a patient with colorectal cancer who developed a rash secondary to bevacizumab that correlated with response. A 40-year-old patient with stage IV colorectal cancer received FOLFOX-4 and bevacizumab, which he tolerated very well except for a skin rash related to bevacizumab. The rash cleared every time bevacizumab was eliminated from the chemotherapy regimen. When use of bevacizumab was resumed, similar rash reappeared. Therefore, we believe that this observation of the rash emergence was linked to bevacizumab administration. The most common toxicities associated with bevacizumab include hypertension, hemorrhage, gastrointestinal perforation, arterial thromboembolism, wound healing and proteinuria. Exfoliative dermatitis and a nonspecific rash have been reported with bevacizumab. This case report, we believe, is the first report of a possible correlation between a rash and a positive drug response associated with bevacizumab, and may initiate further investigation of similar observation.     

雷替曲塞与奥沙利铂在老年晚期结直肠癌患者中的联合应用研究

目的观察雷替曲塞与奥沙利铂在老年晚期结直肠癌患者中的联合应用价值。方法选择本院2009年1月～2011年6月收治的经临床病理证实的老年晚期结直肠癌患者43例,随机分为研究组和对照组,研究组22例患者给予奥沙利铂联合雷替曲塞化疗,对照组21例患者给予亚叶酸钙＋氟尿嘧啶＋奥沙利铂联合化疗,两组均以3周为1个周期,治疗2个周期后评价治疗效果及安全性。结果研究组有效率明显高于对照组（P〈O．05）;两组药物不良反应中血小板减少、周围神经毒性、脱发、转氨酶异常、腹泻等差异无统计学意义（P〉O．05）,研究组疲劳、恶心呕吐发生率明显低于对照组,差异有统计学意义（P〈O．05）。结论雷替曲塞与奥沙利铂在老年晚期结直肠癌患者中的近期疗效优于标准方案,且患者消化道不良反应较轻,值得应用。     

UGT1A1基因多态性与伊立替康治疗晚期结直肠癌毒性和疗效的关系

目的：探讨UGT1A1＊28/＊6基因多态性与伊立替康治疗晚期结直肠癌的毒性和疗效的关系。方法：选取2011年6月–2013年6月在我科治疗的晚期结直肠癌患者,共计102例,对其进行UGT1A1＊28/＊6基因检测,随访记录患者行伊立替康化疗后的不良反应和近期疗效,比较不同基因型患者之间有无差异。结果：不同UGT1A1＊28/＊6基因型患者中3~4级中性粒细胞减少和迟发性腹泻发生率无显著差异。联合UGT1A1＊28和＊6两位点分析,野生型、单点变异型和双点变异型患者中3~4级中性粒细胞减少发生率逐渐升高,三者有显著差异且升高趋势有统计学意义（4.3%、17.4%、57.1%,P=0.005,趋势检验P=0.002）。UGT1A1＊28基因型对治疗有效率（RR）和疾病控制率（DCR）无显著影响,但UGT1A1＊6基因突变者较野生型者RR、DCR均明显降低（P=0.023,P=0.032）。联合两位点分析,野生型、单点变异型和双点变异型患者RR、DCR均有显著差异（P=0.002,P=0.008）,且DCR降低趋势有统计学意义（95.7%、73.9%、42.9%,趋势检验P=0.001）。结论：在预测伊立替康毒性及疗效时,联合检测UGT1A1＊28/＊6两位点基因较单独检测一个位点更有价值。     

精神分裂症患者的多药耐药基因多态性与利培酮的疗效及不良反应的相关性

目的观察中国汉族精神分裂症患者多药耐药基因多态性与利培酮临床疗效和不良反应的相关性。方法入选192例符合DSM-IV精神分裂症诊断的患者,给予利培酮每天2～6 mg,治疗8周。在治疗基线、第4,8周,用阳性与阴性症状量表(PANSS)评估临床疗效。用聚合酶链式反应(PCR)和限制酶切法,检测患者rs1045642和rs2235048的基因多态性。不良反应观察指标为锥体外系不良反应(EPS)发生率、各实验室检查值的变化。结果 PANSS减分率在rs1045642和rs2235048不同基因型及等位基因间分布差异无统计学意义(P>0.05);药物不良反应和EPS的发生率在各基因型和等位基因间差异无统计学意义(P>0.05)。结论多药耐药基因rs1045642和rs2235048的基因多态性与利培酮的疗效和安全性可能无关联。     

Combined treatment with Bevacizumab and standard chemotherapy restores abnormal immune parameters in advanced colorectal cancer patients

Background Bevacizumab, a monoclonal antibody (mAb) targeting vascular endothelial growth factor (VEGF), has produced promising results when combined with chemotherapy in the treatment of advanced colorectal cancer (CRC). The aim of the present study was to define the immunological profile of metastatic CRC patients at baseline and following chemotherapy with either irinotecan/5-fluorouracil/leucovorin (IFL) alone or IFL in combination with.bevacizumab (B-IFL). Methods Peripheral blood mononuclear cells (PBMCs) obtained from healthy donors (HD) (n = 20) and patients (n = 40) were tested for T-cell proliferation in the autologous mixed lymphocyte reaction (auto-MLR), and cytokine production following stimulation with anti-CD3 mAb. Results,PBMCs obtained from CRC patients prior to treatment exhibited lower auto-MLR responses and low production of IL-2, IFN-γ, IL-12 and IL-18 cytokines, whereas IL-4 and IL-10 cytokines were increased as compared to HD (p < 0.001, for all parameters) following in vitro stimulation with anti-CD3 mAb. During treatment, and in particular in week 12 of evaluation, IL-2 (p < 0.001 for both IFL and B-IFL groups), IFN-γ (p < 0.001 for IFL and p = 0.001 for B-IFL), IL-12 (p < 0.001 for both IFL and B-IFL) and IL-18 (p < 0.001 for both IFL and B-IFL) production, as well as auto-MLR responses increased (p < 0.001 for both IFL and B-IFL), whereas IL-4 (p < 0.001 for IFL and p = 0.001 for B-IFL) and IL-10 [p < 0.001 for IFL and p = 0.067 (non-significant) for B-IFL] production decreased over baseline in the two treatment groups, yet their respective values never reached those of HD. Moreover, IL-2, IFN-γ production, and auto-MLR were higher in the B-IFL over the IFL treatment group (p < 0.001, p < 0.04, p < 0.001, respectively). Conclusion Our study demonstrates that the abnormal immune parameters observed in metastatic CRC patients at presentation can substantially improve during treatment with either IFL or B-IFL. The immune parameters examined can provide a sensitive and valuable tool for monitoring immune function in CRC patients, and could be applied as surrogate markers predicting treatment-related outcome.     

Cyclin D1 and epidermal growth factor polymorphisms associated with survival in patients with advanced colorectal cancer treated with Cetuximab

The study aimed to investigate whether polymorphisms in genes of the EGFR signaling pathway are associated with clinical outcome in advanced colorectal cancer (CRC) patients treated with single-agent Cetuximab. Polymorphisms of interest in the EGFR pathway include: cyclin D1 (CCND1) A870G, cyclooxygenase 2 (Cox-2) G-765C, epidermal growth factor (EGF) A61G, epidermal growth factor receptor (EGFR) codon R497 K, EGFR CA dinucleotide repeat in intron 1, interleukin (IL)-8 T-251A and vascular endothelial growth factor (VEGF) C936 T gene polymorphisms. Thirty-nine metastatic CRC patients were enrolled in the IMCL-0144 trial and treated with single-agent Cetuximab. Using the polymerase chain reaction-restriction fragment length polymorphism method, gene polymorphisms of CCND1, COX-2, EGF, EGFR, IL-8 and VEGF were assessed from genomic DNA extracted from blood samples. A significant association was found between the CCND1 A870G polymorphism and overall survival in our 39 CRC subjects. Patients with the AA homozygous genotype survived for a median of 2.3 months [95% confidence interval (CI)=2.1-5.7], whereas those with any G allele (AG, GG genotype) survived for a median of 8.7 months (95% CI=4.4-13.5) (P=0.019, log-rank test). When we analysed the cyclin D1 and EGF polymorphisms together, patients with favourable genotypes (EGF any A allele and CCND1 any G allele) showed a median survival time of 12 months (95% CI=4.8-15.2), whereas patients with any two unfavourable genotypes (EGF GG or CCND1 AA) showed a median survived time of 4.4 months (95% CI=2.1-5.7) (P=0.004, log-rank test). The findings of this pilot study suggest that the cyclin D1 A870G and the EGF A61G polymorphisms may be useful molecular markers for predicting clinical outcome in CRC patients treated with single-agent Cetuximab.     

Linkage disequilibrium between the 677C>T and 1298A>C polymorphisms in human methylenetetrahydrofolate reductase gene and their contributions to risk of colorectal cancer

A common polymorphism in a folate-metabolizing gene, methylenetetrahydrofolate reductase (MTHFR) 677C>T has been associated with reduced risk of colorectal cancer. In this study, we investigated whether a second common polymorphism of the gene, MTHFR 1298A>C, is an independent risk factor for colorectal cancer and if it is associated with plasma folate and total homocysteine (tHcy) levels. We also examined whether the 677C>T and 1298A>C polymorphisms are in linkage disequilibrium and whether combined heterozygosity confers additional (or reduced) risk of colorectal cancer. We conducted a nested case-control study of 211 incident colorectal cancer cases and 343 controls in the prospective Physicians' Health Study. The MTHFR 677C>T and 1298A>C polymorphisms were in linkage disequilibrium in this population. Compared to MTHFR 1298AA genotype, multivariate-adjusted relative risk of colorectal cancer was 0.73 (95% CI 0.37-1.43) for the MTHFR 1298CC genotype. The slight reduction in risk was not a result of its linkage disequilibrium with the 677C>T polymorphism. This polymorphism was not significantly correlated with the plasma folate and tHcy levels. The combined heterozygosity did not modify the cancer risk; nor did it change the plasma folate and tHcy significantly. We conclude that the MTHFR 1298A>C polymorphism is a less substantial independent risk factor for colorectal cancer compared to the 677C>T polymorphism.     

单核苷酸多态性与NSCLC铂类化疗敏感性的关系

目的探讨ERCC1(C118T)、XRCC1(G399A)的单核苷酸多态性(SNP)与非小细胞肺癌(NSCLC)对铂类为主化疗方案敏感性的关系。方法经病理学确诊的晚期NSCLC患者120例,采用铂类为主的两药联合化疗方案,2～3个周期后进行临床疗效评价。根据cDNA芯片原理制作目的基因芯片,利用双色荧光探针杂交进行ERCC1、XRCC1的多态性的基因分型,比较不同基因型与化疗敏感性的关系。结果 ERCC1(C118T)至少携带1个T等位基因型的患者化疗有效率为44.7%,显著高于C/C基因型的19.2%(P<0.05);携带XRCC1(G399A)G/G基因型者化疗有效率为43.8%,高于至少携带1个A等位基因的19.4%(P<0.05)。结论 ERCC1、XRCC1基因多态性与NSCLC患者对铂类药物化疗的敏感性相关。     

乌苯美司联合卡培他滨治疗晚期老年结直肠癌临床观察

目的观察乌苯美司联合卡培他滨治疗老年晚期结直肠癌临床疗效和对免疫功能的影响。方法选择晚期结直肠癌患者共52例,随机分为治疗组26例和对照组26例。对照组采用卡培他滨进行治疗,治疗组在对照组的基础上加用乌苯美司片,连续治疗8周。结果有效率治疗组为34.6%,对照组为11.5%,两组比较,差异有统计学意义（P〈0.05）;治疗组T辅助淋巴细胞（CD3＋、CD4＋）增加,而对照组减少,差异有统计学意义（P〈0.05）;治疗组KPS评分稳定率高于对照组,体重稳定,差异有统计学意义（P〈0.05）,两组胃肠道反应、手足综合征及血液学毒性方面比较差异无统计学意义（P〉0.05）。结论乌苯美司联合卡培他滨可提高晚期结直肠癌患者临床疗效及免疫功能,改善患者生活质量。