XRCC1单核苷酸多态性预测晚期NSCLC铂类药物化疗的敏感性

目的研究XRCC1单核苷酸多态性与晚期非小细胞肺癌(non-small cell lung cancer,NSCLC)对以顺铂(cisplatin,DDP)或卡铂(carboplatin,CBP)为基础药物的化疗敏感性的关系。方法经病理学确诊的晚期NSCLC患者97例,采用DDP或CBP为基础药物的方案化疗,3个周期后进行疗效评价。以聚合酶链反应(PCR)结合限制性片段长度多态性(RFLP)检测XRCC1Arg194Trp和Arg399Gln基因型,并比较基因型与化疗敏感性的关系。结果(1)携带XRCC1194Arg/Trp的患者有效率高于携带Arg/Arg、Trp/Trp基因型的患者(P<0.05);携带至少一个Trp等位基因基因型患者的化疗敏感性是携带Arg/Arg基因型的3.4倍(OR=3.39,95%,CI=1.32~8.70,P<0.05)。(2)携带XRCC1399Arg/Arg、Arg/Gln、Gln/Gln基因型患者的有效率分别为36.4%、22.9%、28.6%,差异无统计学意义(P>0.05)。尚未发现XRCC1Arg194Trp和Arg399Gln基因多态性存在联合作用。结论XRCC1Arg194Trp单核苷酸多态性可能与晚期NSCLC对铂类药物的化疗敏感性相关。     

DNA损伤修复基因XRCC1和XPD遗传多态与晚期非小细胞肺癌对铂类药物的敏感性

目的 探讨DNA损伤修复基因XRCC1和XPD的遗传多态与晚期非小细胞肺癌（NSCLC）对以铂类为主化疗药物敏感性的关系。方法 以聚合酶链反应（PCR）结合限制性片段长度多态性（RFLP）,检测200例以顺铂（DDP）或卡铂（CBP）为主要化疗方案的NSCLC患者XRCC1 Arg194Trp和XPD Lys751Gln多态基因型,并比较不同基因型与化疗敏感性的关系。结果 化疗总有效（CR＋PR）率为36．0％,其中CR1例,PR71例,SD94例,PD34例。携带XRCC1第194位密码子Arg／Trp或Trp／Trp基因型的个体化疗敏感性是XRCC1第194位密码子Arg／Arg基因型携带者的2．48倍（95％CI为1．36～4．51,P=0．003）;未发现XPD Lys751Gln多态与化疗敏感性的相关性。联合分析这两个遗传多态发现,XRCC1 Arg194Trp和XPD Lys751Gln多态在NSCLC对铂类药物敏感性中存在一定的联合作用（趋势检验,P=0．004）。结论XRCC1 Arg194Trp和XPDLys751Gin遗传多态可能与NSCLC铂类药物敏感性有关。     

XRCC1单核苷酸多态与晚期非小细胞肺癌对铂类药物化疗敏感性的相关性

背景与目的DNA修复能力与肿瘤细胞对铂类药物的敏感性密切相关。本研究探讨DNA修复基因XRCC1单核苷酸多态性与非小细胞肺癌(non-smallcelllungcancer,NSCLC)患者对顺铂(cisplatin,DDP)或卡铂(carboplatin,CBP)为主的化疗方案敏感性的关系。方法经病理学确诊的晚期NSCLC患者105例,采用DDP或CBP为主的方案化疗,2～3个周期后进行临床疗效评价。以PCR-RFLP进行XRCC1Arg194Trp和Arg399Gln多态的基因分型,比较不同基因型对化疗敏感性的影响。比值比(OR)及其95%可信区间(CI)由logistic回归模型计算。结果携带至少一个Trp等位基因者化疗有效率为43.1%,显著高于携带Arg/Arg基因型的20.3%(OR=2.97,95%CI=1.15～7.72;P<0.05)。携带XRCC1399Arg/Arg基因型者化疗有效率为41.5%,显著高于携带至少一个Gln等位基因者的21.2%(OR=2.65,95%CI=1.03～6.87;P<0.05)。这两个多态之间存在联合作用,同时携带194Arg/Trp和399Arg/Arg基因型的患者,治疗有效率为66.7%,明显高于携带其它基因型的患者(有效率20.0%～23.1%)。结论XRCC1基因多态与NSCLC患者对铂类药物化疗的敏感性相关。     

XRCC1基因多态性与卵巢癌对铂类药物化疗敏感性的相关性研究

目的 探讨X线修复交叉互补基因1（XRCC1）Arg194Trp和Arg399Gln位点多态性与卵巢癌对铂类药物化疗敏感性之间的关系。方法 选取82例首次术后以铂类为基础化疗达6个周期的卵巢癌患者,采用聚合酶链反应 限制性片段长度多态性分析（PCR RFLP）检测外周血XRCC1 Arg194Trp和Arg399Gln位点的基因型,分别比较两个位点的不同基因型与化疗敏感性及两个位点之间的关系。结果 XRCC1 Arg194Trp存在3个基因型,即Arg／Arg、Arg／Trp、Trp／Trp,基因分布频率分别为47.6％、43.9％、8.5％;XRCC1 Arg399Gln亦存在3个基因型,即Arg／Arg、Arg／Gln、Gln／Gln,基因分布频率分别为25.6％、40.2％、34.1％。XRCC1 Arg399Gln 的不同基因型在FIGO分期和年龄分组中的差异均有统计学意义（P＜0.05）。化疗敏感组与不敏感组两个位点多态性基因型之间的差异均有统计学意义（P＜0.05）。XRCC1 Arg194Trp的Trp／Trp和Arg 399Gln的Gln/Gln基因型比Arg／Arg基因型更易对铂类药物产生耐药性,比值比分别增加至13.50倍（95％CI：1.461～124.739）和7.65倍（95％CI：2.012～29.088）。同时携带Arg194Trp Arg／Trp和Arg399Gln Gln／Gln基因型的患者对化疗不敏感率高达84.62％（OR=22.00,95％CI：2.534～190.998;P＜0.05）。结论 XRCC1 Arg194Trp和Arg399Gln位点基因多态性与卵巢癌对铂类药物的化疗敏感性相关,并且两位点之间存在联合效应。     

XRCC1和XRCC3单核苷酸多态性与晚期非小细胞肺癌铂类药物化疗疗效的相关性

背景与目的 DNA修复基因多态性预测铂类药物化疗敏感性对非小细胞肺癌(non-small cell lung cancer,NSCLC)个体化治疗具有重要意义.本研究旨在探讨X线修复交错互补基因1(X-ray repair cross complementing gene 1,XRCC1)和X线修复交错互补基因3(X-ray repair cross complementing gene 3,XRCC3)单核苷酸多态性与晚期NSCLC患者对铂类药物化疗疗效的关系.方法 采用PCR-RFLP方法检测130例以含铂方案化疗的晚期NSCLC患者外周血DNA中XRCC1 Arg194 Trp、Arg399 Gln和XRCC3 Thr241 Met基因多态性,分析其基因型与化疗疗效的关系.结果 130例晚期NSCLC患者采用含铂方案化疗2个周期后,化疗总有效率为33.8％.XRCC1 194和399基因多态性与铂类药物化疗敏感性相关,而XRCC3 241基因多态性与化疗敏感性无关(P=0.145).携带至少1个XRCC1 194 Trp等位基因者化疗有效率至少是携带Arg/Arg基因型患者的2.5倍(42.1％vs22.2％,OR=2.545,95％CI:1.159-5.590,P=0.020).携带XRCC1399 Arg/Arg基因型者的化疗有效率为45.5％,明显高于携带至少1个Gln等位基因者(21.9％)(OR=0.336,95％CI:0.156-0.722,P=0.005).XRCC1 194和399基因多态性之间存在联合作用,同时携带至少1个XRCC1 194 Trp等位基因和399 Arg/Arg基因型者的化疗有效率明显高于同时携带194 Arg/Arg和399 Arg/Gln基因型者(44.4％ vs 18.8％,OR=3.467,95％CI:1.223-9.782,P=0.019).XRCC1和XRCC3基因多态性在化疗敏感性方面存在一定的联合作用,携带至少1个XRCC1 194 Trp等位基因和399 Arg/Arg野生型基因同时又携带XRCC3 241 Thr/Met基因型者的化疗有效率明显高于其它基因型携带者.结论 XRCC1和XRCC3的多态联合可能与晚期NSCLC患者对铂类药物化疗疗效具有相关性.     

DNA修复酶XRCC1基因多态与非小细胞肺癌对GP方案化疗的敏感性

目的 研究DNA修复酶XRCC1基因Codon 194和Codon 399多态与非小细胞肺癌（NSCLC）患者对吉西他滨/顺铂（GP）方案化疗敏感性的关系.方法 收集经病理学确诊的NSCLC 57例,所有病例化疗前抽静脉血,提取白细胞DNA,用PCR-RFLP技术检测XRCC1 194和399基因型.所有患者均经PDD/GEM化疗方案治疗.结果 ①NSCLC患者中,XRCC1 194 Arg/Arg、 Arg/Trp 、Trp/Trp基因型者分别为30例（52.6%）、23例（40.4%）和4例（7.0%）;XRCC1 399 Arg/Arg、 Arg/Gln、Gln/Gln基因型者分别为31例（54.4%）、23例（40.3%）和3例（5.3%）.经化疗后,19例患者有效,总有效率33.3%.②XRCC1 194 Trp/Trp、Tp/Arg和Arg/Arg基因型者的化疗有效率分别为50.0%、52.2%和16.7%.携带Trp等位基因者的化疗有效率（51.9%）显著高于Arg/Arg基因型者（χ^2=6.41,P=0.0113）;XRCC1 399 Arg/Arg、Arg/Gln和Gln/Gln基因型者的化疗有效率分别为35.5%、34.8%和0,各组间的差异无显著性.XRCC1 194与XRCC1 399多态之间在化疗敏感性方面存在明显的交互作用,同时携带194 Arg/Arg和399 Arg/Arg基因型者的化疗有效率仅为7.7%（1/13）,而同时携带XRCC1 194 Trp等位基因和399 Arg/Arg基因型者的化疗有效率为58.8%（10/17）,2组之间差异显著（Fisher＇s双侧检验：P=0.0067）.结论 DNA修复酶基因XRCC1多态与NSCLC对GP方案化疗的敏感性有关,患者的基因型检测有可能作为预测NSCLC 对GP方案化疗敏感性的指标.     

碱基切除修复基因多态性与晚期非小细胞肺癌铂类药物化疗敏感性

目的：探讨DNA碱基切除修复通路中XRCC1 Arg399Gln和ADPRT Val762Ala基因多态性与晚期非小细胞肺癌（NSCLC）铂类药物化疗敏感性的关联,并与先前报道的XRCC1 T-77C、Argl94Trp联合分析其预测作用。方法：收集接受铂类药物为基础化疗的晚期NSCLC患者107例,用PCR—RFLP法检测基因型,分析各基因型与铂类药物化疗有效率的关联,并以非条件Logistic回归模型对患者年龄、性别、病理类型、临床分期和治疗方案进行校正。结果：对XRCC1 Arg399Gln多态性进行单因素分析时,发现携带至少1个Gln等位基因的患者的化疗有效率是携带Arg／Arg基因型者的0．42倍（95％CI：0．19—0．93）,差异具有统计学意义;经多因素校正后发现携带至少1个Gln等位基因的患者的化疗有效率是携带Arg／Arg基因型者的0．52倍（95％CI：0．22—1．26）,但差异不再具有统计学意义。对ADPRT Val762Ala多态性进行多因素分析时,发现携带至少1个Ala等位基因的患者的化疗有效率是携带Val／Val基因型者的1．57倍（95％CI：0．67—3．66）。联合分析各患者4个多态性位点的铂类药物敏感基因型的总数目与铂类药物化疗有效率的关联,并经多因素分析校正后,发现携带3—4个铂类药物敏感基因型的患者的化疗有效率是具有0—2个铂类药物敏感基因型者的4．15倍（95％CI：1．54—11．19）,差异具有统计学意义。结论：XRCC1 Arg399Gln多态性与铂类药物化疗敏感性的关系需进一步确认,似乎携带野生型Arg／Arg者对铂类药物化疗更敏感;但未能发现ADPRT Val762Ala多态性与锥苑矧别眇德魄牲存在明显关联;4个多态性位点联合分析的预测效能高于单个位点。     

XRCC1单核苷酸多态性与鼻咽癌铂类化疗敏感度的相关性

目的 探讨鼻咽癌铂类化疗敏感度与X射线交错互补修复基因1 codon194和codon399单核苷酸多态性的相关性。方法 收集广西医科大学第四附属医院2012年9月1日至2013年12月31日鼻咽部肿物活检确诊为鼻咽癌患者资料,采用限制性片段长度多态性聚合酶链反应技术检测鼻咽癌患者外周血DNA XRCC1 codon194和codon399单核苷酸多态性。顺铂+氟尿嘧啶方案诱导化疗2周期后复查MRI,按照RECIST 1.1标准评价其化疗敏感度,分析单核苷酸多态性（Single nucleotide polymorphism,SNP）与化疗敏感度的关系。结果 XRCC1 codon399 Gln/Gln基因型携带者化疗敏感度为Arg/Arg基因型携带者的3.500倍（P＜0.05）。XRCC1 codon399不含Arg基因型（即Gln/Gln）携带者化疗敏感度为含Arg基因型（Arg/Arg 和 Arg/Gln）携带者的3.274倍,（P＜0.05）。携带XRCC1 codon194各基因型患者化疗敏感度之间差异无明显统计学意义（P＞0.05）。结论 XRCC1 codon399 单核苷酸多态性有可能成为鼻咽癌铂类化疗敏感度的预测因子。     

晚期非小细胞肺癌对铂类药物的化疗敏感性与p53和p73基因多态的关系

目的探讨细胞凋亡相关基因p53和p73的遗传多态,与晚期非小细胞肺癌（NSCLC）对铂类药物化疗敏感性的关系。方法以聚合酶链反应（PCR）-限制性片段长度多态性（RFLP）和突变扩增阻抑系统（ARMS）分析方法,对165例以顺铂（DDP）或卡铂（CBP）为主进行化疗的晚期NSCLC患者,进行p53第72密码子Arg→Pro多态,和p73第2外显子G4C14-A4T14多态的检测,2～3个疗程后进行效果评价。以非条件Logistic回归模型比较不同基因型与化疗疗效的关系。结果携带p53 72Pro等位基因患者的化疗敏感性,是携带p53 72Arg／Arg基因型患者的2、46倍（95％CI,1．11～5．45,P=0．026）;而携带至少1个p73突变等位基因（A4T14）的患者,其化疗敏感性是携带p73 G4C14／G4C14基因型患者的2．22倍（95％讲,1．14～4、30,P=0．019）。2个多态位点合并分析结果显示,同时携带p53和p73野生基因型的患者,化疗有效率为7．7％;而携带1个、2个和≥3个p53和p73变异等位基因的患者,化疗有效率分别为34．8％、42．2％和40、7％。结论p53和p73基因遗传多态与晚期NSCLC患者对以铂类药物为主的化疗敏感性有关。     

XRCC 1 Arg399Gln基因多态性对铂类药物化疗胃癌患者预后的影响

目的：研究DNA修复酶X射线损伤交叉互补蛋白1（X-ray repair cross-complementary protein1，XRCCl）基因Arg399Gln多态性对接受铂类药物辅助化疗的胃癌患者预后的影响。方法：选取经病理学确诊的胃癌患者84例，采用含铂类药物的联合化疗方案进行辅助化疗。化疗前采集患者外周血，采用聚合酶链反应．连接酶检测反应（polymerase chain reaction-ligation detection reaction，PCR-LDR）技术检测XRCCl基因Arg399Gln的多态性。结果：84例胃癌患者中，49例（58．3％）携带XRCCl的399Axg／Arg基因型，30例（35．7％）携带Arg／Gln基因型，5例（6．0％）携带Gin／Gin基因型；截止到随访结束，分别有63．1％（53／84）和55．2％（43／84）的患者出现复发和死亡，其中携带Arg／Arg基因型的胃癌患者复发率和死亡率均显著低于携带Arg／Gln或Gln／Gln基因型患者（P〈0.05）。COX多因素分析显示，携带Arg／Arg基因型的患者具有较好的无复发生存期和总生存期预后（P〈0．05）。结论：XRCClArg399Gln基因多态性与术后胃癌患者接受铂类药物化疗后的预后有关，可以在一定程度上判断术后胃癌患者接受铂类药物化疗的预后情况。     

Prognostic Significance of GSTP1, XRCC1 and XRCC3 Polymorphisms in Non-small Cell Lung Cancer Patients

Aim: Individual differences in chemosensitivity and clinical outcome in non-small cell lung cancer (NSCLC)patients treatment with platinum-based chemotherapy may be due to genetic factors. Our study aimed toinvestigate the prognostic role of GSTP1, XRCC1 and XRCC3 in NSCLC patients treated with chemotherapy.Methods: A total of 460 cases were consecutively selected from The Affiliated Hospital of Nantong Universitybetween Jan. 2003 to Nov. 2006, and all were followed-up until Nov. 2011. Genotyping of GSTP1 Ile105Val, XRCC1Arg194Trp, XRCC1 Arg399Gln and XRCC3 Thr241Met was conducted by duplex polymerase-chain-reactionwith confronting-two-pair primer methods. Results: Patients with GSTP Val/Val exhibited a shorter survivaltime, and had a 1.89 fold greater risk of death than did those with the IIe/IIe genotype. For XRCC1 Arg194Trp,the variant genotype Trp/Trp was significantly associated with a decreased risk of death from NSCLC whencompared with the Arg/Arg. Individuals carrying XRCC1 399Gln/Gln genotype had a longer survival time,with a lowered risk of death from NSCLC. Conclusion: This study indicated that GSTP1 Ile105Val, XRCC1Arg194Trp and XRCC1Arg399Gln genes have a role in modifying the effect of platinum-based chemotherapyfor NSCLC patients in a Chinese population. Our findings provide information for therapeutic decisions forindividualized therapy in NSCLC cases.     

XRCC1 and XRCC3 polymorphisms and their role as effect modifiers of unsaturated fatty acids and antioxidant intake on colorectal adenomas risk.

Whereas animal and in vitro studies support a role of unsaturated fatty acids in colon carcinogenesis, the epidemiologic evidence is inconclusive. Using a large sigmoidoscopy-based case-control study (753 cases and 799 controls) in Los Angeles County, we investigated possible associations between single-nucleotide polymorphisms in the XRCC1 (codons 194 Arg/Trp and codon 399 Arg/Gln) and XRCC3 (codon 241 Thr/Met) genes and colorectal adenoma risk and their possible role as modifiers of the effect of monounsaturated fatty acid, the ratio of omega-6/omega-3 polyunsaturated fatty acids, and antioxidant intake. We found no evidence of associations between the XRCC1 codon 194 Arg/Trp or Trp/Trp genotypes and the XRCC3 codon 241 Thr/Met or Met/Met genotypes. Subjects with the XRCC1 Gln/Gln genotype were inversely associated with adenoma risk (odds ratio, 0.6; 95% confidence interval, 0.4-0.9; P = 0.01) when compared with subjects with Arg/Arg and Arg/Gln genotypes combined. We found no evidence of gene-dietary fat interactions for the XRCC3 codon 241 polymorphism. However, our data suggest an XRCC1-unsaturated fat interaction. High monounsaturated fatty acid intake was associated with adenoma risk only among subjects with the XRCC1 codon 194 Arg/Arg and codon 399 Gln/Gln combined genotypes (P for interaction = 0.018). High omega-6/omega-3 polyunsaturated fatty acid ratios were associated with adenoma risk among subjects with the XRCC1 codon 194 Arg/Arg and codon 399 Gln/Gln or the codon 194 Arg/Trp or Trp/Trp and codon 399 Arg/Arg or Arg/Gln combined genotypes (P for interaction = 0.026). These interactions were not modified by antioxidant intake. However, low antioxidant intake was associated with an inverse association only among subjects with the XRCC1 codon 194 Arg/Trp or Trp/Trp and codon 399 Arg/Arg or Arg/Gln combined genotypes (P for interaction = 0.022), which was independent of unsaturated fat intake. Our data suggest that the XRCC1 codon 194 and codon 399 single nucleotide polymorphisms may modify the effect of unsaturated fatty acid and antioxidant intake and that this XRCC1 effect modification may explain, in part, previously reported inconsistencies on the role of unsaturated fatty acids and adenoma risk.     

The association of XRCC1 gene single nucleotide polymorphisms with response to neoadjuvant chemotherapy in locally advanced cervical carcinoma

Background

Platinum-based neoadjuvant chemotherapy (NAC) is new therapeutic strategy for locally advanced cervical carcinoma, but the variables used to predict NAC response are still infrequently reported. The aim of our study was to investigate the association between XRCC1 gene single nucleotide polymorphisms (SNPs) and NAC response.

Methods

Seventy patients with locally advanced cervical carcinoma who underwent NAC were collected. SNPs of XRCC1 (at codon 194 and 399) and XRCC1 protein expression were detected. The association of XRCC1 gene SNPs and protein expression with NAC response were analyzed.

Results

Response to NAC was not statistically significant in three genotypes, Arg/Arg, Arg/Trp, Trp/Trp of XRCC1 at codon 194(X² = 1.243, P = 0.07), while responses were significantly different in genotypes Arg/Arg, Arg/Gln, Gln/Gln of XRCC1 at codon 399 (X² = 2.283, P = 0.020). The risk of failure to chemotherapy in the patients with a Gln allele(Arg/Gln+Gln/Gln) was significantly greater than that with Arg/Arg(OR = 3.254, 95%CI 1.708 ~ 14.951). The expression level of XRCC1 protein was significantly associated with response to NAC. Moreover, the genotype with the Gln allele(Arg/Gln+Gln/Gln) at codon 399, but not codon at 194, presented a significantly higher level of XRCC1 protein expression than that with Arg/Arg genotype (F = 2.699, p = 0.009).

Conclusion

SNP of XRCC1 gene at codon 399 influences the response of cervical carcinoma to platinum-based NAC. This is probably due to changes in expression of XRCC1 protein, affecting response to chemotherapy.     

DNA repair gene polymorphism associated with sensitivity of lung cancer to therapy

This study aimed to investigate association between single-nucleotide polymorphisms (SNPs) of excision repair cross-complementing gene 1 (ERCC1), excision repair cross-complementing gene 2 (ERCC2), and X-ray repair cross-complementing group 1 (XRCC1) with sensitivity of advanced non-small cell lung cancer (NSCLC) patients to platinum-based chemotherapy. A total of 89 NSCLC patients were recruited and treated with two cycles of platinum-based chemotherapy. DNA was extracted from peripheral lymphocytes for detection of SNPs of ERCC1 Asn118Asn, ERCC2 Lys751Gln, and XRCC1 Arg399Gln. The overall response rate of these patients was 29.2%. There was no statistically significant difference of treatment response between the wild genotypes and the variant genotypes for the ERCC1 Asn118Asn and ERCC2 Lys751Gln gene. The distributions of genotypes XRCC1 Arg399Gln differed significantly between the response and non-response groups (76.9 vs. 23.1%, P = 0.001). The XRCC1 399Arg/Arg genotype carriers had a higher response rate than that of the Gln genotype carriers (OR = 4.81, 95%CI = 1.778-13.013, P = 0.002). The combination of the favorable genotypes of ERCC1, ERCC2, and XRCC1 had a higher response rate compared to that of patients with other genotypes. The combined polymorphisms of ERCC1, ERCC2, and XRCC1 may be associated with sensitivity of NSCLC to platinum-based chemotherapy. Further studies will verify these SNPs as biomarkers for prediction of platinum-based chemotherapy responses of NSCLC patients.     

Prediction Value of XRCC 1 Gene Polymorphism on the Survival of Ovarian Cancer Treated by Adjuvant Chemotherapy

Objective: We conducted a prospective study to test the association between three amino acid substitutionpolymorphismic variants of DNA repair genes, XRCC1 (Arg194Trp), XRCC1(Arg280His) and XRCC1(Arg399Gln), and clinical outcome of ovarian cancer patients undergoing adjuvant chemotherapy. Methods:195 patients with primary advanced ovarian cancer and treated by adjuvant chemotherapy were included in ourstudy. All were followed-up from Jan. 2007 to Jan. 2012. Genotyping of XRCC1 polymorphisms was conductedby TaqMan Gene Expression assays. Results: The XRCC1 194 Trp/Trp genotype conferred a significant riskof death from ovarian cancer when compared with Arg/Arg (HR=1.56, 95%CI=1.04-3.15). Similarly, thosecarrying the XRCC1 399 Gln/Gln genotype had a increased risk of death as compared to the XRCC1 399Arg/Arg genotype with an HR (95% CI) of 1.98 (1.09-3.93). Conclusion: This study is the first to provide evidencethat XRCC1 gene polymorphisms would well be useful as surrogate markers of clinical outcome in ovariancancer cases undergoing adjuvant chemotherapy.