p53基因多态性与宫颈癌关系的初步研究

背景与目的:p53基因多态性可影响人乳头状瘤病毒(human papillo-mavirus,HPV)介导的p53降解.本研究的目的是观察p53基因多态性在广东妇女中的分布情况及了解不同p53基因型对宫颈癌发生的影响.方法:收集2002年9月～2003年5月在中山大学肿瘤防治中心妇科治疗的宫颈癌患者46例(病例组)及妇科良性肿瘤患者84例(对照组)的宫颈涂片,用PCR对由涂片中提取的DNA进行HPV DNA检测及p53多态性检测.结果:HPV DNA阳性率在病例组和对照组中分别为47.8%和20.2%.在病例组中,Arg/Arg、Pro/Pro和Arg/Pro基因型分别占56.5%、21.7%和21.7%;在对照组中,Arg/Arg、Pro/Pro和Arg/Pro基因型分别占71.4%、20.2%和8.3%.Arg/Arg(OR,0.520;95%CI,0.245～1.102)和Arg/Pro基因型(OR,1.095;95%CI,0.454～2.639)在病例组和对照组之间无显著性差异;而Pro/Pro基因型在两组之间有显著性差异(OR,3.056;95%CI,1.076～8.678),但在HPV阳性妇女中,这种基因型分布的无显著性差异.结论:Arg/Arg基因型可能不是宫颈癌的高危因素,而Pro/Pro基因型患者可能易患宫颈癌.     

p53Arg72Pro多态性与HPV相关宫颈癌发生机制

[目的]探讨p53Arg72Pro多态性与HPV相关宫颈癌发生机制的关系。[方法]采用PCR技术检测210例宫颈癌和95例正常宫颈组织的HPV16DNA．采用免疫组化方法及TUNEL检测p53Arg72Pro三种基因型中p53、p21、Bax、Ki-67蛋白（P1）表达以及细胞凋亡（AI）。[结果]宫颈癌HPV16阳性率为70．5％,与正常宫颈组织（7．4％）相比差异具有统计学意义（P〈0．05）。HPV16阳性的宫颈癌中：①p53蛋白阴性和弱阳性表达率（73．6％）高于强阳性率（26．4％）,其中p53Arg的阴性表达率（39．2％）高于p53Pro（16．7％）,差异有统计学意义（P〈0．05）;②p21蛋白阴性和弱阳性组中,p53Pro型中PI高于p53Arg型,差异有统计学意义（P〈0．05）;④Bax蛋白阴性和弱阳性组中,p53Pro型中AI低于p53Arg型,差异有统计学意义（P〈0．05）。[结论]p53蛋白可被HPV16E6蛋白降解,其中p53Arg蛋白更易被降解;p53Arg和p53Pro蛋白被降解后,两者抑制细胞增殖能力的降低和诱导细胞凋亡能力的降低程度不同．其中p53Pro蛋白转录激活p21和Bax基因的功能及细胞周期阻滞作用的降低更明显。     

湖北地区汉族人群p53基因第72位密码子多态性与宫颈鳞癌相关性

[目的]探讨p53基因第72位密码子多态性与湖北地区汉族人群宫颈癌相关性。[方法]采用PCR法检测104例宫颈鳞癌及84例正常宫颈组织标本中p53基因第72位密码子的基因型。[结果]p53基因第12位密码子的3种基因型Arg/Arg、Arg/Pro、Pro/Pro在宫颈鳞癌组比例分别为38.5%、44.2%和17.3%;对照组中分别为52.4%、40.5%和7.1%。Pro/Pro基因型在宫颈鳞癌组中所占比例显著高于正常宫颈组织(P=0.018)。[结论]p53基因第72位密码子Pro/Pro基因型是湖北地区汉族女性发生宫颈鳞癌的遗传易感因素之一。     

P21^WAF1/CIP1、BaX蛋白在维吾尔族宫颈癌p53Arg72Pro不同基因型中的表达研究

目的初步探讨p53Arg72Pro不同基因型的生物学功能以及在新疆维吾尔族宫颈癌发生机制中的相关作用。方法采用免疫组化的方法检测110例维吾尔族宫颈癌和45例维吾尔族正常宫颈组织中p53基因第四外显子第72位密码子Arg／Pro（p53Arg72Pro）三种基因型Arg／Arg、Pro／Arg、Pro／Pro型中P21^WAF1/CIP1、Bax蛋白的表达。结果在维吾尔族宫颈癌组织中P21^WAF1/CIP1、Bax蛋白的阳性表达率均高于正常宫颈组织，其表达差异有统计学意义（P〈0．05），同时在p53Arg72Pro三种基因型中Pro／Pro型的Bax蛋白阳性高表达率最高66．67％（10／15），其表达差异有统计学意义（P〈0．05）。而P21^WAF1/CIP1蛋白阳性表达率在Arg／Arg型中最高58．5％（24／41），但其差异并无统计学意义（P〉0．05）。结论p53Arg72Pro三种基因型在诱导细胞凋亡、转录激活以及调节细胞周期方面可能存在差异，p53Arg72Pro多态性可能通过不同的机制引起宫颈癌的发生。     

基因多态性与宫颈癌易感性研究进展

目的：总结基因多态性与宫颈癌易感性的研究现状。方法：应用PubMed及CHKD期刊全文数据库检索系统,以“基因多态性、宫颈癌、易感性”等为关键词。检索1999-2013的相关文献80篇,纳入标准：1）宫颈癌易感性研究进展;2）基因多态性与宫颈癌癌易感性的关系。根据纳入标准,最后纳入分析29篇文献。结果：1）DRB1＊15等位基因/DRB1＊15-DQB1＊06单体型与HPV感染或宫颈癌前病变有关,巴西妇女中HLA-DQB1＊05与HPV16阳性宫颈鳞癌呈正相关;2）中国人群中,Pro/Pro基因型在宫颈癌和对照人群中表达有明显差异,葡萄牙北部人群中ASCUS、LSIL、HSIL、ICC患者及正常人宫颈细胞进行检测,未发现p53Arg72Pro在不同人群中的分布有差异;3）TNF-α基因启动子区-238A等位基因可明显降低宫颈癌风险,TNF-α-308G/A多态性与浸润型宫颈癌的发展相关;4）中国妇女人群中,XRCC1 399Gln/Gln基因型与宫颈癌相关性是XRCC1 399Arg/Gln基因型的2.32倍;然而在阿根廷妇女中,XRCC1399Arg/Gln基因型会降低患宫颈癌的风险。结论：1）HLA多态性与宫颈癌易感性和HPV感染相关;2）P53基因多态性与不同地域宫颈癌易感性不同;3）TNF不同位点基因多态性与宫颈癌易感性相关性不同;4）DNA修复基因多态性与宫颈癌易感性关系报道不同。     

P53基因CD72Arg／Pro多态性与贲门腺癌生物学行为的研究

目的 探讨P53基因CD72 Arg／Pro多态性与中国汉族人贲门腺癌生物学行为的关系。方法 应用PCR—RFLP法对67例贲门腺癌患者和138名正常对照组人群P53基因CD72Arg／Pro多态性进行检测。结果 病例组P53基因Pro等位基因频率(0．672)和Pro／Pro基因型频率(47．8％)都显著高于正常对照组(0．413和13．0％)(P＜0．01)；携带Pro／Pro基因型者患贲门腺癌的风险比携带Arg／Arg基因型者显著升高，OR为8．30，95％CI：3．49—19．77(P＜0．01)。P53基因型分布和贲门腺癌的病理分化程度存在相关性(P＜0．01)。Pro／Pro基因型频率分布由高到低依次为：低分化组(69．6％)＞中分化组(42．3％)＞高分化组(27．8％)。有淋巴结转移的患者Pro／Pro基因型频率(63.3％)高于无淋巴结转移的患者(35．1％)(P＜0．05)。结论 P53基因Pro／Pro基因型是贲门腺癌的遗传易患因素，携带Pro／Pro基因型的贲门腺癌患者肿瘤恶性程度高、预后较差。     

p53基因第72位密码子突变与食管鳞癌临床病理特征关系的研究

目的研究p53基因第72位密码子（p53 codon72）突变与人食管鳞癌临床病理特征的关系。方法应用聚合酶链反应-限制性片段长度（PCR-RFLP）方法检测118例人食管鳞癌组织及癌旁正常食管黏膜组织的p53 codon72的突变及其差异，并分析其与食管鳞癌临床病理特征的关系。结果p53 codon72的Arg／Arg和Pro／Pro或Arg基因型在癌组织和癌旁正常食管黏膜组织的频率分别为11．0％和38．1％、4．2％和7.60A。p53 codon72Arg／Pro基因型在癌组织和癌旁正常食管黏膜组织分布差异具有显著性（χ^2=55.75，P〈0.01），p53 codon72突变与p53蛋白表达有关（χ^2=15．21，P〈0．01）；且p53 codon72的Pro等位基因与食管癌的TNM分期、分化程度和淋巴结转移均呈显著相关（P〈0．01）。结论抑癌基因p53第72位密码子突变在食管癌发生、发展中可能起重要作用。     

p73及p53基因多态性与甘肃武威人群胃癌风险相关性研究

[目的]评价p73基因G4C14-to-A4T14双核苷酸多态性（p73 G4A DNP）和p53基因第72密码子单核苷酸多态性（p53 Arg72Pro SNP）与甘肃武威市人群胃癌高发风险及胃癌不同病理亚型的相关性。[方法]p73G4ADNP的基因分型采用两双相对引物多聚酶链式反应法,p53 Arg72Pro SNP基因分型采用PCR-RFLP法。[结果]共检查胃癌病例385例以及健康对照412人。胃癌组中弥漫型胃癌305例（79.22%）,肠型胃癌80例（20.78%）。对照组p73AT/AT、AT/GC及GC/GC基因型的频率分别为28.15%、47.09%和24.76%;胃癌组分别为21.98%、45.04%和32.98%;以AT/AT作为指示物,胃癌组和弥漫型胃癌的GC/GC纯合子基因型频率均高于对照组,优势比（OR）分别为1.71（95%CI,1.16～2.51）和1.87（1.24～2.81）。对照组p53基因Pro/Pro、Pro/Arg以及Arg/Arg基因型的频率分别为27.18%、50.49%及22.33%;胃癌组则分别为21.82%、45.45%和32.73%;以Pro/Pro为指示物,胃癌组和弥漫型胃癌Arg/Arg基因型频率显著高于对照组,OR分别为1.83（95%CI,1.24～2.70）和2.25（95%CI,1.47～3.43）。[结论]携带p73 G4A GC/GC基因型或p53 Arg/Arg基因型可能会增加胃癌,尤其是弥漫性胃癌的发病风险。     

云南省住院肺癌患者HPV16/18感染及p53codon72多态性检测分析

目的分析云南省住院肺癌患者HPV16/18感染以及p53codon72位点基因多态性。方法收集2012-12-01-2013-09-30昆明医科大学第一附属医院胸外科手术切除的63例肺癌组织和24例肺良性病变组织,采用聚合酶链反应(polymerase chain reaction,PCR)分别检测肺癌组织和肺良性病变组织中HPV16/18以及p53codon72的DNA。结果肺癌组织的HPV16/18阳性检出率为47.63%,显著高于肺良性病变组织8.33%,χ2=11.535,P=0.001。HPV16/18感染仅与肿瘤分化程度相关,u=6.853,P=0.021;与性别(χ2=0.640,P=0.424)、年龄(χ2=0.049,P=0.825)、吸烟史(χ2=0.965,P=0.326)、肿瘤类型(u=0.593,P=0.764)、肿瘤分期(u=0.885,P=0.625)和转移情况(χ2=0.688,P=0.407)无关。p53condon72Arg/Arg、Pro/Pro和Arg/Pro在肺癌组织的分布频率分别为28.57%、53.97%和17.46%,肺良性病变组织的分布频率分别为29.17%、29.17%和41.67%,差异有统计学意义,χ2=6.489,P=0.038。p53condon72Arg/Arg、Pro/Pro和Arg/Pro在HPV阳性肺癌组织的分布频率分别为16.67%、70.00%和13.33%,在HPV阴性肺癌组织的分布频率分别为39.39%、39.39%和21.21%,差异有统计学意义,χ2=6.127,P=0.046。结论云南省住院肺癌患者中高危HPV16/18型呈高感染,p53Pro/Pro基因分型高表达,两者均为该地区肺癌发生的高危因素。     

p53 codon72多态性与HPV相关宫颈癌易患性的关系

高危型人乳头瘤病毒(humanpapillomavirus，HPV)感染是重要的宫颈癌致病因素。Storey等研究认为p53第4外显子72密码为精氨酸(Arg)纯合子的个体比脯氨酸(Pro)纯合子个体更易于发生HPV相关宫颈癌，但对此研究结果存在广泛争议。研究人群选择、标本取材、实验设计等不同是导致研究结果差异的原因。     

The p53 Arg72Pro polymorphism, human papillomavirus, and invasive squamous cell cervical cancer.

A. Storey et al. [Nature (Lond.), 393: 229-234, 1998)] reported a 7-fold increased risk of cervical cancer associated with having an Arg/Arg polymorphism at codon 72 of p53 compared with the Pro/Arg heterozygotes (odds ratio, 7.4; 95% confidence interval, 2.1-29.4). Complementary in vitro studies suggested that the HPV E6 oncoprotein more readily targets the arginine form, as opposed to the proline form, of p53 for degradation. We investigated the impact of this polymorphism in a population-based case-control study of invasive cervical cancer. Using a PCR assay to detect the p53 codon 72 polymorphism, we tested blood samples from 111 women with invasive squamous cell cancer of the cervix identified by a population-based registry and 164 random-digit telephone-dialed controls. The distribution of the genotype among control women was 38% heterozygous, 7% proline homozygous, and 55% arginine homozygous, and among the cases was 38%, 6%, and 56%, respectively. There was no increased risk of squamous cell invasive cervical cancer associated with homozygosity for the arginine allele (odds ratio, 1.0; 95% confidence interval, 0.6-1.7). Furthermore, there was no modification of this result by human papillomavirus (HPV) DNA status of the tumor, age, or smoking status. Among controls, there was no association between the polymorphism and HPV-16 L1 seropositivity. However, among case subjects, the codon 72 polymorphism may be related to HPV 16L1 seropositivity status.     

Cutaneous squamous cell carcinoma and p53 codon 72 polymorphism: a need for screening?

The association between human papillomavirus (HPV)-associated cervical cancer and cutaneous squamous cell carcinoma and codon 72 polymorphism in the p53 gene is not unequivocal. Especially, it is not known whether carriers of the arginine form have an increased risk of cancer that necessitates screening. The alternative is that the polymorphism is a tumor marker instead of a risk factor. We set out a case-control study to determine the risk of squamous cell carcinoma of the skin in individuals with the p53 codon 72 arginine genotype in order to establish the possible need for screening. The distribution of the different p53 codon 72 genotypes was examined in 86 subjects with a history of cutaneous squamous cell carcinoma and in 168 controls. Additionally, 121 subjects who had had histologically proven basal cell carcinoma and 108 subjects who had had non-familial malignant melanoma were tested. p53 polymorphism was evaluated by polymerase chain reaction (PCR) using DNA samples from peripheral blood lymphocytes. In a subgroup of patients with squamous cell carcinoma and controls, the presence of epidermodyplasia verruciformis human papillomavirus (EV-HPV) DNA was determined in plucked eyebrow hair. Differences in the distributions of the genotypes among cases and controls were calculated, and univariate and multivariate analyses were performed to assess the risk to develop cutaneous squamous cell carcinoma in the presence of the p53 codon 72 arginine genotype. Frequency distributions of the three different genotypes (homozygous for the arginine allele, heterozygous for the two alleles, and homozygous for the proline allele) were similar among the squamous cell carcinoma group and the control group: 47.1%, 46.0% and 6.9% versus 47.8%, 45.8% and 6.4%, respectively. Statistical analysis showed no significant differences between these groups. In patients with squamous cell carcinoma and controls who harbored EV-HPV DNA in their plucked eyebrow hair, similar results were obtained. The distributions of the p53 codon 72 genotypes in the basal cell carcinoma and malignant melanoma group were also not significantly different from the control group. p53 codon 72 arginine homozygosity does not appear to represent a significant risk factor for cutaneous squamous cell carcinoma and screening seems not to be indicated. Mol. Carcinog. 30:56-61, 2001.     

Étude du codon 72 du gène p53 dans la prédisposition au cancer du col de l’utérus au Sénégal

Beside human papilloma virus infection, several genetic factors have been involved in susceptibility to cervical cancer. The arginine allele at codon 72 in p53 tumor suppressor gene has been reported to be a risk-factor in different ethnic groups. Our aim was to study this polymorphism as a risk-factor in Senegal. We conducted a case-control association study by recruiting 30 patients with cervical cancer clinically followed up in the Curie Institute in Dakar, and 93 healthy female controls without diagnosed cervical cancer. For each individual, DNA was extracted from whole blood. The codon 72 polymorphism was genotyped by PCR-RFLP. We did not find any association between the arginine allele and susceptibility to cervical cancer in our population (P = 0.354). Moreover, any correlation between the arginine allele and histological lesions was observed. Even if we did not find any correlation between the arginine allele and susceptibility to cervical cancer, p53 as a tumor suppressor gene remains a good genetic marker in tumours biology.     

p53 polymorphism in human papillomavirus-associated esophageal cancer

Human papillomavirus type 16/18 (HPV-16/18) is implicated in the pathogenesis of squamous cell carcinoma (SCC) of the cervix and esophagus. The arginine allele at codon 72 of p53 was found to be more susceptible to degradation by HPV E6 protein than is the proline allele in vivo, thus resulting in a high frequency of cervical SCC in individuals homozygous for arginine at the codon. There are controversial results from several clinical studies of cervical SCC. In the present study, encoding regions of p53 codon 72 and HPV-16/18 E6 were directly sequenced, using pairs of primary esophageal SCC tissue and corresponding normal mucosa, which were from 75 patients (Japanese, n = 38; Chinese, n = 37). The arginine allele alone was detected in 70.6% (12 of 17) of HPV-positive cases but only in 43.1% (25 of 58) of HPV-negative cases (P < 0.05). In contrast, such a significant correlation between p53 polymorphism and HPV infection was not evident in corresponding normal mucosae. Because our findings between tumor specimens and the normal mucosae differed, we suggest that the frequent loss of proline allele in HPV-associated carcinogenesis of the esophagus major plays some role. The particular type of p53 polymorphism may indicate a potential candidate for HPV-associated SCC.     

Proline homozygosity in codon 72 of p53: a risk genotype for human papillomavirus related cervical cancer in Indian women

The objective of the present study was to determine the codon 72 genotypic frequencies of p53 in Indian women and to analyze the association of this polymorphism with human papillomavirus (HPV) related cervical cancer (CaCx). We used tissues derived from 55 women diagnosed with squamous cell carcinoma of the cervix (of whom 46 were HPV types 16/18 positive) and cervical scrapes derived from 201 cytologically normal women (of whom 84 were HPV types 16/18 positive) as controls. The DNA isolated from these samples was genotyped for p53 polymorphism by polymerase chain reaction and restriction fragment length polymorphism method. The genotypic frequency of homozygous arginine among women with CaCx was 27% and this did not differ with the controls. But, proline homozygosity of 33% in the malignant samples was significantly higher than controls (OR=2.23; 95% CI: 1.14-4.35; P=0.02). The associated risk of this genotype towards CaCx was more prominent (OR=2.67; 95% CI: 1.16-6.15; P=0.02) when analysis was restricted to HPV 16/18 positive women. Thus, proline homozygosity at codon 72 of p53 and not arginine homozygosity, could be a risk factor for development of CaCx associated with high risk HPV among Indian women.     

Retention of the p53 codon 72 arginine allele is associated with a reduction of disease-free and overall survival in arginine/proline heterozygous breast cancer patients.

PURPOSE: The arginine to proline substitution at codon 72 represents a common aminoacidic polymorphism of the p53 protein. Recent data suggest that p53 codon 72 may modulate the response to cancer therapy. The aim of this study was to test the hypothesis that the p53 codon 72 genotype, evaluated in the tumor tissue and in the disease-free lymph node, is related to differences in disease-free and overall survival among breast cancer-affected patients. EXPERIMENTAL DESIGN: We assessed the p53 codon 72 genotype in DNA from disease-free lymph nodes and neoplastic tissues obtained from 67 women affected by breast cancer who underwent surgical resection at the Bologna Breast Cancer Surgical Unit from 1993 to 1995. RESULTS: We found that the retention of the p53 codon 72 arginine allele in the tumor tissue of proline/arginine heterozygous breast cancer patients is associated with statistically significant reduced disease-free and overall survivals. CONCLUSIONS: Our findings suggest that the genotyping for p53 codon 72 locus in both the tumor tissue and in the lymph node of breast cancer patients could contribute to identify a subset of arginine/proline heterozygous patients who have a reduced survival that is associated with the specific retention of the arginine allele in the tumor tissue.     

No association between P53 codon 72 polymorphism and risk of squamous cell carcinoma of the head and neck

An initial report suggested that patients homozygous for the arginine allele at codon 72 of P53 were at increased risk for human papillomavirus (HPV)-related cervical cancer, but other groups have not confirmed this finding. Since approximately 18-36% of head and neck cancers are HPV-related, we examined the genotypic frequencies at that locus in 163 cases with squamous cell carcinoma of the head and neck (SCCHN) and 163 ethnically matched controls. We found no significant excess of arginine homozygotes in cases compared to controls (P= 0.50). No significant differences in allele frequencies were observed when the data were stratified by tobacco exposure or by cancer site. These findings suggest a limited role, if any, for this P53 polymorphism in SCCHN.     

p53 codon 72 polymorphism and risk of intra-epithelial and invasive cervical neoplasia in Greek women.

In 1998, Storey and co-workers suggested that individuals homozygous for arginine (Arg) at codon 72 of the p53 gene are about seven times more susceptible to human papillomavirus (HPV)-related carcinogenesis than heterozygotes. Since then, several studies from Northern Europe, Japan and the USA have failed to demonstrate a similar correlation. By contrast, a study in Brazil as well as one recent study in Italian and Swedish populations showed strong positive associations. We examined the frequency of p53 codon 72 polymorphism in samples from both invasive and intra-epithelial cervical neoplasias (CIN), and compared them with samples from healthy controls. All 88 samples came from women with a Greek ethnic background. Tissue specimens were collected from archival material with histologically diagnosed low-grade CIN (LGCIN), high-grade CIN (HGCIN) or cervical cancer (CxCa). As a control, we used cellular material newly collected by cytobrush from the cervices of 30 healthy women with normal cytological and colposcopical examinations. p53 Arg homozygosity (Arg/Arg) alone was associated with four-, six- or eight-fold increased risks for LGCIN, HGCIN or invasive cancer, respectively. The frequency of the p53Arg/Arg genotype and of the proline (Pro) allele showed significant linear trends according to the degree of severity of the lesion (P = 0.0007 and P = 0.0009, respectively). Exclusion of the ten HPV16/18-negative cases did not substantially alter the Arg/Arg frequency among the groups nor the significant linear trend. Our results confirm the initial findings of Storey and co-workers, as well as the data of the Brazilian and the recent European study, but do not accord with those of the other aforementioned studies. Variations in ethnic background, laboratory performance, verification of the HPV status, definition of controls, and sample size are the most plausible explanations for this controversy. In all our samples, the distribution of the p53 alleles fits the Hardy-Weinberg equilibrium and the 0.48 frequency of the Pro allele in our controls accords well with the percentages previously reported for different ethnic groups as characteristic of the assumed north-south cline. Some authors assert that the discrepancy in the results could not be attributed to differences in the methods; however, the Brazilian study emphasized the effect of inter-laboratory variation in detecting the association between p53 polymorphism and cervical cancer. Regarding the control group, our samples were only from women with a cytologically and colposcopically benign cervical epithelium. We think that simply choosing 'normal volunteers' for collecting control DNA blood samples without knowing the status of their cervical epithelium is indeed a possible source of bias. Finally, it is very unlikely that loss of heterozygosity at the p53 locus could be a factor interfering with the allelotype distribution. Our present small study results, which suggest a biologically relevant association, provide strong evidence that homozygous arginine at codon 72 of p53 may confer a higher susceptibility to HPV-associated intra-epithelial and invasive cervical neoplasia.     

The R72P P53 mutation is associated with familial breast cancer in Jewish women

BRCA1/BRCA2 mutations account for a substantial proportion of familial breast cancer, but clearly mutations in additional genes exist, one candidate being the p53 gene. To evaluate its putative involvement in inherited predisposition to breast/ovarian cancer in Jewish high-risk women, mutational analysis of the p53 gene (exons 4-9) was carried out using exon-specific polymerase chain reaction followed by denaturing gradient gel electrophoresis (DGGE) analysis, complemented by DNA sequencing of abnormally migrating fragments. Overall, 132 Jewish breast cancer patient non-BRCA1/2 mutation carriers and 167 average risk controls (Ashkenazi (n=60), non-Ashkenazi (n=107)) were genotyped, and no inactivating p53 germline mutations were detected. Consistent migration abnormalities were noted in 167 fragments, 134 of which were shown to be the Arg72Pro polymorphism, whereas migration abnormalities in fragments containing exons 4 (n=2) and 6 (n=23) and introns 3 (n=4) and 9 (n=4) corresponded to five previously described polymorphisms. Allele distribution of the R72P missense mutation between ethnically diverse Jewish breast cancer cases and average risk controls showed significant differences: among non-Ashkenazi breast cancer cases, 62.5%, 33.3% and 4.2% were homozygous, heterozygous and homozygous for the Arg72, Arg72Pro and the Pro72 polymorphism, respectively, whereas for controls, the distribution was 22.4%, 65.4% and 12.2%, respectively (P=0.00052), and among Ashkenazi breast cancer cases, allele distribution was 68.5%, 29.6% and 1.9%, whereas for controls, the distribution was 50%, 40% and 10%, respectively (P=0.0125). We conclude that arginine homozygosity at codon 72 of the p53 gene is associated with a significant increased breast cancer risk in Jewish high-risk population.     

TP53 mutation, allelism and survival in non-small cell lung cancer

TP53 is well-recognized as a mutational target in cancers and common variation in the TP53 gene has been investigated as potentially contributing to cancer susceptibility. The codon 72 polymorphism has been proposed to alter the phenotype of TP53 mutations, and TP53 mutations have been reported to occur preferentially on the arginine allele. Using a consecutive case series of non-small cell lung cancer we have investigated whether TP53 mutations occur preferentially on the arginine or proline allele, and whether the combination of mutation and allelism confers differences in the clinical phenotype. The overall prevalence of TP53 mutation was 26% (76/293). The majority of mutations occurred on the arginine allele (51/60, 85%), and there was corresponding strong selection for loss of the proline allele [87% of loss of heterozygosity (LOH) events were loss of proline]. However, there was no statistically significant difference in the prevalence of mutation by constitutional genotype and among heterozygotes with LOH, TP53 mutation prevalence did not differ by the codon 72 polymorphism (48% on arginine versus 40% on proline). Importantly, patient survival did significantly differ: those patients having a TP53 mutation on the proline allele had the worst survival outcomes (hazards ratio = 2.6, P < 0.03). Further, this phenotype was limited to those patients with advanced disease, where mutation on the proline allele was associated with a significantly worse outcome compared with those without mutation or with mutation on the arginine allele (P < 0.001). Our data suggest that there are selective pressures for loss of the TP53 proline allele in non-small cell lung cancer. Further, the combination of mutation with the codon 72 proline variant predicts poorer patient survival, particularly in a disease that has progressed outside the lung, a finding that warrants further investigation.