Effect of p53 codon 72 genotype on breast cancer survival depends on p53 gene status

In vitro studies suggest that p53 codon 72 genotype alters the apoptotic capacity of p53 protein, with the 72 arginine (R) form of wild-type p53 harboring a greater apoptosis-inducing potential than the 72 proline (P) variant. The aim of this study was to investigate whether the association between the p53 codon 72 genotype and breast cancer survival was modified by p53 gene status. In our study, we examined the p53 codon 72 genotype and p53 mutations (through exons 4-9) in paraffin-embedded specimens from 414 breast cancer patients with a median follow-up of 8.2 years. We report that the p53 codon 72 genotype was significantly associated with disease-free survival (DFS, p = 0.02) but not with disease-specific survival (DSS, p = 0.24) in the entire study population (n = 414). In contrast, the codon 72 genotype was strongly associated with both DFS (p = 0.001) and DSS (p = 0.04) among patients with a wild-type p53 tumor (n = 346), patients with the P/P variant had worse DFS and DSS than did those with the P/R or R/R variant in this subgroup of patients. More importantly, as compared with the P/R or R/R variant, the P/P variant remained an independent prognostic factor of DFS among patients with a wild-type p53 tumor (HR = 2.5; 95%CI = 1.4-4.4; p = 0.003). We conclude that the effect of p53 codon 72 genotype on breast cancer survival is dependent on p53 gene status, the P/P variant is strongly associated with poor prognosis among patients with a wild-type p53 tumor.     

Risk of cervical cancer is not increased in Chinese carrying homozygous arginine at codon 72 of p53.

Homozygous arginine at codon 72 (HA72) of p53 was found in 22% of normal cervices and 30.0% of cervical cancers and no significant difference was detected between normal and cervical cancer with or without HPV 16/18. There was no correlation between HA72 and risk of cervical cancer in Chinese.     

p53基因codon 72多态性与乳腺癌术后放化疗疗效相关性分析

目的:分析p53基因codon 72多态性与乳腺癌患者术后放化疗的预后相关性。方法:选取北京大学肿瘤医院乳腺癌患者术后接受放化疗427 例,采用聚合酶链反应- 限制性片段长度多态性（PCR-RFLP ）方法分析其p53基因codon 72多态性,比较不同基因型患者间复发及生存的差异。结果:全部患者基因型分布为Pro/Pro 型18.3%（78/427）、Pro/Arg型44.0%（188/427）、Arg/Arg型37.7%（161/427）。3 种基因型间无局部复发生存（LRFS）、无局部区域复发生存（LRRFS ）、无远处转移生存（DDFS）及总生存（OS）均无显著性差异（均P>0.05）。 427 例患者中雌激素受体（ER）阳性为303 例,其中Arg/Arg基因型患者OS明显优于Pro/Pro 基因型患者（χ2=6.330,P=0.042）。 在多因素分析中p53基因codon 72多态性是ER阳性患者LRFS、LRRFS 、DDFS及OS的独立预后因素,Pro/Pro 基因型的患者较Arg/Arg基因型的局部复发风险增加5.9 倍（HR= 5.9,95%CI 1.1～31.1,P=0.036）,局部区域复发风险增加3.1 倍（HR= 3.1,95%CI 1.1～9.1,P=0.039）,远处转移风险增加2.8 倍（HR= 2.8,95%CI 1.3～6.0,P=0.010）,死亡风险增加4 倍（HR= 4.0,95%CI 1.3～12.0,P=0.013）。 结论:在ER阳性的乳腺癌术后接受放化疗患者中,Pro/Pro 基因型的局部及局部区域复发风险、远处转移风险、死亡风险均高于Arg/Arg基因型。      

The p53 codon 72 proline allele is endowed with enhanced cell-death inducing potential in cancer cells exposed to hypoxia

The preferential retention of the arginine allele at the p53 codon 72 locus is commonly observed in tumours from arginine/proline heterozygotes. Considering that cancer cells are harboured in a hypoxic environment in vivo, we here tested the hypothesis that the p53 codon 72 proline allele confers a survival disadvantage in presence of hypoxia. Here, we show that the transient transfection of the proline allele in p53 null cancer cells exposed to low oxygen tension or to the hypoxia-mimetic drug Desferoxamine induces a higher amount of cell death than the arginine allele. Accordingly, proline allele transiently transfected cell lines express lower levels of hypoxia pro-survival genes (HIF-1alpha, carbonic anhydrase IX, vascular endothelial growth factor, heme oxygenase-I, hepatocyte growth factor receptor, vascular endothelial growth factor receptor 2), compared to those transiently transfected with the arginine allele. Further, we report that the exposure of the arginine/proline heterozygote MCF-7 breast cancer cell line to cytotoxic concentration of Desferoxamine for several weeks, gives raise to hypoxia-resistant clones, carrying the arginine, but not the proline allele. These data indicate that the p53 codon 72 proline allele is less permissive for the growth of cancer cells in a hypoxic environment, and suggest that the preferential retention of the arginine allele in the tumour tissues of arginine/proline heterozygous patients may depend upon its lowered capacity to induce cell death in a hypoxic tumour environment.     

Systematic review and meta-analysis of the association between P53 codon 72 polymorphism and colorectal cancer

Background

A number of studies has evaluated the association between P53 codon 72 polymorphism and colorectal cancer. However, results were inconsistent. To clarify the role of this polymorphism in colorectal cancer, we conducted a meta-analysis on this topic.

Methods

Two authors independently searched the PubMed and EMBASE database from 1966 to January 2010 for studies regarding the association of P53 codon 72 polymorphism with colorectal cancer. Summary odds ratios with their corresponding 95% confidence intervals were calculated by using random-effects model.

Results

The combined results showed that P53 codon 72 variant genotypes were not associated with colorectal cancer risk when compared to Arg/Arg genotype (Pro/Pro: OR = 1.02, 95% CI = 0.80–1.29; Arg/Pro: OR = 1.00, 95% CI = 0.86–1.16; Pro allele: OR = 1.00, 95% CI = 0.86–1.17). When stratifying for study population, design and cancer location, no statistically significant results were observed either.

Conclusion

Our data indicate that the P53 codon 72 polymorphism may be not associated with colorectal cancer risk.     

p53 codon 72 polymorphism and the risk of lung cancer in a Korean population

The aim of this study was to assess whether p53 codon 72 polymorphism is associated with an increased risk of lung cancer (LC) in a South Korean population. We conducted a population-based, large-scale, case-control study including 3939 patients with LC and 1700 controls. P53 codon 72 polymorphism was determined by real-time polymerase chain reaction (PCR). The frequencies of p53 codon 72 polymorphisms (Arg/Arg, Arg/Pro, and Pro/Pro) in LC were 37.0%, 46.2%, and 16.7%, respectively; frequencies in the controls were 43.2%, 45.6%, and 11.2%, respectively (p < 0.01). The Arg/Pro and Pro/Pro genotype were significantly associated with increased risk of LC (odds ratio (OR) = 1.22, 95% confidence interval (CI) = 1.06-1.14 and OR = 1.83, 95% CI = 1.48-2.26, respectively) compared with the Arg/Arg genotype. Risk was compared in different subgroups. The OR of Pro/Pro genotype was significantly higher in small cell lung cancer (SCC) and squamous cell carcinoma (SQC) than in adenocarcinoma (ADC). Higher OR of Pro/Pro genotype was also seen among males. However, relationships between gender, age, smoking, and genotypes were not found. P53 codon 72 polymorphism was associated with an increased risk of LC in this Korean population; the association was especially noteworthy in SQC, SCC, and males.     

P53 codon 72 polymorphism and gastric cancer: a meta-analysis of the literature

Studies investigating the association between p53 codon 72 polymorphism and gastric cancer risk report conflicting results. The objective of this study was to quantitatively summarize the evidence for such a relationship. Two investigators independently searched the Medline and Embase databases. This meta-analysis included 12 case-control studies, which included 1,665 gastric cancer cases and 2,358 controls. The combined results based on all studies showed that there was no significant difference in genotype distribution [Arg/Arg odds ratio (OR) = 0.96, 95% confidence interval (CI) = 0.79, 1.16; Pro/Pro (OR = 1.21, 95% CI = 0.92, 1.58); Pro/Arg (OR = 0.95, 95% CI = 0.79, 1.14)] between gastric cancer and noncancer patients. When stratifying for race, results were similar except that patients with gastric cancer had a significantly lower frequency of Arg/Arg (OR = 0.84, 95% CI = 0.72, 0.99) than noncancer patients among Asians. Stratified the various studies by the location, stage, Lauren's classification, and histological differentiation of gastric cancer, we found that (i) patients with cardia gastric cancer had a significantly higher frequency of Pro/Pro (OR = 3.20, 95% CI = 1.46,7.01) than those with noncardia gastric cancer among Asians; (ii) patients with advanced (stage III/IV) gastric cancer had a significantly higher frequency of Arg/Arg (OR = 1.48, 95% CI = 1.01, 2.16) than those with early (stage I/II) gastric cancer among Asians; (iii) patients with poor differentiation had a significantly lower frequency of Pro/Pro (OR = 0.13, 95% CI = 0.03, 0.64) than those with well differentiation among Caucasians. This meta-analysis suggests that the p53 codon 72 polymorphism may be associated with gastric cancer among Asians, and that difference in genotype distribution may be associated with the location, stage, and histological differentiation of gastric cancer.     

四川地区P53 Codon 72多态性与宫颈癌关系的初步研究

目的 探讨抑癌基因P53 Codon 72多态性与HPV有关的宫颈癌的关系。 方法 应用聚合酶链反应法分别对30例卵巢浆液性囊腺癌、50例宫颈鳞状细胞癌和30例正常妇女的P53 Codon 72多态性进行检测。 结果 P53 Arg纯合子、P53 Arg/P53 Pro杂合子和P53Pro纯合子正常妇女对照组分别为33.3％、60％和6.7％;而在卵巢癌组分别为40％、53.3％和6.7％;在宫颈癌组分别为80％、14％和6％。上述人群中,宫颈癌P53 Arg纯合子明显高于卵巢癌组和正常妇女对照组(P<0.05)。 结论 p53 Arg纯合子可作为与HPV感染有关的宫颈癌的危险因素。     

p53 Codon 72 polymorphism in gastric cancer susceptibility in patients with Helicobacter pylori-associated chronic gastritis

p53 codon 72, which produces variant proteins with an arginine (Arg) or proline (Pro), has been reported to be associated with cancers of the lung, esophagus and cervix. However, there have been no reports on the p53 codon 72 polymorphism in gastric cancer susceptibility in patients with Helicobacter pylori-associated chronic gastritis (H. pylori-CG). We, therefore, examined the polymorphism in 117 gastric cancer patients (72 intestinal type and 45 diffuse type) with H. pylori-CG and 116 H. pylori-CG patients without gastric cancer as controls. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was performed to analyze the p53 codon 72 polymorphism. The crude genotypic frequencies in the gastric cancer patients were similar to those of the controls. However, when gastric cancers were classified by histologic subtype, the Pro/Pro was more frequent in the patients with diffuse type gastric cancer than in the controls (22.2% of cases vs. 12.1% of controls). The Pro/Pro genotype was associated with a 2.98-fold higher risk of diffuse-type cancer compared to the Arg/Arg genotype (95% confidence interval [CI] 1.07-8.32, p = 0.038). These results suggest that the Pro/Pro genotype at p53 codon 72 contributes to susceptibility for diffuse-type gastric cancer in patients with H. pylori-CG. The p53 codon 72 polymorphism may serve as the genetic marker for the risk assessment of the diffuse-type gastric cancer development in patients with H. pylori-CG.     

p53基因codon 72多态性与乳腺癌的相关性研究*

目的：研究p53基因codon 72 多态性与乳腺癌患者的年龄、病理分期、淋巴结转移、雌激素受体（ER）、孕激素受体（PR）、c-erbB-2、P53蛋白表达情况的相关性。方法：TaqMan探针方法检测277 例乳腺癌患者血液标本的p53基因codon 72多态性。免疫组化SP法检测匹配肿瘤组织中ER、PR、c-erbB-2 和P53蛋白的表达情况。SPSS16.0 软件行统计学分析,p53基因多态性与病理学特征关系用χ2检验,非条件Logistic回归分析基因多态性与ER、PR、c-erbB-2、P53蛋白表达的相关性,计算OR值及其95% 可信区间（95% CI）。 P<0.05为差异有统计学意义。结果：p53基因codon 72基因型为CC/CG/GG,频率分别为22.0% 、51.3% 和26.7% ,携带CC、CG、GG基因型的患者发病年龄逐渐降低,但无统计学差异;p53基因codon 72多态性与临床病理学特征无关,与ER、PR、c-erbB-2 和P53蛋白表达无相关性（P>0.05）。 肿瘤组织P53蛋白表达与ER、PR、c-erbB-2 蛋白表达密切相关（χ2=13.492,P=0.000;χ2=3.970,P=0.046;χ2=17.956,P=0.000）。 结论：p53基因codon 72多态性与P53蛋白表达及病理学特征无相关性,P53蛋白表达与ER、PR、c-erbB-2 蛋白表达关系密切。p53基因codon 72基因型与患者发病年龄的关系有待扩大样本量进一步研究。     

p53 exon 4 (codon 72) polymorphism and exon 7 (codon 249) mutation in breast cancer patients in southern region (Madurai) of Tamil Nadu

Background: We investigated the association between polymorphisms in the p53 tumor suppressor gene and breast cancer risk in women especially in the Southern part of India. Methods: Genotyping was performed for 50 breast cancer women and 50 controls to determine the status of p53 exon 4 codon 72 polymorphism and exon 7 codon 249 mutation and their possible role in breast cancer risk. Results: Frequency of Arg/Arg at codon 72 was 18% in controls and 28% in patients, Arg/Pro frequency was 56% and 66% , Pro/Pro genotype was 8% in controls and 8% in patients. No significance was observed for breast cancer risk with either Arg/Arg or Pro/Pro genotype in codon 72 polymorphism. Similarly, mutation analysis of exon 7 codon 249 revealed that 72% of breast cancer patients have mutation, which is not statistically significant. However, there is a strong association between increase in exon 7 codon 249 mutation and exposure to pollution. Conclusion: The results suggested that there is no risk for exon 4 with Arg/Arg or Pro/Pro polymorphisms in the p53 gene and there is no strong correlation between breast cancer patients and mutation in exon 7 codon 249 in South Indian women.     

P53 Arg72Pro polymorphism and bladder cancer risk--meta-analysis evidence for a link in Asians but not Caucasians

Objective: Individual studies of the associations between P53 codon 72 polymorphism (rs1042522) and bladdercancer susceptibility have shown inconclusive results. To derive a more precise estimation of the relationship,we performed this systemic review and meta-analysis based on 15 publications. Methods: We used odds ratios(ORs) with 95% confidence intervals (CIs) to assess the strength of the association. Results: We found that therewas no association between P53 codon 72 polymorphism and bladder cancer risk in the comparisons of Pro/Pro vs Arg/Arg; Pro/Arg vs. Arg/Arg; Pro/Pro plus Pro/Arg vs. Arg/Arg; Arg/Arg vs. Pro/Arg plus Arg/Arg(OR=1.06 95%CI 0.81-1.39; OR=1.06 95%CI 0.83-1.36; OR=0.98 95%CI 0.78-1.23; OR=1.06 95%CI 0.84-1.32).However, a significantly increased risk of bladder cancer was found among Asians in the homozygote comparison(Pro/Pro vs. Arg/Arg, OR=1.36 95%CI 1.05-1.75, P=0.790 for heterogeneity) and the dominant model (Arg/Proplus Pro/Pro vs. Arg/Arg, OR=1.26 95%CI 1.05-1.52, P=0.564 for heterogeneity). In contrast, no evidence of anassociation between bladder cancer risk and P53 genotype was observed among Caucasian population in anygenetic model. When stratifying for the stage of bladder, no statistical association were found (Pro/Pro vs. Arg/Arg, OR=0.45 95%CI 0.17-1.21; Pro/Arg vs. Arg/Arg, OR=0.60 95%CI 0.28-1.27; Dominant model, OR=0.5695%CI 0.26-1.20; Recessive model, OR=0.62 95%CI0.35-1.08) between P53 codon 72 polymorphism and bladdercancer in all comparisons. Conclusions: Despite the limitations, the results of the present meta-analysis suggestthat, in the P53 codon 72, Pro/Pro type and dominant mode might increase the susceptibility to bladder cancerin Asians; and there are no association between genotype distribution and the stage of bladder cancer.     

Association of Arg72Pro of P53 polymorphism with colorectal cancer susceptibility risk in Malaysian population

Background: Colorectal cancer (CRC) results from the interaction between environmental exposures and genetic predisposition factors. Aims: A case control study was designed and to investigate the genotype frequencies of P53Arg72Pro polymorphism in Malaysian CRC patients and healthy controls and to determine the associated risk of this polymorphism with CRC predisposition. Methods: In this case-control study, peripheral blood samples of 202 sporadic CRC patients and 201 normal controls were collected, DNA extracted and genotyped using the polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) technique. Results: Genotype analysis showed the frequency of homozygous variant (Pro/Pro) genotype (21%) to be significantly higher in cases compared to controls (13%), (p=0.013). On examining the association between variant genotypes and CRC risk, the Pro/Pro homozygous variant genotype showed significantly higher risk association with CRC susceptibility (OR: 2.047, CI: 1.063-4.044, p=0.033). When stratified according to age, we observed that, individuals aged above 50 years and carriers of pro/pro genotype had significantly higher risk with OR: 3.642, CI: 1.166-11.378, p=0.026. Conclusions: Our results suggest that the codon 72 SNP which results in amino acid substitution of Arginine to Proline in cell cycle regulatory gene P53, is associated with sporadic CRC risk and carriers of Pro/Pro genotype and more than 50 years old may have high susceptibility.     

p53 condon72基因多态性与胃癌危险度关系--病例对照研究

目的 :探讨p53密码子 72基因多态性与胃癌危险度的关系 ,及其不同基因型与环境危险因素交互作用对胃癌发病的影响。方法 :在江苏省泰兴市进行以人群为基础的病例对照研究 ,胃癌病例 2 0 4例 ,对照 41 5例。结果 :病例中p53密码子 72的Pro Pro基因型的比例较对照中高 ,Pro Pro或Pro Arg两种基因型与Arg Arg比较OR为 1 50 (1 0 1～ 2 2 3)。p53基因还可与吸烟、饮酒、饮河水、嗜烫食等发生相乘或相加交互作用 ,影响胃癌发病。结论 :p53的Pro等位基因可能与胃癌危险度有关 ,并与其他环境危险因素交互作用 ,增加胃癌发病的危险。     

p53 codon 72 polymorphism in vulval cancer and vulval intraepithelial neoplasia

p53 codon 72 polymorphism was analysed in UK women with human papillomavirus (HPV)-associated vulval intraepithelial neoplasia and vulval squamous cell carcinoma. Arginine homozygotes were significantly less common in either group compared with controls. We conclude that the arginine polymorphism may confer protection against the development of HPV-associated vulval neoplasia.     

Association of p53 codon 72 polymorphism with advanced lung cancer: the Arg allele is preferentially retained in tumours arising in Arg/Pro germline heterozygotes

The association of p53 codon 72 polymorphism with cancer has been investigated by several scientific groups with controversial results. In the present study, we examined the genotypic frequency of this polymorphism in 54 patients with advanced lung cancer and 99 normal controls from the geographical region of Greece. Sputum and bronchial washing samples from each patient were assayed for the presence of human papillomavirus. Codon 72 heterozygous (Arg/Pro) patients were also analysed for loss of heterozygosity at the TP53 locus, in order to determine the lost p53 allele (Arg or Pro). p53 Arg/Arg genotype was significantly increased in lung cancer patients compared to normal controls (50% vs 24.2%, P<0.002). Human papillomavirus was detected only in two patients (3.7%). Loss of heterozygosity at the TP53 locus was found in 14 out of 27 Arg/Pro patients (51.85%). The Pro allele was lost in 11 cases (78.6%), while the Arg allele was lost in three (21.4%). Our results suggest that p53 codon 72 Arg homozygosity is associated with advanced lung cancer, and that the Arg allele is preferentially retained in patients heterozygous for this polymorphism. On the other hand, human papillomavirus infection does not seem to play an important role in lung carcinogenesis.     

P53 (codon 72) and P21 (codon 31) polymorphisms alter in vivo mRNA expression of p21

p21 (Waf1/Cip1) is a downstream target of p53. We evaluated the association between p21 polymorphism (codon 31), p53 polymorphism (codon 72) and their corresponding in vivo mRNA expression. In this study, p21 and p53 genetic polymorphisms (using standard PCR-RFLP techniques) and p21 and p53 gene expressions (using a radiolabelled ribonuclease protection assay (RPA) technique) were evaluated in the peripheral leukocytes of 84 individuals (63 with lung cancer). Log-transformed values of mRNA expression by RPA, which approximated a normal distribution, were analyzed. p53 genotypes did not correlate with p53 mRNA log-expression (P>0.05 for all comparisons), but the Pro allele variants of p53 were associated with a significant decrease in mRNA log-expression of its downstream target, p21. The variant Arg allele of p21 was also associated with a significant decrease in p21 mRNA log-expression. When individuals with at least one variant allele of both p53 and p21 (double-variants) were compared with all other genotype groups, these double-variants had significantly lower log-expression of p21 (P<0.005 by both t-tests (crude) and linear regression analyses (adjusted)). This is translated into an approximate 48% reduction in the geometric mean of the mRNA expression of the double-variants, when compared with all other groups. Results were consistent in both patients with lung cancer (n=63) and in normal controls (n=21). In conclusion, the presence of a p53 Pro allele and/or p21 Arg allele is associated with lower downstream target gene expression of p21.     

p53 codon 72多态性与宫颈癌发生机制的研究

宫颈癌是女性常见的恶性肿瘤,严重影响妇女的生活质量。人乳头状瘤病毒感染是宫颈癌的主要致病因素,近几年的研究发现p53 codon 72多态性与宫颈癌的发生发展密切相关。现主要综述该位点多态性在宫颈癌发生机制中的研究进展。     

Combination of p53 codon 72 polymorphism and inactive p53 mutation predicts chemosensitivity to 5‐fluorouracil in colorectal cancer

There are increasing reports showing the clinical significance of the p53 polymorphism status in terms of the response to chemotherapy. We investigated whether p53 polymorphism and mutation were associated with in vitro sensitivity to 5‐fluorouracil (5‐FU) in patients with colorectal cancer. Chemosensitivity to 5‐FU was evaluated by the collagen gel droplet embedded culture drug sensitivity test. 5‐FU sensitivity of tumor cells without inactive p53 mutation in the arginine/arginine (Arg/Arg) variant was significantly higher than that of tumor cells with or without inactive p53 mutation in other variants (p = 0.022), whereas the 5‐FU sensitivity of tumor cells with inactive p53 mutation in the Arg/Arg variant was significantly lower than that of tumor cells with or without inactive p53 mutation in other variants (p = 0.002). In the Arg/Arg variant, apoptotic cells induced by 5‐FU treatment in patients without inactive p53 mutation were more markedly increased than those in patients with inactive p53 mutation (p = 0.037). Bax and Bcl‐2 protein expressions in tumor tissue treated with 5‐FU were associated with both 5‐FU sensitivity and the apoptotic cell count. Our data show that the Arg/Arg genotype without inactive p53 mutation could be predictive of a more favorable response and the Arg/Arg genotype with inactive p53 mutation a less favorable response to chemotherapy using 5‐FU in CRC. The combination of the p53 codon 72 polymorphism and p53 mutation status is a potential predictive marker of sensitivity to 5‐FU in CRC.