MDM2 and p53 polymorphisms are associated with the development of hepatocellular carcinoma in patients with chronic hepatitis B virus infection

A single-nucleotide polymorphism (SNP) in the promoter region of MDM2, SNP 309, is associated with hepatocellular carcinoma (HCC) in patients with chronic hepatitis C virus infection. The effect of p53 codon 72 polymorphism Arg72Pro on HCC risk remains inconsistent. This study evaluated the association of MDM2 and p53 polymorphisms with the presence and early onset of HCC in Korean patients with chronic hepatitis B virus (HBV) infection. In total, 583 consecutive patients with chronic HBV infection were classified according to the presence (n = 287) or absence (n = 296) of HCC. The MDM2 SNP 309 and p53 Arg72Pro were genotyped using restriction fragment length polymorphism method. The MDM2 G/G and p53 Pro/Pro genotypes were more frequent in HCC group than in non-HCC group (P < 0.001 and P = 0.004, respectively). Multivariate analysis for the presence of HCC revealed that the odds ratio (OR) for MDM2 G/G over T/T was 4.89 (P < 0.001) and that of p53 Pro/Pro over Arg/Arg was 3.03 (P = 0.006). Combined MDM2 G/G and p53 Pro/Pro had a synergistic effect on HCC risk, with an OR of 20.78 (P < 0.001). The mean age of tumor onset in patients with MDM2 G/G genotype was 50.9 years compared with 55.1 with T/T genotype (P = 0.018) and that with p53 Pro/Pro was 49.7 years compared with 52.9 with Arg/Arg (P = 0.040). Thus, MDM2 SNP 309 and p53 Arg72Pro are associated with the early development of HCC in Korean patients with chronic HBV infection.     

Association of p53 codon 72 polymorphism and MDM2 SNP309 with clinical outcome of advanced nonsmall cell lung cancer

BACKGROUND: The purpose of the study was to investigate whether polymorphisms of p53 codon 72 (Arg72Pro) and MDM2 SNP309 (309T>G) affect p53 expression and the clinical outcome of patients with advanced nonsmall cell lung cancer (NSCLC). METHODS: A total of 148 NSCLC patients, previously enrolled in 2 different prospective clinical trials, were genotyped for the p53 Arg72Pro and MDM2 309T>G polymorphisms. Immunohistochemical staining of p53 protein was performed on 61 tumor samples. Genotypes were correlated with p53 expression, clinicopathologic factors, tumor response, and survival. Multivariate logistic or Cox regression analyses were used to adjust for possible confounding variables. RESULTS: The distribution of sex, age, performance status, stage, tumor histology, and smoking habit was not significantly different among polymorphism variants. However, a significant association was observed between p53 Arg72Pro polymorphism and primary resistance to chemotherapy. Patients with the Pro/Pro variant were more likely to be resistant to first-line chemotherapy, especially the irinotecan plus cisplatin regimen, than those with Arg/Arg or Arg/Pro variants (60% vs 27%, P = .014). In multivariate analysis, the Pro/Pro genotype was strongly predictive for shorter progression-free survival (PFS) (hazard ratio [HR] = 1.952, P = .01). The p53 overexpression was associated with MDM2 SNP309. The TT genotype showed more p53 overexpression than TG or GG genotypes (P = .036). In multivariate analysis, the MDM2 TT genotype was independently predictive for longer survival (HR = 1.742, P = .032). CONCLUSIONS: The p53 72Pro/Pro variant was predictive for primary resistance to chemotherapy and shorter progression-free survival. The MDM2 SNP309 was associated with less p53 overexpression and prognostic for worse survival. Genotyping these polymorphisms may be useful for predicting the clinical outcome of advanced NSCLC.     

Risk of MDM2 SNP309 alone or in combination with the p53 codon 72 polymorphism in acute myeloid leukemia

A single nucleotide polymorphism (SNP) in the promoter of MDM2 gene, SNP309 T > G (a T–G exchange at nucleotide 309 in the first intron), can increase the expression level of MDM2, thereby causing an impairment of p53 tumor suppressor activity. A G–C exchange at p53 codon 72 polymorphism results in a substitution of proline (Pro) for arginine (Arg) in the transactivation domain, which was shown to alter the primary structure of the p53 protein. Both polymorphisms have been implicated in cancer. To investigate whether that MDM2 SNP309 and p53 codon 72 polymorphism should be at least partially responsible for genetic susceptibility to acute myeloid leukemia (AML), both polymorphisms were determined in a case–control study consisting of 231 AML patients and 128 normal individuals. The MDM2 SNP309G allele was associated with increased risk of AML. Furthermore, the p53 codon 72 and MDM2 SNP309 polymorphisms did not associate with age of onset and any other clinical parameters studied. When the p53 and MDM2 polymorphisms were combined, no multiplicative joint effect between the MDM2 GG and p53 Pro/Pro genotypes exists in the risk of developing AML. These results suggest that the MDM2 SNP309 homozygous GG genotype may be a genetic susceptibility factor in the pathogenesis of AML.     

MDM2 309 polymorphism predicts outcome in platinum-treated locally advanced head and neck cancer

Chemo-radiotherapy (CRT) with cisplatin-based regimens is curative in a subset of patients with locally advanced (stage III and IV) squamous carcinomas of the head and neck (LAHNSCC), but causes considerable toxicity. To seek predictive biomarkers, we analysed single nucleotide polymorphisms (SNPs) in the p53 and MDM2 genes in LAHNSCC patients treated with cisplatin-based CRT. We analysed germ-line p53 72 Arg/Pro (R/P) and MDM2 309 SNPs and somatic p53 mutational status in 140 LAHNSCC and determined their utility as predictive biomarkers. In cases with wild-type p53, overall survival (OS) was longest in 72RR (median OS=60.8 months) and less favourable in 72PP (median OS=6.7 months, p<0.0001). OS in individuals with 72RP was intermediate between 72RR and 72PP, while in patients with missense p53 mutations, median OS did not reach statistical significance. Median OS was significantly shorter in patients with MDM2 309 SNP genotypes GG or GT, compared to TT (15 vs. 86 months; p<0.0001). The predictive effect of the G allele was maintained independent of age, gender, stage, primary site, nodal status, performance status, EGFR grade, HPV status, p53 mutation and p53 SNP (HR for death 3.241; 95% CI 1.90-5.52, p<0.001). The predictive utility of the MDM2 germ-line 309 SNP, which can be easily determined from peripheral blood, implies that it may be of value in the objective selection of patients for radical CRT. In contrast, the predictive utility of the 72 Arg/Pro SNP in p53 requires mutational analysis of p53, limiting its routine clinical use.     

Clinical implications of the MDM2 SNP309 and p53 Arg72Pro polymorphisms in transitional cell carcinoma of the bladder

Recent studies have shown that functional polymorphisms at the MDM2 SNP309 T/G and p53 Arg72Pro may be associated with cancer susceptibility. However, the role of these polymorphisms on the risk of transitional cell carcinoma of the bladder (TCCB) and clinical outcome remains unknown. SNP309 and p53 Arg72Pro polymorphisms were genotyped in 227 patients and 266 control subjects. The association between each polymorphism, TCCB risk and clinical outcome was evaluated by using a logistic regression model, a Kaplan-Meier curve with the log-rank test, or a Cox proportional hazard model. No significant associations between the polymorphisms and TCCB risk were found. On the MDM2 SNP309, the TT patients with superficial TCCB tended to have a longer recurrence-free survival than the TG or GG patients after transurethral resection (P=0.074). On the p53 Arg72Pro, the Pro/Pro patients with superficial TCCB had a significantly lower risk for recurrence than the Arg/Pro or Arg/Arg patients [Hazard ratio (HR), 0.364; 95% confidence interval (CI), 0.14-0.93]. In contrast, the Pro/Pro patients following radical cystectomy showed a significantly poorer survival and a higher risk of disease-specific death than the Arg/Pro + Arg/Arg patients (HR, 2.76; 95% CI, 1.11-6.84). MDM2 SNP309 and p53 Arg72Pro polymorphisms might influence the clinical outcome of TCCB in a distinctive way between superficial TCCB and invasive TCCB. The results may reflect marked differences in the genetic background between superficial and an invasive type of TCCB.     

Combined effects of MDM2 SNP 309 and p53 mutation on oral squamous cell carcinomas associated with areca quid chewing

The recently identified single nucleotide polymorphism in the MDM2 promoter (SNP 309) may contribute to the early onset of both sporadic and hereditary malignancies in patients with defective p53. We tested this hypothesis by examining the effects of combined MDM2 polymorphisms and somatic p53 mutations on 351 oral squamous cell carcinomas (OSCCs) associated with areca quid chewing. We found that the G allele of MDM2 SNP 309 was associated with early age of onset (p=0.02) and poor differentiation of OSCC tumors (p=0.01). The frequency of lymph node extracapsular spread (LNECS) was increased in individuals having both the MDM2 SNP 309 GG genotype and p53 mutation (chi(2) for trend p=0.04). MDM2 GG genotype and p53 mutations were associated with poor disease-free survival in both early and lymph node positive advanced stage OSCC patients (Hazard ratio=2.77 and 1.93, respectively). Taken together, an interaction between MDM2 SNP 309 and p53 with respect to tumor behaviors (including disease onset, tumor differentiation, LNECS and disease-free survival) was observed in sporadic Taiwanese OSCCs.     

Effects of MDM2 promoter polymorphisms and p53 codon 72 polymorphism on risk and age at onset of squamous cell carcinoma of the head and neck

Both p53 tumor suppressor and murine double minute 2 (MDM2) oncoprotein are crucial in carcinogenesis. We hypothesized that MDM2 promoter single nucleotide polymorphisms (SNPs) SNP309 T > G, A2164G, and p53 codon 72 are associated with risk and age at onset of squamous cell carcinoma of head and neck (SCCHN). We genotyped these SNPs in a study of 1,083 Caucasian SCCHN cases and 1,090 cancer-free controls. Although none of these SNPs individually had a significant effect on risk of SCCHN, nor did their combined putative risk genotypes (i.e., MDM2 SNP309 GT + GG, 2164 AA, and p53 codon 72 CC), we found that individuals with two to three risk genotypes had significantly increased risk of non-oropharyngeal cancer (OR = 1.42; 95% CI = 1.07-1.88). This increased risk was more pronounced among young subjects, men, smokers, and drinkers. In addition, female patients carrying the MDM2 SNP309 GT and GG genotypes showed a 3-yr (56.7 yr) and 9-yr (51.2 yr) earlier age at onset of non-oropharyngeal cancer (P(trend) = 0.007), respectively, compared with those carrying the TT genotype (60.1 yr). The youngest age (42.5 yr) at onset of non-oropharyngeal cancer was observed in female patients with the combined MDM2 SNP309 GG and p53 codon 72 CC genotypes. The findings suggest that MDM2 SNP309, A2164G, and p53 codon 72 SNPs may collectively contribute to non-oropharyngeal cancer risk and that MDM2 SNP309 individually or in combination with p53 codon 72 may accelerate the development of non-oropharyngeal cancer in women. Further studies with large sample sizes are warranted to validate these results.     

MDM2 SNP309 G allele increases risk but the T allele is associated with earlier onset age of sporadic breast cancers in the Chinese population

Sporadic breast cancer in women <40 years is uncommon inCaucasians, in contrast to a much earlier onset in Chinese Asians.However, the molecular determinants for this earlier onset areunclear. It has been reported that SNP309 in the promoter ofMDM2, the negative regulator of p53, affects the onset age ofcancers in females. Essentially, the G allele, rather than theT allele, has been suggested to accelerate the age of canceronset. Hence, we examined if MDM2 and p53 polymorphisms wouldbe determinants of the early onset phenomenon in Chinese women.Our results indicate that the MDM2 SNP309 G allele is more prevalentin the Chinese population compared with reported frequenciesin Caucasians, and increases breast cancer risk of both sporadiccases and those with family history. However, it was the T/Tgenotype that was associated with earlier onset age of sporadicbreast cancers in contrast to the G allele that was associatedwith the familial cases. Though p53 codon 72 single-nucleotidepolymorphism (SNP) did not affect general cancer risk or ageof onset, arginine homozygozity, in contrast to proline homozygozity,was found to decrease breast cancer risk in the later onsetsporadic cases. Both SNP309 and codon 72 polymorphisms did notaffect the stage of cancer. Together, the data suggest thatthough the MDM2 SNP309 G allele is a risk factor for breastcancer, it does not accelerate, but delays the onset of thesporadic disease in Chinese women, highlighting that differencesin ethnicity and family history may influence the role of MDM2SNP309 in cancer susceptibility. Abbreviations: Arg, arginine; ER, estrogen receptor; OR, odds ratio; PCR, polymerase chain reaction; Pro, proline; SNP, single-nucleotide polymorphism Received September 3, 2007; revised January 17, 2008; accepted January 18, 2008.     

MDM2 promoter SNP309 is associated with an increased susceptibility to chronic lymphocytic leukemia and correlates with MDM2 mRNA expression in Chinese patients with CLL

A single nucleotide polymorphism (SNP) at position 309 in the promoter region of MDM2 leading to increased expression of MDM2 and attenuated function of p53 has recently been suggested as an unfavorable prognostic marker in chronic lymphocytic leukemia (CLL) although this has been questioned. The MDM2 SNP309 genotypes in 173 CLL patients and 260 healthy controls were detected by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, which was confirmed by direct DNA sequencing. Compared with the T/T genotype, the SNP309 G/G genotype instead of T/G heterozygote was associated with a significantly increased risk of CLL (OR = 2.84; 95% CI 1.61-5.03; p < 0.001). Age at onset of CLL was similar irrespective of MDM2 status. MDM2 mRNA expression within CLL of G/G genotype was significantly higher than that in T/G (p = 0.009) and T/T genotypes (p < 0.001). Excluding patients with p53 deletions or mutations enhanced the significance of the findings (G/G vs. T/T, p < 0.001; G/G vs. T/G p = 0.001), which prompted us to study the role of the polymorphism in p53 wild-type individuals. In the p53 wild-type groups, survival analysis showed that the patients with MDM2 SNP309 G/G and T/G genotypes both had significantly shorter treatment-free survival (TFS) than SNP309 T/T genotype. Notably, univariate and multivariate analyses showed that MDM2 SNP309 genotypes were associated with TFS. These data show that MDM2 309G polymorphisms contribute to the risk of developing CLL. The unfavorable MDM2 SNP309 G/G genotype was associated with an increase of MDM2 mRNA expression. MDM2 SNP309 was found to be associated with TFS in p53 wild-type Chinese CLL populations.     

Role of the MDM2 Promoter Polymorphism (-309T>G) in Acute Myeloid Leukemia Development

Background: The human homologue of the mouse double minute 2 (MDM2) gene is a negative regulator ofTp53. MDM2-309T>G a functional promoter polymorphism was found to be associated with overexpressionthereby attenuation of Tp53 stress response and increased cancer susceptibility. We have planned to evaluate thepossible role of MDM2-309T>G polymorphism with risk and response to chemotherapy in AML. Materials andMethods: A total of 223 de novo AML cases and 304 age and sex matched healthy controls were genotyped for theMDM2-309T>G polymorphism through the tetra-primer amplification refractory mutation system (ARMS)-PCRmethod. In order to assess the functional relationship of -309T>G SNP with MDM2 expression level, we quantifiedMDM2 mRNA in 30 primary AML blood samples through quantitative RT-PCR. Both the (-309T>G) genotypesand the MDM2 expression were correlated with disease free survival (DFS) rates among patients who haveachieved complete remission (CR) after first induction chemotherapy. Results: MDM2-309T>G polymorphismwas significantly associated with AML development (p<0.0001). The presence of either GG genotype or G alleleat MDM2-309 confered 1.79 (95% CI: 1.12-2.86; p<0.001) and 1.46 fold (95%CI: 1.14-1.86; p= 0.003) increasedAML risk. Survival analysis revealed that CR+ve cases with GG genotype had significantly increased DFS rates(16months, p=0.05) compared to CR+ve TT (11 months) and TG (9 months) genotype groups. Further, MDM2expression was also found to be significantly elevated in GG genotype patients (p=0.0039) and among CR+vecases (p=0.0036). Conclusions: The MDM2-309T>G polymorphism might be involved in AML development andalso serve as a good prognostic indicator.     

MDM2 SNP309 modifies the prognostic significance of the p53 mutational status in patients with ovarian cancer

A single nucleotide polymorphism (SNP309) of MDM2 causes elevated MDM2 levels and an attenuation of p53 function. The aim of the present study was to examine the clinical relevance of the MDM2 SNP309 in ovarian cancer.MDM2 SNP309 genotype was analyzed in 198 patients with primary ovarian cancer. MDM2 expression was investigated using immunohistochemistry. A functional yeast-based assay and subsequent sequencing were performed to determine p53 mutational status. Of the patients, 44.4% (88 of 198) exhibited the common variant (T/T), 40.9% (81 of 198) the heterozygous variant (T/G) and 14.7% (29 of 198) the homozygous variant (G/G) MDM2 SNP309 genotype. MDM2 SNP309 was not associated with p53 mutational status, MDM2 expression, clinicopathological parameters or prognosis. In patients with the T allele (T/T and T/G genotype), p53 wild type carcinomas were associated with significantly improved recurrence-free (p<0.001) and overall survival (p<0.001) as compared to p53 mutant carcinomas. In contrast, p53 mutational status did not possess prognostic relevance in G/G carriers. A possible functional impairment of the p53 pathway caused by the G/G genotype of the MDM2 SNP309 may modify the association between p53 mutational status and prognosis in ovarian cancer.     

TP53 mutations predict for poor survival in de novo diffuse large B-cell lymphoma of germinal center subtype

Presence of TP53 mutations has been associated with poor prognosis in diffuse large B-cell lymphoma (DLBCL), although this has remained controversial. The TP53 codon 72 polymorphism has shown negative impact on cancer survival, but this has not been analyzed in DLBCL. Furthermore, the MDM2 SNP309 has been associated with earlier age of onset in DLBCL. Here, we investigated the clinical impact of TP53 mutations, MDM2 SNP309 and TP53 codon 72 polymorphisms on survival in DLBCL of germinal center (GC) and non-GC subtypes. Thirteen of the 102 (12.7%) patients displayed TP53 mutations. Overall, TP53 mutations had a significant effect on lymphoma-specific survival (LSS, P=0.009) and progression-free survival (PFS, P=0.028). In particular, inferior survival was observed in TP53-mutated DLBCLs of GC subtype (LSS, P=0.002 and PFS, P=0.006). Neither MDM2 SNP309 nor the TP53 codon 72 polymorphism had an impact on age of onset or survival. Altogether, our data suggests that TP53 mutations are associated with poor outcome in GC-DLBCL patients.     

P53 Arg72Pro and MDM2 SNP309 Polymorphisms Cooperate to Increase Lung Adenocarcinoma Risk in Chinese Female Non-smokers: A Case Control Study

Background: Cell cycle deregulation is a major component of carcinogenesis. The p53 tumor suppressorgene plays an important role in regulating cell cycle arrest, and mouse double minute 2 (MDM2) is a keyregulator of p53 activity and degradation. Abnormal expression of p53 and MDM2 occurs in various cancersincluding lung cancer. Methods: We investigated the distribution of the p53 Arg72Pro (rs1042522) and MDM2SNP309 (rs2279744) genotypes in patients and healthy control subjects to assess whether these single nucleotidepolymorphisms (SNPs) are associated with an increased risk of lung adenocarcinomas in Chinese female nonsmokers.Genotypes of 764 patients and 983 healthy controls were determined using the TaqMan SNP genotypingassay. Results: The p53 Pro/Pro genotype (adjusted OR = 1.55, 95% CI = 1.17–2.06) significantly correlated withan increased risk of lung adenocarcinoma, compared with the Arg/Arg genotype. An increased risk was also notedfor MDM2 GG genotype (adjusted OR = 1.68, 95% CI = 1.27–2.21) compared with the TT genotype. Combinedp53 Pro/Pro and MDM2 GG genotypes (adjusted OR = 2.66, 95% CI = 1.54–4.60) had a supermultiplicativeinteraction with respect to lung adenocarcinoma risk. We also found that cooking oil fumes, fuel smoke, andpassive smoking may increase the risk of lung adenocarcinomas in Chinese female non-smokers who carry p53or MDM2 mutant alleles. Conclusions: P53 Arg72Pro and MDM2 SNP309 polymorphisms, either alone or incombination, are associated with an increased lung adenocarcinoma risk in Chinese female non-smokers.     

Involvement of p53 R72P polymorphism in the association of MDM2-SNP309 with breast cancer

The allelic variant MDM2-SNP309 (T>G) has been suggested to influence cancer development, but the clinical correlation between the risk allele and breast cancer remains controversial. The genetic background and the ethnicity of selected subgroups may influence the power of these risk genotypes. In this study, we investigated whether MDM2-SNP309 is associated with p53 R72P genetic polymorphism for the risk of breast cancer development in Asian Taiwanese, which has not been well-studied in this regard. Two hundred and fifty-five patients and 324 cancer-free controls were included, and we found that the MDM2-SNP309 TG and GG genotypes displayed marginally increased risks of breast cancer (GG vs. TT: OR = 1.7, 95% CI = 0.93 to 3.09; TG + TT vs. TT: OR = 1.57, 95% CI = 0.98 to 2.56). The breast cancer risk associated with MDM2-SNP309 was enhanced after stratification for the homozygous GG genotype at p53 codon 72 representing the Arg form of this genotype (GG vs. TT: OR = 3.7, 95% CI = 1.144 to 12.02; TG + GG vs. TT: OR = 2.7, 95% CI = 1.027 to 6.895). Also, the median age at diagnosis of patients with MDM2-SNP309 GG increased from 4 years earlier to 9 years earlier than TT patients after stratification for the GG genotype at p53 codon 72. Moreover, the G-allele of MDM2-SNP309 exhibited a stronger capacity than the T-allele to drive the full-length P2 promoter of the MDM2 gene in several human cell lines, suggesting that the association between MDM2-SNP309 and breast cancer is likely multifactorial rather than due to inconsistent gene expression in different cancer sources.     

Polymorphisms of p53 and MDM2 genes are associated with severe toxicities in patients with non-small cell lung cancer

Adverse events in platinum-based chemotherapy for patients with advanced non-small cell lung cancer (NSCLC) are major challenges. In this study, we investigated the role of the p53 and MDM2 genes in predicting adverse events in NSCLC patients treated with platinum-based chemotherapy. Specifically, we examined the p53 p. Pro72Arg (rs1042522), MDM2 c.14 + 309T>G (rs2279744) and MDM2 c.− 461C > G (rs937282) polymorphisms using PCR-based restriction fragment length polymorphism (RFLP) in 444 NSCLC patients. We determine that MDM2 c.14 + 309T > G was significantly associated with severe hematologic and overall toxicities for advanced NSCLC patients treated with platinum-based chemotherapy, especially for patients aged 57 and younger. This was also true for patients with adenocarcinoma. Second, we determine that severe gastrointestinal toxicities in patients with heterozygous MDM2 c.−461C > G were significantly higher than in patients with the G/G genotype. Third, patients with the MDM2 c.−461C > G − c.14 + 309T > G CT haplotype show much higher toxicities than those of CG haplotype. Moreover, patients carrying the MDM2 c.−461 > G –c.14 + 309T > G CG/CT diplotype exhibited higher toxicities than those carrying CG/CG. Fourth, we found that the p53 p. Pro72Arg polymorphism interacts with both age and genotype. In addition, no significant associations were observed between the 3 SNPs and the response to first-line platinum-based chemotherapy in advanced NSCLC patients. In summary, we found that the p53 p. Pro72Arg, MDM2 c.14 + 309T > G and MDM2 c.−461C > G polymorphisms are associated with toxicity risks following platinum-based chemotherapy treatment in advanced NSCLC patients. We suggest that MDM2 c.14 + 309T > G may be used as a candidate biomarker to predict adverse events in advanced NSCLC patients who had platinum-based chemotherapy treatment.