Homozygosity for Pro of p53 Arg72Pro as a potential risk factor for hepatocellular carcinoma in Chinese population

Frequency of somatic mutations in TERT promoter, TP53 and CTNNB1 genes in patients with hepatocellular carcinoma from Southern Italy

Somatic mutations in the TERT promoter and in the TP53 and CTNNB1 genes are considered drivers for hepatocellular carcinoma (HCC) development. They show variable frequencies in different geographic areas, possibly depending on liver disease etiology and environmental factors. TP53, CTNNB1 and TERT genetic mutations were investigated in tumor and non-tumor liver tissues from 67 patients with HCC and liver tissue specimens from 41 control obese subjects from Southern Italy. Furthermore, TERT expression was assessed by reverse transcription-quantitative PCR. Neither CTNNB1 mutations or TP53 R249S substitution were detected in any case. The TP53 R72P polymorphism was found in 10/67 (14.9%) tumors, but was not found in either non-tumor tissues (P=0.001) or controls (P=0.009). TERT gene promoter mutations were found in 29/67 (43.3%) tumor tissues but were not found in either non-tumor (P<0.0001) or control liver specimens (P<0.0001). The most frequent mutation in the tumors was the known hot spot at -124 bp from the TERT ATG start site (-124G>A, 28 cases, 41.8%; P<0.0001). A new previously never reported TERT promoter mutation (at -297 bp from the ATG, -297C>T) was found in 5/67 (7.5%) tumors, in 0/67 (0%) non-tumor (P<0.0001), and in 0/41 (0%) controls (P=0.07). This mutation creates an AP2 consensus sequence, and was found alone (1 case) or in combination (4 cases) with the -124 bp mutation. The mutation at -124 and -297 bp induced a 33-fold (P<0.0001) and 40-fold increase of TERT expression levels, respectively. When both mutations were present, TERT expression levels were increased >300-fold (P=0.001). A new TERT promoter mutation was identified, which generates a de novo binding motif for AP2 transcription factors, and which significantly increases TERT promoter transcriptional activity.

TP53 Gene Pro72Arg (rs1042522) Single Nucleotide Polymorphism as Not a Risk Factor for Colorectal Cancer in the Iranian Azari Population

Background:

The p53 protein participates critically in several cellular functions such as cell growth and DNA repair. Polymorphisms in the TP53locus have repeatedly been implicated in the pathogenesis of cancers all over the world. Over 200 single nucleotide polymorphisms (SNPs) have been characterized, but one well-known example at at codon 72, Pro72Arg(rs1042522), has the displayed inconsistent results with regard to cancer risk. Herein, we aimed to evaluate whether Pro72Arg(rs1042522) single nucleotide polymorphism (SNP) in TP53gene might be associated with risk of colorectal cancer in the Iranian Azari population.

Methods:

Blood samples were taken from 100 healthy controls and 100 colorectal cancer patients with Iranian-Azeri ethnicity. Genotyping was performed with Tetra-ARMS PCR.

Results:

The alleles of the TP53gene Pro72ArgSNP did not significantly differ in prevalence between patients and controls (P>0.05). Additionally, genotypes of Pro72ArgSNP were not significantly associated with colorectal cancer risk in the studied population.

Conclusions:

Pro72ArgSNP of TP53gene may not be involved in the disease pathogenesis in Iranian Azari patients with colorectal cancer.

Association between MDM2 SNP309, p53 Arg72Pro, and hepatocellular carcinoma risk: A MOOSE-compliant meta-analysis

Epidemiological studies have determined the associations between polymorphisms on the promoter of MDM2 (SNP309) and the codon 72 on exon 4 of p53 (p53 Arg72Pro) and the risk of hepatocellular carcinoma (HCC); however, the results were not always consistent. The aim of the present meta-analysis was to evaluate the overall associations between these 2 variants and HCC risk.The MEDLINE, Web of science, EMBASE, Cochrane Library, and CNKI databases were searched for eligibility studies and the data were synthesized under the fixed- or random-effects model. Heterogeneity among the studies was evaluated with the Cochrane test Q and I statistic.For MDM2 SNP309, the pooled odds ratio (OR) from 15 independent studies with a total of 4038 cases and 5491 controls suggested a significant association for the variant with HCC risk [allele model, G vs T: pooled OR = 1.48, 95% confidence interval (95% CI) = 1.26-1.73; pooled OR = 1.53, 95% CI = 1.26-1.81, for G/T vs T/T; pooled OR = 2.04, 95% CI = 1.54-2.71 for G/G vs T/T]. For p53 Arg72Pro, a total of 21 studies with 7285 cases and 9710 controls suggested that the variant was also associated with HCC risk under common genetic model (allele Pro vs Arg, pooled OR = 1.13, 95% CI = 1.02-1.25; Pro/Pro vs Arg/Arg, pooled OR = 1.32, 95% CI =1.06-1.64). No publication bias was found for all the meta-analysis as suggested by the Begg funnel plot and Egger tests.These results suggested that variants MDM2 SNP309 and p53 Arg72Pro are susceptibility factors for HCC; however, more studies are warranted to validate the results.

Interaction between p53 codon 72 and MDM2 309T>G polymorphisms and the risk of hepatocellular carcinoma

The p53 tumor suppressor and its negative regulator, murine double minute 2 (MDM2), play critical roles in carcinogenesis. P53 codon 72 and MDM2 309T>G polymorphisms could influence p53 and MDM2 function, respectively, and might affect cancer susceptibility. We therefore investigated the association between these two SNPs, alone or in combination, and the risk of hepatocellular carcinoma (HCC) in Chinese. In this case-control study, we genotyped p53 codon 72 and MDM2 309T>G polymorphisms in 985 HCC cases and 992 cancer-free age- and sex-matched controls and evaluated their associations with the risk of HCC. Although no significant main effects were found for these two SNPs in the single-locus analysis and stratified analysis by age, sex, smoking, drinking, and hepatitis B virus (HBV) infection, we found that individuals carrying at least one G allele of the MDM2 309T>G polymorphism had statistically significant increased risk of HCC among those with the p53 Pro/Pro genotype (adjusted odds ratio (OR) = 2.23, 95 % confidence interval (95%CI) = 1.20-4.14 for TG genotype; adjusted OR = 2.67, 95%CI = 1.32-5.42 for GG genotype), and the interaction between p53 codon 72 and MDM2 309T>G was significant (P interaction = 0.017). Our findings suggest that the interaction of p53 codon 72 and MDM2 309T>G may play an important role in the etiology of HCC. More studies with well-designed and large sample sizes are required to validate these observations.

Alcohol consumption and liver cancer risk: a meta-analysis

PURPOSE

Alcohol is a confirmed risk factor of liver cancer. Yet, its dose-response function and synergistic effects with other risk factors remain unclear.

METHODS

We performed a meta-analysis on publications up to May 2014. A total of 112 publications were identified. The meta-relative risk (mRR) and the dose-response trend were calculated. Tests for heterogeneity, publication bias, and sensitivity analyses were performed. The synergy index (SI) was recorded or calculated, whenever possible.

RESULTS

Compared to individuals who never drank or drank at very low frequencies, the mRR for ever drinkers was 1.29 (95% confidence interval, CI 1.16-1.42) and 1.46 (95% CI 1.27-1.65) for case-control studies, and 1.07 (95% CI 0.87-1.27) for cohort studies. Being a current drinker was associated with an increased liver cancer risk in case-control studies (mRR = 1.55, 95% CI 0.38-2.73), but not in cohort studies (mRR = 0.86, 95% CI 0.74-0.97). The dose-response relation between alcohol and liver cancer was apparent with RR = 1.08 (95% CI 1.04-1.11) for 12 g/day (~1 drink), 1.54 (95% CI 1.36-1.74) for 50 g/day, 2.14 (95% CI 1.74-2.62) for 75 g/day, 3.21 (95% CI 2.34-4.40) for 100 g/day, and 5.20 (95% CI 3.25-8.29) for 125 g/day of alcohol consumption. There were synergistic effects of alcohol consumption with hepatitis (S = 2.14, 95% CI 1.31-2.98) and with diabetes (S = 3.57, 95% CI 2.29-4.84) on the risk of liver cancer, although this may be subject to publication bias.

CONCLUSION

Overall, one alcoholic drink per day (~12 g/day) may be associated with a 1.1 times higher liver cancer risk. Further studies on the synergistic effects of alcohol consumption and other major risk factors are warranted.

TP53 R72P polymorphism modulates DNA methylation in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is characterized by widespread epidemiological and molecular heterogeneity. Previous work showed that in the western part of North Africa, a region of low incidence of HCC, mutations are scarce for this tumor type. As epigenetic changes are considered possible surrogates to mutations in human cancers, we decided, thus, to characterize DNA methylation in HCC from North-African patients.

METHODS

A set of 11 loci was investigated in a series of 45 tumor specimens using methylation-specific and combined-bisulfite restriction assay PCR. Results obtained on clinical samples were subsequently validated in liver cancer cell lines.

RESULTS

DNA methylation at tumor suppressor loci is significantly higher in samples displaying chromosome instability. More importantly, DNA methylation was significantly higher in Arg/Arg when compared to Pro/Pro genotype carriers at codon 72 rs1042522 of TP53 (65% vs 20% methylated loci, p = 0.0006), a polymorphism already known to affect somatic mutation rate in human carcinomas. In vitro experiments in cell lines indicated that enzymes controlling DNA methylation were differentially regulated by codon 72 Arg or Pro isoforms of p53. Furthermore, the Arg72-carrying version of p53 was shown to re-methylate DNA more rapidly than the pro-harboring isoform. Finally, Pro-carrying cell lines were shown to be significantly more resistant to decitabine treatment (two-fold, p = 0.005).

CONCLUSIONS

Our data suggest that Arg72Pro polymorphism in a WT p53 context may act as a primary driver of epigenetic changes in HCC. It suggests, in addition, that rs1042522 genotype may predict sensitivity to epigenetic-targeted therapy. This model of liver tumorigenesis that associates low penetrance genetic predisposition to epigenetic changes emerges from a region of low HCC incidence and it may, therefore, apply essentially to population living in similar areas. Surveys on populations submitted to highly mutagenic conditions as perinatally-acquired chronic hepatitis B or aflatoxin B1 exposure remained to be conducted to validate our observations as a general model.

Prognostic impact of telomere maintenance gene polymorphisms on hepatocellular carcinoma patients with chronic hepatitis B

Our goal was to determine whether single-nucleotide polymorphisms (SNPs) of telomere maintenance genes influence the development and clinical outcomes of patients with hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC). We evaluated 20 SNPs of five telomere maintenance genes in 702 patients with HCC and 351 hepatitis B virus surface antigen-positive controls without HCC. Significant SNPs were then validated in an independent cohort of 857 HCC patients and 429 controls. We assessed the association of each SNP with the development of HCC and overall survival through a multivariate Cox proportional analysis. A significantly increased risk of HCC development was identified for the telomerase-associated protein 1 (TEP1) rs1713449 SNP in both the discovery and replication phases (combined odds ratio = 1.42, P = 9.378 × 10(-5) ). In addition, the TEP1 rs1713449, TEP1 rs872072, protection of telomeres 1 homolog rs7784168, telomerase reverse transcriptase rs13167280, and telomeric repeat binding factor 1 rs2306494 SNPs had a significant effect on the overall survival, and a similar survival effect was validated in the replication cohort. Moreover, there was a significant dose-dependent association between the number of putatively high-risk genotypes of the five aforementioned SNPs and overall survival. The median survival time was significantly prolonged for patients with HCC with two or fewer putatively high-risk genotypes versus those with three or more high-risk genotypes (85 versus 44 months, log-rank P = 4.483 × 10(-5) ), and this was demonstrated in the replication cohort (52 versus 37 months, log-rank P = 0.026).

CONCLUSION

These observations suggest that the SNPs of telomere maintenance genes play a potential role in the development of HCC and the survival of HCC patients with chronic HBV infections.

The association between polymorphism of P53 Codon72 Arg/Pro and hepatocellular carcinoma susceptibility: evidence from a meta-analysis of 15 studies with 3,704 cases

Emerging evidence has shown that p53gene participates in human carcinogenesis as tumor suppressors. Polymorphism of p53 gene codon72 arginine (Arg)/proline (Pro) (rs1042522) may influence the function of p53 protein and then affect the processing of carcinogenesis. It has been suggested that p53 codon72 Arg/Pro polymorphism is associated with susceptibility to hepatocellular carcinoma (HCC). However, published results are inconsistent and inconclusive. To examine the validity of the association between the polymorphism and HCC risk, we performed this meta-analysis. We have conducted a search of case-control studies on the associations of p53 codon72 polymorphism with susceptibility to HCC in PubMed, ScienceDirect, BioMed central, Springer, EBSCO, Wanfang databases, and Chinese National Knowledge Infrastructure databases. A total of 15 studies were identified with 3,704 cases and 4,559 controls for codon72 Arg/Pro polymorphism. The result did support a significant genetic association between Pro allele and susceptibility to HCC in all the genetic models. Similarly, subgroup analysis showed significant associations between the Arg/Pro polymorphism and susceptibility to HCC when stratifying by race, gender, source of controls, and hepatitis virus infection status. This meta-analysis suggests that p53 codon72 Arg/Pro polymorphism may be associated with the risk of HCC, especially in subgroup analysis of Asian and Caucasian population, hospital-based population, the female, and the individuals infected with hepatitis virus. However, well-designed studies based on different ethnic groups with larger sample size and more detailed data are needed to confirm these conclusions.

The association between polymorphism of P53 codon 72 Arg/Pro and hepatocellular carcinoma susceptibility: evidence from a meta-analysis of 15 studies with 3704 cases

BACKGROUND

Emerging evidence has shown that p53gene participates in human carcinogenesis as tumor suppressors. Polymorphism of p53 gene codon 72 Arg/Pro (rs1042522) may influence the function of p53 protein and then affect the processing of carcinogenesis. It has been suggested that p53 codon 72 Arg/Pro polymorphism is associated with susceptibility to hepatocellular carcinoma (HCC). However, published results are inconsistent and inconclusive. To examine the validity of the association between the polymorphism and HCC risk, we performed this meta-analysis.

METHODOLOGY/PRINCIPAL FINDINGS

We have conducted a search of case-control studies on the associations of p53 codon 72 polymorphism with susceptibility to HCC in PubMed, ScienceDirect, Bio-Med central, Springer-link, EBSCO, Wanfang databases and Chinese National Knowledge Infrastructure (CNKI) databases. A total of 15 studies were identified with 3704 cases and 4559 controls for codon 72 Arg/Pro polymorphism. The result did support a significant genetic association between Pro allele and susceptibility to HCC in all the genetic models. Similarly, subgroup analysis showed significant associations between the Arg/Pro polymorphism and susceptibility to HCC when stratifying by race, gender, source of controls and hepatitis virus infection status.

CONCLUSIONS/SIGNIFICANCE

This meta-analysis suggests that p53 codon 72 Arg/Pro polymorphism may be associated with the risk of HCC, especially in subgroup analysis of Asian and Caucasian population, hospital-based population, the female, and the individuals infected with hepatitis virus. However, well-designed studies based on different ethnic groups with larger sample size and more detailed data are needed to confirm these conclusions.

Association between TP53 Arg72Pro polymorphism and hepatocellular carcinoma risk: a meta-analysis

BACKGROUND

Previous studies on the association between the TP53 Arg72Pro polymorphism and hepatocellular carcinoma (HCC) risk obtained controversial findings. This study aimed to quantify the strength of the association by meta-analysis.

METHODS

We searched PubMed and Wangfang databases for published studies on the association between the TP53 Arg72Pro polymorphism and HCC risk, using the pooled odds ratio (OR) with its 95% confidence intervals (95% CI) for assessment.

RESULTS

10 studies with a total of 2,026 cases and 2,733 controls were finally included into this meta-analysis. Overall, the TP53 Arg72Pro polymorphism was not associated with HCC risk (all P values greaterth HCC risk in Caucasians in three genetic models (For Pro versus Arg, OR = 1.20, 95%CI 1.03-1.41; For ProPro versus ArgArg, OR = 1.74, 95%CI 1.23-2.47; For ProPro versus ArgPro/ArgArg, OR = 1.85, 95%CI 1.33-2.57). However, there was no significant association between the TP53 Arg72Pro polymorphism and HCC risk in East Asians (all P values greater than 0.10). No evidence of publication bias was observed.

CONCLUSION

Meta-analyses of available data suggest an obvious association between the TP53 Arg72Pro and HCC risk in Caucasians. However, the TP53 Arg72Pro polymorphism may have a race-specific effect on HCC risk and further studies are needed to elucidate this possible effect.

TP53 codon 72 polymorphism with hepatocellular carcinoma: a metaanalysis

OBJECTIVE

The association between codon 72 polymorphism of the tumour protein p53 (TP53) gene - which results in a missense mutation of arginine (R) to proline (P) - and susceptibility to hepatocellular carcinoma (HCC) is controversial. A metaanalysis was performed in order to define this relationship more precisely.

METHODS

Published studies of TP53 codon 72 polymorphism and the risk of HCC were identified. Data were extracted, and summary odds ratios (OR) and 95% confidence intervals (95% CI) were calculated. Pooled ORs were determined for an additive model (R/R versus P/P), a dominant model ([R/R + R/P] versus P/P) and a recessive model (R/R versus [R/P + P/P]).

RESULTS

The meta-analysis included seven case-control studies (total 1511 cases and 2165 controls). The risk of cancer was significantly decreased in the overall dominant model and the dominant model in Asian populations. A significantly decreased risk was found for all models in hospital-based but not population-based studies. There was no association between polymorphism and cancer risk when data were stratified according to hepatitis B or C virus infection status.

CONCLUSION

The TP53 codon 72 polymorphism may be a risk factor for HCC.

Polymorphisms of DNA repair genes in Korean hepatocellular carcinoma patients with chronic hepatitis B: possible implications on survival

BACKGROUND & AIMS

We aimed at determining whether single nucleotide polymorphisms (SNPs) of DNA repair genes influence the development and clinical outcomes of hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC).

METHODS

We evaluated 14 SNPs of eight DNA repair genes in 708 patients with HCC and 388 HBsAg positive controls without HCC. The Kaplan-Meier methods with log-rank test and Cox regression models were used to compare survival of HCC patients according to the genotype.

RESULTS

The SNP of XRCC4 rs1805377 was significantly associated with decreased risk of HCC development (OR, 0.592; p=0.028) and improved overall survival of patients with HCC (median survival time (MST) of 48, 72, and 89 months for the AA, AG, and GG genotypes, respectively; p=0.044). In addition, SNP of OGG1 rs1053133 was significantly associated with postoperative recurrence (OR, 0.604; p=0.049), tumor differentiation (OR, 0.571; p=0.041), and improved survival of resected HCC (MST of 55 and 108 months for the GG and GC/CC genotypes, p=0.001). The multivariate analysis showed that OGG1 rs1052133, XRCC1 rs25487, ERCC5 rs2018836, ERCC5 rs3818356, and XRCC4 rs1805377 had a significant effect on survival. Moreover, a strong dose-dependent association was observed between the number of putative high-risk genotypes of OGG1, XRCC1, ERCC5, and XRCC4 with the overall survival. The MST of HCC with ≥2 putative high-risk genotypes was significantly prolonged compared to those with ≥3 high-risk genotypes (76 vs. 46 months, respectively, p=0.002).

CONCLUSIONS

Polymorphisms of DNA repair genes play a potential role in the development, progression, and survival of Korean HCC patients with chronic HBV infection.

Association between XRCC1 ARG399GLN and P53 ARG72PRO polymorphisms and the risk of gastric and colorectal cancer in Turkish population

Gastric cancer is one of the most common cancers of the gastrointestinal system, and its overall five-year survival rate is still 15 % to 20 %, as it can mostly be diagnosed at an advanced stage. On the other hand, although colorectal cancer has a rather good prognosis, mortality is one half that of the incidence.As carcinogenesis is believed to involve reactive radicals that cause DNA adduct formation, impaired repair activity, and weakened tumour suppression, it would help to understand the role of the polymorphisms of nucleotide excision repair enzyme XRCC1 and of tumour suppressor gene p53 in gastric and colorectal cancers. Our study included 94 gastric cancer patients, 96 colorectal cancer patients, and 108 cancer-free individuals as control with the aim to see if there was an association between XRCC1 Arg399Gln and p53 Arg72Pro polymorphisms and cancer susceptibility. DNA was extracted from peripheral blood cells and genotypes were determined using the polymerase chain reaction-restriction fragment length polymorphism. Polymorphism p53 Arg72Pro was not associated with either gastric or colorectal carcinoma, while XRCC1 Arg399Gln was not associated with the increased risk of colorectal cancer. However, XRCC1 homozygous Gln allele at codon 399 was associated with 2.54 times higher risk of gastric cancer.

Associations between P53 Arg72Pro and development of digestive tract cancers: a meta-analysis

BACKGROUND AND AIMS

The relationships between P53 Arg72Pro and risks of digestive tract cancers have been extensively studied, and conclusive results were unavailable.

METHODS

Fifty three case-control studies were included through searching the databases of Medline, Embase and CNKI (up to August 2010). The odds ratio (OR) and 95% confidence interval (95% CI) were used to investigate the strength of the associations.

RESULTS

The results showed that there were no overall associations between P53 Arg72Pro and risks of digestive tract cancers. Subgroup analyses showed that P53 Arg72Pro was associated with risk of gallbladder and pancreatic cancer (OR [95% CI]: 1.44 [1.13-1.83] for Pro carriers vs. ArgArg). In addition, subgroup analyses also suggested that the Pro allele was associated with increased risks of digestive tract cancers among Asians (1.19 [1.01-1.42] for ProPro vs. ArgArg). Meanwhile, Pro allele was also suggested to be associated with increased risk of gastric cancer (1.33 [1.02-1.74] for ProPro vs. ArgPro for diffuse type of gastric cancer and 1.29 [1.05-1.57] for ProPro vs. Arg carriers for gastric cardia cancer) and colorectal cancer (1.26 [1.05-1.51] for ProPro vs. ArgPro for population-based case-control studies; 1.43 [1.09-1.87] for ProPro vs. ArgArg for colon cancer; 1.49 [1.09-2.06] for ProPro vs. ArgArg for rectal cancer and 2.22 [1.44-3.44] for ProPro vs. ArgArg for early stage of colorectal cancer).

CONCLUSIONS

This meta-analysis suggests that Pro allele in P53 Arg72Pro is significantly associated with the increased risks of digestive tract cancers, especially for Asians, and for gastric cancer, colorectal cancer and gallbladder and pancreatic cancer.

p53 codon 72 polymorphism is associated with susceptibility to hepatocellular carcinoma in the Turkish population: a case-control study

The tumor suppressor p53 gene plays a crucial role in preventing carcinogenesis through its ability to induce cell cycle arrest and apoptosis following DNA damage and oncogene activation. A guanine (G)/cytosine (C) common single nucleotide polymorphism (SNP) at second position of codon 72 in exon 4 of p53 gene determines a arginine (Arg) to proline (Pro) (Arg72Pro) aminoacidic substitution within the proline-rich domain of p53 protein. Arg72 and Pro72 allele are different from a biochemical and biological point of view and many reports suggest that they can modulate individual cancer susceptibility. To determine the association of the p53 Arg72Pro polymorphism with the risk of hepatocellular carcinoma (HCC) development in a Turkish population, a hospital-based case-control study was designed consisting of 119 subjects with HCC and 119 cancer-free control subjects matched for age, gender, smoking and alcohol status. The genotype frequency of the p53 Arg72Pro polymorphism was determined by using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Our data shows that the Pro/Pro genotype of the p53 Arg72Pro polymorphism is associated with increased risk of HCC development in this Turkish population (OR = 3.20, 95% CI: 1.24-8.22, P = 0.02). Furthermore, according to stratified analysis, a significant association was observed between the homozygote Pro/Pro genotype and HCC risk in the subgroups of male gender (OR = 3.01, 95% CI: 1.14-7.97, P = 0.03) and patients with hepatitis B virus (HBV)-related HCC (OR = 4.04, 95% CI: 1.46-11.15, P = 0.007). Because our results suggest for the first time that the Pro/Pro homozygote of p53 Arg72Pro polymorphism may be a genetic susceptibility factor for HCC (especially in the male gender and HBV-infected patients) in the Turkish population, further independent studies are required to validate our findings in a larger series, as well as in patients of different ethnic origins.

p53 codon 72 polymorphism and liver cancer susceptibility: A meta-analysis of epidemiologic studies

AIM: To evaluate the association between p53 codon 72 polymorphism and liver cancer risk by means of meta-analysis.

METHODS: Two investigators independently searched the Medline, Embase and Chinese Biomedicine databases. Summary odds ratios and 95% CI for p53 codon 72 polymorphism and liver cancer were calculated in fixed-effects model (Mantel-Haenszel method) and random-effects model (DerSimonian and Laird method) when appropriate.

RESULTS: This meta-analysis included 1115 liver cancer cases and 1778 controls. The combined results based on all studies showed that there was a statistically significant link between Pro/Pro genotype and liver cancer, but not between Arg/Arg or Pro/Arg genotype and liver cancer. When stratifying for race, similar results were obtained, i.e. patients with liver cancer had a significantly higher frequency of Pro/Pro genotype than non-cancer patients among Asians. After stratifying the various studies by control source, gender, family history of liver cancer and chronic hepatitis virus infection, we found that (1) patients among hospital-based studies had a significantly higher frequency of Pro/Pro and a significantly lower frequency of Arg/Arg genotype than individuals without cancer; (2) female patients with liver cancer had a significantly lower frequency of Arg/Arg and a higher frequency of Pro/Arg+Pro/Pro genotypes than female individuals without cancer; (3) subgroup analyses for family history of liver cancer did not reveal any significant association between p53 codon 72 polymorphism and liver cancer development; and (4) patients with negative hepatitis virus infection had a significantly higher frequency of Pro/Pro and a significantly lower frequency of Arg/Arg genotype than individuals without cancer.

CONCLUSION: This meta-analysis suggests that the p53 codon 72 polymorphism may be associated with liver cancer among Asians.

Association between MDM2-SNP309 and hepatocellular carcinoma in Taiwanese population

AIM: To investigate the risk association and compare the onset age of hepatocellular carcinoma (HCC) patients in Taiwan with different genotypes of MDM2-SNP309.

METHODS: We analyzed MDM2-SNP309 genotypes from 58 patients with HCC and 138 cancer-free healthy controls consecutively. Genotyping of MDM2-SNP309 was conducted by restriction fragment length polymorphism assay.

RESULTS: The proportion of homozygous MDM2-SNP309 genotype (G/G) in cases and cancer-free healthy controls was similar (17.2% vs 16.7%). Multivariate analysis showed that the risk of G/G genotype of MDM2-SNP309 vs wild-type T/T genotype in patients with HCC was not significant (OR = 1.265, 95% CI = 0.074-21.77) after adjustment for sex, hepatitis B or C virus infection, age, and cardiovascular disease/diabetes. Nevertheless, there was a trend that GG genotype of MDM2-SNP309 might increase the risk in HCC patients infected with hepatitis virus (OR = 2.568, 95% CI = 0.054-121.69). Besides, the homozygous MDM2-SNP309 genotype did not exhibit a significantly earlier age of onset for HCC.

CONCLUSION: Current data suggest that the association between MDM2-SNP309 GG genotype and HCC is not significant, while the risk may be enhanced in patients infected by hepatitis virus in Taiwan.

Contribution of polymorphism in codon 72 of TP53 gene to laryngeal cancer in Polish patients

The amino acid substitution Arg72Pro in the TP53 protein has an impact on the biochemical and biological activity of this protein, and is associated with several types of cancers. However, the Arg72Pro polymorphism exhibits inconsistent contribution as a risk factor in various cancer types. Therefore, using PCR-RFLPs, we investigated the distribution of Arg72Pro genotypes and alleles in patients with laryngeal cancer (n=123) and controls (n=300) in Poland. We observed that patients with the Pro/Pro and Arg/Pro TP53 genotypes displayed a 1.755-fold increased risk of laryngeal cancer (95% CI=1.149-2.680, P=0.0099). However, we did not find a significant increase in laryngeal cancer risk for the homozygous Pro/Pro TP53 genotype OR=2.093 (95% CI=1.046-4.192, P=0.0530). This result suggests that the TP53Pro variant may contribute to the risk of laryngeal cancer development in Polish patients.

Coordinate regulation of gallbladder motor function in the gut-liver axis

Gallstones are one of the most common digestive diseases with an estimated prevalence of 10%-15% in adults living in the western world, where cholesterol-enriched gallstones represent 75%-80% of all gallstones. In cholesterol gallstone disease, the gallbladder becomes the target organ of a complex metabolic disease. Indeed, a fine coordinated hepatobiliary and gastrointestinal function, including gallbladder motility in the fasting and postprandial state, is of crucial importance to prevent crystallization and precipitation of excess cholesterol in gallbladder bile. Also, gallbladder itself plays a physiopathological role in biliary lipid absorption. Here, we present a comprehensive view on the regulation of gallbladder motor function by focusing on recent discoveries in animal and human studies, and we discuss the role of the gallbladder in the pathogenesis of gallstone formation.

The effect of Z-FA.FMK on D-galactosamine/TNF-alpha-induced liver injury in mice

Cathepsin B is a cysteine proteinase, considered to have an important role in apoptosis, which is activated by D-galactosamine and tumor necrosis factor-alpha (D-GalN/TNF-alpha). Benzyloxycarbonyl-L-phenylalanine fluoromethyl ketone (Z-FA.FMK) is a cathepsin B inhibitor used in research on apoptotic pathways. The aim of this study was to investigate the role of Z-FA.FMK on apoptotic cell death, cell proliferation and liver damage induced by a D-GalN/TNF-alpha combination in mice. In the study, 1 h after administration of 8 mg/kg Z-FA.FMK by intravenous injection, D-GalN (700 mg/kg) and TNF-alpha (15 microg/kg) were administered by a single intraperitoneal injection. In the group given D-GalN/TNF-alpha, the following results were found: Degenerative changes in the liver tissue, significant increase in the number of both TUNEL and activated caspase-3-positive hepatocytes, a decrease in the number of PCNA-positive hepatocytes, an increase in lipid peroxidation (LPO) levels and a decrease in glutathione (GSH) and DNA levels in the liver tissue. In contrast, in the group given D-GalN/TNF-alpha and Z-FA.FMK, a decrease in the damage of the liver tissue, a significant decrease in TUNEL and activated caspase-3-positive hepatocytes, a significant increase in the number of PCNA-positive hepatocytes, a decrease in the LPO levels, an increase in GSH and DNA levels in the liver tissue were found. As a result, microscopic and biochemical evaluations indicate that Z-FA.FMK plays a protective role against liver injury induced by D-GalN/TNF-alpha and it has an inverse effect on hepatocyte apoptosis and proliferation in BALB/c mice.

Polymorphism of XRCC1 and the frequency of mutation in codon 249 of the p 53 gene in hepatocellular carcinoma among guangxi population, China

In hepatocellular carcinoma (HCC), hotspot mutation in codon 249 of the p53 gene has been associated with exposure to aflatoxin B1 (AFB1). While the polymorphism of DNA repair gene X-ray repair cross-complementary group 1 (XRCC1) Arg399Gln may be related with AFB1-DNA adducts and gene mutations. Five hundred one HCCs were included in this study to investigate the role of the XRCC1 codon 399 polymorphism on hotspot mutation in codon 249 of the p53 gene. The genotypes of XRCC1 codon 399 and p53 codon 249 were examined by PCR-RFLP. The HCC patients with XRCC1 genotypes with 399 Gln (namely: XRCC1-AG/GG) exhibited a significantly higher frequency of the p53 hotspot mutations in codon 249 than those with the wild-type homozygote of XRCC1 [namely: XRCC1-AA, adjusted odds ratio (OR) = 6.77, 95% confidence interval (CI) = 4.34-10.57]. Compared with those individuals who did express XRCC1-AA as reference (OR = 1), moreover, individuals featuring XRCC1-AG/GG and AFB1-DNA adducts did experience a significantly greater frequency of the hotspot mutation in codon 249 of the p53 gene (adjusted OR = 28.37, 95% CI = 13.19-61.02, P < 0.01). This study suggests that the XRCC1 Arg399Gln polymorphism and AFB1-DNA adducts are associated with the increased frequency of the p53 mutations in codon 249.

A Review of the Literature on the Pain Experience of Chinese Patients With Cancer

Over 2 million new cases of cancer are diagnosed annually in China. In addition, cancer is the leading cause of death in China. Because cancer is often diagnosed in more advanced stages in China, a higher percentage of patients will experience pain related to their disease or treatment. This article presents a review and critique of the studies that examined the experience of pain in Chinese cancer patients. Because pain is a subjective experience with multiple dimensions, this review used the multiple dimensions of cancer pain to describe the pain experience in adult Chinese patients with cancer. The results from 24 studies of cancer pain in Chinese patients are summarized. Most of these descriptive correlational studies evaluated the physiologic and sensory dimensions of the pain experience. Most of the patients reported moderate to severe pain and that pain interfered with their normal activities and mood. In contrast, little information is available about the impact of cancer pain on the cognitive and sociocultural dimensions of the pain experience for Chinese patients.

New mutations in the human p53 gene--a regulator of the cell cycle and carcinogenesis

Mutations in the tumor suppressor gene p53 often lead to disarrangement of the cell cycle and of genetic integrity control of cells that may contribute to tumor development. We studied p53 gene mutations in 26 primary tumors of colorectal cancer patients. Mutations in p53 were found in 17 tumors (65.4%). All point mutations affected the DNA binding domain of p53 and were localized in exons 4-8 of the gene. Mutant p53 isoforms with altered domain structure and/or with alternative C-terminus arising from frameshift mutations or abnormal splicing were found in six tumors. Mutations Leu111Gln and Ser127Phe were shown in colorectal cancer for the first time. Isoforms p53-305 with C(4) insertion in codons 300/301 and p53i9* including an additional 44 nucleotides of the 3 -end of intron 9 were discovered for the first time. Mutations of p53 were associated with lymph node metastases and III/IV stage of tumors that are signs of unfavorable prognosis in colorectal cancer.

p53 codon 72 polymorphism in patients affected with ulcerative colitis

BACKGROUND

The p53 tumor suppressor protein plays a fundamental role in maintaining genomic integrity through its ability to arrest the cell cycle in G1 and induce apoptosis. The proapoptotic activity of p53 seems to be strictly related to proline-rich regions, homologous to the SH3 binding domain. In the literature, reported data suggest a role for polymorphism at codon 72 of p53 in the predisposition to neoplastic transformation, although the results are still controversial. In this study, we investigated Arg72Pro polymorphism of p53 and related this polymorphism to clinical parameters in patients affected with ulcerative colitis (UC).

METHODS

We studied 243 consecutive outpatients affected with well-established UC. The control group comprised 142 healthy blood donors, with age and sex comparable to those of the patients.

RESULTS

p53 Pro/Pro was significantly related to the clinical course and duration of disease (odds ratio, 55.8 and 8.8, respectively). Nineteen of 24 patients with Pro homozygosity had a duration of disease >7 years. In contrast, 87 of 123 patients with Arg/Arg had short-standing UC (< or =7 yrs) and 66 of 96 with Arg/Pro had short-standing UC (chi-squared, 22.86; P < 0.0001). Thirty-four of 243 patients affected with UC had a positive family history for colorectal carcinoma (CRC). In those patients p53, Pro/Pro was significantly related to a family history of CRC (odds ratio, 38.1).

CONCLUSIONS

These preliminary data suggest that polymorphism at codon 72 of the p53 gene influences the clinical course of UC, with continuous disease associated with p53 Pro homozygosity.

MDM2 promoter SNP309 is associated with the risk of hepatocellular carcinoma in patients with chronic hepatitis C

PURPOSE

A single nucleotide polymorphism (SNP) in the promoter region of MDM2 gene, SNP309, has recently been shown to be associated with accelerated tumor formation in both hereditary and sporadic cancers in humans. However, the association of SNP309 with hepatocellular carcinoma is unknown. We evaluated the association of SNP309 with the risk of hepatocellular carcinoma development among Japanese patients with chronic hepatitis C virus infection.

EXPERIMENTAL DESIGN

We genotyped the SNP309 at the MDM2 promoter in 435 Japanese patients with chronic hepatitis C virus infection, including 187 patients with hepatocellular carcinoma and 48 healthy subjects, using a fluorogenic PCR. Presence of SNP was also confirmed by direct sequencing of the MDM2 promoter region.

RESULTS

The proportion of G/G genotype of the SNP309 in patients with hepatocellular carcinoma (33%) was significantly higher than that in patients without hepatocellular carcinoma (23%), with an odds ratio (95% confidence interval) of 2.28 (1.30-3.98). A multivariate analysis revealed that MDM2 SNP309 (G/G versus T/T), age >60 years, male gender, presence of cirrhosis, serum alpha-fetoprotein >20 mug/L, and serum albumin <3.2 g/dL were independently associated with the hepatocellular carcinoma development at odds ratio of 2.27, 2.46, 3.08, 4.15, 4.87, and 6.33, respectively.

CONCLUSIONS

The MDM2 promoter SNP309 is associated with the presence of hepatocellular carcinoma in Japanese patients with chronic hepatitis C.

Evaluation of p53 codon 72 polymorphism in adenocarcinomas of the colon and rectum in La Plata, Argentina

AIM: To evaluate the potential association between p53 codon 72 polymorphism and sporadic colorectal adenocarcinoma development, and human papillomavirus (HPV) infection.

METHODS: One-hundred and nine controls and 53 patients with colon cancer from the city of La Plata, Argentina were analyzed. p53 codon 72 genotypes and HPV infection were identified using allele-specific polymerase chain reaction and nested polymerase chain reaction, respectively.

RESULTS: The differences in the distribution of p53 codon 72 polymorphism between the cases and controls were statistically significant. The arginine allele had a prevalence of 0.65 in controls and 0.77 in cases. The corresponding odds ratio for the homozygous arginine genotype was 2.08 (95% CI, 1.06-4.05; P<0.05). Lack of association was found between p53 polymorphism and HPV infection in the set of adenocarcinomas.

CONCLUSION: The findings of the present study indicate that p53 codon 72 arginine homozygous genotype may represent a genetic predisposing factor for colon cancer development. However, further studies are needed in order to elucidate the role of p53 codon 72 polymorphism in colorectal cancer.

Anti-hepatoma activity and mechanism of ursolic acid and its derivatives isolated from Aralia decaisneana

AIM

To investigate the anti-tumor activity of ursolic acid (UA) and its derivatives isolated from Aralia decaisneana on hepatocellular carcinoma both in vitro and in vivo.

METHODS

In vivo cytotoxicity was first screened by 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay. Morphological observation, DNA ladder, flow cytometry analysis, Western blot and real time PCR were employed to elucidate the cytotoxic mechanism of UA. Implanted mouse hepatoma H22 was used to evaluate the growth inhibitory effect of UA in vivo.

RESULTS

UA could significantly inhibit the proliferation of HepG2 and its drug-resistance strain, R-HepG2 cells, but had no inhibitory effect on primarily cultured normal mouse hepatocytes whereas all the six derivatives of UA could not inhibit the growth of all tested cell lines. Further study on mechanism demonstrated that apoptosis and G0/G1 arrest were involved in the cytotoxicity and cleavage of poly-(ADP-ribose)-polymerase (PARP). Downregulation of cyclooxygenase-2 (COX-2) protein and upregulation of heat shock protein (HSP) 105 mRNA correlated to the apoptosis of HepG2 cells treated with UA. In addition, UA also could inhibit the growth of H22 hepatoma in vivo.

CONCLUSION

UA is a promising anti-tumor agent, but further work needs to be done to improve its solubility.