p53-based blood test for p53PIN3 and risk for sporadic ovarian cancer

Association of p53 (-16ins-pro) haplotype with the decreased risk of differentiated thyroid carcinoma in Iranian-Azeri patients

Association of P53 polymorphisms with the increased risk of various cancers has been investigated in numerous studies. However, the results were conflicting and no polymorphism has been determined as a definite risk factor. It is likely that the study of P53 combined genotypes and haplotypes may be more useful than individual polymorphisms. Thus, in this study, we analyzed the associations of intron 3 Ins16bp and exon 4 Arg72Pro polymorphisms, as well as their combined genotypes and haplotypes with the risk of differentiated thyroid carcinoma in Iranian-Azeri patients. This case-control study was performed on 84 Iranian Azeri patients with differentiated thyroid carcinoma and 150 healthy subjects. Intron 3 genotype was determined using PCR products analysis on polyacrylamide gels and AS-PCR was used for genotyping Arg72Pro polymorphism. The javastat online statistics package software and SHEsis program were applied for data analysis. There was no significant difference in genotype frequencies of both two polymorphisms between cases and controls. However, the (-16 ins/-16 ins) (Arg/Pro) genotype combination had a noticeable but not significant association with decreased risk of thyroid cancer development (OR = 0.497 95%CI: 0.209-1.168 P = 0.080) and also the frequency of (-16 ins-Pro) haplotype was significantly higher in controls rather than patients (OR = 0.543 95%CI: 0.326-0.903 P = 0.018). In our study, there was association between (-16 ins-Pro) haplotype with decreased risk of differentiated thyroid carcinoma development in Iranian-Azeri patients.

Association of TP53 PIN3 polymorphism with breast cancer in Moroccan population

TP53 is a tumor suppressor gene involved in cell cycle progression control, DNA damage repair, genomic stability, and apoptosis. Some polymorphisms in this gene have been associated with the development of a number of cancers including breast carcinoma. PIN3 Ins16bp polymorphism has been widely studied in different populations for an association with breast cancer risk. In most case-control studies, a duplicated allele has been more frequent in cases rather than controls but there are also inconsistent results. The present study aimed to assess the association of PIN3 Ins16bp polymorphism of p53 with breast cancer risk in Moroccan population. This case-control study was performed on 105 female patients with confirmed breast cancer and 114 healthy controls. The genotype frequency was 69.5 % (A1A1), 26.7 % (A1A2), and 3.8 % (A2A2) in patients and 68.4 % (A1A1), 24.6 % (A1A2), and 7 % (A2A2) in controls. No statistically significant association was observed between PIN3 Ins16bp polymorphism and breast cancer risk with odds ratio of 1.07 (confidence interval (CI) = 0.58-1.97, p = 0.83) for the heterozygous A1A2 and 0.53 (CI = 0.15-1.85, p = 0.32) for mutated homozygous A2A2.According to our preliminary genetic analysis, PIN3 Ins16pb polymorphism could not be assessed as a marker of risk factor for predisposition to breast cancer in Moroccan population. However, a high frequency of A2 allele (19.3 %) in our population suggested that PIN3 Ins16pb polymorphism may be a valuable marker for study in other cancers with larger groups.

Less common genotype variants of TP53 polymorphisms are associated with poor outcome in adult patients with adrenocortical carcinoma

CONTEXT

The Li-Fraumeni tumor syndrome is strongly associated with adrenocortical carcinoma (ACC) and is caused by germline mutations in TP53 in 70% of cases. Also, TP53 polymorphisms have been shown to influence both cancer risk and clinical outcome in several tumor entities. We, therefore, investigated TP53 polymorphisms in a cohort of adult patients with ACC.

OBJECTIVE

Evaluation of the role of TP53 polymorphisms in adult patients with ACC.

SUBJECTS AND METHODS

Peripheral blood for DNA extraction was collected from 72 ACC patients. Polymorphism analysis was carried out by amplification and sequencing of exons and adjacent intron sections of TP53. Results were correlated with clinical data and the distribution of the polymorphisms was compared with published Caucasian control groups.

RESULTS

Compared with control groups, genotype frequencies of analyzed TP53 polymorphisms among ACC patients were significantly different in three out of four polymorphisms: IVS2+38G>C (G/G, P=0.0248), IVS3ins16 (NoIns/NoIns, P<0.0001; NoIns/Ins, P<0.0001), and IVS6+62A>G (G/G, P<0.0001; G/A, P<0.0001). Overall, the survival of ACC patients, which harbored at least one of the less frequent genotype variants of four analyzed polymorphisms (n=23), was significantly inferior (median survival: 81.0 months in patients with the common homozygous genotypes vs 20.0 months in patients with the less frequent genotypes, HR 2.56, 95% CI 1.66-7.07; P=0.001). These results were confirmed by multivariable regression analysis (HR 2.84, 95% CI 1.52-7.17; P=0.037).

CONCLUSION

Some TP53 polymorphisms seem to influence overall survival in ACC patients. This effect was observed for a combination of polymorphic changes rather than for single polymorphisms.

Mutations and polymorphisms in TP53 gene--an overview on the role in colorectal cancer

A functionally normal TP53 is essential to protect organisms from developing cancer. Somatic mutations in the gene represent one of the highest recurring perturbations in human tumours, including colorectal cancer (CRC). However, the variegated phenotype of wide spectrum of somatic mutations in TP53 and the complexity of the disease prevent a straight interpretation of the mutational analysis in tumours. In addition to the presence of somatic mutations, polymorphic features of the gene may also contribute to alteration of the normal TP53 functioning and variants, mainly in the form of single nucleotide polymorphisms, can be expected to impact susceptibility to sporadic CRC. In the present study, we reviewed the potential role of alterations in the TP53 gene, both somatic mutations and inherited sequence variations, in predisposition to CRC and in the prognosis and response to therapy. The available data from association studies have mostly shown contradictory outcomes. The majority of the studies were based on limited sample sizes and focussed on a limited number of polymorphisms, with main being the rs1042522 (Arg72Pro). Thus far, there is no possible generalisation of the role of TP53 as also a predictor of therapeutic response and prognosis. The effects of TP53, and its abnormalities, on the response of tumours to cytotoxic drugs, radiation and chemoradiation are complex. However, from studies it is emerging that the inherited genetics of TP53 pathway components could be utilised to further define patient populations in their abilities to induce p53 activity in response to either DNA damaging or p53-targeted therapies.

Haplotype analysis of p53 polymorphisms: Arg72Pro, Ins16bp and G13964C in Tunisian patients with familial or sporadic breast cancer

BACKGROUND

The p53 polymorphisms have been extensively studied as putative breast cancer susceptibility variants. The present study was undertaken to investigate the association of p53 Arg72Pro, Ins16bp and G13964C polymorphisms and their haplotypes with breast cancer risk in Tunisian women.

METHODS

Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) on 159 patients and 132 controls.

RESULTS

The G13964C intronic variant was significantly associated with familial breast cancer risk (p=0.0018) while the genotypic distribution was similar for p53 Arg72Pro and Ins16bp in patients and controls. Moreover, the (NoIns-C), (Arg-C) and (NoIns-Arg-C) haplotypes were significantly associated with familial breast cancer risk (p=0.0021, p=0.0096 and p=0.0084, respectively) while there was a trend of association between the (Ins-Arg) and (Ins-Arg-G) haplotypes and the risk of sporadic breast cancer. Only the G/C genotype as well as the (NoIns-C) haplotype remained significant after correction for multiple testing.

CONCLUSION

Our data revealed an association between the G/C genotype and the (NoIns-C) haplotype and the risk of familial breast cancer in Tunisian women. However, these observations need to be confirmed due to the limited statistical power of our study and the small number of cases.

Polymorphisms in p53 and the p53 pathway: roles in cancer susceptibility and response to treatment

The p53 tumour suppressor protein lies at the crossroads of multiple cellular response pathways that control the fate of the cell in response to endogenous or exogenous stresses and inactivation of the p53 tumour suppressor signalling pathway is seen in most human cancers. Such aberrant p53 activity may be caused by mutations in the TP53 gene sequence producing truncated or inactive mutant proteins, or by aberrant production of other proteins that regulate p53 activity, such as gene amplification and overexpression of MDM2 or viral proteins that inhibit or degrade p53. Recent studies have also suggested that inherited genetic polymorphisms in the p53 pathway influence tumour formation, progression and/or response to therapy. In some cases, these variants are clearly associated with clinico-pathological variables or prognosis of cancer, whereas in other cases the evidence is less conclusive. Here, we review the evidence that common polymorphisms in various aspects of p53 biology have important consequences for overall tumour susceptibility, clinico-pathology and prognosis. We also suggest reasons for some of the reported discrepancies in the effects of common polymorphisms on tumourigenesis, which relate to the complexity of effects on tumour formation in combination with other oncogenic changes and other polymorphisms. It is likely that future studies of combinations of polymorphisms in the p53 pathway will be useful for predicting tumour susceptibility in the human population and may serve as predictive biomarkers of tumour response to standard therapies.

Construction of a high resolution linkage disequilibrium map to evaluate common genetic variation in TP53 and neural tube defect risk in an Irish population

Genetic and environmental factors contribute to the etiology of neural tube defects (NTDs). While periconceptional folic acid supplementation is known to significantly reduce the risk of NTDs, folate metabolic pathway related factors do not account for all NTDs. Evidence from mouse models indicates that the tumor protein p53 (TP53) is involved in implantation and normal neural tube development. To determine whether genetic variation in TP53 might contribute to NTD risk in humans, we constructed a high resolution linkage disequilibrium (LD) map of the TP53 genomic region based on genotyping 21 markers in an Irish population. We found that nine of these variants can be used to capture the majority of common variation in the TP53 genomic region. In contrast, the 3-marker haplotype commonly reported in the TP53 literature offers limited coverage of the variation in the gene. We used the expanded set of polymorphisms to measure the influence of TP53 on NTDs using both case-control and family based tests of association. We also assayed a functional variant in the p53 regulator MDM2 (rs2279744). Alleles of three noncoding TP53 markers were associated with NTD risk. A case effect was seen with the GG genotype of rs1625895 in intron 6 (OR = 1.37 [1.04-1.79], P = 0.02). A maternal effect was seen with the 135/135 genotype of the intron 1 VNTR (OR = 1.86 [1.16-2.96], P = 0.01) and the TT genotype of rs1614984 (RR = 0.58 [0.37-0.91], P = 0.02). As multiple comparisons were made, these cannot be considered definitive positive findings and additional investigation is required.

Effect of the p53 codon 72 and intron 3 polymorphisms on non-small cell lung cancer (NSCLC) prognosis

A total of 42 polymorphisms have been identified in the TP53 gene. The polymorphic site of p53 at codon 72 in exon 4 and p53PIN3, a 16 bp insertion/duplication in intron 3, are the most studied. We tested p53PIN3 and the combined effect of the p53 codon72 and PIN3 polymorphisms on prognosis in 101 NSCLC cases. This study provides support for the prognostic effects of the multi-variant alleles from p53 exon 4 and intron 3, resulting in a significantly poorer prognosis in NSCLC. This approach highlights the value of examining multiple polymorphisms in genes to improve survival estimates.

Tagging single nucleotide polymorphisms in cell cycle control genes and susceptibility to invasive epithelial ovarian cancer

High-risk susceptibility genes explain <40% of the excess risk of familial ovarian cancer. Therefore, other ovarian cancer susceptibility genes are likely to exist. We have used a single nucleotide polymorphism (SNP)-tagging approach to evaluate common variants in 13 genes involved in cell cycle control-CCND1, CCND2, CCND3, CCNE1, CDK2, CDK4, CDK6, CDKN1A, CDKN1B, CDKN2A, CDKN2B, CDKN2C, and CDKN2D-and risk of invasive epithelial ovarian cancer. We used a two-stage, multicenter, case-control study. In stage 1, 88 SNPs that tag common variation in these genes were genotyped in three studies from the United Kingdom, United States, and Denmark ( approximately 1,500 cases and 2,500 controls). Genotype frequencies in cases and controls were compared using logistic regression. In stage 2, eight other studies from Australia, Poland, and the United States ( approximately 2,000 cases and approximately 3,200 controls) were genotyped for the five most significant SNPs from stage 1. No SNP was significant in the stage 2 data alone. Using the combined stages 1 and 2 data set, CDKN2A rs3731257 and CDKN1B rs2066827 were associated with disease risk (unadjusted P trend = 0.008 and 0.036, respectively), but these were not significant after adjusting for multiple testing. Carrying the minor allele of these SNPs was found to be associated with reduced risk [OR, 0.91 (0.85-0.98) for rs3731257; and OR, 0.93 (0.87-0.995) for rs2066827]. In conclusion, we have found evidence that a single tagged SNP in both the CDKN2A and CDKN1B genes may be associated with reduced ovarian cancer risk. This study highlights the need for multicenter collaborations for genetic association studies.

p53 genotypes and haplotypes associated with risk of breast cancer

INTRODUCTION

The biological significance of sequence variants in form of SNPs needs to be carefully evaluated, as conflicting associations with cancer predisposition have been reported. Haplotypes, the combination of closely linked alleles on a chromosome, play key roles in the study of the genetic basis of disease. There is strong evidence that different polymorphisms within a single gene in cis position can interact to create a large effect on the observed phenotype. Several polymorphisms have been reported in the p53 gene. Some of these are within the coding region and may affect the function of the p53 protein, others are within introns or non-coding regions, and their significance is unclear. In this study, we investigated the association of specific p53 genotypes and haplotypes with risk of breast cancer.

METHODS

One hundred and fifteen patients with breast cancer and 63 healthy individuals were analyzed. DNA was isolated by salting out. The polymorphic sites were analyzed by PCR RFLP. Pearson's chi(2) and Kolmogorof Simirnow tests were used for statistical analyses. Extended haplotype frequencies were estimated.

RESULTS

The distribution of the genotypes was similar for all three polymorphisms in the cases and the controls. Our estimated haplotype results indicate that the intron 3 (+16bp)|exon 4 (Arg) diplotype and the intron 3 (+16bp)|exon 4 (Arg)|intron 6 (G) haplotype combinations are overrepresented in the breast cancer group, suggesting that the intron 3 (+16bp)|exon 4 (Arg) alleles may play a role in breast carcinogenesis.

CONCLUSION

We conclude that two haplotypes harboring the intron 3 polymorphic (+16bp) allele are associated with a higher risk of breast cancer in the Turkish population.

Single tube genotyping of GSTM1, GSTT1 and TP53 polymorphisms by multiplex PCR

Glutathione S-transferases (GST) are enzymes involved in the conjugation of a number of human carcinogens, while p53 tumour suppressor gene is the most frequently mutated gene identified till now in human neoplasias. Typically, GSTM1 and GSTT1 genotyping are performed together, with several different protocol described and sometimes with the risk of misclassification due to "false negative", depending on the internal positive control employed. Here, we report a modification of the classical multiplex polymerase chain reaction (PCR) method, allowing the genotyping of GSTM1, GSTT1, together with a polymorphism within the intron 3 of TP53 tumour suppressor gene (a 16 base pairs (bp) duplication) in a single tube, with an appropriate internal positive control. To test the applicability of the method, the frequencies of the deleted alleles of GSTM1 and GSTT1 (null genotypes), and the 16 bp duplication of TP53 gene were assayed in a series of Caucasian DNA samples.

A haplotype containing the p53 polymorphisms Ins16bp and Arg72Pro modifies cancer risk in BRCA2 mutation carriers

Germline mutations in the BRCA1 and BRCA2 genes confer a high lifetime risk of developing breast and other cancers; however, remarkable differences exist regarding disease manifestation in mutation carriers. It has been suggested that other genetic and/or environmental factors modify not only the appearance but also the age of onset and type of tumor in BRCA1/2-associated cases. The aim of the present study was to investigate the role of two p53 polymorphisms (c.97-147ins16bp and c.215c>g, p.Arg72Pro) as potential modifiers. For this purpose we investigated the possible association between the two polymorphisms and disease status in 447 BRCA1/2 mutation carriers belonging to 170 Spanish breast and/or ovarian cancer families. Genotype and haplotype analyses revealed that the presence of a specific haplotype carrying the allele without the 16-bp insertion and the variant allele for the Arg72Pro (No Ins-72Pro haplotype) was associated with an earlier age of onset in BRCA2 mutation carriers. We found an increased risk of developing a first primary tumor (breast or ovarian) before 35 years of age for individuals who carried at least one No Ins-72Pro haplotype (OR: 2.69; 95% CI: 1.15-6.29; P=0.022). We confirmed these data by a functional study in which we compared different p53 genotypes in relation to their apoptotic response after cell treatment with a cytotoxic drug (AraC). Our results revealed a decrease in p53 apoptotic rate associated with the No Ins-72Pro haplotype.

Polymorphisms in the p53 pathway

The p53 tumor suppressor gene continues to be distinguished as the most frequently mutated gene in human cancer; this gene can be found mutated in up to 50% of human tumors of diverse histological type. It is generally accepted that the ability of p53 to induce either growth arrest or programmed cell death in response to diverse stimuli underlies the powerful selection against this protein in the development of cancer. It is somewhat surprising, then, to find p53 and several target genes in this pathway containing polymorphisms that impair their function. The nature of these polymorphic variants, and the mechanism whereby they impair the function of the p53 pathway, are reviewed here-in. The impact of these polymorphisms on cancer risk and the efficacy of therapy are only now becoming unraveled. Of particular relevance in these efforts will be the generation of mouse models of polymorphic variants in p53 and its target genes. Equally important will be better-controlled human studies, where-in haplotypes for p53 (that is, combinations of different polymorphisms in the p53 gene) and for p53-target genes are taken into account, instead of analyses of single gene variants, which have largely predominated to date. Studies in both regards should shed light on an emerging area in cancer biology, the significance of inter-individual differences in genotype on cancer risk, prognosis, and the efficacy of cancer therapy.

Mutation and homozygous deletion analyses of genes that control the G1/S transition of the cell cycle in skin melanoma: p53, p21, p16 and p15

INTRODUCTION

The role of genes involved in the control of progression from the G1 to the S phase of the cell cycle in melanoma tumors is not fully known.

MATERIAL AND METHODS

The aims of our study were to analyse alterations in p53, p21, p16 and p15 genes in melanoma tumors and melanoma cell lines by single strand conformational polymorphism (SSCP), and to detect homozygous deletions. We analysed the DNA from 39 patients with primary and metastatic melanomas, and from 9 melanoma cell lines.

RESULTS

The SSCP technique showed heterozygous defects in the p53 gene in 8 of 39 (20.5%) melanoma tumors: three point mutations in intron sequences (introns 1 and 2) and exon 10, and three new polymorphisms located in introns 1 and 2 (C to T transition at position 11701 in intron 1; C insertion at position 11818 in intron 2; and C insertion at position 11875 in intron 2). One melanoma tumor exhibited two heterozygous alterations in the p16 exon 1 (stop codon and missense mutation). No defects were found in the remaining genes. Homozygous deletions were more frequent in melanoma cell lines than in melanoma tumors in p21, p16 and p15 (22.2%, 44.4%, and 44.4% versus 7.7%, 2.5%, and 5.1% respectively). TP53 did not show homozygous deletions.

CONCLUSIONS

Our results suggest that these genes are involved in melanoma tumorigenesis; but perhaps not in the major targets. Other suppressor genes that may be informative of the mechanism of tumorigenesis in skin melanomas need to be studied.

A TP53 polymorphism is associated with increased risk of colorectal cancer and with reduced levels of TP53 mRNA

We undertook a case-control study to examine the possible associations of the TP53 variants Arg > Pro at codon 72 and p53PIN3, a 16 bp insertion/duplication in intron 3, with the risk of colorectal cancer (CRC). The p53PIN3 A2 allele (16 bp duplication) was associated with an increased risk (OR 1.55, 95% CI 1.10-2.18, P = 0.012), of the same order of magnitude as that observed in previous studies for other types of cancer. The Pro72 allele was weakly associated with CRC (OR = 1.34, 95% CI 0.98-1.84, P = 0.066). The possible functional role of p53PIN3 was investigated by examining the TP53 mRNA transcripts in 15 lymphoblastoid cell lines with different genotypes. The possibility that the insertion/deletion could lead to alternatively spliced mRNAs was excluded. However, we found reduced levels of TP53 mRNA associated with the A2 allele. In conclusion, the epidemiological study suggests a role for p53PIN3 in tumorigenesis, supported by the in vitro characterization of this variant.

Analyses of p53 expression pattern and BRCA mutations in patients with double primary breast and ovarian cancer

OBJECTIVE

To analyze the somatic pattern of p53 expression and BRCA germline mutation status in Israeli patients with both ovarian (OvCa) and breast cancer (BrCa).

METHODS

The study group comprised 43 Israeli patients with OvCa, all of whom had previous primary BrCa. p53 immunohistochemistry (IHC) on all available archival tissues and genotyping for the three predominant Jewish germline BRCA1-2 mutations were carried out. Samples from 64 patients with solitary OvCa and 61 with solitary BrCa were similarly analyzed as controls.

RESULTS

p53 expression pattern and the immunopositivity rate were similar in the ovarian and breast tumors within the study group and in the two control groups: positive p53 staining was detected in 68% of ovarian tumors in the study group compared with 71.9% in the controls, and in 19.4% of the BrCa tissues versus 21.3% in the controls. Within the study group, advanced stage OvCa had a higher rate of p53 expression (84%) compared to early stage disease (38.5%) (P = 0.006). This difference was not apparent in the solitary OvCa control group. OvCa in BRCA1-2 mutation carriers from the study group were more likely to display positive p53 staining (79%), especially in tumors diagnosed before the age of 60 (90%) compared with the OvCa of noncarriers (60%), but this difference was statistically insignificant. The p53 expression rate in BrCa samples from the study group was not associated with BRCA1-2 mutation status.

CONCLUSIONS

Positive p53 expression, detected by IHC, in OvCa patients with previous primary BrCa is significantly higher in advanced stage disease in BRCA1-2 mutation carriers. There is a higher positive p53 expression somatically in OvCa in BRCA1-2 carriers in whom OvCa was diagnosed before the age of 60 years, although this trend is not statistically significant. These observations suggest that somatic p53 inactivation may be an important event in ovarian tumorigenesis in this subset of patients.

The genetics of ovarian cancer

A family history of ovarian cancer confers an increased risk of ovarian cancer. We review the literature quantifying the familial risks associated with ovarian cancer and assess the evidence that the familial clustering of ovarian cancer is genetically determined. We then describe the known high-penetrance genes, the ovarian cancer risks attached to them and their contribution to ovarian cancer in families and in the general population. The evidence for the existence of other ovarian cancer genes is then considered.

Associations between common polymorphisms in TP53 and p21WAF1/Cip1 and phenotypic features of breast cancer

The tumour suppressor gene TP53 and its downstream effector p21 are thought to play major roles in the development of breast cancer. We investigated three common sequence variants in TP53 and p21 for possible associations with the risk of breast cancer and with various phenotypic features of this disease. A total of 351 cases were available for study. Germline DNA obtained from female subjects of similar age but without cancer was used to estimate the TP53 and p21 genotype frequencies in a control population. A single nucleotide polymorphism in intron 2 of p21 was associated with slightly increased breast cancer risk (RR = 1.4, P = 0.011) and with well/moderately differentiated tumour histology (P = 0.029). The 16 bp insertion polymorphism in intron 3 of TP53 was associated with poor histological grade (OR = 2.3, P = 0.013) independently of other pathological features. The codon 31 polymorphism in p21 was strongly linked to negative progesterone receptor status (OR = 3.4, P = 0.0001), suggesting this variant may have functional significance for the progesterone signalling pathway in breast cancer. These results add to the growing body of evidence that genetic variants can influence not only the risk of breast cancer but also the disease phenotype.

p53 and WAF1 polymorphisms in Jewish-Israeli women with epithelial ovarian cancer and its association with BRCA mutations

OBJECTIVE

To investigate whether polymorphic p53 and WAF1 alleles are associated with clinical, demographic and histopathological features and BRCA mutation in women with ovarian cancer.

DESIGN

A cross-sectional study.

POPULATION

Two hundred and twenty-one nonselected Israeli women with epithelial ovarian cancer.

METHODS

DNA was analysed for known polymorphisms in intron 3 (a 16 nucleotide single repeat) and intron 6 (a G to A change at nucleotide 13,494) of the p53 gene, the S31R polymorphism in the WAF1 gene, and for three predominant Jewish mutations in the BRCA genes (185delAG and 5382insC in BRCA1, and 6174delT in BRCA2).

MAIN OUTCOME MEASURE

The rate of polymorphic p53 and WAF1 alleles and their association with BRCA mutation, ethnic origin, age and stage at diagnosis, and family history of cancer.

RESULTS

Of the tested women, 72 (32.6%) were either BRCA1 (n = 57) or BRCA2 (n = 15) mutation carriers. Sixty-eight of 213 (31.9%) were heterozygous for intron 3 polymorphism, 67/193 (34.7%) for intron 6 polymorphism, and 22/154 (14.3%) for S31R of the WAF1 gene. The p53 and WAF1 polymorphism rate did not differ between BRCA mutation carriers and noncarriers. No significant association between specific p53 or WAF1 genotypes, and clinical, histopathological or demographic variables was observed.

CONCLUSION

In Jewish-Israeli women with sporadic and familial ovarian cancer, p53 or WAF1 polymorphisms do not seem to affect the phenotype.

Intron variants of the p53 gene are associated with increased risk for ovarian cancer but not in carriers of BRCA1 or BRCA2 germline mutations

Two biallelic polymorphisms in introns 3 and 6 of the p53 gene were analysed for a possible risk-modifying effect for ovarian cancer. Germline DNA was genotyped from 310 German Caucasian ovarian cancer patients and 364 healthy controls. We also typed 124 affected and 276 unaffected female carriers with known deleterious BRCA1 or BRCA2 germline mutation from high-risk breast-ovarian cancer families. Genotyping was based on PCR and high-resolution gel electrophoresis. German ovarian cancer patients who carried the rare allele of the MspI restriction fragment length polymorphism (RELP) in intron 6 were found to have an overall 1.93-fold increased risk (95% confidence internal (CI) 1.27-2.91) which further increased with the age at diagnosis of 41-60 years (odds ratio (OR) 2.71, 95% CI 1.10-6.71 for 41-50 and OR 2.44, 95% CI 1.12-5.28 for 51-60). The 16 bp duplication polymorphism in intron 3 was in a strong linkage to the MspI RFLP. In BRCA1 or BRCA2 mutation carriers, no difference in allele frequency was observed for carriers affected or unaffected with ovarian cancer. Our data suggest that intronic polymorphisms of the p53 gene modify the risk for ovarian cancer patients but not in carriers with BRCA1 or BRCA2 mutations.

Molecular aspects of ovarian cancer. Is gene therapy the solution?

Genetic abnormalities of cancer cells are complex and usually nonspecific. Genetic anomalies specific to ovarian cancer have not been reported. This article focuses on what molecular anomalies are known in ovarian cancer and describes the first trials that have used transfer of genes to reestablish a normal cellular function in this disease. Suicide gene therapy has been the prototype of this new therapeutic approach.

TP53 intron 6 polymorphism and the risk of ovarian and breast cancer

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Susceptibility to endometrial cancer: influence of allelism at p53, glutathione S-transferase (GSTM1 and GSTT1) and cytochrome P-450 (CYP1A1) loci

A case-control study was designed to identify associations between polymorphisms at p53, cytochrome P-450 (CYP1A1) and glutathione-S-transferases and endometrial cancer susceptibility. Among all polymorphisms analysed, an insertional variant in p53 (P53PIN3) and two polymorphisms in the 3'-end and exon 7 of CYP1A1 showed significant association with enhanced endometrial cancer risk.

p53 mutation is associated with high S-phase fraction in primary fallopian tube adenocarcinoma

Fallopian tube carcinoma (FTC) is a rare but lethal gynaecological malignancy. Four out of seven FTCs were identified with three point missense mutations, one single base deletion and one silent point mutation in the p53 gene. Genital-type HPV sequences were not detected. The S-phase fraction of tumours with mutant and wild-type p53 was 25.74% (median) and 12.55% (median) respectively.