TP53 and P21 polymorphisms: response to cisplatinum/paclitaxel-based chemotherapy in ovarian cancer

Inhibition of PP2A by LB100 sensitizes bladder cancer cells to chemotherapy by inducing p21 degradation

PURPOSE

Bladder carcinoma (BLCA) is the most common urinary tract malignancy and exhibits a poor response to chemotherapy. Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase involved in a wide variety of regulatory cellular processes, including apoptosis and the DNA-damage response (DDR). LB100, a small molecule inhibitor of PP2A, has been shown to act as a chemo-sensitizer in multiple types of cancer. However, the anti-tumor effect and mode of action of LB100 in BLCA have yet to be identified.

METHODS

In vitro and in vivo experiments were performed to assess the anti-tumor effect of LB100 alone or in combination with gemcitabine. Mass spectrometry (MS)-based phosphoproteomics analysis was used to identify the downstream substrates of PP2A and to explore the mechanism underlying LB100-induced DNA damage and apoptosis. In addition, we established a chemo-resistant BLCA cell line (RT-112-R) by prolonged drug exposure and determined the effect of LB100 in enhancing genotoxicity in BLCA cell lines and xenograft mouse models.

RESULTS

We found that LB100 is sufficient to induce an anti-tumor response in BLCA cells by inducing DNA damage and apoptosis both in vitro and in vivo. Furthermore, we found that PP2A potentially dephosphorylates p-p21-ser130 to stabilize p21. Inhibition of PP2A by LB100 increased the level of p-p21-ser130, subsequently leading to a reduction in p21 level in a dose-dependent manner. In addition, we found that treatment of LB100 abrogated the G1/S cell cycle checkpoint, resulting in increased phosphorylation of γH2AX in BLCA cells. Moreover, LB100 enhanced genotoxicity in chemo-resistant BLCA cells by inducing DNA damage and apoptosis in vitro and in vivo.

CONCLUSION

Our findings indicate that PP2A may serve as a potential therapeutic target in BLCA through regulating p21 stability.

Association of Molecular Genetic Markers of TP53, MDM2, and CDKN1A Genes with Progression-Free Survival of Patients with Ovarian Cancer after Platinum-Based Chemotherapy

We studied the association of polymorphic markers of cell cycle control genes (Arg72Pro of the TP53 gene, T(-410)G of the MDM2 gene, and Ser31Arg of the CDKN1A gene) in ovarian cancer and progression-free survival following platinum-based chemotherapy. Tumor tissue samples obtained from 49 patients who had undergone chemotherapy were examined. Patients received standard platinum-based chemotherapy and were observed until disease progression. Polymorphic markers of genes were evaluated by PCR-RFLP and real-time PCR. In patients carrying the G allele of the T(-410)G marker of the MDM2 gene, a decreasing trend was observed in median progression-free survival. An increase in the median progression-free survival was observed in carriers of the Pro allele of the TP53 gene (p=0.045). Furthermore, a stronger association was noted with carriers of the minor Pro/Pro homozygous genotype relative to the Arg/Arg genotype (p=0.007). In the subgroup of patients who underwent optimal or complete cytoreductive surgery, carriage of the minor Arg allele of the Ser31Arg marker (CDN1A gene) was associated with a decrease in the median progression-free survival time (p=0.004).

Rethinking ovarian cancer genomics: where genome-wide association studies stand?

Genome-wide association studies (GWAS) allow the finding of genetic variants associated with several traits. Regarding ovarian cancer (OC), 15 GWAS have been conducted since 2009, with the discovery of 49 SNPs associated with disease susceptibility and 46 with impact in the clinical outcome of patients (p < 5.00 × 10-2). Among them, 14 variants reached the genome-wide significance (p < 5.00 × 10−8). Despite the results obtained, they should be validated in independent sets. So far, five validation studies have been conducted which could confirm the association of 12 OC susceptibility SNPs. Consequently, post-GWAS studies are crucial unravel the biological plausibility of GWAS’ findings and the allelic spectrum of OC.

Genetic variants as ovarian cancer first-line treatment hallmarks: A systematic review and meta-analysis

BACKGROUND

The potential predictive value of genetic polymorphisms in ovarian cancer first-line treatment is inconsistently reported. We aimed to review ovarian cancer pharmacogenetic studies to update and summarize the available data and to provide directions for further research.

METHODS

A systematic review followed by a meta-analysis was conducted on cohort studies assessing the involvement of genetic polymorphisms in ovarian cancer first-line treatment response retrieved through a MEDLINE database search by November 2016. Studies were pooled and summary estimates and 95% confidence intervals (CI) were calculated using random or fixed-effects models as appropriate.

RESULTS

One hundred and forty-two studies gathering 106871 patients were included. Combined data suggested that GSTM1-null genotype patients have a lower risk of death compared to GSTM1-wt carriers, specifically in advanced stages (hazard ratio (HR), 0.68; 95% CI, 0.48-0.97) and when submitted to platinum-based chemotherapy (aHR, 0.61; 95% CI, 0.39-0.94). ERCC1 rs11615 and rs3212886 might have also a significant impact in treatment outcome (aHR, 0.67; 95% CI, 0.51-0.89; aHR, 1.28; 95% CI, 1.01-1.63, respectively). Moreover, ERCC2 rs13181 and rs1799793 showed a distinct ethnic behavior (Asians: aHR, 1.41; 95% CI, 0.80-2.49; aHR, 1.07; 95% CI, 0.62-1.86; Caucasians: aHR, 0.10; 95% CI, 0.01-0.96; aHR, 0.18; 95% CI, 0.05-0.68, respectively).

CONCLUSION(S)

The definition of integrative predictive models should encompass genetic information, especially regarding GSTM1 homozygous deletion. Justifying additional pharmacogenetic investigation are variants in ERCC1 and ERCC2, which highlight the DNA Repair ability to ovarian cancer prognosis. Further knowledge could aid to understand platinum-treatment failure and to tailor chemotherapy strategies.

TP53 codon 72 polymorphism and breast cancer risk in Bangladeshi population

BACKGROUND

Breast cancer, a hereditary or heterogeneous sporadic disease, is the most common cancer in women worldwide. The tumor suppressor TP53 gene has been found to be the most commonly mutated genes in many types of human cancers, including breast cancer. This study aimed to investigate the association of codon 72 polymorphism of TP53 gene with breast cancer risk in Bangladeshi females.

METHODS

The study included 125 cases and 125 healthy controls. Genotyping and polymorphism were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis.

RESULTS

The frequencies of the three genotypes Arg/Arg, Arg/Pro, and Pro/Pro were 43.2, 33.6, and 23.2% in cases, whereas 48.8, 40.8, and 10.4% in controls, respectively. The frequency of mutant homozygous (Pro/Pro) genotype was significantly increased in breast cancer patients as compared with controls (23.2 vs 10.4%), and showed 2.52-fold significantly increased risk for breast cancer (OR 2.5199, 95% CI 1.19-5.33, p = 0.0157). The frequencies of Pro/Pro genotype were significantly higher in breast cancer cases with non-breast feeding status. Pro allele frequency was found to be significantly increased in breast cancer cases (OR 1.4978, 95% CI 1.0357-2.1662, p = 0.0318).

CONCLUSIONS

Our data suggest that mutant (Pro/Pro) homozygosity at codon 72 of TP53 gene is significantly associated with breast cancer susceptibility in Bangladeshi women. In addition, this association was significantly related to lactating status.

Combinatorial Cytotoxic Effects of Damnacanthal and Doxorubicin against Human Breast Cancer MCF-7 Cells in Vitro

Despite progressive research being done on drug therapy to treat breast cancer, the number of patients succumbing to the disease is still a major issue. Combinatorial treatment using different drugs and herbs to treat cancer patients is of major interest in scientists nowadays. Doxorubicin is one of the most used drugs to treat breast cancer patients. The combination of doxorubicin to other drugs such as tamoxifen has been reported. Nevertheless, the combination of doxorubicin with a natural product-derived agent has not been studied yet. Morinda citrifolia has always been sought out for its remarkable remedies. Damnacanthal, an anthraquinone that can be extracted from the roots of Morinda citrifolia is a promising compound that possesses a variety of biological properties. This study aimed to study the therapeutic effects of damnacanthal in combination with doxorubicin in breast cancer cells. Collectively, the combination of both these molecules enhanced the efficacy of induced cell death in MCF-7 as evidenced by the MTT assay, cell cycle, annexin V and expression of apoptosis-related genes and proteins. The effectiveness of doxorubicin as an anti-cancer drug was increased upon addition of damnacanthal. These results could provide a promising approach to treat breast cancer patients.

Improvement of a predictive model in ovarian cancer patients submitted to platinum-based chemotherapy: implications of a GST activity profile

PURPOSE

The success of chemotherapy in ovarian cancer (OC) is directly associated with the broad variability in platinum response, with implications in patients survival. This heterogeneous response might result from inter-individual variations in the platinum-detoxification pathway due to the expression of glutathione-S-transferase (GST) enzymes. We hypothesized that GSTM1 and GSTT1 polymorphisms might have an impact as prognostic and predictive determinants for OC.

METHODS

We conducted a hospital-based study in a cohort of OC patients submitted to platinum-based chemotherapy. GSTM1 and GSTT1 genotypes were determined by multiplex PCR.

RESULTS

GSTM1-null genotype patients presented a significantly longer 5-year survival and an improved time to progression when compared with GSTM1-wt genotype patients (log-rank test, P = 0.001 and P = 0.013, respectively). Multivariate Cox regression analysis indicates that the inclusion of genetic information regarding GSTM1 polymorphism increased the predictive ability of risk of death after OC platinum-based chemotherapy (c-index from 0.712 to 0.833). Namely, residual disease (HR, 4.90; P = 0.016) and GSTM1-wt genotype emerged as more important predictors of risk of death (HR, 2.29; P = 0.039; P = 0.036 after bootstrap). No similar effect on survival was observed regarding GSTT1 polymorphism, and there were no statistically significant differences between GSTM1 and GSTT1 genotypes and the assessed patients' clinical-pathological characteristics.

CONCLUSION

GSTM1 polymorphism seems to have an impact in OC prognosis as it predicts a better response to platinum-based chemotherapy and hence an improved survival. The characterization of the GSTM1 genetic profile might be a useful molecular tool and a putative genetic marker for OC clinical outcome.

TP53 Codon 72 Polymorphism Predicts Efficacy of Paclitaxel Plus Capecitabine Chemotherapy in Advanced Gastric Cancer Patients

BACKGROUND AND AIMS

The present study analyzed the relationship between TP53 codon 72 polymorphisms and the clinical outcome of advanced gastric cancer patients receiving capecitabine plus paclitaxel chemotherapy.

METHODS

Three hundred patients with advanced gastric cancer treated with paclitaxel and capecitabine combination chemotherapy were enrolled in the present study. Genomic DNA was extracted from peripheral blood leukocytes and determined using allele specific polymerase chain reaction (AS-PCR). Correlation between TP53 codon 72 polymorphisms and treatment response, gastric cancer survival was analyzed.

RESULTS

The Pro/Pro genotypes of TP53 codon 72 were significantly correlated with a lower response rate to capecitabine plus paclitaxel chemotherapy in patients with gastric cancer when compared to the Arg/Arg genotype (30.6 vs. 63.2%, p value 0.000). Multivariate survival analysis also showed that the progression free survival (PFS) and overall survival (OS) for patients with Pro/Pro genotypes of TP53 codon 72 were worse than for those with the Arg/Arg genotype (hazard ratio [HR] = 2.177, p = 0.009; HR = 2.145, p = 0.038, respectively).

CONCLUSIONS

TP53 codon 72 polymorphisms was effective in predicting the response to chemotherapy and correlate with PFS and OS in patients with advanced gastric cancer treated with paclitaxel and capecitabine chemotherapy.

A compensatory role of NF-κB to p53 in response to 5-FU-based chemotherapy for gastric cancer cell lines

Despite of remarkable improvement of postoperative 5-FU–based adjuvant chemotherapy, the relapse rate of gastric cancer patients who undergo curative resection followed by the adjuvant chemotherapy remains substantial. Therefore, it is important to identify prediction markers for the chemotherapeutic efficacy of 5-FU. We recently identified NF-κB as a candidate relapse prediction biomarker in gastric cancer. To evaluate the biological significance of NF-κB in the context of 5-FU–based chemotherapy, we analyzed the NF-κB-dependent biological response upon 5-FU treatment in gastric cancer cell lines. Seven genes induced by 5-FU treatment in an NF-κB-dependent manner were identified, five of which are known p53 targets. Knockdown of RELA, which encodes the p65 subunit of NF-κB, decreased both p53 and p53 target protein levels. In contrast, NF-κB was not affected by TP53 knockdown. We also demonstrated that cell lines bearing Pro/Pro homozygosity in codon72 of p53 exon4, which is important for NF-κB binding to p53, are more resistant to 5-FU than those with Arg/Arg homozygosity. We conclude that NF-κB plays an important role in the response to 5-FU treatment in gastric cancer cell lines, with a possible compensatory function of p53. These results suggest that NF-κB is a potential 5-FU-chemosensitivity prediction marker that may reflect 5-FU-induced stress-response pathways, including p53.

Effect of TP53 codon 72 and MDM2 SNP309 polymorphisms on survival of gastric cancer among patients who receiving 5-fluorouracil-based postoperative adjuvant chemotherapy

PURPOSE

Several studies have examined the prognostic value of the TP53 Arg72Pro polymorphism (rs1042522) and/or MDM2 SNP309 (rs2279744) in multiple tumors. Our aim was to determine whether these two genetic variants were correlated with clinical outcome of gastric cancer.

METHODS

We genotyped the two SNPs, TP53 codon 72 polymorphism and MDM2 SNP309, in 940 gastric cancer patients with complete follow-up information and analyzed the correlation between the SNPs and gastric cancer survival.

RESULTS

The two SNPs were not significantly associated with gastric cancer survival. However, the TP53 codon 72 polymorphism had a prominent correlation with clinical outcome of patients receiving 5-fluorouracil (5-Fu)-based postoperative chemotherapy [Arg/Arg + Arg/Pro vs. Pro/Pro, adjusted hazard ratio (HR) = 1.63, 95 % confidence interval (CI) = 1.08-2.44]. Moreover, the unfavorable effect of Arg allele on survival outcome was more predominant for subgroups of older (age >60 years), male, intestinal histology type, advanced stage (T3/T4), and none metastasis of lymph node (N0) or distant (M0) (adjusted HR = 2.34, 95 % CI = 1.24-4.44 for age >60 years; 1.72, 1.10-2.69 for male; 2.30, 1.10-4.80 for intestinal; 1.62, 1.01-2.59 for T3/T4; 3.42, 1.26-9.24 for N0; and 1.62, 1.06-2.47 for M0). Among multiple chemotherapy regimens, the association was only significant in the subgroup of 5-Fu/calcium folinate plus oxaliplatin (FOLFOX) chemotherapy regimen (adjusted HR = 4.47, 95 % CI = 1.21-16.55).

CONCLUSIONS

Our findings showed that TP53 codon 72 polymorphism was associated with survival of gastric cancer patients treated with 5-Fu-based postoperative chemotherapy. The codon 72 polymorphism may be a potential prognostic factor.

Ovarian cancer and DNA repair: DNA ligase IV as a potential key

Ovarian cancer (OC) is the sixth most common cancer and the seventh cause of death from cancer in women. The etiology and the ovarian carcinogenesis still need clarification although ovulation may be determinant due to its carcinogenic role in ovarian surface epithelium. The link between ovarian carcinogenesis and DNA repair is well established and it became clear that alterations in DNA damage response may affect the risk to develop OC. Polymorphisms are variations in the DNA sequence that exist in normal individuals of a population and are capable to change, among other mechanisms, the balance between DNA damage and cellular response. Consequently, genetic variability of the host has a great role in the development, progression and consequent prognosis of the oncologic patient as well as in treatment response. Standard treatment for OC patients is based on cytoreductive surgery, followed by chemotherapy with a platinum agent and a taxane. Although 80% of the patients respond to the first-line therapy, the development of resistance is common although the mechanisms underlying therapy failure remain mostly unknown. Because of their role in oncology, enzymes involved in the DNA repair pathways, like DNA Ligase IV (LIG4), became attractive study targets. It has been reported that variations in LIG4 activity can lead to a hyper-sensitivity to DNA damage, deregulation of repair and apoptosis mechanisms, affecting the susceptibility to cancer development and therapy response. To overcome resistance mechanisms, several investigations have been made and the strategy to target crucial molecular pathways, such as DNA repair, became one of the important areas in clinical oncology. This review aims to elucidate the link between DNA repair and OC, namely which concerns the role of LIG4 enzyme, and how genetic polymorphisms in LIG4 gene can modulate the activity of the enzyme and affect the ovarian carcinogenesis and treatment response. Moreover, we try to understand how LIG4 inhibition can be a potential contributor for the development of new cancer treatment strategies.

Role of common genetic variants in ovarian cancer susceptibility and outcome: progress to date from the Ovarian Cancer Association Consortium (OCAC)

In this article, we review the current knowledge of the inherited genetics of epithelial ovarian cancer (EOC) susceptibility and clinical outcome. We focus on recent developments in identifying low-penetrance susceptibility genes and the role of the Ovarian Cancer Association Consortium (OCAC) in these discoveries. The OCAC was established to facilitate large-scale replication analyses for reported genetic associations for EOC. Since its inception, the OCAC has conducted both candidate gene and genome-wide association studies (GWAS); the latter has identified six established loci for EOC susceptibility, most of which showed stronger association with the serous histological subtype. Future GWAS and sequencing studies are likely to result in the discovery of additional susceptibility loci and may result in established associations with clinical outcome. Additional rare and uncommon ovarian cancer loci will likely be uncovered from high-throughput next-generation sequencing studies. Applying these novel findings to establish improved preventative and clinical intervention strategies will be one of the major challenges of future work.

Genetic polymorphisms as predictive and prognostic biomarkers in gynecological cancers: a systematic review

PURPOSE

Numerous studies have explored the potential role of genetic polymorphisms as predictive or prognostic biomarkers in gynecologic malignancies. A systematic review for all eligible polymorphisms has not yet been reported. The aim of this study was to summarize the current status of the field and provide direction for future research.

DESIGN

We searched literature databases (MEDLINE, EMBASE, Cochrane) from 2006 to April 2011 to identify studies evaluating the association between gene polymorphisms and clinical outcome in ovarian, endometrial, cervical, or vulvar cancer. The main outcome measures were overall survival (OS) and progression-free survival (PFS). Studies reporting relationships between polymorphisms and toxicity were also included.

RESULTS

Sixty two studies met the inclusion criteria. The median sample size was 140. Most of the included studies (n=50, 81%) were conducted in ovarian cancer patients. Almost a third assessed potential predictive associations between gene polymorphism and outcome in ovarian cancer. The most commonly evaluated genes were ERCC1, VEGF, ABCB1 (MDR), and GSTP1. Most studies (n=44, 71%) were observational case-series. Only four studies (6%) included a validation arm and patient population ethnicity was explicitly stated only in 27% of included studies.

CONCLUSION

No consistent association between any gene polymorphism and clinical outcome in gynecological cancers has been found across studies. There is incomplete adherence to the REMARK guidelines and inadequate methodology reporting in most studies. Moving forward, analysis of large trial-based clinical samples; adherence to the highest methodological standards, and focus on validation analyses are necessary to identify clinically useful pharmacogenomic biomarkers of outcome.

Meta-analysis shows significant association of the TP53 Arg72Pro with ovarian cancer risk

Growing bodies of studies have been conducted on the association of TP53 Arg72Pro polymorphism with susceptibility to ovarian cancer and have yielded conflicting results. Thus, a meta-analysis was performed to summarize the possible association. 18 case-control studies, including 2,193 ovarian cancer cases and 5,175 controls were identified. The quality of the studies was assessed according to a predefined scale. The strength of the associations between TP53 Arg72Pro polymorphism and ovarian cancer was measured by crude odds ratios (ORs) with 95% confidence intervals (CIs). Overall, no significant association was found between TP53 Arg72Pro polymorphism and ovarian cancer risk when all studies pooled into the meta-analysis in all genetic model. In the subgroup analysis by ethnicity, still no association of this polymorphism with ovarian cancer risk was obtained for all comparison models. However, significantly decreased risks of ovarian cancer were found for Arg/Arg versus Arg/Pro+Pro/Pro (OR 0.84, 95% CI 0.74-0.96) when the analysis was restricted to high quality studies. Conversely, when it was restricted to low quality studies, significantly increased risks were observed for Arg/Arg versus Pro/Pro (OR 1.58, 95% CI 1.09-2.28) and Arg/Arg+Arg/Pro versus Pro/Pro: (OR 1.50, 95% CI 1.10-2.06), which might be spurious due to the poor design of these studies. In conclusion, this meta-analysis suggests that the Arg allele is at a moderately reduced risk for ovarian cancer and this polymorphism might protect against ovarian carcinogenesis.

Relationships between genetic polymorphisms and transcriptional profiles for outcome prediction in anticancer agent treatment

In the era of personal genomics, predicting the individual response to drug-treatment is a challenge of biomedical research. The aim of this study was to validate whether interaction information between genetic and transcriptional signatures are promising features to predict a drug response. Because drug resistance/susceptibilities result from the complex associations of genetic and transcriptional activities, we predicted the inter-relationships between genetic and transcriptional signatures. With this concept, captured genetic polymorphisms and transcriptional profiles were prepared in cancer samples. By splitting ninety-nine samples into a trial set (n = 30) and a test set (n = 69), the outperformance of relationship-focused model (0.84 of area under the curve in trial set, P = 2.90 x 10⁻⁴) was presented in the trial set and validated in the test set, respectively. The prediction results of modeling show that considering the relationships between genetic and transcriptional features is an effective approach to determine outcome predictions of drug-treatment.

Testicular cancer survivorship: research strategies and recommendations

Testicular cancer represents the most curable solid tumor, with a 10-year survival rate of more than 95%. Given the young average age at diagnosis, it is estimated that effective treatment approaches, in particular, platinum-based chemotherapy, have resulted in an average gain of several decades of life. This success, however, is offset by the emergence of considerable long-term morbidity, including second malignant neoplasms, cardiovascular disease, neurotoxicity, nephrotoxicity, pulmonary toxicity, hypogonadism, decreased fertility, and psychosocial problems. Data on underlying genetic or molecular factors that might identify those patients at highest risk for late sequelae are sparse. Genome-wide association studies and other translational molecular approaches now provide opportunities to identify testicular cancer survivors at greatest risk for therapy-related complications to develop evidence-based long-term follow-up guidelines and interventional strategies. We review research priorities identified during an international workshop devoted to testicular cancer survivors. Recommendations include 1) institution of lifelong follow-up of testicular cancer survivors within a large cohort setting to ascertain risks of emerging toxicities and the evolution of known late sequelae, 2) development of comprehensive risk prediction models that include treatment factors and genetic modifiers of late sequelae, 3) elucidation of the effect(s) of decades-long exposure to low serum levels of platinum, 4) assessment of the overall burden of medical and psychosocial morbidity, and 5) the eventual formulation of evidence-based long-term follow-up guidelines and interventions. Just as testicular cancer once served as the paradigm of a curable malignancy, comprehensive follow-up studies of testicular cancer survivors can pioneer new methodologies in survivorship research for all adult-onset cancer.

Genetic polymorphisms of p21 and risk of second primary malignancy in patients with index squamous cell carcinoma of the head and neck

p21 plays an important role in modulating cell cycle control, inducing apoptosis, and inhibiting cell growth, subsequently affecting cancer risk. We investigated the association between two putatively functional single-nucleotide polymorphisms (SNPs) of p21 (p21 C98A and p21 C70T) among 1282 patients diagnosed with incident squamous cell carcinoma of the head and neck (SCCHN) and risk of second primary malignancy (SPM) in an ongoing molecular epidemiology study. We used Log-rank test and Cox proportional hazard models to assess the association of these two SNPs with SPM-free survival and SPM risk. We found that patients with either p21 variant genotypes of the two polymorphisms had a significantly reduced SPM-free survival compared with patients with either p21 wild-type homozygous genotypes (Log-rank test, P = 0.0016). Compared with patients having the p21 98 CC and p21 70 CC genotypes, the patients having p21 98 CA/AA and p21 70 CT/TT variant genotypes had a significantly greater risk of developing SPM, respectively, [hazard ratio (HR) = 1.80, 95% CI = 1.14-2.82 for p21 C98A and HR = 1.82, 95% confidence interval (CI) = 1.16-2.85 for p21 C70T]. Moreover, after combining the variant genotypes of two SNPs, patients with variant genotypes had a significantly moderately increased risk for SPM compared with patients with no variant genotypes (HR = 2.00, 95% CI = 1.26-3.00), and the risk was particularly pronounced in several subgroups. Our results support an increased risk of SPM after index SCCHN with both p21 polymorphisms individually and in combination.

Pharmacogenomics of taxane/platinum therapy in ovarian cancer

OBJECTIVES

Taxane (paclitaxel or docetaxel) and platinum (cisplatin or carboplatin) chemotherapy is commonly used in the treatment of ovarian cancer. Despite an initial high response to therapy, the 5-year survival rate remains low. The identification of pharmacogenomic markers to identify patients unlikely to respond or at risk for severe toxicity will assist in the goal of individualizing ovarian cancer treatment.

MATERIALS AND METHODS

Most studies have assessed single nucleotide polymorphisms from genes involved in the pharmacokinetics and pharmacodynamics of the drugs.

RESULTS

Unfortunately, most markers identified have not been replicated in subsequent studies.

CONCLUSIONS

Other mechanisms of variability, including epigenetic control of gene expression and copy number variation, may play important roles. In addition, nongenetic influences such as concurrent medications, and physiological and environmental factors could also affect individual responses to taxane and platinum therapy.

Genetic polymorphisms and the efficacy and toxicity of cisplatin-based chemotherapy in ovarian cancer patients

Platinum drugs are among the most active and widely used agents in the treatment of different cancers. However, the great individual variability in both outcome and toxicity of platinum chemotherapy requires the identification of genetic markers that can be used to screen patients before treatment. In this study, 21 polymorphisms in 10 genes, the protein activities of which may be addressed in different aspects of cisplatin metabolism, were tested for correlations with efficacy and toxicity of cisplatin-cyclophosphamide regimen in 104 ovarian cancer patients. The glutathione S-transferase P1 (GSTP1) Ile105Val polymorphism was strongly associated with progression-free survival (chi(2)=12.12, P=0.002). The allelic status of the GSTA1 -69 C>T polymorphism correlated with the overall survival: patients with T/T genotype survived longer than C/C carriers (P=0.044). Thrombocytopenia, anemia and neuropathy were less frequent among patients with the GSTM1-null or GSTM3 intron 6 AGG/AGG genotypes. Severe neutropenia was associated with the TP53 72 Pro/Pro, XPD 312 Asp/Asn and XRCC1 399 Arg/Arg genotypes. A higher risk of nephrotoxicity was noted for patients with the heterozygous ERCC1 19007 T/C and 8092 C/A genotypes. No correlations were found between genotypes and complete tumor responses.

Family History of Cancer Rather Than p53 Status Predicts Efficacy of Pegylated Liposomal Doxorubicin and Oxaliplatin in Relapsed Ovarian Cancer

Background:

The aim of the study was to assess the efficacy of pegylated liposomal doxorubicin (PLD) and oxaliplatin in patients affected by relapsed epithelial ovarian cancer with a family history of BRCA and p53 mutations.

Methods:

Seventy-two women received a median of 7.5 courses of PLD at 30 to 35 mg/m2 plus oxaliplatin at 70 mg/m2, and associations between BRCA1/2 and TP53 status and overall survival (OS) were determined. Thirty-eight had a short platinum-free interval (PFI; <12 months), and 34 had a long PFI (≥12 months).

Results:

Nine patients had BRCA1 mutations, and 1 had a BRCA2 mutation. Platinum sensitivity was associated with OS (P = 0.0001). At a median follow-up of 9.3 months, objective response rate, median time to progression, and OS were 47.3%, 5.8 months, and 12.9 months, respectively, in short PFI compared with the 76.5%, 11.5 months, and 47.7 months in long PFI. p53 status did not correlate to these parameters. The median time to progression was 11.5 months for high-risk patients versus 6.5 months for patients with sporadic cancer (P = 0.0188), and the median OS from the start of treatment was 48.7 and 16.2 months (P = 0.0032), respectively. Toxicity was mostly grade 1 or 2.

Conclusions:

High response rates in the long-PFI patients indicate that this treatment is beneficial and well tolerated. Platinum sensitivity and positive family history and/or a BRCA1/BRCA2 mutation are a useful predictor of response.

TP53 codon 72 polymorphism associated with prognosis in patients with advanced gastric cancer treated with paclitaxel and cisplatin

PURPOSE

The present study analyzed the polymorphisms of apoptosis-related genes and their impact on the response to chemotherapy and survival of patients with advanced gastric cancer.

PATIENTS AND METHODS

Fifty-seven patients with advanced gastric cancer treated with paclitaxel and cisplatin combination chemotherapy were enrolled in the present study. The genomic DNA was extracted from paraffin-embedded tissue, and the single nucleotide polymorphisms (SNPs) of ten apoptosis-related genes [LTA, TP53, BCL2L11, BID, FASL, caspase 3, caspase 6, caspase 7, and caspase 9] determined using a polymerase chain reaction-restriction fragment length polymorphism assay.

RESULTS

The Arg/Pro and Pro/Pro genotypes of TP53 codon 72 were significantly correlated with a lower response rate to the combination chemotherapy when compared to the Arg/Arg genotype (35.7 vs. 66.7%, P-value 0.019) in a logistic regression analysis. A multivariate survival analysis also showed that the time to progression for the patients with the Arg/Pro and Pro/Pro genotypes of TP53 codon 72 was worse than for the patients with the Arg/Arg genotype (Hazard ratio = 3.056, P-value = 0.047), whereas the overall survival was not significantly different.

CONCLUSION

The TP53 codon 72 SNP was found to be predictive of the response to chemotherapy and correlate with the time to progression in patients with advanced gastric cancer treated with paclitaxel and cisplatin chemotherapy.

Pharmaco(epi)genomics in ovarian cancer

Ovarian cancer shows considerable variability in its chemoresponse, however, the prospect of individualized medicine holds high hopes for improving patient survival. The influence of interindividual genomic polymorphisms on drug response (pharmacogenomics) is well established, and a variety of candidate loci in ovarian tumors have been identified, including ERCC1, ABCB1 and p53 variants. Recently pharmacoepigenomic modulators of key genes and pathways, such as promoter methylation (MLH1 and BRCA1 genes) and microRNA regulation (PTEN/AKT and NF-κB pathways) have been implicated in ovarian cancer chemoresponse. Epigenomic studies have until now mainly focused on tumor-specific changes, although germ-line epigenetic change may also be of importance. However, assessing the relevance of these potential pharmaco(epi)genomic biomarkers in clinical trials requires well powered studies in homogeneous populations, with independent validation sets, to distinguish real associations from false-positives. In addition, the selection of one gene or locus as having sufficient phenotypic effect to impact on clinical outcome may be an oversimplification. Integrated approaches that identify stable pharmacogenomic and epigenomic patterns and their relationship with expression patterns and gene function will be increasingly necessary.

Effects of common germ-line genetic variation in cell cycle genes on ovarian cancer survival

PURPOSE

Somatic alterations have been shown to correlate with ovarian cancer prognosis and survival, but less is known about the effects on survival of common inherited genetic variation. Of particular interest are genes involved in cell cycle pathways, which regulate cell division and could plausibly influence clinical characteristics of multiple tumors types.

EXPERIMENTAL DESIGN

We examined associations between common germ-line genetic variation in 14 genes involved in cell cycle pathway (CCND1, CCND2, CCND3, CCNE1, CDKN1A, CDKN1B, CDKN2A, CDKN2B, CDKN2C, CDKN2D, CDK2, CDK4, CDK6, and RB1) and survival among women with invasive ovarian cancer participating in a multicenter case-control study from United Kingdom, Denmark, and United States. DNAs from up to 1,499 women were genotyped for 97 single-nucleotide polymorphisms that tagged the known common variants (minor allele frequency > or = 0.05) in these genes. The genotypes of each polymorphism were tested for association with survival by Cox regression analysis.

RESULTS

A nominally statistically significant association between genotype and ovarian cancer survival was observed for polymorphisms in CCND2 and CCNE1. The per-allele hazard ratios (95% confidence intervals) were 1.16 (1.03-1.31; P = 0.02) for rs3217933, 1.14 (1.02-1.27; P = 0.024) for rs3217901, and 0.85 (0.73-1.00; P = 0.043) for rs3217862 in CCND2 and 1.39 (1.04-1.85; P = 0.033) for rs3218038 in CCNE1. However, these were not significant after adjusting for multiple hypothesis tests.

CONCLUSION

It is unlikely that common variants in cell cycle pathways examined above associated with moderate effect in survival after diagnosis of ovarian cancer. Much larger studies will be needed to exclude common variants with small effects.

Haplotype analysis of TP53 polymorphisms, Arg72Pro and Ins16, in BRCA1 and BRCA2 mutation carriers of French Canadian descent

BACKGROUND

The TP53 polymorphisms Arg72Pro (Ex4+199 G>C) and Ins16 (IVS3+24 ins16) have been proposed to modify risk of breast cancer associated with germline BRCA1 and BRCA2 mutations. Allele frequencies of these polymorphisms were investigated to determine if they modify risk in BRCA mutation carriers in breast cancer cases drawn from French Canadian cancer families, a population shown to exhibit strong founder effects.

METHODS

The frequencies of the TP53 alleles, genotypes and haplotypes of 157 index breast cancer cases comprised of 42 BRCA1 mutation carriers, 57 BRCA2 mutation carriers, and 58 BRCA mutation-negative cases, where each case was drawn from independently ascertained families were compared. The effect of TP53 variants on the age of diagnosis was also investigated for these groups. The TP53 polymorphisms were also investigated in 112 women of French Canadian descent with no personal history of cancer.

RESULTS

The BRCA mutation-positive groups had the highest frequency of homozygous carriers of the 72Pro allele compared with mutation-negative group. The TP53 polymorphisms exhibited linkage disequilibrium (p < 0.001), where the 72Arg and Ins16minus alleles occurred in strong disequilibrium. The highest frequency of carriers of Ins16minus-72Arg haplotype occurred in the BRCA mutation-negative groups. The BRCA1 mutation carriers homozygous for the 72Pro allele had the youngest ages of diagnosis of breast cancer. However none of these observations were statistically significant. In contrast, the BRCA2 mutation carriers homozygous for the 72Pro allele had a significantly older age of diagnosis of breast cancer (p = 0.018). Moreover, in this group, the mean age of diagnosis of breast cancer in carriers of the Ins16minus-72Arg haplotype was significantly younger than that of the individuals who did not this carry this haplotype (p = 0.009).

CONCLUSION

We observed no significant association of breast cancer risk with TP53 genetic variants based on BRCA1/2 mutation carrier status. Although the small sample size did not permit analysis of all possible haplotypes, we observed that BRCA2 mutation carriers harboring the Ins16minus-72Arg haplotype had a significantly younger mean age of diagnosis of breast cancer. These observations suggest that investigations in a larger French Canadian sample are warranted to further elucidate the effects of TP53 variants on age of diagnosis of breast cancer among BRCA1 and BRCA2 mutation carriers.

Prognostic role of p53 codon 72 polymorphism in gastric cancer patients treated with fluorouracil-based adjuvant chemotherapy

OBJECTIVE

The polymorphism of p53 codon 72 (Arg72Pro) has been suggested to play an important role in many cancers and may influence the response to chemotherapy. Our aim was to investigate the association of p53 Arg72Pro polymorphism with the clinical outcome of gastric cancer patients treated with 5-FU-based adjuvant chemotherapy.

METHODS

The p53 codon 72 genotype was determined in blood samples from 110 Chinese patients with gastric cancer treated with 5-fluorouracil (5-FU)-based adjuvant chemotherapy, using polymerase chain reaction-ligation detection reaction (PCR-LDR) method.

RESULTS

Kaplan-Meier survival analysis showed that gastric cancer patients with Pro/Pro genotype had shorter relapse-free survival (chi(2) = 10.632, P = 0.005) and overall survival (chi(2) = 7.104, P = 0.029) than patients with other genotypes. Cox multivariate analysis showed that Pro/Pro genotype was associated with statistically significant reduced relapse-free survival (adjusted OR = 3.049, 95% CI: 1.363-6.819, P = 0.007) and overall survival (adjusted OR = 2.581, 95% CI: 1.052-6.330, P = 0.038).

CONCLUSION

These results suggested that p53 codon 72 polymorphism appears to be an independent prognostic factor in gastric cancer patients treated with 5-FU-based adjuvant chemotherapy.

TP53 codon 72 polymorphism in susceptibility, overall survival, and adjuvant therapy response of gliomas

TP53 is a key tumor suppressor gene that encodes a transcriptional factor involved in several cellular mechanisms, including growth arrest, DNA repair, and induction of apoptosis. In addition to TP53 gene mutations, a common polymorphism, Arg72Pro, has been involved in the carcinogenesis process. The Pro72 variant has been associated with a slower induction of apoptosis and may influence the risk of cancer development. The role of Arg72Pro polymorphism in glioma susceptibility is poorly characterized. With the objective of analyzing the role of the TP53 Arg72Pro polymorphism in glioma risk, overall survival, and patient therapy response in a Portuguese population, we conducted a retrospective case-control study, including 171 patients with gliomas and 526 cancer-free individuals. The Arg72Pro genotype was assessed by the polymerase chain reaction-restriction fragment length polymorphism technique. No statistically significant differences were observed in the genotypic and allelic frequencies between glioma and control groups, and no statistically significant differences were observed with stratification of gliomas into distinct histological subtypes: astrocytic (n = 115), glioblastoma (n = 75), and oligodendroglial (n = 54) tumors. No significant association was observed between TP53 Arg72Pro and patient overall survival, but Kaplan-Meier analysis of glioma patients harboring the Pro72 allele showed a significantly longer survival with adjuvant therapy. In this first assessment of the role of TP53 Arg72Pro polymorphism in a large series of Portuguese glioma tumors, no association was observed with glioma susceptibility or overall survival, except for patients submitted to adjuvant therapy.

Pharmacogenetic assessment of toxicity and outcome after platinum plus taxane chemotherapy in ovarian cancer: the Scottish Randomised Trial in Ovarian Cancer

PURPOSE

Standard therapy for advanced ovarian cancer consists of a platinum agent in combination with a taxane, which has a 5-year survival rate of approximately 45%. The large individual variability for ovarian cancer patients in both outcome and toxicity risk from chemotherapy makes the identification of pharmacogenetic markers that can be used to screen patients before therapy selection an attractive prospect.

PATIENTS AND METHODS

We assessed 27 selected polymorphisms based on previously described associations or putative functional effects in 16 key genes from pathways that may influence cellular sensitivity to taxanes (ABCB1, ABCC1, ABCC2, ABCG2, CDKN1A, CYP1B1, CYP2C8, CYP3A4, CYP3A5, MAPT, and TP53) and platinum (ABCC2, ABCG2, ERCC1, ERCC2, GSTP1, MPO, and XRCC1) using polymerase chain reaction and Pyrosequencing in 914 ovarian cancer patients from the Scottish Randomised Trial in Ovarian Cancer phase III trial who were treated at presentation with carboplatin and taxane regimens after cytoreductive surgery.

RESULTS

No reproducible significant associations between genotype and outcome or toxicity were found for any of the genes analyzed. Previously reported genotype associations could not be replicated in this large study of a well-defined patient population within one specific clinical trial.

CONCLUSION

There are no clear candidates for taxane/platinum pharmacogenetic markers. This study highlights the need for validation of putative genetic markers in large, well-defined clinical sample sets.

Association of TP53 codon 72 polymorphism and the outcome of adjuvant therapy in breast cancer patients

INTRODUCTION

Single-nucleotide polymorphisms (SNPs) in codon 72 of the TP53 (also known as p53) gene (rs1042522) and in the promoter region of the MDM2 gene (SNP309; rs2279744) have been suggested to play roles in many cancers. We investigated whether these SNPs were associated with patient outcome and the effect of adjuvant systemic therapy.

METHODS

The genotypes of TP53 codon 72 and MDM2 SNP309 were defined among 557 primary Japanese breast cancer patients (median follow-up, 61.7 months). The effects of several variables on survival were tested by Cox's proportional hazards regression analysis.

RESULTS

We showed that the Pro/Pro genotype of TP53 codon 72 was associated with poorer disease-free survival (DFS) than other genotypes by Kaplan-Meier analysis (P = 0.049) and multivariate Cox's proportional hazards regression analysis (P = 0.047, risk ratio of recurrence = 1.67), whereas MDM2 SNP309 status was not associated with DFS. The association of the Pro/Pro TP53 genotype with poorer DFS was especially significant in patients who received adjuvant chemotherapy (P = 0.009). In contrast, among the patients who had received adjuvant hormonal therapy or no adjuvant systemic therapy, TP53 codon 72 genotype was not associated with DFS.

CONCLUSION

The Pro/Pro genotype of TP53 codon 72 appears to be an independent prognostic marker in breast cancer patients.

TP53 mutations in human cancers: functional selection and impact on cancer prognosis and outcomes

A large amount of data is available on the functional impact of missense mutations in TP53 and on mutation patterns in many different cancers. New data on mutant p53 protein function, cancer phenotype and prognosis have recently been integrated in the International Agency for Research on Cancer TP53 database (http://www-p53.iarc.fr/). Based on these data, we summarize here current knowledge on the respective roles of mutagenesis and biological selection of mutations with specific functional characteristic in shaping the patterns and phenotypes of mutations observed in human cancers. The main conclusion is that intrinsic mutagenicity rates, loss of transactivation activities, and to a lesser extent, dominant-negative activities are the main driving forces that determine TP53 mutation patterns and influence tumor phenotype. In contrast, current experimental data on the acquisition of oncogenic activities (gain of function) by p53 mutants are too scarce and heterogenous to assess whether this property has an impact on tumor development and outcome. In the case of inherited TP53 mutations causing Li-Fraumeni and related syndromes, the age at onset of some tumor types is in direct relation with the degree of loss of transactivation capacity of missense mutations. Finally, studies on large case series demonstrate that TP53 mutations are independent markers of bad prognosis in breast and several other cancers, and that the exact type and position of the mutation influences disease outcome. Further studies are needed to determine how TP53 haplotypes or loss of alleles interact with mutations to modulate their impact on cancer development and prognosis.

Gastric cancer in a Caucasian population: Role of pepsinogen C genetic variants

AIM: To study the role of an insertion/deletion polymorphism in the pepsinogen C (PGC) gene, an effective marker for terminal differentiation of the stomach mucosa, in the susceptibility to the development of gastric lesions.

METHODS: The study was performed with 99 samples of known gastric lesions and 127 samples without evidence of neoplastic disease. PCR was employed and the 6 polymorphic alleles were amplified: Allele 1 (510 bp), Allele 2 (480 bp), Allele 3/4 (450/460 bp), Allele 5 (400 bp) and Allele 6 (310 bp).

RESULTS: Our results revealed that Allele 6 carriers seemed to have protection against the development of any gastric lesion (OR = 0.34; P < 0.001), non-dysplastic lesions associated with gastric adenocarcinoma such as atrophy or intestinal metaplasia (OR = 0.28; P < 0.001) or invasive GC (OR = 0.39; P = 0.004).

CONCLUSION: Our study reveals that the Allele 6 carrier status has a protective role in the development of gastric lesions, probably due to its association with higher expression of PGC. Moreover, the frequency of Allele 6 carriers in the control group is far higher than that obtained in Asian populations, which might represent a genetic gap between Caucasian and Asian populations.

Importance of xeroderma pigmentosum group D polymorphisms in susceptibility to ovarian cancer

The purpose of this study was to evaluate the role of XPD genotypes as genetic indicator of susceptibility to ovarian cancer. We have used a case-control study. We analysed DNA samples from 141 ovarian cancer patients and 202 control subjects, for three XPD polymorphisms using PCR-RFLP. We observed that Asn312Asn XPD genotype carriers have increased susceptibility of ovarian cancer (OR=2.46 95% CI 1.20-5.06; P=0.015). Furthermore, we found that carriers of Gln751Gln XPD genotype have an increased susceptibility of ovarian cancer (OR=3.40 95% CI 1.61-7.15; P=0.001). Asn312Asn and Gln751Gln are particularly associated with an early-stage of disease. Our results suggest an important role for Asn312Asn and Gln751Gln XPD polymorphisms in the susceptibility to ovarian cancer.

Common polymorphisms inTP53 andMDM2 and the relationship toTP53 mutations and clinical outcomes in women with ovarian and peritoneal carcinomas

The importance of somatic TP53 mutations and germline TP53 codon 72 genotype in the survival of women with epithelial ovarian cancer is controversial. Recent data suggest that a promoter polymorphism in the MDM2 gene may influence age of cancer onset in a gender-specific fashion. We sought to determine the relationship between somatic TP53 mutations, germline genotypes at TP53 codon 72 and MDM2 SNP309, and overall survival and response to chemotherapy in a large series of patients with ovarian and peritoneal carcinomas. Of the 188 cancers, 103 (54.8%) had a TP53 mutation, of which 71% were missense mutations and 29% were null mutations. TP53 mutation status and mutation type (null vs. missense) did not influence response to therapy or overall survival. Women with the codon 72 Pro/Pro had a decreased overall survival (median, 29 months) compared with women with one or two arginine alleles (median, 49 months; P=0.04). Somatic mutation or deletion was equally common for either codon 72 allele. Age of diagnosis was not influenced by codon 72 but showed a trend for younger age in women with somatic TP53 mutations and the MDM2 G/G genotype.