Genetic polymorphisms of p21 are associated with risk of squamous cell carcinoma of the head and neck

Molecular mechanisms underlying oesophageal cancer development triggered by chronic alcohol consumption

This review explores the mechanisms underlying alcohol‐induced oesophageal carcinogenesis, including DNA damage, oxidative stress, and nutritional deficiencies. Alcohol metabolism primarily involves alcohol dehydrogenase (ADH) converting ethanol to acetaldehyde, which can cause DNA damage, inhibit repair mechanisms, and form DNA adducts thus inhibiting DNA replication. Plus, it delves into the epidemiological evidence, genetic susceptibility, epigenetic modifications, biomarkers, and preventive strategies associated with alcohol‐related oesophageal cancers. Consumption of alcohol increases the risk of gastroesophageal reflux disease thus compromising mucosal integrity of the oesophagus as dysregulation of cytokines such as IL‐18, TNFA, GATA3, TLR4, and CD68 expands the intercellular spaces of epithelial cells. Genetic variants, such as ADH1B rs1229984 and ALDH2 rs671, significantly influence susceptibility to alcohol‐related oesophageal cancers, with these variations affecting acetaldehyde metabolism and cancer risk. Understanding these factors is crucial for early detection, effective treatment, and the development of targeted prevention strategies. Biomarkers, such as miRNA and metabolite markers, offer non‐invasive methods for early detection, while advanced endoscopic techniques provide better diagnostic accuracy. Pharmacological interventions, such as statins and proton pump inhibitors, also show potential for reducing cancer progression in high‐risk individuals. Despite advances, late‐stage oesophageal cancer diagnoses are still common, highlighting the need for better screening and prevention. Further research, including this study, should aim to improve early detection, personalise prevention, and explore new treatments to reduce cases and enhance outcomes in alcohol‐related oesophageal cancers.

Polymorphism at codon 31 of CDKN1A (p21) as a predictive factor for bevacizumab therapy in glioblastoma multiforme

Glioblastoma (GBM), a prevalent and malignant brain tumor, poses a challenge in surgical resection due to its invasive nature within the brain parenchyma. CDKN1A (p21, Waf-1), a cyclin-dependent kinase inhibitor, plays a pivotal role in regulating cell growth arrest, terminal differentiation, and apoptosis. The existence of natural variants of CDKN1A has been associated with specific cancer types. In this retrospective study, our objective was to identify polymorphic variants of CDKN1A, specifically c.93C > A (codon 31 Ser31Arg), and investigate its potential impact within the scope of bevacizumab therapy for glioblastoma multiforme. This study involved a cohort of 139 unrelated adult Chinese GBM patients in Taiwan. Genomic DNA extracted from tumor samples was utilized for genotyping using the polymerase chain reaction (PCR) restriction fragment length polymorphism method (PCR-RFLP analysis). Through unconditional logistic regression analysis, odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were calculated. Our findings unveiled that among these GBM patients, the distribution of codon 31 polymorphisms was as follows: 23.02% were Serine homozygotes (Ser/Ser), 27.34% were Arginine homozygotes (Arg/Arg), and 49.64% were Serine/Arginine heterozygotes (Ser/Arg). While CDKN1A c.93C > A polymorphisms did not exhibit a direct association with overall survival in GBM patients, noteworthy survival benefits emerged among individuals with Arg/Arg and Arg/Ser genotypes who received combined concurrent chemoradiotherapy (CCRT) and bevacizumab treatment compared to those who underwent CCRT alone. Our findings indicate a significant involvement of the CDKN1A c.93C > A polymorphism in the development and onset of GBM, offering potential implications for the early prognostication of bevacizumab therapy outcomes.

Risk of second primary cancer in patients with head and neck squamous cell carcinoma: a systemic review and meta-analysis

OBJECTIVES

Second primary cancer is a common event in patients with head and neck squamous cell carcinoma. However, the incidence and relevant factors vary by studies. We conducted a systematic review and meta-analysis of observational studies to estimate the incidence and relevant risk factors.

MATERIALS AND METHODS

PubMed and Web of Science were searched for studies published between January 2000 and December 2020 that reported the incidence of SPC in HNSCC patients. Per 1000-person-year incidence and odds ratios were used to estimate the incidence and potential risk factors. Due to the high heterogeneity, random-effects models were used to estimate the incidence and 95% confidence interval.

RESULTS

Seven thousand seven hundred thirteen articles were identified from the databases, in which 60 studies were included in this meta-analysis. The pooled incidence of the total, synchronous, and metachronous SPC in patients with HNSCC were 29.116 per 1000-person-year, 6.960 per 1000-person-year, and 26.025 per 1000-person-year, respectively. The head and neck region was the most common area where SPC occurred, followed by the lung (7.472 per 1000-person-year) and upper digestive tract (2.696 per 1000-person-year). Smoking, alcohol consumption, betel quid chewing, primary cancer of T1-2, and N0 were risk factors, while HPV infection (OR 0.47, 95% CI 0.30-0.72) was the protective factor.

CONCLUSIONS

SPC is frequently observed in HNSCC patients and had great impact on the prognosis. The findings could promote a more individualized follow-up strategy for SPC in HNSCC patients.

CLINICAL RELEVANCE

This systemic review and meta-analysis provide sufficient evidence for the establishment of the follow-up strategy for head and neck squamous cancer patients.

TP53 and p21 (CDKN1A) polymorphisms and the risk of systemic lupus erythematosus

BACKGROUND

The p53 and p21 proteins are important regulators of cell cycle and apoptosis and may contribute to autoimmune diseases, such as systemic lupus erythematosus (SLE). As genetic polymorphisms may cause changes in protein levels and functions, we investigated associations of TP53 and p21 (CDKN1A) polymorphisms (p53 72 G > C-rs1042522; p53 PIN3-rs17878362; p21 31 C > A-rs1801270; p21 70 C > T-rs1059234) with the development of systemic lupus erythematosus (SLE) in a Southeastern Brazilian population.

METHODS

Genotyping of 353 female volunteers (cases, n = 145; controls, n = 208) was performed by polymerase chain reaction, restriction fragment length polymorphism and/or DNA sequencing. Associations between TP53 and p21 polymorphisms and SLE susceptibility and clinical manifestations of SLE patients were assessed by logistic regression analysis.

RESULTS

Protective effect was observed for the genotype combinations p53 PIN3 A1/A1-p21 31 C/A, in the total study population (OR 0.45), and p53 PIN3 A1/A2-p21 31 C/C, in non-white women (OR 0.28). In Whites, p53 72 C-containing (OR 3.06) and p53 PIN3 A2-containing (OR 6.93) genotypes were associated with SLE risk, and higher OR value was observed for the combined genotype p53 72 G/C-p53 PIN3 A1/A2 (OR 9.00). Further, p53 PIN3 A1/A2 genotype was associated with serositis (OR 2.82), while p53 PIN3 A2/A2 and p53 72 C/C genotypes were associated with neurological disorders (OR 4.69 and OR 3.34, respectively).

CONCLUSIONS

Our findings showed that the TP53 and p21 polymorphisms included in this study may have potential to emerge as SLE susceptibility markers for specific groups of patients. Significant interactions of the TP53 polymorphisms with serositis and neurological disorders were also observed in SLE patients.

Joint effect of human papillomavirus exposure, smoking and alcohol on risk of oral squamous cell carcinoma

BACKGROUND

Smoking, alcohol consumption, and human papillomavirus (HPV) infection are known risk factors for oral squamous cell carcinoma (OSCC) including SCC of oropharynx (SCCOP) and SCC of oral cavity (SCCOC). Researchers have examined each of these risk factors independently, but few have observed the potential risk of their interaction. This study investigated the interactions among these risk factors and risk of OSCC.

METHODS

Totally 377 patients with newly diagnosed SCCOP and SCCOC and 433 frequency-matched cancer-free controls by age and sex were included. Multivariable logistic regression was performed to calculate ORs and 95% CIs.

RESULTS

We found that overall OSCC risk was independently associated with smoking (adjusted OR(aOR), 1.4; 95%CI, 1.0-2.0), alcohol consumption (aOR, 1.6; 95%CI, 1.1-2.2), and HPV16 seropositivity (aOR, 3.3; 95%CI, 2.2-4.9), respectively. Additionally, we found that HPV16 seropositivity increased the risk of overall OSCC in ever-smokers (aOR, 6.8; 95%CI, 3.4-13.4) and ever-drinkers (aOR, 4.8; 95%CI, 2.9-8.0), while HPV16-seronegative ever-smokers and ever-drinkers had less than a twofold increase in risk of overall OSCC (aORs, 1.2; 95%CI, 0.8-1.7 and 1.8; 95%CI, 1.2-2.7, respectively). Furthermore, the increased risk was particularly high for SCCOP in HPV16-seropositive ever-smokers (aOR, 13.0; 95%CI, 6.0-27.7) and in HPV16-seropositive ever-drinkers (aOR, 10.8; 95%CI, 5.8-20.1), while the similar increased risk was not found in SCCOC.

CONCLUSION

These results suggest a strong combined effect of HPV16 exposure, smoking, and alcohol on overall OSCC, which may indicate a strong interaction between HPV16 infection and smoking and alcohol consumption, particularly for SCCOP.

Association between CDKN1A gene rs1801270 polymorphisms and susceptibility to colorectal cancser in an Iranian population

CDKN1A gene is implicated in cell differentiation, development process, repair, apoptosis, senescence, migration, and tumorigenesis. Somatic alterations and polymorphisms may interfere in the function of CDKN1A, and this could affect the individual susceptibility to colorectal cancer (CRC). Here in, we evaluated the importance of single nucleotide polymorphic variants in codon 31 of CDKN1A (rs1801270: C > A) for the development of colorectal cancer in an Iranian population. A total of 150 CRC patients and 150 healthy controls were enrolled in this study. Genomic DNA was extracted from peripheral blood specimens. Genotypes were determined using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) assay. In CRC patients, the genotype frequencies detected were 90%, 8.0% and 2.0%2 for CC, AC and AA genotypes while the genotype frequencies in control group were 78%, 20.7% and 1.35% 1.35% for CC, AC and AA genotype, respectively. There were statistically significant differences in the distribution of CDKN1A rs1801270 genotypes and allele frequencies between colorectal cancer patients and healthy controls (p value = 0.021). Also, results indicated a significant negative association between AC genotype and risk of colorectal cancer occurrence. (Odds ratio (OR)=0.357; 95% confidence interval (CI)=0.168-0.760, p = 0.007). Our data suggest that the AC genotype may have a protective role in the development of CRC in an Iranian population.

In silico identification and in vitro expression analysis of breast cancer-related m6A-SNPs

Research on m6A-associated SNPs (m6A-SNPs) has emerged recently due to their possible critical roles in many key biological processes. In this sense, several investigations have identified m6A-SNPs in different diseases. In order to gain a more complete understanding of the role that m6A-SNPs can play in breast cancer, we performed an in silico analysis to identify the m6A-SNPs associated with breast cancer and to evaluate their possible effects. For this purpose, we downloaded SNPs related to breast cancer and a list of m6A-SNPs from public databases in order to identify which ones appear in both. Subsequently, we assessed the identified m6A-SNPs in silico by expression quantitative trait loci (eQTL) analysis and differential gene expression analysis. We genotyped the m6A-SNPs found in the in silico analysis in 35 patients with breast cancer, and we carried out a gene expression analysis experimentally on those that showed differences. Our results identified 981 m6A-SNPs related to breast cancer. Four m6A-SNPs showed an eQTL effect and only three were in genes that presented an altered gene expression. When the three m6A-SNPs were evaluated in the tissue sample of our breast cancer patients, only the m6A-SNP rs76563149 located in ZNF354A gene presented differences in allele frequencies and a low gene expression in breast cancer tissues, especially in luminal B HER2+ subtype. Future investigations of these m6A-SNPs should expand the study in different ethnic groups and increase the sample sizes to test their association with breast cancer and elucidate their molecular function.

Gene polymorphisms of cyclin-dependent kinase inhibitor and matrix metalloproteinase-9 in Sudanese patients with esophageal squamous cell carcinoma

BACKGROUND

The polymorphisms of the cyclin-dependent kinase inhibitor (CDKN1A) gene and matrix metalloproteinase-9 (MMP9) gene may increase one's susceptibility to malignancies. In this study, the association of the single nucleotide polymorphisms (SNPs) CDKN1A rs1059234 c.70C>T at the 3' untranslated region and MMP9 rs17576 (c.836A>G, p.Gln279Arg) with esophageal squamous cell carcinoma (ESCC) in Sudanese individuals were investigated.

MATERIALS AND METHODS

A case-control study involving age- and gender-matched groups were conducted in a cancer center in eastern Sudan (Gadarif) between April and October 2020. The case group consisted of ESCC patients, whereas the control group comprised healthy subjects. Polymerase chain reaction-restriction fragment length polymorphism was performed for the genotyping of the CDKN1A rs1059234 and MMP9 rs17576 SNPs. The genotyping results were confirmed by Sanger sequencing.

RESULTS

The genotype distributions for CDKN1A rs1059234 and MMP9 rs17576 were in agreement with the Hardy-Weinberg equilibrium. The variant allele T in CDKN1 rs1059234 c.70C>T was significantly more prevalent in the ESCC patients than in the healthy controls [51.3% vs. 19.2%; OR = 4.4; 95% CI (2.6-7.4); p < 0.001]. Moreover, in CDKN1A rs1059234, the genotype TC + TT [76.9% vs. 38.4%; OR = 5.3; 95% CI (2.6-10.7); p < 0.001] was more frequent in the cases than in the controls, and it was significantly associated with ESCC risk. In MMP9 rs17576, the variant allele G was also significantly prevalent in the cases relative to the controls, and it was significantly associated with increased ESCC risk in the cases compared with the controls [27.5% vs. 1.9%; OR = 19.4; 95%CI (5.8-64.1); p < 0.001]. Both genotypes containing the allele G (AG + GG) were the most common genotypes in the cases [48.7% vs. 3.8%; OR = 23.7; 95%CI (6.8-81.7); p < 0.001], and they significantly increased the risk of ESCC.

CONCLUSION

A significant increase in ESCC risk is associated with the SNPs CDKN1A rs1059234 and MMP9 rs17576.

CDKN1A (p21 gene) polymorphisms correlates with age in esophageal cancer

BACKGROUND

CDKN1A gene encoding p21 is an important tumour supressor involved in the pathogenesis of cancers. A few studies have been devoted to the association between CDKN1A single nucleotide polymorphisms (SNPs) and esophageal cancer (EC) in China, India and Iran. The aim of this case-control study was to investigate the association of CDKN1A polymorphisms with EC risk in the Turkey population for the first time.

METHODS

In the present study, CDKN1A SNPs (rs1801270 C > T, rs1059234 C > A and rs3176352 C > G) were genotyped with the use of TaqMan SNP genotyping assays in 102 patients and 119 controls.

RESULTS

The genotypes and alleles of CDKN1A SNPs were not significantly different among patients and controls. However, TT-genotype and T-allele of the rs1059234, the rs1801270 CC-genotype and rs3176352 G-allele were significantly associated with EC risk for ≤ 55 age (p < 0.05). In those over 55 age, CC-genotype and C-allele of the rs1059234 was significantly associated with EC (p < 0.05). The rs1059234 T-carriers had a higher risk of high globulin level (p = 0.017) and low albumin/globulin ratio (p = 0.019) when compared to non-T carriers (CC). The rs3176352 CC-genotype carriers had a higher risk of esophageal adenocarcinoma (EAC) subtype when compared to CG-genotype carriers and CG-genotype carriers had a higher risk of squamous cell carcinoma (ESCC) subtype (OR/95% CI = 4.00/1.06-15.08, p = 0.04). The rs3176352 CC-genotype is also a risk factor for the higher BMI (p = 0.04) and the higher CA-19-9 level (p = 0.009).

CONCLUSION

Our study suggests that the CDKN1A polymorphisms may play an important role in EC risk in relation to age. Future studies are needed to validate our findings.

Single nucleotide polymorphisms and the risk of developing a second primary cancer among head and neck cancer patients: a systematic literature review and meta-analysis

BACKGROUND

Head and Neck Cancer (HNC) survivors are at increased risk of developing a second primary cancer (SPC). Along with the environmental risk factors, genetic factors have been associated with a potential increased susceptibility to SPC development. We aim to identify the Single Nucleotide Polymorphisms (SNPs) that contribute to SPC development among HNC survivors through a systematic review and meta-analysis.

METHODS

We searched PubMed, Scopus and ISI Web of Science for eligible studies published in English until January 31st, 2020. We included studies reporting primary data that evaluated the association between SNPs and SPC risk in HNC patients. Data were pooled in a random-effect meta-analyses, when at least two studies on the same SNP evaluated the same genotype model. Heterogeneity was assessed using the χ2-based Q-statistics and the I2 statistics. Quality of the included studies was assessed using the Q-Genie tool.

RESULTS

Twenty-one studies, of moderate to good quality, were included in the systematic review. Fifty-one genes were reported across the included studies to have significant associations with an increased SPC risk. Overall, 81 out of 122 investigated SNPs were significantly associated with the SPC risk. Seven studies were included in the meta-analysis, which showed five SNPs associated with an increased risk of SPC: p21C70T, CT + TT (HR = 1.76; 95% CI: 1.28-2.43); FASLG -844C > T, CT + TT (HR = 1.82; 95% CI: 1.35-2.46), P21 C98A, CA + AA (HR = 1.75; 95% CI: 1.28-2.38); FAS -670A > G (HR = 1.84; 95% CI: 1.28-2.66) and GST-M1, Null genotype (HR = 1.54; 95% CI: 1.13-2.10).

CONCLUSIONS

The identified SNPs in our systematic review and meta-analysis might serve as potential markers for identification of patients at high risk of developing SPC after primary HNC.

PROSPERO REGISTRATION NUMBER

CRD42019135612 .

Association between tobacco substance usage and a missense mutation in the tumor suppressor gene P53 in the Saudi Arabian population

The tumor suppressor gene TP53 and its downstream genes P21 and MDM2 play crucial roles in combating DNA damage at the G1/S cell cycle checkpoint. Polymorphisms in these genes can lead to the development of various diseases. This study was conducted to examine a potential association between tobacco substance usage (TSU) and single-nucleotide polymorphism (SNP) at the exon regions of the P53, P21, and MDM2 genes by comparing populations of smokers and non-smokers from Saudi Arabia. P53 rs1042522 (C/G), P21 rs1801270 (A/C), and MDM2 rs769412 (A/G) were investigated by genotyping 568 blood specimens: 283 from male/female smokers and 285 from male/female non-smokers. The results obtained from the smokers and their control non-smokers were compared according to age, sex, duration of smoking, and type of TSU. Heterozygous CG, homozygous GG, and CG+GG genotypes, as well as the G allele of rs1042522 were significantly associated with TSU in Saudi smokers compared with non-smokers. The C allele frequency of rs1801270 was also associated with TSU in smokers (OR = 1.33, p = 0.049) in comparison with non-smokers, in younger smokers (≤29 years) (OR = 1.556, p = 0.03280) in comparison with non-smokers of the same age, in smokers who had smoked cigarettes for seven years or less (OR = 1.596, p = 0.00882), and in smokers who had consumed shisha (OR = 1.608, p = 0.04104) in comparison with the controls. However, the genotypic and allelic frequencies for rs769412 did not show significant associations with TSU in Saudis. The selected SNP of P53 was strongly associated with TSU and may be linked to TSU-induced diseases in the Saudi Arabian population.

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).

The Effect of Resveratrol or Curcumin on Head and Neck Cancer Cells Sensitivity to the Cytotoxic Effects of Cisplatin

Natural compounds can modulate all three major phases of carcinogenesis. The role of the natural compounds such as resveratrol (RSV) and curcumin (CRM) in modulation of anticancer potential of platinum-based drugs (CisPt) is still a topic of considerable debate. In order to enhance head and neck cancer (HNSCC) cells' sensitivity to the cytotoxic effects of CisPt combined treatments with RSV or CRM were used. The study aim was to evaluate how the RSV or CRM associated to CisPt treatment modulated some cellular processes such as proliferation, P21 gene expression, apoptotic process, and cell cycle development in HNSCC tumor cell line (PE/CA-PJ49) compared to a normal cell line (HUVEC). The results showed that RSV or CRM treatment affected the viability of tumor cells more than normal cells. These natural compounds act against proliferation and sustain the effects of cisplatin by cell cycle arrest, induction of apoptosis and amplification of P21 expression in tumor cells. In conclusion, using RSV or CRM as adjuvants in CisPt therapy might have a beneficial effect by supporting the effects induced by CisPt.

Susceptibility of Multiple Primary Cancers in Patients With Head and Neck Cancer: Nature or Nurture?

Multiple primary cancers (MPCs) are major obstacles to long-term survival in head and neck cancer (HNSCC), however, the molecular mechanism underlying multiple carcinogenesis remains unclear. “Field cancerization” is a classical theory to elaborate the malignant progression of MPCs. Apart from environmental and immune factors, genetic factors may have great potential as molecular markers for MPCs risk prediction. This review focuses on inherited and acquired gene mutations in MPCs, including germ-line mutation, single-nucleotide polymorphism, chromosomal instability, microsatellite instability and DNA methylation. And definition and prognosis of MPCs have also been discussed. These may pave the way for the early detection, prevention and effective treatment of MPCs in HNSCC.

Telomere length in workers was effected by omethoate exposure and interaction between smoking and p21 polymorphisms

Omethoate is an organophosphorus pesticide that poses a major health hazard, especially DNA damage. The purpose of this study was to investigate the factors affecting telomere length in workers exposed to omethoate by analyzing the interaction between cell cycle gene polymorphism and environmental factors. The exposure group consisted of 118 workers exposed to omethoate for 8-10 years, the control group comprised 115 healthy people without occupational toxicant exposure history. The telomere length of genomic DNA from peripheral blood leucocyte was determined with real-time PCR. Polymerase chain reaction and restriction fragment length polymorphism was used to detect the polymorphisms in p53, p21 and MDM2 gene. The telomere length in the (CA + AA) genotypes for p21 rs1801270 polymorphism was longer than that in the CC genotype in control group (P = 0.015). The generalized linear model analysis indicated the interaction of the p21 rs1801270 polymorphic (CA + AA) genotypes and smoking has a significant effect on telomere length (β = -0.258, P = 0.085). The prolongation of telomere length in omethoate-exposed workers was associated with genotypes (CA + AA) of p21 rs1801270, and interactions of (CA + AA) genotypes and smoking factor.

Increased Arf/p53 activity in stem cells, aging and cancer

Arf/p53 pathway protects the cells against DNA damage induced by acute stress. This characteristic is the responsible for its tumor suppressor activity. Moreover, it regulates the chronic type of stress associated with aging. This is the basis of its anti‐aging activity. Indeed, increased gene dosage of Arf/p53 displays elongated longevity and delayed aging. At a cellular level, it has been recently shown that increased dosage of Arf/p53 delays age‐associated stem cell exhaustion and the subsequent decline in tissue homeostasis and regeneration. However, p53 can also promote aging if constitutively activated. In this context, p53 reduces tissue regeneration, which correlates with premature exhaustion of stem cells. We discuss here the current evidence linking the Arf/p53 pathway to the processes of aging and cancer through stem cell regulation.

Cervical Cancer Genetic Susceptibility: A Systematic Review and Meta-Analyses of Recent Evidence

INTRODUCTION

Cervical cancer (CC) has one of the highest mortality rates among women worldwide. Several efforts have been made to identify the genetic susceptibility factors underlying CC development. However, only a few polymorphisms have shown consistency among studies.

MATERIALS AND METHODS

We conducted a systematic review of all recent case-control studies focused on the evaluation of single nucleotide polymorphisms (SNPs) and CC risk, stringently following the "PRISMA" statement recommendations. The MEDLINE data base was used for the search. A total of 100 case-control studies were included in the meta-analysis. Polymorphisms that had more than two reports were meta-analyzed by fixed or random models according to the heterogeneity presented among studies.

RESULTS

We found significant negative association between the dominant inheritance model of p21 rs1801270 polymorphism (C/A+A/A) and CC (pooled OR = 0.76; 95%CI: 0.63-0.91; p<0.01). We also found a negative association with the rs2048718 BRIP1 polymorphism dominant inheritance model (T/C+C/C) and CC (pooled OR = 0.83; 95%CI: 0.70-0.98; p = 0.03), as well as with the rs11079454 BRIP1 polymorphism recessive inheritance model and CC (pooled OR = 0.79; 95%CI: 0.63-0.99; p = 0.04). Interestingly, we observed a strong tendency of the meta-analyzed studies to be of Asiatic origin (67%). We also found a significant low representation of African populations (4%).

CONCLUSIONS

Our results provide evidence of the negative association of p21 rs1801270 polymorphism, as well as BRIP1 rs2048718 and rs11079454 polymorphisms, with CC risk. This study suggests the urgent need for more replication studies focused on GWAS identified CC susceptibility variants, in order to reveal the most informative genetic susceptibility markers for CC across different populations.

The effects of p21 gene C98A polymorphism on development of uterine leiomyoma in southeast Iranian women

Uterine leiomyoma (UL) is a monoclonal tumor which arises from uninhibited proliferation of a single myometrial cell; therefore, the imbalance in cell cycle regulation could be a key event in its development. In the present study, we aimed to assess the association of p21 gene polymorphisms and UL. Genomic DNA was extracted from blood samples of 154 women with UL and 197 age-, BMI-, and ethnically matched controls. p21 C98A (rs1801270) and C70T (rs1059234) polymorphism genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. The CA genotype of p21 C98A polymorphism was significantly higher in UL women (28 %) compared to the controls (18 %), and the UL risk was 1.8-fold greater in women with CA genotype compared to CC genotype before and after adjusting for age, BMI, and ethnicity (OR, 1.8 [95 % CI, 1.1 to 3]; P = 0.02). There was no association between the AA genotype of p21 C98A polymorphism and UL. Moreover, the frequency of p21 98A allele was significantly higher in the UL women compared to controls (17 vs. 12 %, p = 0.04). The p21 C70T polymorphism did not correlate with UL before and after adjusting for age, BMI, and ethnicity. There was no difference in haplotype frequency of p21 C70T and C98A polymorphisms between UL patients and the controls. CA genotype of p21 C98A polymorphism may be a risk factor for UL susceptibility; however, p21 C70T polymorphism did not associate with UL.

Roles of CDKN1A gene polymorphisms (rs1801270 and rs1059234) in the development of cervical neoplasia

The CDKN1A gene product is a p53 downstream effector, which participates in cell differentiation, development process, repair, apoptosis, senescence, migration, and tumorigenesis. The objective of our study was investigated the importance of two polymorphisms in the CDKN1A gene, rs1801270 (31C>A) and rs1059234 (70C>T), for the development of cervical lesions in a Southeastern Brazilian population (283 cases, stratified by lesion severity, and 189 controls). CDKN1A genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and/or DNA sequencing. CDKN1A 31A allele presents a genetic pattern of protection for the development of high-grade cervical lesions (CC vs CA genotype: OR = 0.60; 95 % CI = 0.38-0.95; p = 0.029; CA+AA vs CC genotype: OR = 0.60; 95 % CI = 0.39-0.93; p = 0.021). Allele distributions of the CDKN1A 70C>T polymorphism were also different between the two study groups, with the CDKN1A 70T allele being less prevalent among cases. Moreover, the double heterozygote genotype combination 31CA-70CT decreases the chance of developing high-grade squamous intraepithelial lesion (HSIL) and cancer (OR = 0.55; 95 % CI = 0.32-0.93; p = 0.034) by 50 %, representing a protective factor against the development of more severe cervical lesions.

Association of p21 3' UTR gene polymorphism with cancer risk: Evidence from a meta-analysis

Numerous studies have investigated the risk of cancer associated with the polymorphism of p21 3' UTR (rs1059234 C > T), but results have been inconsistent. We performed this meta-analysis to drive a more precise estimation of the association between this polymorphism and risk of cancer. A comprehensive search was conducted to identify all case-control studies of the rs1059234 C > T polymorphism of p21 3' UTR and cancer susceptibility. A total of eleven eligible studies, including 3,099 cases and 4,354 controls, relating to the rs1059234 polymorphism of p21 3' UTR to the risk of cancer were identified. Multivariate and univariate methods revealed no association between this polymorphism and cancer risk. However, subgroup analysis by cancer type suggested that rs1059234 C > T polymorphism was associated with increased risk of squamous cell carcinoma of the head and neck (SCCHN) (dominant model CT + TT vs. CC: OR = 1.51, 95% CI = 1.17-1.94). No significant association was found in other subgroup analyses. This meta-analysis suggested that rs1059234 polymorphism of p21 3' UTR may be associated with increased SCCHN risk. And larger scale primary studies are required to further evaluate the interaction of p21 3' UTR rs1059234 polymorphism and cancer risk in specific populations.

Association of p53 and p21 polymorphisms with prostate cancer

Cell cycle deregulation is common in human cancer. Alterations of the tumor-suppressor gene p53 and its downstream effector p21 have been indicated in the development of numerous human malignancies. Therefore, we hypothesize that the p53 codon 72 polymorphism, either on its own or in combination with p21 (C98A and C70T) polymorphisms, modifies the risk of prostate cancer within the Slovak population, and no previous studies have investigated these gene-gene interactions in the pathogenesis of prostate cancer in the Slovak population. Polymerase chain reaction-restriction fragment length polymorphism was used to determine the p53 and p21 genotypes in subjects comprising 300 prostate cancer patients and 446 healthy individuals. These 3 polymorphisms individually did not correlate with the prostate cancer risk. Conversely, the interaction between the p53 and p21 polymorphisms significantly decreased the risk of prostate cancer, with the odds ratio (OR) being 0.49 [95% confidence interval (CI), 0.27-0.86; P<0.05] for subjects carrying the p53 codon 72 arginine (Arg)/proline (Pro)+Pro/Pro and p21 C98A CA genotypes compared to the combined reference genotypes p53 codon 72 Arg/Arg and p21 C98A CC. Neither the p53 genotypes nor the p21 genotypes showed statistically significant differences in Gleason score or serum prostate-specific antigen levels (P>0.05). A decreased risk of prostate cancer association with the p21 C98A CA genotype (OR=0.58; 95% CI, 0.36-0.93; P<0.05) in non-smokers compared to the non-smokers with the p21 C98A CC genotype was observed. Smokers carrying the p53 codon 72 Pro/Pro genotype were not at any significant risk of prostate cancer (OR=2.97; 95% CI, 0.51-17.15) compared to the non-smokers with the Arg/Arg genotype. Taken together, to the best of our knowledge this is the first study to show that a combination of the variant genotypes of p53 codon 72 and p21 C98A may modify the prostate cancer risk within the Slovak population.

Quantitative Assessment the Relationship between p21 rs1059234 Polymorphism and Cancer Risk

p21 is a cyclin-dependent kinase inhibitor, which can arrest cell proliferation and serve as a tumor suppressor. Though many studies were published to assess the relationship between p21 rs1059234 polymorphism and various cancer risks, there was no definite conclusion on this association. To derive a more precise quantitative assessment of the relationship, a large scale meta-analysis of 5,963 cases and 8,405 controls from 16 eligible published case-control studies was performed. Our analysis suggested that rs1059234 was not associated with the integral cancer risk for both dominant model [(T/T+C/T) vs C/C, OR=1.00, 95% CI: 0.84-1.18] and recessive model [T/T vs (C/C+C/T), OR=1.03, 95% CI: 0.93-1.15)]. However, further stratified analysis showed rs1059234 was greatly associated with the risk of squamous cell carcinoma of head and neck (SCCHN). Thus, larger scale primary studies are still required to further evaluate the interaction of p21 rs1059234 polymorphism and cancer risk in specific cancer subtypes.

Association Between p21 Ser31Arg Polymorphism and Gastrointestinal Tract Tumor Risk: A Meta-analysis

Human p21 gene is characterized by a polymorphism at codon 31 leading to a Serine-to- Arginine (S/R), two different alleles of p21 Ser31Arg (rs 1801270) polymorphism have been shown to differ significantly in their transcriptional efficiency. More and more investigations are now being carried out to examine a possible link between the p21 Ser31Arg polymorphism and cancer. However, the results were inconclusive. Therefore, we carried out a systematic review and meta-analysis to examine whether this polymorphism is associated with gastrointestinal tract tumor in Asian. Seven studies (n = 2690), comprising 967 cases and 1723 controls in Asian population, were included in our study. The meta-analysis showed significant association between Ser-allele or Ser/Ser genotype and the susceptibility to gastrointestinal tract tumor in overall studies (Ser-allele vs. Arg-allele: OR = 1.17, 95% CI: 1.04-1.31; Ser/Ser vs. Arg/Arg: OR = 1.38, 95% CI: 1.09-1.75; Ser/Ser vs. Arg/Ser: OR = 1.27, 95% CI: 1.05-1.53; Ser/Ser vs. Arg/Ser + Arg/Arg: OR = 1.29, 95% CI: 1.07-1.54). Despite the limitations, the results of the present meta-analysis suggested that, in the p21 Ser31Arg polymorphism, Ser-allele and Ser/Ser genotype might be risk factors for gastrointestinal tract tumor in Asian populations.

Tyms double (2R) and triple repeat (3R) confers risk for human oral squamous cell carcinoma

The oral cancer is responsible for approximately 3 % of cases of cancer in Brazil. Epidemiological studies have associated low folate intake with an increased risk of epithelial cancers, including oral cancer. Folic acid has a key role in DNA synthesis, repair, methylation and this is the basis of explanations for a putative role for folic acid in cancer prevention. The role of folic acid in carcinogenesis may be modulated by polymorphism C677T in MTHFR and tandem repeats 2R/3R in the promoter site of TYMS gene that are related to decreased enzymatic activity and quantity and availability of the enzyme, respectively. These events cause a decrease in the synthesis, repair and DNA methylation, which can lead to a disruption in the expression of tumor suppressor genes as TP53. The objective of this study was investigate the distribution of polymorphisms C677T and tandem repeats 2R/3R associated with the development of oral squamous cell carcinoma (OSCC). 53 paraffin-embedded samples from patients who underwent surgery but are no longer at the institution and 43 samples collected by method of oral exfoliation by cytobrush were selected. 132 healthy subjects were selected by specialists at the dental clinics of the Faculdade de Odontologia de Pernambuco-FOP. The MTHFR genotyping was performed by PCR-RFLP, and the TYMS genotyping was performed by conventional PCR. Fisher's Exact test at significant level of 5 %. Odds ratios (ORs) and 95 % confidence intervals (CIs) were used to measure the strength of association between genotype frequency and OSCC development. The results were statistically significant for the tandem repeats of the TYMS gene (p = 0.015). The TYMS 2R3R genotype was significantly associated with the development of OSCC (OR = 3.582; 95 % CI 1.240-10.348; p = 0.0262) and also the genotype 3R3R (OR = 3.553; 95 % CI 1.293-9.760; p = 0.0345). When analyzed together, the TYMS 2R3R + 3R3R genotypes also showed association (OR = 3.518; 95 % CI 11.188-10.348; p = 0.0177). No differences for the MTHFR C677T polymorphisms distribution were found between the oral cancer patients and controls subjects in our study (p = 0.499). Therefore, these data suggest that determination of TYMS tandem repeats could provide information on the comprehension of the risk factors and prevention of the OSCC.

BAX and CDKN1A polymorphisms correlated with clinical outcomes of gastric cancer patients treated with postoperative chemotherapy

This study aims to examine the correlation between two single nucleotide polymorphisms (SNPs) of apoptosis-related genes and clinical outcomes in gastric cancer. A total of 221 patients with stage T2 and T3 gastric cancer treated with postoperative chemotherapy between 2003 and 2008 were retrospectively collected in this study to explore the association of rs4645878 located in BAX gene and rs1801270 located in CDKN1A gene with survival, recurrence, and toxicity to chemotherapy. Additionally, immunohistochemistry was used to detect the BAX expression in gastric cancer tissues. Patients carrying at least one variant genotype in BAX SNP (rs4645878) showed a significantly increased recurrence risk [hazard ratio (HR) 2.63; 95 % confidence internal (95 % CI) 1.71-4.03] and poor survival (HR 2.89; 95 % CI 1.88-4.44). Moreover, the recurrence and survival rate in patients with GA genotype was 72.7 and 24.7 %, respectively, compared with total recurrence rate of 54.8 %, P = 0.006, and compared with total survival rate of 46.6 %, P = 0.001. In addition, the GA genotype was related to lower BAX expression in gastric cancer tissues. The CDKN1A (rs1801270) mutant genotype was associated with a significantly decreased risk of hematologic toxicity [odds ratio (OR) 0.28; 95 % CI 0.12-0.63]. SNPs located in BAX and CDKN1A genes are closely associated with clinical outcomes in patients with gastric cancer.

Polymorphisms of CDKN1A gene and risk of retinoblastoma

Retinoblastoma (RB) is a malignant neoplasia that occurs mostly in children under 5 years. Recently, CDKN1A gene has been shown to be up-regulated in a context of loss of function of pRb. This gene encodes the p21 protein, which is the bona fide effector of p53. We hypothesized whether two putatively functional single nucleotide polymorphisms (SNPs) of CDKN1A (rs1801270 C>A and rs1059234 C>T) may influence the risk and/or survival of RB patients. We genotyped both SNPs in 141 RB patients and 120 unrelated healthy individuals. Statistical analyses consisted of chi-square (χ(2)), odds ratio (OR) and survival curves by Kaplan-Meier method. We found that patients who carry the genotype CA for rs1801270 and CT for rs1059234 were associated to an increased risk of RB [OR = 2.5, 95% confidence interval (CI) = 1.38-4.53], whereas patients with CC for both polymorphisms were associated to a lower risk of developing RB (OR = 0.43, 95% CI = 0.25-0.74). On the other hand, Kaplan-Meier curves did not show statistically significant differences in survival among the studied polymorphisms. We conclude that the minor alleles of rs1801270 and rs1059234 polymorphisms may act as risk factors for the development of RB in our sample.

SUMMARY

The minor alleles of polymorphisms rs1801270 C>A and rs1059234 C>T in CDKN1A (p21) gene may act as risk factors for the development of RB; however, they do not seem to influence overall survival.

Cell cycle suppressor proteins are not related to HPV status or clinical outcome in patients with vulvar carcinoma

Interactions between the cyclin-dependent kinase inhibitors (CDKI) and human papillomavirus (HPV) infection in the pathogenesis of vulvar carcinoma are still incomplete. This study aimed to evaluate the prognostic relevance of these proteins in vulvar cancer. One hundred and thirty-nine patient specimens assembled in a tissue microarray were evaluated for p16, p21, p27, and pRb by immunohistochemistry. HPV status was assessed by a linear array HPV genotyping test. In 16 cases with available frozen tumor, quantitative real-time reverse transcriptase-polymerase chain reaction for CDKN2A(p16), CDKN1A, and Rb was performed. Protein expression was considered positive in 40 patients for p16, 35 for p21, 28 for p27, and 19 for pRb. HPV was positive in 43 of the 105 evaluable cases. Expression of CDKIs and pRb, with the exception of p16, seem to be linked to the early phases of vulvar carcinogenesis. Although p16 and p21 protein expression was associated with early stages of disease, no prognostic significance was found when analyzing CDKI proteins or detecting HPV status, limiting their clinical usage. No association was observed between expression of CDKI proteins and HPV status, suggesting that in spite of this association found in cervical cancer, this seems not to be valid for vulvar carcinoma.

The role of p21 3'UTR gene polymorphism in the risk of prostate cancer: a pilot study

The cell cycle regulator p21 plays an important role in regulating critical cell activities including cell cycle control, DNA repair and apoptosis. Consequently, it may affect the efficacy of the response to DNA damage and tumor development. The aim of our study was to evaluate the frequencies of the p21 C70T polymorphism, the association between this genetic variant and smoking status, and the serum prostate-specific antigen (PSA) levels and Gleason score in 118 prostate cancer patients and 130 males routinely screened for prostate cancer in the Slovak population. Blood samples were collected from all individuals for DNA isolation, used for subsequent genotyping assays via PCR-RFLP methods. Overall, we did not observe any significant association between this polymorphism and prostate cancer risk. An analysis of the association between the p21 genotypes and smoking was then conducted. Among smokers, CC and CT genotypes were associated with a non‑significant increased risk (OR=1.48; 95% CI, 0.80-2.76 and OR=1.15; 95% CI, 0.27‑4.77, respectively; p>0.05) in comparison to non-smokers with the CC genotype. Patients with a CT genotype and serum PSA levels≥10 ng/ml had an 84% decrease in prostate cancer risk (OR=0.16; 95% CI, 0.03-0.75; p<0.05) compared to cases with serum PSA levels <10 ng/ml and the CC genotype. No significant association was detected between Gleason score and prostate cancer risk. Based on these results, we concluded that the p21 C70T polymorphism is associated with decreased risk of prostate cancer in Slovak men. To confirm these findings, a systematic approach is required to identify sequence variants in this and other related genes, and subsequently, to test for an association between such variants, smoking status and tumor-specific clinicopathological characteristics in large samples.

Association of p21 Ser31Arg and p53 Arg72Pro polymorphisms with lung cancer risk in CAPUA study

BACKGROUND

The aim of this study was to investigate how Ser31Arg polymorphisms in p21 may modify lung cancer susceptibility. Because p21 is the major downstream mediator of p53, we analyzed the combined effect of two polymorphisms, p21 Ser31Arg and TP53 Arg72Pro, to elucidate whether polymorphic variants determine the risk of lung cancer.

METHODS

This was designed as a hospital-based case-control study, and included 675 cases and 675 control subjects matched by ethnicity, gender, and age. Genotypes were determined by polymerase chain reaction restriction fragment length polymorphism, and multivariate unconditional logistic regression was performed to analyze the results.

RESULTS

Subjects who carried the p21 Ser31Arg allele had a higher risk of lung cancer (adjusted odds ratio [OR] 1.38; 95% confidence interval [CI] 0.99-2.03). This risk was increased in men aged younger than 55 years (adjusted OR 2.35; 95% CI 1.00-5.51). Smokers had an increased risk of lung cancer (adjusted OR 2.23; 95% CI 1.24-4.02). Men younger than 55 years carrying risk alleles for both genes (p21 Ser31Arg and TP53 Arg72Pro) had an increased risk (adjusted OR 5.78; 95% CI 1.38-24.19), as did smokers with both risk alleles (adjusted OR 4.52; 95% CI 1.52-13.50).

CONCLUSION

The presence of both variant alleles increased the risk of developing lung cancer in men, particularly in smokers younger than 55 years.

Association between p21 Ser31Arg polymorphism and cancer risk: a meta-analysis

P21 (CDKN1A), a key cell cycle regulatory protein that governs cell cycle progression from G1 to S phase, can regulate cell proliferation, growth arrest, and apoptosis. The Ser31Arg polymorphism is located in the highly conserved region of p21 and may encode functionally distinct proteins. Although many epidemiological studies have been conducted to evaluate the association between the p21 Ser31Arg polymorphism and cancer risk, the findings remain conflicting. This meta-analysis with 33 077 cases and 45 013 controls from 44 published case-control studies showed that the variant homozygous 31Arg/Arg genotype was associated with an increased risk of numerous types of cancers in a random-effect model (homozygote comparison: OR = 1.17, 95% CI = 0.99 to 1.37, P = 0.0002 for the heterogeneity test; recessive model comparison: OR = 1.16, 95% CI = 1.01 to 1.33, P = 0.0001 for the heterogeneity test). Stratified analysis revealed that increased cancer risk associated with the 31Arg/Arg genotype remained significant in subgroups of colorectal cancer, estrogen-related cancer, Caucasians, population-based studies, studies with matching information or a larger sample size. Heterogeneity analysis showed that tumor type contributed to substantial between-study heterogeneity (recessive model comparison: Χ(2) = 21.83, df = 7, P = 0.003). The results from this large-sample sized meta-analysis suggest that the p21 31Arg/Arg genotype may serve as a potential marker for increased cancer risk.

Genetic variants of p27 and p21 as predictors for risk of second primary malignancy in patients with index squamous cell carcinoma of head and neck

Background

Cell cycle deregulation is common in human cancer, and alterations of p27 and p21, two critical cell cycle regulators, have been implicated in the development of many human malignancies. Therefore, we hypothesize that p27 T109G polymorphism individually or in combination with p21 (C98A and C70T) polymorphisms modifies risk of second primary malignancy (SPM) in patients with index squamous cell carcinoma of head and neck (SCCHN).

Methods

A cohort of 1,292 patients with index SCCHN was recruited between May 1995 and January 2007 at the M.D. Anderson Cancer Center and followed for SPM occurrence. Patients were genotyped for the three polymorphisms. A log-rank test and Cox proportional hazards models were used to compare SPM-free survival and SPM risk.

Results

We found that patients with p27 109 TG/GG, p21 98 CA/AA and p21 70 CT/TT variant genotypes had a worse SPM-free survival and an increased SPM risk than those with the corresponding p27109 TT, p21 98 CC, and p21 70 CC common genotypes, respectively. After combining the three polymorphisms, there was a trend for significantly increased SPM risk with increasing number of the variant genotypes (P_trend = 0.0002). Moreover, patients with the variant genotypes had an approximately 2.4-fold significantly increased risk for SPM compared with those with no variant genotypes (HR, 2.4, 95% CI, 1.6-3.6).

Conclusions

These results suggest that p27 T109G polymorphism individually or in combination with p21 (C98A and C70T) polymorphisms increases risk of SPM in patients with index SCCHN.

P21 Ser31Arg Polymorphism and Cervical Cancer Risk: A Meta-Analysis

Background

Studies investigating the association between p21 genetic polymorphism Ser31Arg and cervical cancer (CC) risk report conflicting results. The aim of this study was to quantitatively summarize the evidence for p21 polymorphism and CC risk.

Methods

Two investigators independently searched the MEDLINE, Embase, CNKI, and Chinese Biomedicine databases. Summary odds ratios (ORs) and 95% confidence intervals (CIs) for p21 polymorphism and CC were calculated in a fixed effects model (the Mantel-Haenszel method) and a random effects model (the DerSimonian and Laird method) when appropriate. The pooled ORs were performed for codominant model (Arg/Arg vs Ser/Ser and Arg/Ser vs Ser/Ser), dominant model (Arg/Arg + Arg/Ser vs Ser/Ser), and recessive model (Arg/Arg vs Arg/Ser + Ser/Ser). Subgroup analyses were performed by country, matched controls, and Hardy-Weinberg equilibrium in the controls and study sample size.

Results

This meta-analysis included 10 case-control studies from an Asian population, which included 1415 CC cases and 1947 controls. Overall, the variant genotypes (Arg/Arg and Arg/Ser) of Ser31Arg were not associated with CC risk, when compared with the wild-type homozygote Ser/Ser (Arg/Arg vs Ser/Ser: OR, 1.30; 95% CI, 0.81-2.08; Arg/Ser vs Ser/Ser: OR, 1.06; 95% CI, 0.72-1.55). Similarly, no associations were found in the dominant and recessive models (dominant model: OR, 1.05; 95% CI, 0.73-1.51; recessive model: OR, 1.28; 95% CI, 0.86-1.90). Stratified analyses also detected no significant association in any subgroup, except among those studies from "other" country and those studies with controls deviated from Hardy-Weinberg equilibrium.

Conclusion

No association was found between the p21 polymorphism Arg31Ser and risk of CC among Asians. In the future, additional studies based on white and African American patients should be performed to re-evaluate the association.

Identification of single nucleotide polymorphisms in the p21 (CDKN1A) gene and correlations with longevity in the Italian population

Longevity in humans is determined by multiple environmental and genetic factors. We have investigated possible associations between longevity and Single Nucleotide Polymorphisms (SNPs) in the p21 (CDKN1A) gene, a stress-inducible senescence-associated cell cycle inhibitor, expression of which upregulates genes implicated in several age-related diseases. By sequencing the promoter and exons of p21 in genomic DNA of ten individuals over 90 years old, we have identified 30 SNPs, many of which had not been previously characterized. A cluster of minor alleles within the -4547/-3489 bp region did not alter the basal activity or p53 responsiveness of the p21 promoter. We then compared the frequency of 41 p21 SNPs between 184 centenarians and 184 younger subjects in the Italian population. Rare alleles of two exon-derived SNPs, rs1801270 and rs1059234, were significantly under-represented among the centenarians; no significant differences were found for 39 non-exonic SNPs. SNP rs1801270 causes Ser to Arg substitution at amino acid 31 and SNP rs1059234 leads to a nucleotide change in the 3'-untranslated region. Previous studies showed that the rare alleles of these two SNPs may play a role in cancer. These p21 alleles may be potentially detrimental to longevity and therefore are rare in centenarians.

Association of selected polymorphisms of CCND1, p21, and caspase8 with colorectal cancer risk

It has been well elucidated that the signal transduction of cell-cycle control pathway and apoptosis pathway plays an important role in the normal growth and differentiation of organisms. To test the hypothesis that mutants of key genes involved in cell-cycle regulation and apoptosis might contribute to the increased risk of colorectal cancer (CRC), a population-based case-control study was carried out in Jiashan County, Zhejiang Province. The study population was composed of 373 CRC cases and 838 controls. Five genetic variants including CCND1 G870A, p21 codon31 C/A, p21 3'UTR C/T, caspase8 IVS12-19G/A, and caspase8 6n del/ins were genotyped. The associations of the polymorphisms with CRC were estimated by logistical regression model after adjustment for the important covariates. The interactive effect among the five selected genetic polymorphisms on CRC was explored by multifactor dimensionality reduction (MDR) software. The significant association between five single-nucleotide polymorphisms (SNPs) and CRC risk was not observed, respectively. However, caspase8 del/del showed a marginally significant association with the increased risk of rectum cancer [adjusted odds ratio (OR) (95% confidence interval, CI) = 1.92 (0.97-3.79); P = 0.06]. Furthermore, the MDR analysis indicated that the best interactive model for CRC included three factors-CCND1 G870A, caspase8 IVS12-19G/A, and caspase8 6 n del/ins-with 53.44% testing balanced accuracy and 10/10 cross-validation consistency, but the model was no longer significant after the 1000 times permutation test (P = 0.25). Our findings suggest that the selected polymorphisms of p21, CCND1, and caspase8 may not contribute to the risk of colorectal cancer.

The six-nucleotide deletion/insertion variant in the CASP8 promoter region is inversely associated with risk of squamous cell carcinoma of the head and neck

Caspase 8 (CASP8) is an apoptosis-related cysteine peptidase involved in the death receptor pathway and likely in the mitochondrial pathway. A CASP8 promoter region six-nucleotide deletion/insertion (-652 6N ins/del) variant and a coding region D302H polymorphism are reportedly important in cancer development, but no reported study has assessed the associations of these genetic variations with risk of head and neck cancer. In a hospital-based study of non-Hispanic whites, we genotyped CASP8 -652 6N del and 302H variants in 1,023 patients with squamous cell carcinoma of the head and neck (SCCHN) and 1,052 cancer-free controls. Crude and adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated using unconditional logistic regression models. The CASP8 -652 6N del variant genotypes or haplotypes were inversely associated with SCCHN risk (adjusted OR, 0.70; 95% CI, 0.57-0.85 for the ins/del + del/del genotypes compared with the ins/ins genotype; adjusted OR, 0.73; 95% CI, 0.55-0.97 for the del-D haplotype compared with the ins-D haplotype). Furthermore, the number of the CASP8 -652 6N del (but not 302H) variant allele tended to correlate with increased levels of camptothecin-induced p53-mediated apoptosis in T lymphocytes from 170 cancer-free controls. We concluded that the CASP8 -652 6N del variant allele may contribute to the risk of developing SCCHN in non-Hispanic white populations. Further validation by population-based case-control studies and rigorous mechanistic studies is warranted.

Genetic variants of p21 and p27 and pancreatic cancer risk in non-Hispanic Whites: a case-control study

OBJECTIVES

p21 (WAF1/Cip1/CDKN1A) and p27 (Kip1/CDKN1B) are members of the Cip/Kip family of cyclin-dependent kinase inhibitors, which can induce cell cycle arrest and serve as tumor suppressors. We hypothesized that genetic variants in p21 and p27 may modify individual susceptibility to pancreatic cancer.

METHODS

To test this hypothesis, we evaluated the associations of the Ser31Arg polymorphism in p21 and the Gly109Val polymorphism in p27, and their combinations, with pancreatic cancer risk in a case-control study of 509 pathologically confirmed pancreatic adenocarcinoma patients and 462 age- and sex-matched cancer-free controls in non-Hispanic whites.

RESULTS

We found that the heterozygous and homozygous variant genotypes combined in a dominant model of the p21 polymorphism were associated with increased risk of pancreatic cancer compared with the homozygous wild type (adjusted odds ratio [ORadjusted], 1.70; 95% confidence interval [CI], 1.13-2.55). This increased risk was more pronounced in carriers with the p27 homozygous wild type (ORadjusted, 2.20; 95% CI, 1.32-3.68) and in nonsmokers (ORadjusted, 2.16; 95% CI, 1.14-4.10), although the p27 polymorphism alone was not associated with pancreatic cancer risk.

CONCLUSIONS

These results indicate that the p21 polymorphism may contribute to susceptibility to pancreatic cancer, particularly among p27 homozygous wild-type carriers and nonsmokers.

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.

Association of genetic polymorphisms, mRNA expression of p53 and p21 with chronic benzene poisoning in a chinese occupational population

DNA damage induced by benzene reactive metabolites is thought of as an important mechanism underlying benzene hematotoxicity and genotoxicity, and genetic variation in cell-cycle control genes may contribute to susceptibility to chronic benzene poisoning (CBP). Using a case-control study that included 307 benzene-poisoned patients and 299 workers occupationally exposed to benzene in south China, we aimed to investigate the association between genetic polymorphisms of p53 and p21 and the odds of CBP. To investigate whether benzene exposure may influence mRNA expression of p53 and p21 in benzene-exposed workers, we also chose 39 CBP workers, 38 occupationally benzene-exposure workers, and 37 nonexposure workers in the same region of China. PCR-restriction fragment length polymorphism technique was applied to detect polymorphisms of p53 (rs17878362, rs1042522, and rs1625895) and p21 (rs1801270 and rs1059234), and real-time PCR was applied to detect the quantity of gene mRNA expression. We found that p21 C98A variant genotypes (CA+AA) or C70T variant genotypes (CT+TT) were associated with decreased odds of CBP [odds ratio (OR), 0.51; 95% confidence interval (95% CI), 0.32-0.83, and OR, 0.53; 95% CI, 0.29-0.95, respectively. Further analysis showed the decreased odds of CBP in the subjects with p21 CC/AT diplotype (OR, 0.51; 95% CI, 0.30-0.85). In addition, p53 mRNA expression of CBP workers or benzene-exposure workers was significantly lower than that of nonexposure workers. Although these results require confirmation and extension, our results show that polymorphisms in p21 may be protective against the risk of CBP in the Chinese occupational population.

Essential oil composition and antioxidant activity of Pterocarya fraxinifolia

Current research into free radicals has confirmed that plants rich in antioxidants play an essential role in the prevention of many diseases. The potential antioxidant activities of Pterocarya fraxinifolia bark and leaves investigated employing six in vitro assay systems. IC50 for DPPH radical-scavenging activities were 3.89 +/- 0.09 for leaves and 41.57 +/- 1.30 microg mL(-1) for bark, respectively. The leaf extract exhibited a good reducing power at 2.5 and 80 microg mL(-1) that was comparable with Vit C (p > 0.05). The extracts also showed weak nitric oxide-scavenging activity and Fe2+ chelating ability. The peroxidation inhibition of extracts exhibited values from 92 to 93% at 72nd h, almost at the same pattern of Vitamin C activity (p > 0.05). Based on higher total phenol and flavonoid contents in leaves, higher antioxidant activities were observed in leaf extract. In addition, chemical composition of leaf essential oil was determined. The major compound was bisabolol oxide A (23.6%). Sesquiterpenes and monoterpenes are the major compounds in leaves essential oil. Presence of these compounds may be a reason for the good antioxidant activity of leaf extract.

Association of p73 G4C14-to-A4T14 polymorphism with human papillomavirus type 16 status in squamous cell carcinoma of the head and neck in non-Hispanic whites

BACKGROUND

The tumor protein p73 interacts with the human papillomavirus type 16 (HPV-16) oncoproteins E6 and E7, and p73 variation may modify the interaction between p73 protein and HPV-16 oncogenic proteins and contribute to cellular malignant transformation.

METHODS

In this case-case comparison study, the authors analyzed HPV-16 status in tumor specimens and genotyped the p73 G4C14-to-A4T14 polymorphism using genomic DNA from blood of 202 non-Hispanic white patients with squamous cell carcinoma of the head and neck (SCCHN). Odds ratio (OR) and 95% confidence intervals (95% CIs) were calculated in univariate and multivariable logistic regression models to examine the association between the p73 polymorphism and HPV-16 status in SCCHN.

RESULTS

Compared with the p73 GC/GC genotype, the AT/AT and combined GC/AT + AT/AT variant genotypes were associated significantly with HPV-16-positive tumor status among patients with SCCHN (adjusted OR, 5.32; 95% CI, 1.32-21.4; adjusted OR, 1.91; 95% CI, 1.03-3.53, respectively). There was a significant dose-effect relation between the AT allele and HPV-16-positive tumor status in patients with SCCHN (trend test: P = .014). Moreover, the stratified analyses indicated that the association between HPV-16-positive tumor status and the combined p73 GC/AT + AT/AT genotypes was more pronounced among several subgroups of patients who were older, men, ever drinkers, and those with oropharyngeal cancer.

CONCLUSIONS

The p73 polymorphism was associated with HPV-16 status in SCCHN and may serve as a marker of positive HPV-16 tumor status in patients with SCCHN, particularly those with oropharyngeal cancer.

CASP3 polymorphisms and risk of squamous cell carcinoma of the head and neck

PURPOSE

Caspase-3 plays a central role in executing cell apoptosis and thus in carcinogenesis, but little is known about the role of CASP3 variants in susceptibility to SCCHN.

EXPERIMENTAL DESIGN

Genotype and haplotypes of the first intron (rs4647601:G>T and rs4647602:C>A) and 5'-untranslated region (UTR; rs4647603:G>A) of CASP3 (NT_022792.17) were determined for 930 SCCHN patients and 993 cancer-free controls in a U.S. non-Hispanic white population. Odds ratio (OR) and 95% confidence interval (95% CI) were calculated in multivariate logistic regression analysis.

RESULTS

We found that the CASP3 rs4647601:TT variant genotype was associated with an increased risk of SCCHN (adjusted OR, 1.32; 95% CI, 1.00-1.73) compared with the GG genotype. This risk was more evident in the subgroups of younger (< or =56 years) subjects, males, and never smokers with a significant trend for increased risk with increased number of variant T allele (P < 0.05 for all). However, these risks were not found for other two SNPs. Furthermore, individuals with two copies of haplotypes TCG or GCA were found to have a significant increased risk of SCCHN (OR, 1.31; 95% CI, 1.07-1.61) compared with the other haplotypes, and this risk was more evident in less advanced diseases (OR, 1.45; 95% CI, 1.11-1.89) than in the advanced diseases (OR, 1.22; 95% CI, 0.96-1.54).

CONCLUSIONS

These results suggested that genetic variation in CASP3 may contribute to SCCHN risk. Larger studies are needed to confirm our findings.

Combined effects of the p53 codon 72 and p73 G4C14-to-A4T14 polymorphisms on the risk of HPV16-associated oral cancer in never-smokers

Because p53 and p73 are associated with critical cellular processes and can be inactivated or degraded by the human papillomavirus (HPV) E6 oncoprotein, we investigated the combined effects of p53 codon 72 and p73 G4C14-to-A4T14 polymorphisms on the risk of HPV16-associated oral cancer. We analyzed genotype data from 326 patients with squamous cell carcinoma of the oral cavity or oropharynx and 349 cancer-free controls. We found that HPV16 seropositivity was associated with an increased risk of oral cancer [adjusted odds ratio (OR), 3.42; 95% confidence interval (CI), 2.28-5.13], especially among never-smokers (adjusted OR, 8.20; 95% CI, 3.66-18.4) and subjects with variant genotypes [adjusted OR for p53 Arg/Pro + Pro/Pro (Pro carriers), 5.00; 95% CI, 2.72-9.21; adjusted OR for p73 GC/AT + AT/AT (AT carriers), 3.83; 95% CI, 1.98-7.41]. HPV16 seropositivity was also associated with an significantly increased risk of oral cancer in all three risk groups with combined genotypes [adjusted ORs (95% CIs) were 2.28 (1.15-4.54) for p53 Arg/Arg and p73 GC/GC, the low-risk group; 3.97 (2.14-7.36) for p53 Arg/Arg and p73 AT carriers or p53 Pro carriers and p73 GC/GC, the medium-risk group and 5.11 (2.00-13.0) for p53 Pro carriers and p73 AT carriers, the high-risk group]. Moreover, HPV16-seropositive never-smokers in the high-risk group exhibited an approximately 11-fold greater risk of oral cancer (adjusted OR, 11.3; 95% CI, 1.22-106.0) than did HPV16-seronegative never-smokers in the low-risk group. These findings suggest that the combined variants of p53 and p73 significantly increase the risk of HPV16-associated oral cancer, especially among never-smokers.

Polymorphisms of p21 and p27 jointly contribute to an earlier age at diagnosis of pancreatic cancer

p21 and p27, members of the kinase inhibitor protein (KIP) family, bind to cyclin-CDK complexes to inhibit their catalytic activity and induce cell cycle arrest. The purpose of our study was to identify whether the p21 (C-to-A), and p27 (T-to-G) polymorphisms were associated with age at diagnosis of pancreatic cancer, either independently or jointly. Two hundred and five patients with a diagnosis of pancreatic cancer were genotyped for the p21 and p27 polymorphisms. We found patients with the p21 variant genotype (CA/AA) had an earlier age at diagnosis than those with the wild-type genotype (CC) (log-rank, P=0.001; HR=1.89; 95%CI, 1.28-2.78). The p21 and p27 polymorphisms combined had a joint effect on age-associated risk for early diagnosis of pancreatic cancer (log-rank, P=0.004; HR=2.91; 95%CI, 1.49-5.67). Our findings suggest that the p21 polymorphism independently and p21 and p27 polymorphisms jointly contribute to a significantly earlier age at diagnosis of pancreatic cancer.

P21 and p27: roles in carcinogenesis and drug resistance

Human cancers arise from an imbalance of cell growth and cell death. Key proteins that govern this balance are those that mediate the cell cycle. Several different molecular effectors have been identified that tightly regulate specific phases of the cell cycle, including cyclins, cyclin-dependent kinases (CDKs) and CDK inhibitors. Notably, loss of expression or function of two G1-checkpoint CDK inhibitors - p21 (CDKN1A) and p27 (CDKN1B) - has been implicated in the genesis or progression of many human malignancies. Additionally, there is a growing body of evidence suggesting that functional loss of p21 or p27 can mediate a drug-resistance phenotype. However, reports in the literature have also suggested p21 and p27 can promote tumours, indicating a paradoxical effect. Here, we review historic and recent studies of these two CDK inhibitors, including their identification, function, importance to carcinogenesis and finally their roles in drug resistance.

Influence of cancer-related gene polymorphisms on clinicopathological features in colorectal cancer

BACKGROUND AND AIM

Single nucleotide polymorphisms (SNP) are shown to be related with cancer incidence. It has been reported that CCND1, p21(cip1)DCC, MTHFR, and EXO1 are related with the risk of malignant neoplasm, but few studies have mentioned the prognosis of the patients. We investigated the SNP of patients and related this to clinicopathological features, including survival rate.

METHOD

DNA from the tissues of primary colorectal cancer was obtained from surgical resections of 114 patients (68 males and 46 females, 29-83 years). The CCND1 polymorphism was analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and those of other genes were investigated by the TaqMan method. The polymorphisms obtained were statistically analyzed for the relationship with clinicopathological features.

RESULTS

The CG + GG allele was more invasive than the CC allele in histological tumor depth in the DCC codon 201 (P = 0.0086). The 677TT allele in MTHFR had a larger tumor size than the 677CC allele (P = 0.028). In EXO1 P757L polymorphism, patients with the TT allele had a statistically reduced survival rate compared with the other alleles. In CCND1 polymorphisms, we found no statistical significance in clinicopathological features.

CONCLUSIONS

From these preliminary data, these polymorphisms would be candidates predicting the clinicopathological features of colorectal cancer, but further more systematic gene analyses are warranted.