Genetic variants of p21 and p27 and hepatocellular cancer risk in a Chinese Han population: a case-control study

Contribution of Cyclin Dependent Kinase Inhibitor 1A Genotypes to Childhood Acute Lymphocytic Leukemia Risk in Taiwan

BACKGROUND/AIM

The disruption of cell-cycle control can lead to an imbalance in cell proliferation, often accompanied by genomic instability, which in turn can facilitate carcinogenesis. This study aimed to examine the impact of CDKN1A rs1801270 and rs1059234 polymorphisms on the risk of childhood acute lymphocytic leukemia (ALL) in Taiwan.

MATERIALS AND METHODS

The genotypes of CDKN1A rs1801270 and rs1059234 in 266 childhood ALL cases and 266 controls were determined using PCR-RFLP techniques.

RESULTS

The genotypic and allelic frequencies for CDKN1A rs1801270 and rs1059234 did not significantly differ between childhood ALL cases and controls (all p>0.05). However, stratified analysis revealed that the CDKN1A rs1801270 AA variant was associated with a reduced risk of childhood ALL in males (OR=0.40, 95%CI=0.20-0.82, p=0.0178). Additionally, the AC and AA genotypes of rs1801270 were linked to a lower risk classification for childhood ALL and longer survival times (OR=0.57 and 0.31, 95%CI=0.33-0.97 and 0.18-0.56, p=0.0538 and 0.0001, respectively). No significant associations were found for rs1059234 in the stratified analyses (p>0.05 for all).

CONCLUSION

Although CDKN rs1801270 and rs1059234 genotypes were not associated with an overall risk of childhood ALL, CDKN1A rs1801270 polymorphism may serve as a protective predictor in males and as a potential marker for better prognosis of childhood ALL. Validation in larger and more diverse populations is necessary to confirm the feasibility of this predictor.

Research Progress on the Anti-Liver Cancer Mechanism and Toxicity of Rhubarb Anthraquinone

Ethnopharmacological Relevance

Rhubarb has the effect of breaking blood stasis and abnormal mass, and was often used to treat various tumor diseases including liver cancer in ancient China. Recipes containing rhubarb have anti-liver cancer properties and are still used today. However, the main components and mechanism of action of rhubarb against liver cancer are still unclear.

Aim of the Review

To conduct a review of the anti-liver cancer effects and toxicity of rhubarb anthraquinones (AQs).

Materials and Methods

This article reviewed the effects of rhubarb AQs in the treatment of liver cancer and the signaling pathways involved, and discussed the toxicity and pharmacokinetics of rhubarb AQs by searching the Web of Science, PubMed and CNKI databases.

Results

Rhubarb (Rhei Radix et Rhizoma) is a traditional Chinese medicine that has been existed for thousands of years and is used as an anti-cancer drug. Modern pharmacological research shows that rhubarb AQs, as the main component of rhubarb, contains emodin, rhein, chrysophanol, physcione and aloe-emodin, which has anti-liver cancer effects and can be considered as a potential therapeutic drug for liver cancer. However, many modern studies have shown that rhubarb AQs have certain toxicity, which hinders in-depth research on rhubarb AQs.

Conclusion

Rhubarb AQs can be used as a potential anti-liver cancer drug, but its research still has many limitations. Strengthening research on related experiments and finding a balance between toxicity and efficacy are all directions worth studying in the future.

PPIH as a poor prognostic factor increases cell proliferation and m6A RNA methylation in hepatocellular carcinoma

RNA-binding proteins (RBPs) play a crucial role in the biological processes of liver hepatocellular carcinoma (LIHC). Peptidyl-prolyl cis-trans isomerase H (PPIH), an RBP, possesses prolyl isomerase activity and functions as a protein chaperone. The relationship between PPIH and LIHC has not yet been fully elucidated. This study elucidated potential mechanisms through which PPIH affects the prognosis of LIHC. Bioinformatics analysis and in vitro experiments revealed that PPIH expression was higher in LIHC tissues than in normal tissues. PPIH was identified as an independent prognostic factor, with high PPIH expression being associated with worse prognoses. Moreover, PPIH increased the m6A RNA methylation level and promoted cell proliferation by modulating DNA replication and the expression of cell cycle-related genes in LIHC cells. Bioinformatics analysis also revealed that PPIH expression increased immune cell infiltration and the expression of immune checkpoint proteins. Collectively, these findings indicate that PPIH might promote LIHC progression by enhancing the m6A RNA methylation level, increasing cell proliferation, and altering the tumor immune microenvironment. Our study demonstrates that PPIH, as a poor prognostic factor, may lead to LIHC malignancy through multiple pathways. Further in-depth research on this topic is warranted.

Fas -670 A/G polymorphism predicts prognosis of hepatocellular carcinoma after curative resection in Chinese Han population

BACKGROUND

Apoptosis, also called programmed cell death, is a genetically controlled process against hyperproliferation and malignancy. The Fas-Fas ligand (FasL) system is considered a major pathway for apoptosis in cells and tissues. Thus, this study aimed to investigate whether single nucleotide polymorphisms (SNPs) in Fas and FasL gene may have effects on the recurrence and survival of patients with hepatocellular carcinoma (HCC) after curative hepatectomy.

METHODS

We investigated the relationship between Fas rs1800682, rs2234767 and FasL rs763110 polymorphisms and recurrence-free survival (RFS) as well as overall survival (OS) in 117 Chinese Han patients with HCC who underwent hepatectomy.

RESULTS

In Kaplan-Meier survival analysis, only Fas rs1800682 (-670 A/G) was associated with RFS and OS. Compared with AA genotype, the AG/GG genotype was significantly associated with better RFS (P = 0.008) and OS (P = 0.020). Moreover, multivariate Cox regression analysis showed that Fas rs1800682 remained as a significant independent predictor of RFS for HCC patients with hepatectomy [AG/GG vs. AA: adjusted hazard ratio = 0.464, 95% confidence interval: 0.275-0.782, P = 0.004], but was not an independent predictor of OS (P = 0.395).

CONCLUSIONS

This study demonstrated that Fas -670 G allele may play a protective role in the recurrence and survival of HCC patients with hepatectomy. Furthermore, Fas rs1800682 polymorphism might be a promising biomarker for HCC patients after hepatectomy.

Genetic polymorphism of fibroblast growth factor receptor 2 and trinucleotide repeat-containing 9 influence the susceptibility to HCV-induced hepatocellular carcinoma

BACKGROUND

Fibroblast growth factor receptor 2 (FGFR2) and trinucleotide repeat-containing 9 (TRNC9) gene polymorphisms have been associated with some cancers. We aimed to assess the association of FGFR2 rs2981582 and TRNC9 rs12443621 polymorphisms with hepatocellular cancer risk.

METHODS

One hundred patients with HCV-induced HCC, 100 patients with chronic HCV infection, and 100 controls were genotyped for FGFR2 rs2981582 and TNRC9 rs12443621 using allele-specific Real-Time PCR analysis.

RESULTS

FGFR2 rs2981582 genotype TT was associated with increased risk of HCC when compared to controls (OR = 3.09, 95% CI = 1.24-7.68). However, it was significantly associated with a lower risk of HCC when using HCV patients as controls (OR = 0.21, 95% CI = 0.09-0.5), and T-allele of FGFR2 appears to be a protective allele against HCC in HCV patients (OR = 0.42, 95% CI = 0.21-0.85). While AG and GG genotypes of TNRC9 rs12443621 were linked with significantly increased risk of HCC (OR = 3.91, 95% CI = 2.02-7.6 and OR = 9.26, 95% CI = 3.21-26.7 respectively) and HCV patients carrying G allele were at increased risk of HCC by 2.7-fold. A significant high frequency of small tumor size and early-stage of HCC were observed in patients carrying FGFR2 rs2981582 genotype CT and TT (P = 0.029 and <0.001 respectively), while, TNRC9 rs12443621 genotype AG and GG were associated large tumor size and late-stage of HCC (P < 0.001 and 0.015 respectively).

CONCLUSIONS

SNPs in rs2981582 for FGFR2 and rs12443621 for TNRC9 gene were associated with HCC susceptibility, suggesting their implication in hepatocarcinogenesis in chronically HCV-infected patients.

Autophagy-Related Gene Pairs Signature for the Prognosis of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) has been recognized as the third leading cause of cancer-related deaths worldwide. There is increasing evidence that the abnormal expression of autophagy-related genes plays an important role in the occurrence and development of HCC. Therefore, the study of autophagy-related genes can further elucidate the genetic drivers of cancer and provide valuable therapeutic targets for clinical treatment. In this study, we used 232 autophagy-related genes extracted from the Human Autophagy Database (HADb) and Molecular Signatures Database (MSigDB) to construct 1884 autophagy-related gene pairs. On this basis, we developed a prognostic model based on autophagy-related gene pairs using least absolute shrinkage and selection operator (LASSO) Cox regression to evaluate the prognosis of patients after liver cancer resection. We then used 845 liver cancer samples from three different databases to test the reliability of the risk signature through survival analysis, receiver operating characteristic (ROC) curve analysis, univariate and multivariate analysis. To further explore the underlying biological mechanisms, we conducted an enrichment analysis of autophagy-related genes. Finally, we combined the signature with independent prognostic factors to construct a nomogram. Based on the autophagy-related gene pair (ARGP) signature, we can divide patients into high- or low-risk groups. Survival analysis and ROC curve analysis verified the validity of the signature (AUC: 0.786—0.828). Multivariate Cox regression showed that the risk score can be used as an independent predictor of the clinical outcomes of liver cancer patients. Notably, this model has a more accurate predictive effect than most prognostic models for hepatocellular carcinoma. Moreover, our model is a powerful supplement to the HCC staging indicator, and a nomogram comprising both indicators can provide a better prognostic effect. Based on pairs of multiple autophagy-related genes, we proposed a prognostic model for predicting the overall survival rate of HCC patients after surgery, which is a promising prognostic indicator. This study confirms the importance of autophagy in the occurrence and development of HCC, and also provides potential biomarkers for targeted treatments.

A genetic variant in the promoter of CD46 is associated with the risk and prognosis of hepatocellular carcinoma

CD46 (also known as membrane cofactor protein), which is a member of the membrane-bound complement regulatory protein family, has been reported to cause cancer cells to escape complement-dependent cytotoxicity. However, the association between CD46 polymorphisms and the risk of hepatocellular carcinoma (HCC) has not been investigated. This two-stage association study was conducted to assess the relationship between the tagging single nucleotide polymorphisms (tagSNPs) of CD46 and HCC risk and prognosis. A series of functional analyses were performed to study the underlying mechanisms. Among the eight tagSNPs, rs2796267 (P = .003) and rs2796268 (P = .011) were found to modify HCC risk in the discovery set. Only rs2796267 (P < .0001) was confirmed to be associated with HCC susceptibility in the validation set. Compared with the wild-type AA genotype, the GG genotype significantly increased the HCC risk (adjusted odds ratio [OR] = 2.03; 95% confidence interval [CI], 1.34-3.08; P = .001). Moreover, subgroups analysis suggested a positive correlation among male and younger patients, especially among drinkers, smokers, and hepatitis B surface antigen-positive individuals. In functional analyses, we found that the rs2796267 G allele in the promoter region of CD46 could increase the expression of CD46 by affecting the binding affinity of STAT5a. Furthermore, Cox regression analysis revealed that the rs2796267 AG/GG genotype was significantly associated with worse prognosis of resected patients with HCC (hazard ratio = 2.27; 95% CI, 1.27-4.05; P = .006). These results suggest that the CD46 rs2796267 polymorphism may contribute to susceptibility and prognosis of HCC by altering promoter activity.

Germline CDKN1B Loss-of-Function Variants Cause Pediatric Cushing's Disease With or Without an MEN4 Phenotype

CONTEXT

Germline loss-of-function CDKN1B gene variants cause the autosomal dominant syndrome of multiple endocrine neoplasia type 4 (MEN4). Even though pituitary neuroendocrine tumors are a well-known component of the syndrome, only 2 cases of Cushing's disease (CD) have so far been described in this setting.

AIM

To screen a large cohort of CD patients for CDKN1B gene defects and to determine their functional effects.

PATIENTS

We screened 211 CD patients (94.3% pediatric) by germline whole-exome sequencing (WES) only (n = 157), germline and tumor WES (n = 27), Sanger sequencing (n = 6), and/or germline copy number variant (CNV) analysis (n = 194). Sixty cases were previously unpublished. Variant segregation was investigated in the patients' families, and putative pathogenic variants were functionally characterized.

RESULTS

Five variants of interest were found in 1 patient each: 1 truncating (p.Q107Rfs*12) and 4 nontruncating variants, including 3 missense changes affecting the CDKN1B protein scatter domain (p.I119T, p.E126Q, and p.D136G) and one 5' untranslated region (UTR) deletion (c.-29_-26delAGAG). No CNVs were found. All cases presented early (10.5 ± 1.3 years) and apparently sporadically. Aside from colon adenocarcinoma in 1 carrier, no additional neoplasms were detected in the probands or their families. In vitro assays demonstrated protein instability and disruption of the scatter domain of CDKN1B for all variants tested.

CONCLUSIONS

Five patients with CD and germline CDKN1B variants of uncertain significance (n = 2) or pathogenic/likely pathogenic (n = 3) were identified, accounting for 2.6% of the patients screened. Our finding that germline CDKN1B loss-of-function may present as apparently sporadic, isolated pediatric CD has important implications for clinical screening and genetic counselling.

p27-V109G Polymorphism Is Not Associated with the Risk of Prostate Cancer: A Case-Control Study of Han Chinese Men in Central China

Objective

We conducted an update meta-analysis aiming to verify the association between p27-V109G polymorphism and cancer risk, particular for prostate cancer (PCa). Then, we conducted a case-control study of Han Chinese in central China to verify the evidence-based results.

Methods

Relevant studies were collected from diverse databases up to March 2017. In addition, a hospital-based (H-B) case-control study enrolling 90 PCa patients and 140 healthy controls was included to verify these evidence-based findings. Genetic risk was calculated by odds ratio (OR) with its corresponding 95% confidence interval (CI). The p27-V109G polymorphism was determined by MassARRAY genotyping method.

Results

Finally, twenty-four published studies comprising 9627 cases and 12,102 controls were enrolled for the current meta-analysis. Overall analysis suggested that p27-V109G polymorphism decreased overall cancer risk in allelic contrast, heterozygote, and dominant models. When stratified analysis was conducted by ethnicity, data revealed that p27-V109G polymorphism was associated with a decreased cancer risk in Caucasians. Highlighted in the subgroup analysis by cancer type, we uncovered a significantly decreased risk of PCa in allelic contrast, dominant, homogeneous, and recessive models. However, in the validation case-control study, we failed to uncover a positive association between p27-V109G polymorphism and PCa risk. In addition, negative results were also identified when subgroup analyses were stratified by age, tumor grade, tumor stage, PSA levels, and other measurements.

Conclusion

Although evidence-based results suggest that p27-V109G polymorphism plays a protective role in overall cancer risk, particularly for PCa, our case-control study failed to validate any association between this particular polymorphism and PCa risk.

Genetic association between the cyclin-dependent kinase inhibitor gene p27/Kip1 polymorphism (rs34330) and cancer susceptibility: a meta-analysis

The p27 rs34330 (-79C/T) polymorphism has been widely studied for human cancer susceptibility. The current findings, however, still remained controversial. Therefore, we performed the meta-analysis to provide a more accurate result. Eligible studies were identified from PubMed database up to June 2015. The association of p27 rs34330 polymorphism and cancer susceptibility was estimated with odds ratios and corresponding 95% confidence intervals. The meta-analysis was performed with Stata 12. A total of ten studies with 11,214 cases and more than 8,776 controls were included in the meta-analysis (including breast, lung, thyroid, endometrial, and hepatocellular cancer). In pooled analysis, p27 gene rs34330 polymorphism significantly increased the cancer susceptibility. Subgroup analysis indicated that the elevated risk was observed under all the genetic models for Asians and under three genetic models for Caucasians. Results of sensitivity analysis were similar to the overall results. The results suggested that the p27 rs34330 polymorphism increased the cancer susceptibility, especially in Asians. Further well-designed and large sample size studies are warranted to verify the conclusion.

Association of VEGFA polymorphisms with susceptibility and clinical outcome of hepatocellular carcinoma in a Chinese Han population

Vascular endothelial growth factor A (VEGFA) is an important angiogenesis regulator, which plays an important role in angiogenesis and progression of tumor, including hepatocellular carcinoma (HCC). We aimed at determining whether single nucleotide polymorphisms of VEGFA gene influence the development and clinical outcomes of HCC. We analyzed four potential functional polymorphisms (936C/T, 634G/C, 1612G/A, 2578C/A) of VEGFA gene in 476 HCC patients and 526 controls using matrix-assisted laser desorption ionization time-of-flight mass spectrometry method. Serum VEGF levels were measured by enzyme-linked immunosorbent assay. The Kaplan-Meier methods with log-rank test and Cox regression models were used to compare survival of resected HCC patients according to the genotype. We found that only the VEGFA 2578C/A polymorphism was significantly associated with decreased risk of HCC (AA/AC vs. CC; adjusted OR = 0.69, 95% CI = 0.51-0.93). Furthermore, the 2578C/A polymorphism was associated with significantly decreased postoperative recurrence (AA/AC vs. CC, adjusted OR = 0.51; 95% CI, 0.29-0.88) and improved overall survival (AA/AC vs. CC, adjusted HR = 0.27, 95% CI = 0.13-0.52) of resected HCC patients. In addition, the VEGF serum levels in HCC patients were significantly higher than those in healthy controls, although no significant association between VEGFA genotype and serum levels of VEGF was observed. These results suggest that the VEGFA 2578 C/A polymorphism may play a potential role in the development and clinical outcome of HCC among Chinese Han population.

Relationships between cell cycle pathway gene polymorphisms and risk of hepatocellular carcinoma

AIM: To investigate the associiations between the polymorphisms of cell cycle pathway genes and the risk of hepatocellular carcinoma (HCC).

METHODS: We enrolled 1127 cases newly diagnosed with HCC from the Tumor Hospital of Guangxi Medical University and 1200 non-tumor patients from the First Affiliated Hospital of Guangxi Medical University. General demographic characteristics, behavioral information, and hematological indices were collected by unified questionnaires. Genomic DNA was isolated from peripheral venous blood using Phenol-Chloroform. The genotyping was performed using the Sequenom MassARRAY iPLEX genotyping method. The association between genetic polymorphisms and risk of HCC was shown by P-value and the odd ratio (OR) with 95% confidence interval (CI) using the unconditional logistic regression after adjusting for age, sex, nationality, smoking, drinking, family history of HCC, and hepatitis B virus (HBV) infection. Moreover, stratified analysis was conducted on the basis of the status of HBV infection, smoking, and alcohol drinking.

RESULTS: The HCC risk was lower in patients with the MCM4 rs2305952 CC (OR = 0.22, 95%CI: 0.08-0.63, P = 0.01) and with the CHEK1 rs515255 TC, TT, TC/TT (OR = 0.73, 95%CI: 0.56-0.96, P = 0.02; OR = 0.67, 95%CI: 0.46-0.97, P = 0.04; OR = 0.72, 95%CI: 0.56-0.92, P = 0.01, respectively). Conversely, the HCC risk was higher in patients with the KAT2B rs17006625 GG (OR = 1.64, 95%CI: 1.01-2.64, P = 0.04). In addition, the risk was markedly lower for those who were carriers of MCM4 rs2305952 CC and were also HBsAg-positive and non-drinking and non-smoking (P < 0.05, respectively) and for those who were carriers of CHEK1 rs515255 TC, TT, TC/TT and were also HBsAg-negative and non-drinking (P < 0.05, respectively). Moreover, the risk was higher for those who were carriers of KAT2B rs17006625 GG and were also HBsAg-negative (P < 0.05).

CONCLUSION: Of 12 cell cycle pathway genes, MCM4, CHEK1 and KAT2B polymorphisms may be associated with the risk of HCC.

Genetic Association Between CDKN1B rs2066827 Polymorphism and Susceptibility to Cancer

Much attention has been directed to the association between cancer risk and rs2066827 polymorphism of the CDKN1B gene. However, the results are indefinitive and inconclusive. This study was devised to evaluate the hypothesis that rs2066827 polymorphism is associated with the risk of cancer.Computer-based databases (EMBASE, PubMed, and CNKI) were used to seek all case-control studies evaluating rs2066827 polymorphism and susceptibility to cancer. The genetic risk was assessed by calculating pooled odds ratio (OR) with its corresponding 95% confidence interval (CI). Fixed-effects pooled ORs were calculated by the Mantel-Haenszel method (Ph > 0.05), and random-effects pooled ORs were estimated by the DerSimonian-Laird method (Ph < 0.05).Data on rs2066827 polymorphism and cancer risk were available for 9038 cancer cases and 11,596 controls participating in 17 studies. Carriage of a TG genotype was associated with a minor but significant decrease in the risk of cancer (pooled OR 0.92, 95% CI: 0.86-0.99; model, TG vs. TT). We observed a moderately decreased risk of ovarian cancer based on 1829 cases and 2868 controls (pooled OR 0.85, 95% CI: 0.74-0.97; model, TG vs. TT). A slightly deceased risk of cancer was also indicated in Caucasians consisting of 6707 cases and 8279 controls (pooled OR 0.91, 95% CI: 0.85-0.98; model, TG vs. TT).These data suggest that carriage of a TG genotype at rs2066827 polymorphism may be associated with decreased susceptibility to cancer, ovarian cancer in particular.

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.

Polymorphisms of the CYP1B1 gene and hepatocellular carcinoma risk in a Chinese population

BACKGROUND

CYP1B1 is a P450 enzyme which is involved in the activation of pro-carcinogens to carcinogens as well as estrogen metabolism. We hypothesized that genetic variants in CYP1B1 may modify individual susceptibility to hepatocellular carcinoma (HCC).

METHODS

To test this hypothesis, we evaluated the associations of three CYP1B1 single nucleotide polymorphisms (SNPs) and HCC risk in a case-control study of 468 HCC cases and 515 cancer-free controls in a Chinese population. The matrix-assisted laser desorption ionization time-of-flight mass spectrometry method and direct DNA sequencing were performed to detect these polymorphisms.

RESULTS

In overall analysis, we found that only the variant G allele of rs1056836 was associated with a significantly increased risk of HCC among the three SNPs (rs10012, rs1056836 and rs1800440). Moreover, we found that the variant genotypes containing the G allele of rs1056836 were associated with a significantly increased risk of HCC among HbsAg-positive individuals (adjusted OR=2.13, 95% CI=1.18, 3.86), but not among HbsAg-negative individuals. When stratifying by smoking status, we found that the variant GG genotype increased a 13.97-fold (95% CI=1.28, 152.94) risk of HCC among smokers. Furthermore, high risk for liver cirrhosis-positive clinical status was exhibited in HCC patients with rs1056836 CG and GG genotypes as compared with CC homozygotes. For the other two SNPs, we did not find any significant evidence of association with HCC risk in any subgroup.

CONCLUSION

This study suggests that CYP1B1 rs1056836 polymorphism may be an important factor contributing to increased susceptibility and pathological development of HCC in Chinese population.

Polymorphisms of cell cycle control genes influence the development of sporadic medullary thyroid carcinoma

BACKGROUND

The role of key cell cycle regulation genes such as, CDKN1B, CDKN2A, CDKN2B, and CDKN2C in sporadic medullary thyroid carcinoma (s-MTC) is still largely unknown.

METHODS

In order to evaluate the influence of inherited polymorphisms of these genes on the pathogenesis of s-MTC, we used TaqMan SNP genotyping to examine 45 s-MTC patients carefully matched with 98 controls.

RESULTS

A multivariate logistic regression analysis demonstrated that CDKN1B and CDKN2A genes were related to s-MTC susceptibility. The rs2066827*GT+GG CDKN1B genotype was more frequent in s-MTC patients (62.22%) than in controls (40.21%), increasing the susceptibility to s-MTC (OR=2.47; 95% CI=1.048-5.833; P=0.038). By contrast, the rs11515*CG+GG of CDKN2A gene was more frequent in the controls (32.65%) than in patients (15.56%), reducing the risk for s-MTC (OR=0.174; 95% CI=0.048-0.627; P=0.0075). A stepwise regression analysis indicated that two genotypes together could explain 11% of the total s-MTC risk. In addition, a relationship was found between disease progression and the presence of alterations in the CDKN1A (rs1801270), CDKN2C (rs12885), and CDKN2B (rs1063192) genes. WT rs1801270 CDKN1A patients presented extrathyroidal tumor extension more frequently (92%) than polymorphic CDKN1A rs1801270 patients (50%; P=0.0376). Patients with the WT CDKN2C gene (rs12885) presented larger tumors (2.9±1.8 cm) than polymorphic patients (1.5±0.7 cm; P=0.0324). On the other hand, patients with the polymorphic CDKN2B gene (rs1063192) presented distant metastases (36.3%; P=0.0261).

CONCLUSION

In summary, we demonstrated that CDKN1B and CDKN2A genes are associated with susceptibility, whereas the inherited genetic profile of CDKN1A, CDKN2B, and CDKN2C is associated with aggressive features of tumors. This study suggests that profiling cell cycle genes may help define the risk and characterize s-MTC aggressiveness.

GSTM3 reverses the resistance of hepatoma cells to radiation by regulating the expression of cell cycle/apoptosis-related molecules

Radiotherapy (RT) is a major modality of hepatoma treatment. However, liver tumors often acquire radioresistance, which contributes to RT failure. The exact mechanisms of the radioresistance in hepatoma cells are largely unknown. Glutathione S-transferase M3 (GSTM3) is a phase II transferase, however, recent studies have suggested that GSTM3 is a potential tumor suppressor. The purpose of the present study was to investigate the role of GSTM3 in reversing radioresistance, and to explore the molecular mechanism of this in the human radiation-resistant PRF/PLC/5R hepatocellular carcinoma (HCC) cell line. The radioresistant PLC/PRF/5R cells were used as cell model, and were derived from PLC/PRF/5 parental cells using fractionated irradiation. The radiosensitivity of the cells was tested by clonogenic assay and flow cytometry analyses. The expression of B-cell chronic lymphocytic leukemia/lymphoma 2 (Bcl-2), Bax, p21, p27 and p53 was analyzed by quantitative polymerase chain reaction and immunoblotting with or without radiation. The results showed that the expression levels of GSTM3 were significantly lower in the PLC/PRF/5R cells than in the PLC/PRF/5 parental cells. GSTM3 overexpression sensitized the PLC/PRF/5R cells to radiation mainly though induction of apoptosis. According to the evidence from Annexin-V/PI staining, it markedly increased the percentage of apoptotic PRF/PLC/5R cells. The clonogenic assay indicated that GSTM3 significantly decreased the RT survival fraction in PRF/PLC/5R cells. Furthermore, GSTM3 increased the expression of cell cycle- and apoptosis-related genes (Bcl-2, Bax, p21, p27 and p53) in PRF/PLC/5R cells with irradiation. These findings suggest that GSTM3 plays an pivotal role in reversing the radioresistance of HCC and may be a potential target for sensitizing HCC cells to RT. The underlying mechanisms may be linked to the cell cycle arrest and apoptosis facilitation.

Quantitative assessment of the relationship between p21 Ser31Arg polymorphism and cervical cancer

Though many studies were published to assess the relationship between p21 Ser31Arg polymorphism and cervical cancer, there was no definite conclusion on this association. To provide a quantitative assessment of the relationship between p21 Ser31Arg polymorphism and cervical cancer, we performed a meta-analysis of 10 eligible studies (1,539 cases and 2,161 controls). All those 10 studies were from Asians. The odds ratios (OR) with 95% confidence intervals (95%CIs) were used to assess the strength of the association, and the pooled ORs were calculated for the codominant model (ArgArg vs. SerSer), the dominant model (ArgArg/SerArg vs. SerSer), and the recessive model (ArgArg vs. SerSer/SerArg). Meta-analysis of those 10 studies showed that there was no association between p21 Ser31Arg polymorphism and cervical cancer risk in Asians under all three models (ArgArg vs. SerSer: OR = 1.04, 95%CI 0.66-1.65, P = 0.86, I(2) = 78%; ArgArg/SerArg vs. SerSer: OR = 0.93, 95%CI 0.66-1.30, P = 0.66, I(2) = 81%; ArgArg vs. SerSer/SerArg: OR = 1.20, 95%CI 0.84-1.73, P = 0.32, I(2) = 72%). Sensitivity analysis performed by omitting each study in turn showed that the pooled results were stable. In summary, there is no association between p21 Ser31Arg polymorphism and cervical cancer risk in Asians. Further studies are needed to assess the possible association between p21 Ser31Arg polymorphism and cervical cancer risk in Caucasians.