Effect of TP53 Arg72Pro and MDM2 SNP309 polymorphisms on the risk of high-grade osteosarcoma development and survival

Genetic variants associated with osteosarcoma risk: a systematic review and meta-analysis

Osteosarcoma (OS) is the most common type of primary bone malignancy. Common genetic variants including single nucleotide polymorphisms (SNPs) have been associated with osteosarcoma risk, however, the results of published studies are inconsistent. The aim of this study was to systematically review genetic association studies to identify SNPs associated with osteosarcoma risk and the effect of race on these associations. We searched the Medline, Embase, Scopus from inception to the end of 2019. Seventy-five articles were eligible for inclusion. These studies investigated the association of 190 SNPs across 79 genes with osteosarcoma, 18 SNPs were associated with the risk of osteosarcoma in the main analysis or in subgroup analysis. Subgroup analysis displayed conflicting effects between Asians and Caucasians. Our review comprehensively summarized the results of published studies investigating the association of genetic variants with osteosarcoma susceptibility, however, their potential value should be confirmed in larger cohorts in different ethnicities.

The effects of common variants in MDM2 and GNRH2 genes on the risk and survival of osteosarcoma in Han populations from Northwest China

Accumulating evidence has shown that both MDM2 and GNRH2 might be related to Osteosarcoma (OS) susceptibility. The study aimed to evaluate the effects of common variants in MDM2 and GNRH2 genes on the risk and survival of osteosarcoma in Han populations from Northwest China. In the study, we recruited 2292 subjects including 596 OS patients and 1696 healthy controls and genotyped 16 selected tag SNPs (6 from GNRH2 and 10 from MDM2). Genetic association analyses were performed at the genotypic and allelic levels. Survival curves were made for OS patients with different genotypes. Two SNPs, rs1690916 (MDM2, P = 0.0002) and rs3761243 (GNRH2, P = 0.0004), were identified to be significantly associated with OS risk. Moreover, SNP rs3761243 was strongly associated with pathological fracture (P = 2.61 × 10^–14), metastasis (P < 2.2 × 10^–16), and Enneking stage (P < 2.2 × 10^–16) in the OS group. Furthermore, survival curves based on different genotypes of SNP rs3761243 were found to be significantly different (P = 0.0003), suggesting increased risk with more copies of C alleles. Our results provide supportive evidence for genetic associations of MDM2 and GNRH2 genes with susceptibility to OS, and for the positive correlation of SNP rs3761243 in GNRH2 with the survival status of OS patients in Han populations from Northwest China.

Pharmacogenomics and Pharmacogenetics in Osteosarcoma: Translational Studies and Clinical Impact

High-grade osteosarcoma (HGOS) is a very aggressive bone tumor which primarily affects adolescents and young adults. Although not advanced as is the case for other cancers, pharmacogenetic and pharmacogenomic studies applied to HGOS have been providing hope for an improved understanding of the biology and the identification of genetic biomarkers, which may impact on clinical care management. Recent developments of pharmacogenetics and pharmacogenomics in HGOS are expected to: i) highlight genetic events that trigger oncogenesis or which may act as drivers of disease; ii) validate research models that best predict clinical behavior; and iii) indicate genetic biomarkers associated with clinical outcome (in terms of treatment response, survival probability and susceptibility to chemotherapy-related toxicities). The generated body of information may be translated to clinical settings, in order to improve both effectiveness and safety of conventional chemotherapy trials as well as to indicate new tailored treatment strategies. Here, we review and summarize the current scientific evidence for each of the aforementioned issues in view of possible clinical applications.

Clonal Evolution of TP53 c.375+1G>A Mutation in Pre- and Post- Neo-Adjuvant Chemotherapy (NACT) Tumor Samples in High-Grade Serous Ovarian Cancer (HGSOC)

Carboplatin/paclitaxel is the reference regimen in the treatment of advanced high-grade serous ovarian cancer (HGSOC) in neo-adjuvant chemotherapy (NACT) before interval debulking surgery (IDS). To identify new genetic markers of platinum-resistance, next-generation sequencing (NGS) analysis of 26 cancer-genes was performed on paired matched pre- and post-NACT tumor and blood samples in a patient with stage IV HGSOC treated with NACT-IDS, showing platinum-refractory/resistance and poor prognosis. Only the TP53 c.375+1G>A somatic mutation was identified in both tumor samples. This variant, associated with aberrant splicing, was in trans configuration with the 72Arg allele of the known germline polymorphism TP53 c.215C>G (p. Pro72Arg). In the post-NACT tumor sample we observed the complete expansion of the TP53 c.375+1G>A driver mutant clone with somatic loss of the treatment-sensitive 72Arg allele. NGS results were confirmed with Sanger method and immunostaining for p53, BRCA1, p16, WT1, and Ki-67 markers were evaluated. This study showed that (i) the splice mutation in TP53 was present as an early driver mutation at diagnosis; (ii) the mutational profile was shared in pre- and post-NACT tumor samples; (iii) the complete expansion of a single dominant mutant clone through loss of heterozygosity (LOH) had occurred, suggesting a possible mechanism of platinum-resistance in HGSOC under the pressure of NACT.

Long telomeres cooperate with p53, MDM2, and p21 polymorphisms to raise pediatric solid tumor risk

BACKGROUND

While leukocyte telomere length has been linked with altered risk in adult cancer, limited information is available on its association with risk in pediatric solid tumors. We investigated the association of telomeric alterations with risk of pediatric solid tumors. We also investigated whether altered telomeres cooperated with the TP53 rs1042522, MDM2 rs2279744 and CDKN1A (p21^cip1 ) rs1059234 single-nucleotide polymorphisms to modify cancer risk.

METHODS

A total of 101 tumor patients and 202 controls were recruited for this age- and gender-matched case-control study. Relative telomere length (RTL) was determined in peripheral blood leukocytes using quantitative real-time polymerase chain reaction (PCR), and the polymorphisms were genotyped using PCR-restriction fragment length polymorphism.

RESULTS

Using median RTL in the healthy controls as a cut-off, children with longer telomeres were at an increased risk of developing a solid tumor (OR, 2.70; P < 0.01). When participants were categorized according to control RTL quartiles, a significant dose-response relationship was observed (χ²  = 10.95; P < 0.001). The risk for tumors increased nearly threefold (P = 0.001) for the triple interaction RTL × TP53 rs1042522 × p21^cip1 rs1059234 compared with the maximum effect of any single factor, although the interaction effect was less than additive. The MDM2 rs2279744 GG genotype reduced pediatric solid tumor risk significantly (OR, 0.51).

CONCLUSION

Combined analysis of telomeres and genetic polymorphisms in the TP53 pathway can provide important clues to understanding pediatric solid tumor etiology.

TP53 in bone and soft tissue sarcomas

Genomic and functional study of existing and emerging sarcoma targets, such as fusion proteins, chromosomal aberrations, reduced tumor suppressor activity, and oncogenic drivers, is broadening our understanding of sarcomagenesis. Among these mechanisms, the tumor suppressor p53 (TP53) plays significant roles in the suppression of bone and soft tissue sarcoma progression. Although mutations in TP53 were thought to be relatively low in sarcomas, modern techniques including whole-genome sequencing have recently illuminated unappreciated alterations in TP53 in osteosarcoma. In addition, oncogenic gain-of-function activities of missense mutant p53 (mutp53) have been reported in sarcomas. Moreover, new targeting strategies for TP53 have been discovered: restoration of wild-type p53 (wtp53) activity through inhibition of TP53 negative regulators, reactivation of the wtp53 activity from mutp53, depletion of mutp53, and targeting of vulnerabilities in cells with TP53 deletions or mutations. These discoveries enable development of novel therapeutic strategies for therapy-resistant sarcomas. We have outlined nine bone and soft tissue sarcomas for which TP53 plays a crucial tumor suppressive role. These include osteosarcoma, Ewing sarcoma, chondrosarcoma, rhabdomyosarcoma (RMS), leiomyosarcoma (LMS), synovial sarcoma, liposarcoma (LPS), angiosarcoma, and undifferentiated pleomorphic sarcoma (UPS).

Association between TP53 rs1042522 gene polymorphism and the risk of malignant bone tumors: a meta-analysis

TP53 is a tumor suppressor gene which is essential for regulating cell division and preventing tumor formation. Several studies have assessed the associations of TP53 single-nucleotide polymorphisms (SNP) with susceptibility of malignant bone tumors, including osteosarcoma and Ewing sarcoma, but the results are inconsistent. In the present meta-analysis, we aimed to elucidate the associations of TP53 rs1042522 genetic polymorphism with the risk of osteosarcoma or Ewing sarcoma. We systematically searched Medline, PubMed, Web of Science, Embase, and the Cochrane Library databases. Eligible studies assessing the polymorphisms in the TP53 rs1042522 gene and risk of malignant bone tumors were incorporated. The pooled odds ratio (OR) with its 95% confidence intervals (95% CIs) were used to assess these possible associations. Five studies with a total of 567 cases and 935 controls were finally included the meta-analysis. Meta-analysis of TP53 rs1042522 polymorphism was significantly associated with an increased risk of malignant bone tumors (G versus C: OR = 1.27, 95% CI 1.08–1.50, P=0.005; GG versus GC/CC: OR = 1.55, 95% CI 1.21–2.00, P=0.001). Moreover, in a stratified analysis, a statistically significant correlation between this SNP and osteosarcoma risk was also observed. Our results suggest that there are significant associations of TP53 rs1042522 polymorphism with malignant bone tumors risk. More studies based on larger sample sizes and homogeneous samples are warranted to confirm these findings.

Overexpression of GRIM-19 accelerates radiation-induced osteosarcoma cells apoptosis by p53 stabilization

AIMS

Osteosarcoma is one of the most aggressive types of primary bone cancer that responds poorly to radiotherapy frequently. The gene associated with retinoid-interferon mortality (GRIM-19) is a tumor suppressor that mediates cell apoptosis in multiple cancer types. However, the role of GRIM-19 in osteosarcoma and the underlying mechanism remain unclear. This study was designed to investigate the role and the underlying mechanism of GRIM-19 in osteosarcoma progression.

MATERIALS AND METHODS

Osteosarcoma tissues and cell lines were utilized to analyze the expressions of GRIM-19 in osteosarcoma by qRT-PCR and Western blot. Methods containing flow cytometry, irradiation exposure, cells inoculation, plasmid transfection, and protein immunoprecipitation were used to investigate the underlying mechanisms of GRIM-19 in osteosarcoma progression.

KEY FINDINGS

GRIM-19 is downregulated in osteosarcoma tissues and cell lines. Exposure to radiation induces osteosarcoma cell apoptosis by upregulation of p53 both in U2OS (p53-wt) and exogenous p53-introduced MG-63 (p53-null) osteosarcoma cells. Overexpression of GRIM-19 accelerates radiation-induced osteosarcoma cells apoptosis by p53 stabilization ex vivo and in vivo. Mechanistically, forced expression of GRIM-19 diminishes the activity of E3 ubiquitin-protein ligase mouse double minute 2 homolog (MDM2), a specific p53 protease, results in the accumulation of p53 and activation of p53-mediated apoptosis.

SIGNIFICANCE

GRIM-19 was proved to modulate radiation-induced osteosarcoma cells apoptosis in a p53 dependent manner by mediating MDM2 activity, which sheds light on the development of GRIM-19-based molecular target therapy on osteosarcoma.

Genetic susceptibility to bone and soft tissue sarcomas: a field synopsis and meta-analysis

Background

The genetic architecture of bone and soft tissue sarcomas susceptibility is yet to be elucidated. We aimed to comprehensively collect and meta-analyze the current knowledge on genetic susceptibility in these rare tumors.

Methods

We conducted a systematic review and meta-analysis of the evidence on the association between DNA variation and risk of developing sarcomas through searching PubMed, The Cochrane Library, Scopus and Web of Science databases. To evaluate result credibility, summary evidence was graded according to the Venice criteria and false positive report probability (FPRP) was calculated to further validate result noteworthiness. Integrative analysis of genetic and eQTL (expression quantitative trait locus) data was coupled with network and pathway analysis to explore the hypothesis that specific cell functions are involved in sarcoma predisposition.

Results

We retrieved 90 eligible studies comprising 47,796 subjects (cases: 14,358, 30%) and investigating 1,126 polymorphisms involving 320 distinct genes. Meta-analysis identified 55 single nucleotide polymorphisms (SNPs) significantly associated with disease risk with a high (N=9), moderate (N=38) and low (N=8) level of evidence, findings being classified as noteworthy basically only when the level of evidence was high. The estimated joint population attributable risk for three independent SNPs (rs11599754 of ZNF365/EGR2, rs231775 of CTLA4, and rs454006 of PRKCG) was 37.2%. We also identified 53 SNPs significantly associated with sarcoma risk based on single studies.Pathway analysis enabled us to propose that sarcoma predisposition might be linked especially to germline variation of genes whose products are involved in the function of the DNA repair machinery.

Conclusions

We built the first knowledgebase on the evidence linking DNA variation to sarcomas susceptibility, which can be used to generate mechanistic hypotheses and inform future studies in this field of oncology.

Candidate germline polymorphisms of genes belonging to the pathways of four drugs used in osteosarcoma standard chemotherapy associated with risk, survival and toxicity in non-metastatic high-grade osteosarcoma

This study aimed to identify associations between germline polymorphisms and risk of high-grade osteosarcoma (HGOS) development, event-free survival (EFS) and toxicity in HGOS patients treated with neo-adjuvant chemotherapy and surgery.

Germline polymorphisms of 31 genes known to be relevant for transport or metabolism of all four drugs used in HGOS chemotherapy (methotrexate, doxorubicin, cisplatin and ifosfamide) were genotyped in 196 patients with HGOS and in 470 healthy age and gender-matched controls. Of these 196 HGOS patients, a homogeneously treated group of 126 patients was considered for survival analyses (survival cohort). For 57 of these, treatment-related toxicity data were available (toxicity cohort).

Eleven polymorphisms were associated with increased risk of developing HGOS (p < 0.05). The distribution of polymorphisms in patients was characterized by a higher Shannon entropy. In the survival cohort (n = 126, median follow-up = 126 months), genotypes of ABCC2_1249A/G, GGH_452T/C, TP53_IVS2+38G/C and CYP2B6*6 were associated with EFS (p < 0.05). In the toxicity cohort (n = 57), genotypes of ABCB1_1236T/C, ABCC2_1249A/G, ABCC2_3972A/G, ERCC1_8092T/G, XPD_23591A/G, XRCC3_18067T/C, MTHFR_1298A/C and GGH_16T/C were associated with elevated risk for toxicity development (p < 0.05).

The results obtained in this retrospective study indicate that the aforementioned germline polymorphisms significantly impact on the risk of HGOS development, EFS and the occurrence of chemotherapy-related toxicity. These findings should be prospectively validated with the aim of optimizing and tailoring HGOS treatment in the near future.

Germline and somatic genetics of osteosarcoma - connecting aetiology, biology and therapy

Clinical outcomes and treatment modalities for osteosarcoma, the most common primary cancer of bone, have changed very little over the past 30 years. The peak incidence of osteosarcoma occurs during the adolescent growth spurt, which suggests that bone growth and pubertal hormones are important in the aetiology of the disease. Tall stature, high birth weight and certain inherited cancer predisposition syndromes are well-described risk factors for osteosarcoma. Common genetic variants are also associated with osteosarcoma. The somatic genome of osteosarcoma is highly aneuploid, exhibits extensive intratumoural heterogeneity and has a higher mutation rate than most other paediatric cancers. Complex pathways related to bone growth and development and tumorigenesis are also important in osteosarcoma biology. In this Review, we discuss the contributions of germline and somatic genetics, tumour biology and animal models in improving our understanding of osteosarcoma aetiology, and their potential to identify novel therapeutic targets and thus improve the lives of patients with osteosarcoma.

A systematic review and meta-analysis of MDM2 polymorphisms in osteosarcoma susceptibility

Two polymorphisms in the murine double minute 2 (MDM2) gene (rs1690916 and rs2279744) have been associated with the risk of osteosarcoma (OS). When we analyzed these two polymorphisms in two new independents cohorts (Spanish and Slovenian), we found no association. In order to clarify this, we conducted a meta-analysis including six populations, with a total of 246 OS patients and 1,760 controls for rs1690916; and 433 OS patients and 1,959 controls for rs2279744. Pooled odds ratio risks and corresponding 95% CI were estimated to assess the possible associations. Our results showed that these two polymorphisms were not associated with the susceptibility of OS under any genetic model studied. In conclusion, the present meta-analysis indicates that MDM2 rs1690916 and rs2279744 cannot be considered as genetic risk factors for OS susceptibility in the different populations. Therefore, the influence of these two polymorphisms on the risk of OS may be less important than previously suggested. Future studies are needed to confirm these results.

The pharmacogenomics of osteosarcoma

Osteosarcoma (OS), the most common malignant tumor of bone, is presently treated with multidrug neoadjuvant chemotherapy protocols, which allow to cure 60-65% of patients but also induce toxicity events that cannot be predicted or efficiently prevented. The identification and validation of pharmacogenomic biomarkers is, therefore, absolutely warranted to provide the bases for planning personalized treatments with the aim to increase the therapeutic benefits and to avoid or limit unnecessary toxicities. As several targeted therapies against molecular and immunological markers in OS are presently under clinical investigation, it may be speculated that some new agents for innovative treatments may emerge in the next years. However, the real improvement of therapeutic perspectives for OS is strictly connected to the identification of pharmacogenomic biomarkers that may stratify patients in responders or non-responders and identify those individuals with higher susceptibility to treatment-associated toxicity. This review provides an overview of the pharmacogenomic biomarkers identified so far in OS, which appear to be promising candidates for a translation to clinical practice, after further investigation and/or prospective validation.

Novel non invasive diagnostic strategies in bladder cancer

Bladder cancer is one of the most commonly diagnosed malignancies worldwide, derived from the urothelium of the urinary bladder and defined by long asymptomatic and atypical clinical picture. Its complex etiopathogenesis is dependent on numerous risk factors that can be divided into three distinct categories: genetic and molecular abnormalities, chemical or environmental exposure and previous genitourinary disorders and family history of different malignancies. Various genetic polymorphisms and microRNA might represent useful diagnostic or prognostic biomarkers. Genetic and molecular abnormalities - risk factors are represented by miRNA or genetic polymorphisms proved to be part of bladder carcinogenesis such as: genetic mutations of oncogenes TP53, Ras, Rb1 or p21 oncoproteins, cyclin D or genetic polymorhisms of XPD,ERCC1, CYP1B1, NQO1C609T, MDM2SNP309, CHEK2, ERCC6, NRF2, NQO1Pro187Ser polymorphism and microRNA (miR-143, −145, −222, −210, −10b, 576-3p). The aim of our article is to highlight the most recent acquisitions via molecular biomarkers (miRNAs and genetic polymorphisms) involved in bladder cancer in order to provide early diagnosis, precise therapy according to the molecular profile of bladder tumors, as well as to improve clinical outcome, survival rates and life quality of oncological patients. These molecular biomarkers play a key role in bladder carcinogenesis, clinical evolution, prognosis and therapeutic response and explain the molecular mechanisms involved in bladder carcinogenesis; they can also be selected as therapeutic targets in developing novel therapeutic strategies in bladder malignancies. Moreover, the purpose in defining these molecular non invasive biomarkers is also to develop non invasive screening programs in bladder malignancies with the result of decreasing bladder cancer incidence in risk population.

Germline gene polymorphisms predisposing domestic mammals to carcinogenesis

Cancer is a complex disease caused in part by predisposing germline gene polymorphisms. Knowledge of carcinogenesis in companion mammals (dog and cat) and some livestock species (pig and horse) is quite advanced. The prevalence of certain cancers varies by breed in these species, suggesting the presence of predisposing genetic variants in susceptible breeds. This review summarizes the present understanding of germline gene polymorphisms, including BRCA1, BRCA2, MC1R, KIT, NRAS and RAD51, associated with predisposition to melanoma, mammary cancer, osteosarcoma and histiocytic sarcoma in dogs, cats, pigs and horses. The predisposing variants in these species are discussed in the context of human germline gene polymorphisms associated with the same types of cancer.

GRM4 gene polymorphism is associated with susceptibility and prognosis of osteosarcoma in a Chinese Han population

Osteosarcoma (OS), the most common primary bone malignancy, occurs primarily in adolescents and young adults. In earlier genome-wide association studies, rs7591996, rs10208273, rs17206779 and rs1906953 were identified as candidate loci for OS in Caucasians but the association of these single-nucleotide polymorphisms (SNPs) with OS in a Chinese Han population remains unknown. We measured the frequency of these four variants in a Chinese Han population to better understand the genetic etiology of OS. Polymerase chain reaction sequencing was used to detect the genotypes of four candidate SNPs in peripheral blood samples collected from 168 OS patients and 216 healthy controls. Logistic regression models were used to estimate the odds ratios and 95 % confidence intervals. We found rs1906953 in the glutamate receptor metabotropic 4 (GRM4) gene was associated significantly with OS in our Chinese Han population; as with the other SNPs, however, no statistically significant difference was detected. Further analysis showed the association between rs1906953 and OS was independent of gender and age. The rs1906953 locus was not associated with Enneking stages or tumor location; however, it was associated significantly with OS metastasis and prognosis. The GRM4 gene polymorphism was associated with the susceptibility and metastasis of OS in a Chinese Han population.

Polymorphisms in miRNA processing genes and their role in osteosarcoma risk

BACKGROUND

The possible associations between genetic variants and osteosarcoma risk have been analyzed without conclusive results. Those studies were focused mainly on genes of biologically plausible pathways. However, recently, another pathway has acquired relevance in cellular transformation and tumorigenesis, the microRNA (miRNA) processing pathway. Dysregulation of the expression levels of genes in this pathway has been described in cancer. Consequently, single nucleotide polymorphisms (SNPs) in genes that codify for proteins involved in the miRNA processing pathway may affect miRNAs, and therefore their target genes, which might be associated with cancer development and progression. The aim of this study was to evaluate whether SNPs in miRNA processing genes confer predisposition to osteosarcoma.

PROCEDURE

We analyzed 72 SNPs in 21 miRNA processing genes in a total of 99 osteosarcoma patients and 387 controls.

RESULTS

A total of three SNPs were associated with osteosarcoma susceptibility. Interestingly, these SNPs were located in miRNA processing genes (CNOT1, CNOT4 and SND1) which are part of the RISC complex. Among them, the association of rs11866002 in CNOT1 was nearly significant after Bonferroni correction.

CONCLUSIONS

This study suggests that SNPs in RISC complex genes may be involved in osteosarcoma susceptibility, especially rs11866002 in CNOT1.

Germline TP53 variants and susceptibility to osteosarcoma

The etiologic contribution of germline genetic variation to sporadic osteosarcoma is not well understood. Osteosarcoma is a sentinel cancer of Li-Fraumeni syndrome (LFS), in which approximately 70% of families meeting the classic criteria have germline TP53 mutations. We sequenced TP53 exons in 765 osteosarcoma cases. Data were analyzed with χ(2) tests, logistic regression, and Cox proportional hazards regression models. We observed a high frequency of young osteosarcoma cases (age <30 years) carrying a known LFS- or likely LFS-associated mutation (3.8%) or rare exonic variant (5.7%) with an overall frequency of 9.5%, compared with none in case patients age 30 years and older (P < .001). This high TP53 mutation prevalence in young osteosarcoma cases is statistically significantly greater than the previously reported prevalence of 3% (P = .0024). We identified a novel association between a TP53 rare variant and metastasis at diagnosis of osteosarcoma (rs1800372, odds ratio = 4.27, 95% confidence interval = 1.2 to 15.5, P = .026). Genetic susceptibility to young onset osteosarcoma is distinct from older adult onset osteosarcoma, with a high frequency of LFS-associated and rare exonic TP53 variants.

Homologous Recombination Repair Polymorphisms and the Risk for Osteosarcoma

Background

DNA repair mechanisms are essential for maintaining genome stability, and genetic variability in DNA repair genes may contribute to cancer susceptibility. Our aim was to evaluate the influence of polymorphisms in the homologous recombination repair genes XRCC3, RAD51, and NBN on the risk for osteosarcoma.

Methods

In total, 79 osteosarcoma cases and 373 controls were genotyped for eight single nucleotide polymorphisms (SNPs) in XRCC3, RAD51, and NBN. Logistic regression was used to determine the association of these SNPs with risk for osteosarcoma.

Results

None of the investigated SNPs was associated with risk for osteosarcoma in the whole cohort of patients, however, in patients diagnosed before the age of thirty years XRCC3 rs861539 C>T and NBN rs1805794 G>C were associated with significantly decreased risk for osteosarcoma (P=0.047, OR=0.54, 95% CI=0.30–0.99 and P=0.036, OR=0.42, 95% CI=0.19–0.94, respectively). Moreover, in the carriers of a combination of polymorphic alleles in both SNPs risk for osteosarcoma was decreased even more significantly (P_trend=0.007). The risk for developing osteosarcoma was the lowest in patients with no wild-type alleles for both SNPs (P=0.039, OR=0.31, 95% CI=0.10–0.94).

Conclusions

Our results suggest that polymorphisms in homologous recombination repair genes might contribute to risk for osteosarcoma in patients diagnosed below the age of thirty years.

The association of MDM2 c.346G>A genetic variant with the risk of osteosarcoma in Chinese

Previous studies suggest that the MDM2 gene is one of the most important candidate genes for influencing the risk of osteosarcoma. This study aims to investigate the potential association of MDM2 c.346G>A genetic variant with the risk of osteosarcoma in Chinese. A total of 738 subjects were recruited in this study. The genotypes of MDM2 c.346G>A genetic variant were detected by the created restriction site-polymerase chain reaction. Our data suggest that the MDM2 c.346G>A genetic variant is associated with the increased risk of osteosarcoma in the homozygote comparison (AA vs. GG: odds ratio [OR]=2.36, 95% confidence interval [CI] 1.30-4.28, χ2=8.35, p=0.004), recessive model (AA vs.

GA/GG

OR=2.32, 95% CI 1.30-4.13, χ2=8.50, p=0.004), and allele comparison (A vs. G: OR=1.27, 95% CI 1.01-1.60, χ2=4.34, p=0.037). Results from this study indicated that the allele-A and genotype-AA of MDM2 c.346G>A genetic variant could be an increased risk factor for the susceptibility to osteosarcoma and might be used as a potential molecular marker for evaluating the risk of osteosarcoma.

Impact of MDM2 gene polymorphism on sarcoma risk

A T>G single nucleotide polymorphism (SNP, rs2279744) of the MDM2 gene has been investigated in sarcoma community, but the findings are conflicting. This study was designed to well define the relationship between SNP rs2279744 and sarcoma risk. We did a systematic computerized search of the PubMed, Web of Science, and Science Direct databases to identify the human case-control studies investigating the relationship between SNP rs2279744 and sarcoma risk with complete genetic data. Pooled odds ratios (ORs) were calculated with the Mantel-Haenszel fixed-effect model or the DerSimonian and Laird random effects model to estimate the risk of sarcoma. Overall analysis included five independent studies. On the whole, the T/G genotype or the combined G/G and T/G genotypes appeared to be associated with approximately 1.40-fold higher risk of sarcoma relative to the T/T genotype (T/G vs. T/T: OR 1.33, 95% CI 1.00-1.77; G/G + T/G vs. T/T: OR 1.42, 95% CI 1.08-1.85). We noted that the Caucasian populations showed a similarly increased risk of sarcoma ascribed to the carriage of the same genotypes (T/G vs. T/T: OR 1.41, 95% CI 1.05-1.90; G/G + T/G vs. T/T: OR 1.49, 95% CI 1.13-1.97). This meta-analysis provides evidence that MDM2 SNP rs2279744 may be significantly associated with increased risk of sarcoma in Caucasian individuals.

Quantitative assessment of the association between HDMX polymorphism and sarcoma

To investigate the effects of the HDMX polymorphism on sarcoma risk. Relevant studies were identified by searching the PubMed, Embase, and Web of Science databases. Data were extracted by two independent investigators. Odds ratios (ORs) and 95 % confidence intervals (CIs) were calculated using a fixed-effects model to assess the association between the HDMX polymorphism and sarcoma risk. We also conducted heterogeneity test, sensitivity analysis, and publication bias test. A meta-analysis of four published case-control studies involving 1,115 subjects (379 cases and 736 controls) showed no statistical association between the HDMX polymorphism and sarcoma risk (ORTT vs. GG 0.88, 95 % CI 0.68-1.14, P heterogeneity 0.819; ORTT + TG vs. GG 0.95, 95 % CI 0.79-1.15, P heterogeneity 0.937; ORTT vs. TG + GG 0.82, 95 % CI 0.65-1.04, P heterogeneity 0.589; ORT allele vs. G allele 0.91, 95 % CI 0.79-1.05, P heterogeneity 0.727; ORTG vs. GG 0.95, 95 % CI 0.74-1.22, P heterogeneity = 0.869). This null result did not alter when data were stratified according to ethnicity. Our meta-analysis indicates that the HDMX polymorphism is unlikely to contribute to individual susceptibility to sarcoma.

Effects of murine double minute 2 polymorphisms on the risk and survival of osteosarcoma: a systemic review and meta-analysis

Murine double minute 2 (MDM2) plays an important role in the carcinogenesis of many cancers including osteosarcoma. We performed a systemic review and meta-analysis to assess the effects of MDM2 polymorphisms on osteosarcoma risk and survival of patients with osteosarcoma. PubMed, Web of Science, and Wanfang databases were searched for eligible studies on the associations of MDM2 polymorphisms with osteosarcoma risk and survival of patients with osteosarcoma. Pooled odds ratio (OR) or hazard ratio (HR) with 95 % confidence intervals (95 % CIs) was used to assess the effects of MDM2 polymorphisms on osteosarcoma risk and survival of patients with osteosarcoma. Overall, MDM2 rs2279744 polymorphism was associated with a risk of osteosarcoma (allele model, OR = 1.60, 95 % CI 1.23-2.07, P < 0.001; codominant model, OR = 2.47, 95 % CI 1.46-4.19, P = 0.001; recessive model, OR = 2.13, 95 % CI 1.32-3.46, P = 0.002; dominant model, OR = 1.61, 95 % CI 1.12-2.33, P = 0.01). MDM2 rs1690916 polymorphism was also associated with a risk of osteosarcoma (OR = 0.60, 95 % CI 0.46-0.77, P < 0.001). However, MDM2 rs2279744 polymorphism was not associated with the overall survival of patients with osteosarcoma (codominant model, HR = 1.01, 95 % CI 0.53-1.91, P = 0.98; recessive model, HR = 1.07, 95 % CI 0.54-2.11, P = 0.85; dominant model, HR = 1.04, 95 % CI 0.65-1.66, P = 0.87). The meta-analysis suggests that MDM2 polymorphisms have some effects on the risk of osteosarcoma but have no effect on the survival of patients with osteosarcoma. Future studies are needed to further assess the effects of MDM2 polymorphisms on the risk and survival of osteosarcoma.

Association of the vascular endothelial growth factor (VEGF) gene single-nucleotide polymorphisms with osteosarcoma susceptibility in a Chinese population

Osteosarcoma (OS) is the most common bone malignancy worldwide. The vascular endothelial growth factor (VEGF) gene plays an important role in the pathogenesis of OS. The objective of this study aimed to detect the potential association between VEGF genetic polymorphisms and OS susceptibility in Chinese Han population. We recruited 330 OS patients and 342 cancer-free controls in this case-control study. Three single-nucleotide polymorphisms (SNPs) (-634 G > C, +936 C > T, and +1612 G > A) of the VEGF gene were investigated by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method and confirmed by direct DNA sequencing. Among these SNPs, we found that the genotypes/alleles of +936 C > T were statistically associated with the increased risk of OS (TT versus (vs.) CC: OR = 2.70, 95% CI 1.34-5.45, χ(2) = 8.2271, p = 0.0041; T vs. C: OR = 1.31, 95% CI 1.02-1.68, χ(2) = 4.3861, p = 0.0362). The T allele and TT genotype of +936 C > T could be factors that increase the risk for susceptibility to OS. The results from this study suggest that VEGF genetic variants are potentially related to OS susceptibility in Chinese Han population and might be used as molecular markers for assessing OS susceptibility.

Polymorphisms in the MDM2 gene and risk of malignant bone tumors: a meta-analysis

There are several studies published to assess the associations of murine double minute 2 (MDM2) genetic polymorphisms with risk of malignant bone tumors, but they reported contradictory results and failed to confirm a strong and consistent association. To assess the evidence regarding the associations of MDM2 genetic polymorphisms with the risk of malignant bone tumors, we conducted a meta-analysis of epidemiological studies. The pooled odds ratio (OR) with its 95% confidence intervals (95% CI) was used to assess these possible associations. Four studies with a total of 3,958 individuals were finally included the meta-analysis. Meta-analysis of two studies on MDM2 SNP309 polymorphism showed that MDM2 SNP309 polymorphism was associated with an increased risk of malignant bone tumors (G versus T: OR = 1.72, 95% CI 1.35-2.20, P < 0.001; GG versus TT: OR = 2.64, 95% CI 1.59-4.39, P < 0.001; GG/GT versus TT: OR = 1.87, 95% CI 1.33-2.62, P < 0.001; GG versus TT/GT: OR = 2.20, 95% CI 1.38-3.51, P = 0.001). Meta-analysis of those two studies on MDM2 rs1690916 polymorphism showed that MDM2 rs1690916 minor allele A was associated with decreased risk of malignant bone tumors (OR = 0.60, 95% CI 0.46-0.77, P < 0.001). Meta-analyses of available data show that there are significant associations of MDM2 SNP309 polymorphism and MDM2 rs1690916 polymorphism with malignant bone tumors.

Genome-wide association study identifies two susceptibility loci for osteosarcoma

Osteosarcoma is the most common primary bone malignancy of adolescents and young adults. In order to better understand the genetic etiology of osteosarcoma, we performed a multi-stage genome-wide association study (GWAS) consisting of 941 cases and 3,291 cancer-free adult controls of European ancestry. Two loci achieved genome-wide significance: rs1906953 at 6p21.3, in the glutamate receptor metabotropic 4 [GRM4] gene (P = 8.1 ×10^-9), and rs7591996 and rs10208273 in a gene desert on 2p25.2 (P = 1.0 ×10^-8 and 2.9 ×10^-7). These two susceptibility loci warrant further exploration to uncover the biological mechanisms underlying susceptibility to osteosarcoma.

Ewing Sarcoma: influence of TP53 Arg72Pro and MDM2 T309G SNPs

The Ewing Sarcoma is an important tumor of bone and soft tissue. The SNPs Arg72Pro of TP53 and T309G of MDM2 have been associated with many cancer types and have been differently distributed among populations worldwide. Based on a case-control design, this study aimed to assess the role of these SNPs in 24 Ewing Sarcoma patients, compared to 91 control individuals. DNA samples were extracted from blood and genotyped for both SNPs by PCR-RFLP and confirmed by DNA sequencing. The results showed an association between the G allele of the T309G and Ewing Sarcoma (P=0.02). Comparing to the TT carriers, the risk of G allele carriers was 3.35 (95% CI=1.22-9.21) with P=0.02. At the genotypic level, an association of the TT genotype with the control group (P=0.03) was found. Comparing to the TT genotype, the risk of TG and GG was 2.97 (95% CI=1.03-8.58) with P=0.04 and 5.00 (95% CI=1.23-20.34) with P=0.02, respectively. No associations regarding the Arg72Pro SNP were found. Considering that the T309G has been associated with several types of cancer, including sarcomas, our results indicate that this SNP may also be important to Ewing Sarcoma predisposition.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Association analysis between genetic variants of MDM2 gene and osteosarcoma susceptibility in Chinese

Osteosarcoma (OS) is the most common pediatric bone malignancy worldwide. The MDM2 gene is an important candidate gene for influencing the susceptibility to OS. The objective of this study aimed to detect the potential association between MDM2 genetic variants and OS susceptibility in Chinese Han population. We recruited 415 OS patients and 431 cancer-free controls in this case-control study. The c.44C>T and c.1002T>C genetic variants in MDM2 gene were investigated using created restriction site-polymerase chain reaction (CRS-PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP), respectively. We found that the genotypes/alleles of c.44C>T and c.1002T>C were statistically associated with the increased risk of OS (for c.44C>T, TT versus (vs.) CC: OR = 2.43, 95% CI 1.49-3.95, p < 0.001; T vs. C: OR = 1.36, 95% CI 1.11-1.67, p = 0.003; for c.1002T>C, CC vs. TT: OR = 2.38, 95% CI 1.37-4.13, p = 0.002; C vs. T: OR = 1.27, 95% CI 1.02-1.56, p = 0.030). The T allele and TT genotype of c.44C>T and C allele and CC genotype of c.1002T>C could be increased risk factors for the susceptibility to OS. Results from this study suggest that MDM2 genetic variants are potentially related to OS susceptibility in Chinese Han population, and might be used as molecular markers for assessing OS susceptibility.

Combined effects of p53 and MDM2 polymorphisms on susceptibility and surgical prognosis in hepatitis B virus-related hepatocellular carcinoma

The p53 signaling pathway works as a potent barrier to tumor progression. Two single nucleotide polymorphisms (SNPs) in the gene loci of p53 pathway, p53 codon 72 Arg72Pro and MDM2 SNP309 (T > G), have been shown to cause perturbation of p53 function, but the effect of the two SNPs on the risk of hepatocellular carcinoma (HCC) remains inconsistent. This study investigated the influence of combined p53 Arg72Pro and MDM2 SNP309 on the risk of developing HCC in patients with chronic hepatitis B virus infection, and evaluated the significance of the two combined SNPs on patient prognosis. In total, 350 HCC patients, 230 non-HCC patients, and 96 healthy controls were genotyped for the p53 Arg72Pro and MDM2 SNP309. The combined p53 Pro/Pro and MDM2 G/G genotype was significantly associated with HCC risk (P = 0.047). Multivariate analysis indicated that combined p53 Pro/Pro and MDM2 G/G genotype was an independent factor affecting recurrence and survival (P < 0.05). Patients with combined p53 Pro/Pro and MDM2 G/G genotypes had a poorer prognosis than other genotypes, P < 0.01 for both disease-free survival (DFS) and overall survival (OS). DFS and OS rates also differed significantly between Barcelona Clinic Liver Cancer (BCLC) stage A patients with combined p53 Pro/Pro and MDM2 G/G and other genotypes (P < 0.05). Thus, the combined p53 Pro/Pro and MDM2 G/G genotype is associated with increased risk of developing HCC and is an independent adverse prognostic indicator in early stage HCC.

Correlation of TP53 and MDM2 genotypes with response to therapy in sarcoma

BACKGROUND

Relatively few sarcomas harbor TP53 (tumor protein p53) mutations, but in many cases, amplification of MDM2 (murine double minute 2) effectively inactivate p53. The p53 pathway activity can also be affected by normal genetic variation.

METHODS

The mutation status of TP53 and expression of MDM2, TP53, and their genetic variants SNP309 and R72P (Arg72Pro) were investigated in 125 sarcoma patient samples and 18 sarcoma cell lines. Association of the different genotypes and gene aberrations with chemotherapy response and survival, as well as response to MDM2 antagonists in vitro was evaluated.

RESULTS

Twenty-two percent of the tumors had mutant TP53 and 20% MDM2 gene amplification. Patients with wild-type TP53 (TP53(Wt) ) tumors had improved survival (P < .001) and TP53(Wt) was an independent prognostic factor (hazard ratio = 0.41; 95% confidence interval = 0.23-0.74; P = .03). Interestingly, there was a trend toward longer time to progression after chemotherapy for tumors with the apoptosis-prone p53 variant R72 (P = .07), which was strongest with doxorubicin/ifosfamide-based regimens (P = .01). Liposarcomas had low R72 frequency (33% versus 56%), but increased levels of MDM2 and MDM4 (51% and 11%, P < .001). MDM2 overexpression on a TP53(Wt) background predicted better response to MDM2 antagonist Nutlin-3a, irrespective of R72P or SNP309 status.

CONCLUSIONS

Improved survival after chemotherapy was found in patients with TP53(Wt) tumors harboring the R72 variant. MDM2 overexpression in TP53(Wt) tumors predicted good response to MDM2 antagonists, irrespective of R72P or SNP309 status. Thus, detailed TP53 and MDM2 genotype analyses prior to systemic therapy are recommended.

The p53 codon 72 PRO/PRO genotype may be associated with initial central visual field defects in caucasians with primary open angle glaucoma

Background

Loss of vision in glaucoma is due to apoptotic retinal ganglion cell loss. While p53 modulates apoptosis, gene association studies between p53 variants and glaucoma have been inconsistent. In this study we evaluate the association between a p53 variant functionally known to influence apoptosis (codon 72 Pro/Arg) and the subset of primary open angle glaucoma (POAG) patients with early loss of central visual field.

Methods

Genotypes for the p53 codon 72 polymorphism (Pro/Arg) were obtained for 264 POAG patients and 400 controls from the U.S. and in replication studies for 308 POAG patients and 178 controls from Australia (GIST). The glaucoma patients were divided into two groups according to location of initial visual field defect (either paracentral or peripheral). All cases and controls were Caucasian with European ancestry.

Results

The p53-PRO/PRO genotype was more frequent in the U.S. POAG patients with early visual field defects in the paracentral regions compared with those in the peripheral regions or control group (p = 2.7×10⁻⁵). We replicated this finding in the GIST cohort (p  = 7.3×10⁻³, and in the pooled sample (p = 6.6×10⁻⁷) and in a meta-analysis of both the US and GIST datasets (1.3×10⁻⁶, OR 2.17 (1.58–2.98 for the PRO allele).

Conclusions

These results suggest that the p53 codon 72 PRO/PRO genotype is potentially associated with early paracentral visual field defects in primary open-angle glaucoma patients.

High incidence of microsatellite instability and loss of heterozygosity in three loci in breast cancer patients receiving chemotherapy: a prospective study

Background

The aim of the study was to evaluate potential chemotherapy-induced microsatellite instability, loss of heterozygosity, loss of expression in mismatch repair proteins and associations with clinical findings in breast cancer patients, especially resistance to chemotherapy and/or development of other tumors in the four years following chemotherapy treatment.

Methods

A comprehensive study of chemotherapy-related effects with a follow-up period of 48 months post treatment was conducted. A total of 369 peripheral blood samples were collected from 123 de novo breast cancer patients. Microsatellite instability and loss of heterozygosity in five commonly used marker loci (including Tp53-Alu of the tumor suppressor gene TP53) were analyzed in blood samples. Sampling was conducted on three occasions; 4–5 weeks prior to the first chemotherapy session (pre-treatment), to serve as a baseline, followed by two consecutive draws at 12 weeks intervals from the first collection. Mismatch repair protein expression was evaluated in cancer tissues using immunohistochemistry for three mismatch-repair related proteins.

Results

A total of 70.7% of the patients showed microsatellite instability for at least one locus, including 18.6% marked as high-positive and 52.1% as low-positive; 35.8% showed loss of heterozygosity in addition to microsatellite instability, while 29.3% exhibited microsatellite stability. The following incidence rates for microsatellite instability and loss of heterozygosity were detected: 39.1% positive for Tp53-Alu, 31.1% for locus Mfd41, and 25.3% for locus Mfd28. A higher occurrence of loss of heterozygosity was noted with alleles 399 and 404 of Tp53-Alu. The mismatch repair protein expression analysis showed that the chemotherapy caused a loss of 29.3% in hMLH1 expression, and 18.7% and 25.2% loss in hMSH2 and P53 expression, respectively. A strong correlation between low or deficient hMSH2 protein expression and occurrence of mismatch repair/loss of heterozygosity events in Mfd41, Tp53-Alu, and Mfd28 was evident. A significant association between mismatch repair/loss of heterozygosity and incidence of secondary tumors was also established.

Conclusion

Our results suggest that microsatellite instability, loss of heterozygosity, and deficiency in mismatch repair may serve as early prognostic factors for potential chemotherapy-related side effects in breast cancer patients.

Orthopaedic research in italy: state of the art

The most significant results in experimental and clinical orthopaedic research in Italy within the last three years have been primarily in major congenital diseases, bone tumors, regenerative medicine, joint replacements, spine, tendons and ligaments. The data presented in the following discussion is comparable with leading international results, highlighting Italian orthopaedic research excellemce as well as its shortcomings.

MDM2 SNP309 contributes to tumor susceptibility: a meta-analysis

The potentially functional polymorphism, SNP309, in the promoter region of MDM2 gene has been implicated in cancer risk, but individual published studies showed inconclusive results. To obtain a more precise estimate of the association between MDM2 SNP309 and risk of cancer, we performed a meta-analysis of 70 individual studies in 59 publications that included 26,160 cases with different types of tumors and 33,046 controls. Summary odds ratios (OR) and corresponding 95% confidence intervals (CIs) were estimated using fixed- and random-effects models when appropriate. Overall, the variant genotypes were associated with a significantly increased cancer risk for all cancer types in different genetic models (GG vs. TT: OR, 1.123; 95% CI, 1.056-1.193; GG/GT vs. TT: OR, 1.028; 95% CI, 1.006-1.050). In the stratified analyses, the increased risk remained for the studies of most types of cancers, Asian populations, and hospital- /population-based studies in different genetic models, whereas significantly decreased risk was found in prostate cancer (GG vs. TT: OR, 0.606; 95% CI, 0.407-0.903; GG/GT vs. TT: OR, 0.748; 95% CI, 0.579-0.968). In conclusion, the data of meta-analysis suggests that MDM2 SNP309 is a potential biomarker for cancer risk.

A comprehensive candidate gene approach identifies genetic variation associated with osteosarcoma

BACKGROUND

Osteosarcoma (OS) is a bone malignancy which occurs primarily in adolescents. Since it occurs during a period of rapid growth, genes important in bone formation and growth are plausible modifiers of risk. Genes involved in DNA repair and ribosomal function may contribute to OS pathogenesis, because they maintain the integrity of critical cellular processes. We evaluated these hypotheses in an OS association study of genes from growth/hormone, bone formation, DNA repair, and ribosomal pathways.

METHODS

We evaluated 4836 tag-SNPs across 255 candidate genes in 96 OS cases and 1426 controls. Logistic regression models were used to estimate the odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Twelve SNPs in growth or DNA repair genes were significantly associated with OS after Bonferroni correction. Four SNPs in the DNA repair gene FANCM (ORs 1.9-2.0, P = 0.003-0.004) and 2 SNPs downstream of the growth hormone gene GH1 (OR 1.6, P = 0.002; OR 0.5, P = 0.0009) were significantly associated with OS. One SNP in the region of each of the following genes was significant: MDM2, MPG, FGF2, FGFR3, GNRH2, and IGF1.

CONCLUSIONS

Our results suggest that several SNPs in biologically plausible pathways are associated with OS. Larger studies are required to confirm our findings.

Using epidemiology and genomics to understand osteosarcoma etiology

Osteosarcoma is a primary bone malignancy that typically occurs during adolescence but also has a second incidence peak in the elderly. It occurs most commonly in the long bones, although there is variability in location between age groups. The etiology of osteosarcoma is not well understood; it occurs at increased rates in individuals with Paget disease of bone, after therapeutic radiation, and in certain cancer predisposition syndromes. It also occurs more commonly in taller individuals, but a strong environmental component to osteosarcoma risk has not been identified. Several studies suggest that osteosarcoma may be associated with single nucleotide polymorphisms in genes important in growth and tumor suppression but the studies are limited by sample size. Herein, we review the epidemiology of osteosarcoma as well as its known and suspected risk factors in an effort to gain insight into its etiology.

Genetic variation at chromosome 8q24 in osteosarcoma cases and controls

Osteosarcoma is a primary bone malignancy that typically occurs during the pubertal growth spurt. Only a few small association studies have evaluated common germ line variation in individuals with osteosarcoma. The 8q24 chromosomal region contains several loci that are associated with risk of many different cancers. We conducted an association study of common single-nucleotide polymorphisms (SNPs) across 8q24 to explore the role this region may play in osteosarcoma risk. We genotyped 214 tag SNPs in 99 osteosarcoma cases and 1430 controls (65 controls from a hospital-based case-control study and 1365 controls from a population-based study). Additive, dominant and recessive genetic models were evaluated using unconditional logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Analyses of nine SNPs previously associated with cancer did not show strong statistically significant associations. Of the remaining 205 SNPs, 7 were statistically significant (P </= 0.05) in one or more genetic models; the most significant association was observed for the additive effect of the minor allele at rs896324 (OR 1.75, 95% CI 1.13-2.69, P = 0.01). This study suggests that several SNPs in 8q24 may be associated with osteosarcoma, but the susceptibility observed was modest. Future large studies of osteosarcoma genetic risk factors are warranted to improve our understanding of the genetic contribution to this cancer of adolescents and young adults.

Single-nucleotide polymorphisms in the p53 signaling pathway

The p53 tumor suppressor pathway is central both in reducing cancer frequency in vertebrates and in mediating the response of commonly used cancer therapies. This article aims to summarize and discuss a large body of evidence suggesting that the p53 pathway harbors functional inherited single-nucleotide polymorphisms (SNPs) that affect p53 signaling in cells, resulting in differences in cancer risk and clinical outcome in humans. The insights gained through these studies into how the functional p53 pathway SNPs could help in the tailoring of cancer therapies to the individual are discussed. Moreover, recent work is discussed that suggests that many more functional p53 pathway SNPs are yet to be fully characterized and that a thorough analysis of the functional human genetics of this important tumor suppressor pathway is required.