Genome-wide association study identifies the GLDC/IL33 locus associated with survival of osteosarcoma patients.

Survival rates for osteosarcoma, the most common primary bone cancer, have changed little over the past three decades and are particularly low for patients with metastatic disease. We conducted a multi-institutional genome-wide association study (GWAS) to identify germline genetic variants associated with overall survival in 632 patients with osteosarcoma, including 523 patients of European ancestry and 109 from Brazil. We conducted a time-to-event analysis and estimated hazard ratios (HR) and 95% confidence intervals (CI) using Cox proportional hazards models, with and without adjustment for metastatic disease. The results were combined across the European and Brazilian case sets using a random-effects meta-analysis. The strongest association after meta-analysis was for rs3765555 at 9p24.1, which was inversely associated with overall survival (HR = 1.76; 95% CI 1.41-2.18, p = 4.84 × 10-7 ). After imputation across this region, the combined analysis identified two SNPs that reached genome-wide significance. The strongest single association was with rs55933544 (HR = 1.9; 95% CI 1.5-2.4; p = 1.3 × 10-8 ), which localizes to the GLDC gene, adjacent to the IL33 gene and was consistent across both the European and Brazilian case sets. Using publicly available data, the risk allele was associated with lower expression of IL33 and low expression of IL33 was associated with poor survival in an independent set of patients with osteosarcoma. In conclusion, we have identified the GLDC/IL33 locus on chromosome 9p24.1 as associated with overall survival in patients with osteosarcoma. Further studies are needed to confirm this association and shed light on the biological underpinnings of this susceptibility locus.

A new mutation in the hMSH2 gene in a Spanish Lynch syndrome family.

We report a new germline mutation in exon 13 of the hMSH2 gene (c.2081T>C; F694S) in a patient diagnosed with colorectal carcinoma. The patient's family fulfilled the clinical criteria of the Bethesda guidelines for Lynch syndrome. The segregation analysis determined the presence of the mutation in the proband's mother (breast cancer younger than 40 years old) and in two healthy daughters. The mutation was not present in 116 normal controls screened. The medical implications for the carrier relatives are discussed.

Methotrexate in pediatric osteosarcoma: response and toxicity in relation to genetic polymorphisms and dihydrofolate reductase and reduced folate carrier 1 expression.

OBJECTIVE: To determine the influence of the genotype and the level of expression of different enzymes involved in folate metabolism on the response to and toxicity of high-dose methotrexate treatment in pediatric osteosarcomas. STUDY DESIGN: DHFR and Reduced folate carrier 1 (RFC1) semiquantitative expression was analyzed in 34 primary and metastatic osteosarcoma tissues by real-time polymerase chain reaction. The following polymorphisms were also analyzed in peripheral blood from 96 children with osteosarcoma and 110 control subjects: C677T, A1298C (MTHFR), G80A (RFC1), A2756G (MTR), C1420T (SHMT), the 28bp-repeat polymorphism, and 1494del6 of the TYMS gene. Treatment toxicity was scored after each cycle according to criteria from the World Health Organization. RESULTS: DHFR and RFC1 expression was lower in initial osteosarcoma biopsy specimens than in metastases (P = .024 and P = .041, respectively). RFC1 expression was moderately decreased in samples with poor histologic response to preoperative treatment (P = .053). Patients with osteosarcoma with G3/G4 hematologic toxicity were more frequently TT than CT/CC for C677T/MTHFR (P = .023) and GG for A2756G/MTR (P = .048 and P = .057 for gastrointestinal and hematologic toxicity, respectively). CONCLUSIONS: The role of C677T/MTHFR and A2756G/MTR on chemotherapy-induced toxicity should be further investigated in pediatric osteosarcomas receiving high-dose methotrexate. Altered expression of DHFR and RFC1 is a feasible mechanism by which osteosarcoma cells become resistant to methotrexate.

Serum Amyloid A concentration is increased in obese children and adolescents.

OBJECTIVE: To compare the circulating concentrations of the acute-phase protein serum amyloid A (SAA) in lean, overweight, and obese children and adolescents and analyze the influence of body fat. STUDY DESIGN: A total of 63 children and adolescents (65% girls) with an average age of 12.1 +/- 2.7 years (range, 6 to 18 years) were included in the study. Each child was classified on the basis of age- and sex-specific body mass index (BMI) percentile as normal weight (BMI <85th percentile; n = 17), overweight (BMI >/=85th and <95th percentiles; n = 26), or obese (BMI >/=95th percentile; n = 20). Body fat was estimated by air-displacement plethysmography. RESULTS: Both overweight and obese children exhibited significantly increased circulating SAA concentrations (log SAA: lean, 0.66 +/- 0.20; overweight, 0.83 +/- 0.29; obese, 0.96 +/- 0.21; P = .002) compared with the lean children. Significant correlations were found between log SAA and body fat (r = 0.48; P < .0001). In multiple linear regression analysis, log C-reactive protein (CRP) (P = .014) and body fat (P = .031) emerged as significant predictors of log SAA. CONCLUSIONS: Plasma SAA concentrations are elevated in overweight and obese children, being strongly related to adiposity and log CRP. This finding suggests that increased body fat may contribute to the development of a low-grade chronic proinflammatory state at an early age, possibly contributing to the obesity-associated cardiovascular disease risk.