1+2: low grade; 3+4: high grade. Immunohistochemistry for biopsies Sections were cut from

formalin-fixed, paraffin-embedded granulation tissue. They were hydrated through graded alcohols. For antigen unmasking, sections were treated in trypsin solution for 10 min at 37°C. Sections were then washed with deionized water and incubated with 3% H2O2 for 5 min. They were incubated in anti-IDH1 mAb (protein technology group, USA) or anti-p53 mAb (Santa Cruz, CA, USA) for 1 h at room temperature, followed by secondary antibody and peroxidase-conjugated Sorafenib manufacturer strepavidin-biotin complex (Santa Cruz, CA, USA) at 37°C for 30 min. Immunoreactivity was visualized with diaminobenzidine (DAB) (Zymed, South San Francisco, CA). Negative controls were obtained by omitting the primary antibody. Evaluation of immunohistochemistry The slides were evaluated under the microscope. The percentage of cells showing positive nuclear staining for p53 was calculated by reviewing the entire spot. For IDH1, cytoplasmic immunostaining was considered to be positive. The staining

patterns were classified into scales on the percentage of cells with positive staining [26, 27]: 0, absence of nuclear (or cytoplasmic) stained cell; 1, <10% positive cells; 2, 10-25% positive cells; 3, 26-50% positive cells; 4, 51-75% positive cells; 5, >75% positive cells. For statistical analysis, osteosarcoma patients were also grouped as either low-staining group (scale 0-3: positive staining ≤ 50%) or high-staining group (scale 4, 5: positive staining >50%). Biopsy Stained less than 10% was considered as a negative result, buy PLX-4720 while stained more than 10% was considered as a positive

one. At least 5 separated foci of neoplastic infiltration in each biopsy were analyzed. Assessment of Immunostaining intensity was completed by three independent observers. RVX-208 Slides were scanned using a microscopy (Carl Zeiss AG, Germany), images were recorded using a digital camera (DC 500, Leica) and the Leica FW 4000 software and images were processed using Adobe Photoshop. Statistical analysis All statistical analyses were performed using the SPSS 13.0 software package for Windows (SPSS Inc., Chicago, IL, USA). The values for the description of the statistical significance of IDH1 or p53 expression in different osteosarcoma cell lines were calculated by independent, two-tailed Student’s t-tests after the Levine’s Test for Equality of Variances. Mann-Whitney U was used for unnormal continuous variables. Categorical variables were analyzed by the Pearson Chis-square test and Fisher’s exact test. Associations were assessed by Pearson correlation coefficient for normal data or Spearman’s correlation coefficient for nonnormal data. Kaplan-Meier test was used for analysis of survival versus IDH1 and survival versus p53 expression. P < 0.05 was considered as statistically significant. P < 0.