One TMA section was also stained with H+E for evaluation by pathologists (CM +CT). Histologic features of the HB samples The sample cohort consists of 98 samples from 84 patients comprising 62 diagnostic tumour biopsies and 36 post-surgical specimens (both diagnostic and surgical specimens available in 14 cases). Histologic information was available for 91 samples. The Epigenetics inhibitor tumours were examined centrally and classified as either wholly epithelial (n = 33) or mixed epithelial and mesenchymal (n = 54). One tumour was diagnosed as hepatocellular carcinoma (fibrolamellar

type) and one as a small cell undifferentiated (SCUD). The epithelial component was further subtyped as pure fetal (n = 43), embryonal (n = 3) or mixed fetal and embryonal (n = 41). Two tumors were subtyped as macrotrabecular type. Focal anaplasia was seen in three tumors and cholangioblastic features in two tumors. Thirteen cases of osteoid formation were noted in the histology reports with additional osteoid formation in a post-chemotherapy sample that lacked osteoid in the diagnostic biopsy. Teratoid features were noted in seven samples. Clinical characteristics of patients for survival analysis Clinical information that classified patients into the two well-defined risk groups was available

for 71 patients in our cohort. Twenty-seven of these were high-risk and forty-four were standard risk. Of these 71 patients, nine were born with low birth weight. PRETEXT classification revealed that there were two PRETEXT stage 1 patients, twenty-two stage 2, thirty-one stage mTOR phosphorylation 3 and sixteen stage 4 patients. Only two patients had serum AFP levels of < 100 at diagnosis, making them high-risk. Eight and seven patients had portal vein and vena cava involvement respectively, and extrahepatic intra-abdominal disease was seen in three patients also making them high-risk cases.

Metastatic disease was present at diagnosis in thirteen children. Relapse or progression in five HR cases resulted in the death of four patients. In the standard-risk group there were six relapses leading to a single death from disease. Immunohistochemistry Briefly, 4 μm TMA slides were Carbohydrate deparaffinized with xylene and ethanol. Antigen retrieval was performed by pressure cooking for 2 minutes in citrate buffer pH6.0. Endogenous peroxidases were blocked with 0.3% hydrogen peroxide and non-specific binding was blocked with normal goat serum. Slides were incubated overnight at 4°C with primary antibodies: Y1234/5-c-Met at 1:300 dilution, Y654-β-catenin at 1:25 dilution and β-catenin at 1:200 (All from Abcam, Cambridge, UK). The EnVision HRP/DAB detection system (Dako, Glostrup, Denmark) was used to visualise the results. Slides were lightly counterstained with haematoxylin. All antibodies were optimized for use in IHC using breast tumour control tissue and the appropriate positive and negative PLX3397 in vitro controls were used.