Biomarker Analysis in Paediatric Tumours Diagnosed within A Single Institution

The incidence of childhood cancers in Australia represents approximately 0.6% of all cancers diagnosed. It can therefore be challenging to undertake investigations of rare childhood tumours, especially those diagnosed within a single institution. As biological molecules in tissue samples degrade over time, biomarker expression may not be validly compared in samples stored for different lengths of time. Sample storage time could therefore significantly affect protein detection in childhood cancer samples of different ages, and therefore affect the results of comparative analyses. Informative neuroblastoma (NB) patient cohorts were identified for 1985-2005, an overall cohort of 174, and an analysis sub-cohort of 56 NB and ganglioneuroblastomas (GNB). Immunohistochemical (IHC) analyses were done on tissue microarrays using five different biomarkers with digital and visual IHC scoring. Significant inverse associations were identified between sample storage time and digital or visual IHC scores for NB84 in the archival TMA, for NSE and NB84 in the analysis TMA, and for TPD52 in the archival TMA. A significant difference in digital TPD52 IHC staining was measured in two NB differentiation groups, and significant differences between digital ALK and MGMT IHC scores were measured in stage 4 and non-stage 4 NB. A significant difference between serum NSE levels was also identified between stage 4 and non-stage 4 patients. Significant differences between digital and visual NSE or NB84 IHC staining were also identified in amplified and non-amplified MYCN gene status. Patients with high digital IHC scores for MGMT, low visual IHC scores for NSE and high visual scores for TPD52 showed significantly poor overall survival. Differential IHC staining of NSE, NB84, ALK, MGMT and TPD52 was visually identified in duplicate tissue cores for 15/46 NB cases. Genomic DNA was extracted from laser captured 6 NB cases and normal kidney tissue, followed by PCR amplification using TPD52 and ALK primers. No significant associations were measured between total yields of extracted DNA and LCM cutting areas or the age of FFPE specimens. The TPD52 product of was successfully PCR amplified from both positive control, NB and normal samples but the ALK products was only successful on a positive control

Therapeutic targeting of the MYC signal by inhibition of histone chaperone FACT in neuroblastoma

Amplification of the MYCN oncogene predicts treatment resistance in childhood neuroblastoma. We used a MYC target gene signature that predicts poor neuroblastoma prognosis to identify the histone chaperone FACT (facilitates chromatin transcription) as a crucial mediator of the MYC signal and a therapeutic target in the disease. FACT and MYCN expression created a forward feedback loop in neuroblastoma cells that was essential for maintaining mutual high expression. FACT inhibition by the small-molecule curaxin compound CBL0137 markedly reduced tumor initiation and progression in vivo. CBL0137 exhibited strong synergy with standard chemotherapy by blocking repair of DNA damage caused by genotoxic drugs, thus creating a synthetic lethal environment in MYCN-amplified neuroblastoma cells and suggesting a treatment strategy for MYCN-driven neuroblastoma