Gene expression of TRK neurotrophin receptors in advanced neuroblastomas in Singapore--a pilot study

The clinical hallmark of neuroblastoma is heterogeneity. Biologically, ploidy and N-Myc amplification are currently the only 2 features used to define risk group and to determine therapy. Tyrosine kinase neurotrophin receptors (Trks, including TrkA, TrkB, and TrkC) are important in the clinical and biological behavior of neuroblastomas. The authors aim to study Trks gene expression in their local population of advanced neuroblastoma patients. Multiplex reverse transcriptase-polymerase chain reaction (RT-PCR) assay on the expression of TrkA, TrkB, TrkB-truncated, and TrkC was performed on a total of 19 advanced neuroblastoma archival tumors, diagnosed in KK Women's and Children's Hospital between 2003 and 2007. Of the 19 tumors investigated, Trks expression was present in 14 (73.6%) cases. Of these cases, 8 (42.1%), 10 (52.6%), 7 (36.8%), and 6 (31.6%) expressed TrkA, TrkB, TrkB-truncated, and TrkC receptor mRNAs, respectively. Subsequently, the authors compared Trks expression with N-Myc amplification status of the 19 patients. N-Myc was amplified in 5 (26.3%) of the cases. Within the non-N-Myc-amplified group, Trks expression was present in 9 (64%) of the 14 cases. The significant expression of Trk isoforms among advanced neuroblastoma cases as evident from this study support their role as possible risk assessment tools alongside N-Myc amplification status.