Briefly, human IGR-N-91 neuroblasts derived from an involved BM collected from a stage 4 disease >1-year-old NB patient were injected subcutaneously into nude mice to give rise to a stage 4 disease.
To this end, we compared the gene expression profiles of metastatic-derived neuroblasts (BM and Myoc) with stage 4 disease profiles from the IGR-N-91 experimental human NB model (9,10) using Agilent long oligonucleotide arrays with 8 arrays (see the section "Microarray Experiments", above).
In this model, although established metastatic neuroblasts exhibit a similar MYCN amplification compared with stage 4 disease-derived neuroblasts, a considerably higher MYCN expression is observed that is consistent with their aggressive biological behavior (10).
The higher differentially up-regulated gene in this set is GALNTI3 (12-fold higher in metastatic neuroblasts compared with primary tumor, P = 9.
To determine whether GALNTI3 might be a potential marker for NB dissemination, we tested for malignant neuroblasts in BM from patients with various stages of NB by measuring GALNTI3 expression.
However, in spite of specific GALNTI3 mRNA detection, the lower limit of the detection of analyses appears less than optimal, and we conclude, therefore, that GALNTI3 expression will be suitable only for detection of malignant neuroblasts at diagnosis or relapse.