PHOX2B and neoplasm: Furthermore, wild-type as well as mutated transcripts of ALK and PHOX2B, and also the wild type transcript of its paralogue PHOX2A, have been found to be overexpressed in the vast majority of NB cell lines and tumor samples analyzed so far [3], [2], [14], [21], [27], [33], thus providing strong indications that up-regulation of these genes is involved in NB molecular pathogenesis.