PHOX2B As a Reliable Marker for Neuroblastoma in Tissue and Cytology Specimens

To investigate the diagnostic utility of immunohistochemistry for paired-like homeobox 2B (PHOX2B) expression in neuroblastomas (NBs) and tumors that mimic them, tissue samples (n = 229) from 157 cases of NB, 210 central nervous system tumors, and 170 extracranial non-NB solid tumors (n = 170) were immunostained for PHOX2B. Additionally, PHOX2B expression in 67 body fluid cytology specimens was analyzed. In tissue specimens, PHOX2B expression was positive in NBs, pheochromocytomas, and paragangliomas but negative in all of the other tumors evaluated. PHOX2B was detected by immunohistochemistry in 5 NB cytology specimens; all of the others were negative. These results suggest that PHOX2B may be a sensitive and specific immunohistochemical marker for the pathological diagnosis and differential diagnosis of NB in both tissue and cytology specimens.