NTRK3 and neoplasm: C2B2 (MAML3) PCPG had low expression of the chromaffin cell markers CARTPT and DLK1 but high expression of early neuroblast markers including ALK, RET, and NTRK3. A subset of PCPG had expression of bridge cell markers (ASCL1, CDH9, ERBB4), including tumors of the C2B1 subtype, for example, a tumor with an H3F3A mutation (E326) and another without a known gene driver (E033)50.