To Be or Not to Be a Germ Cell: The Extragonadal Germ Cell Tumor Paradigm

In the human embryo, the genetic program that orchestrates germ cell specification involves the activation of epigenetic and transcriptional mechanisms that make the germline a unique cell population continuously poised between germness and pluripotency. Germ cell tumors, neoplasias originating from fetal or neonatal germ cells, maintain such dichotomy and can adopt either pluripotent features (embryonal carcinomas) or germness features (seminomas) with a wide range of phenotypes in between these histotypes. Here, we review the basic concepts of cell specification, migration and gonadal colonization of human primordial germ cells (hPGCs) highlighting the analogies of transcriptional/epigenetic programs between these two cell types.

Automated summary

In the human embryo, the genetic program responsible for germ cell specification involves a balance between epigenetic and transcriptional mechanisms, resulting in a unique cell population that can exhibit both germness and pluripotency features. Germ cell tumors, originating from fetal or neonatal germ cells, maintain this balance and can display a wide range of phenotypes with either pluripotent or germness characteristics. This review highlights the similarities in transcriptional and epigenetic programs between human primordial germ cells and germ cell tumors.