OCT4 and SALL4 can be used with caution as second-tier normalizers when determining changes in gene expression in germ cells and germ cell tumour components, but the relative transcript abundance appears variable between different germ cell tumour types.
The aberrant expression and distribution of the OCT-4 transcription factor in seminomas may provide some important clues concerning the cell transformation between germ line stem cells (like PGC) and testicular germ cell tumors.
TSPY protein localized with established germ cell tumor markers, such as the placental alkaline phosphatase, c-KIT, and OCT3/4, in the same tumor cells of both gonadoblastoma and adjacent carcinoma in situ, the precursor for germ cell tumors.
The abundance of factors associated with pluripotency (NANOG and OCT-3/4) and undifferentiated state (AP-2gamma) may explain the remarkable pluripotency of germ cell neoplasms, which are capable of differentiating to various somatic tissue components of teratomas.
Recently, major progress has been made in identifying gene-products related to germ cell tumor development (testis-specific protein-Y encoded and octamer binding transcription factor 3/4) and in recognizing early changes of germ cells (maturation delay, preneoplastic lesions, and in situ neoplasia).
In this issue of Cancer Cell, Gidekel et al. demonstrate that Oct-4, a member of the POU class of homeobox genes, is a critical player in the genesis of testicular germ cell tumors.
Dmrt1 (doublesex and mab-3 related transcription factor (1) is a regulator of testis development in vertebrates that has been implicated in testicular germ cell tumors of mouse and human.
KITLG expression was consistently increased in the presence of PDE11A-inactivating defects, both at the RNA and protein levels, in familial testicular germ cell tumors.
Recent genome wide association studies have identified susceptibility loci for adult testicular germ cell tumors (GCT) near KITLG, SPRY4, BAK1, and DMRT1.
The abundance of factors associated with pluripotency (NANOG and OCT-3/4) and undifferentiated state (AP-2gamma) may explain the remarkable pluripotency of germ cell neoplasms, which are capable of differentiating to various somatic tissue components of teratomas.