As part of this research, the team had determined that the four genes ?OCT 4, NANOG, STELLAR and GDF3-- play a role in prompting human embryonic stem cells to develop into primordial, or earliest-stage, germ cells. Three of these genes -- NANOG, STELLAR and GDF3 ?are located on chromosome 12, at a site designated 12p13.
Because seminoma cells resemble these early-stage cells in structure, and have duplications in genetic material on chromosome 12p13 that are associated with invasive seminoma (though no genes have been linked to the malignancy), the team had subsequently investigated two samples of seminomas, to see if the genes were expressed at elevated levels. They were, as was OCT 4.
The current study demonstrated that the four genes had elevated expressions in the nine seminoma samples examined, when compared with normal testis tissue. GDF3 was elevated in 90 percent of cases, OCT4 was elevated in 56 percent of cases and NANOG and STELLAR expression were elevated in 33 percent of cases.
The team also examined the relative expression of these genes, and four other genes that play an important role in normal testis, in the nine samples. OCT 4 and NANOG were the highest expressed genes in each of the seminoma samples.
The variability of the genes' expression within the very earliest stage of germ cell tumor progression, says Clark, "could tell us something about the potential for these tumors to metastasize."
Finally, they examined breast cancer tissue and normal breast tissue. While normal tissue did not express detectable levels of the genes, both the breast carcinoma cell lines and stage 3
Source:University of California - San Francisco