Oncogenes and tumour suppressor genes in first trimester human fetal gonadal development

Tumour suppressor genes and oncogenes that control proliferation and apopto sis are known to play an important role in embryogenesis, second trimester fetal oocyte loss, adult ovulation, and in adult male testicular degenerati on. We have examined tumour suppressor genes, oncogenes and oestrogen recep tors during first trimester human gonadal differentiation to investigate th eir role at this crucial phase in development. Immunohistochemistry was use d to localize the gene products of Bcl-2, c-erB-2. c-myc, p53, nm23 and oes trogen receptor. As gonadal development occurred at 6-12 weeks gestation, a changing pattern of expression was observed that varied in different cell types. The oestrogen receptor was not present in oogonia, spermatogonia and supporting cells during the first trimester. This study highlights the imp ortance of oncogenes and tumour suppressor genes in first trimester gonadal development.