Preliminary study of oncogene expressions in endometrial cancers. Aberrant estrogen receptor gene and erbB-2...

We studied the expressions of aberrant epidermal growth factor receptor (EGFR) gene or erbB-2, which is highly homologous to EGFR gene, and erbA or estrogen receptor (ER) gene, which is highly homologous to erbA, as a preliminary study, to know which oncogene expressions are associated with the development of endometrial cancers. ErbB-2 mRNA lacked only extracellular domain (EX), suggesting the lack of downregulation of erbB-2 expression by a ligand, which led to regulated tyrosine kinase activity. Mutated DNA binding domain of ER mRNA were found in 3 of the 13 cases, suggesting the promotion disorder of estrogen-inducible proteins in these 3 endometrial cancers. The behavior of aberrant erbB-2 and ER gene co-expressions is considered of similar to that of erbA and erbB co-expressions in the chicken introduced by the avian erythroblastosis virus, which leads to the development of erythroblastosis in the chick, and seems to be associated with the development of endometrial cancer.