Expression of estrogen receptor exon 5 splicing variant (ER E5SV) mRNA in gynaecological cancers

Estrogen receptor exon 5 splicing variant (ER E5SV) mRNA has been found in tumours and the corresponding normal tissues, being transcriptionally active without ligand binding. Therefore, the expression of ER E5SV mRNA in gynaecological cancers was studied. The presence of ER E5SV mRNA was demonstrated in the normal ovary, uterine endometrium and cervix and their corresponding cancers. The ratio of ER E5SV/ER WT mRNA expression increased in some cases of metastatic tumour, but did not decrease in any case. Relative overexpression of ER E5SV mRNA might contribute to dominant positive properties and metastatic potential. Therefore, detection of ER E5SV mRNA abundance might be a useful indicator of metastatic potency in gynaecological cancers.