Detection of oestrogen receptor variants in endometrium, myometrium, leiomyoma and peripheral blood mononuclear cells: comparison to variants present in breast cancer.
Oestradiol has mitogenic and regulatory effects on various organs and cells, mediated mainly by its nuclear receptor (ER). The presence of aberrant ER forms in Oestrogen-dependent tumours has been discussed in correlation with tumour progression. ER variants, generated by alternative splicing, have been detected in human breast cancer, but also in normal mammary glands, therefore their role in tumorigenesis has been questioned. We have investigated, by the use of the reverse transcription polymerase chain reaction amplification technique, the possible existence of ER variants in other normal oestrogen target organs and cells, such as uterus (myometrium and endometrium), in peripheral blood mononuclear cells and in a benign uterus tumour (leiomyoma). We have detected variant ER in these samples and have compared the variant profile to that observed in breast cancer. All tissues and cells studied expressed both wild-type ER and variant species. Variant forms encompassed ER with deletions of exons 2, 5 and 7. Variants with exon 5 deleted were detected only in peripheral blood mononuclear cells and in breast cancer. Variants with exons 2 and 7 deleted were present in all specimens tested. These results corroborate previous findings that the presence of ER variants is not a characteristic of breast cancer. The physiological significance and possible clinical relevance of the variant ER forms remain to be elucidated.
Moutsatsou
P
P
Laboratory of Biological Chemistry, University of Athens Medical School, Greece.
Kassi
E
E
Creatsas
G
G
Coulocheri
S
S
Scheller
K
K
Sekeris
C E
CE
D001483:Base Sequence; D001943:Breast Neoplasms / Q000737:chemistry*; D017931:DNA Primers; D004717:Endometrium / Q000737:chemistry*; D005260:Female; D006801:Humans; D007889:Leiomyoma / Q000737:chemistry*; D007963:Leukocytes, Mononuclear / Q000737:chemistry*; D008969:Molecular Sequence Data; D009215:Myometrium / Q000737:chemistry*; D016133:Polymerase Chain Reaction / Q000379:methods; D012194:RNA-Directed DNA Polymerase; D011960:Receptors, Estrogen / Q000032:analysis* / Q000235:genetics; D017422:Sequence Analysis, DNA; D014594:Uterine Neoplasms / Q000737:chemistry*
D017931:DNA Primers; D011960:Receptors, Estrogen; D012194:RNA-Directed DNA Polymerase