Association between redundant endometrium and endometrial polyps: a pilot study

The aim of this study was to explore the organic features of redundant endometrium (RE), we examined the expression of different endometrial hormone receptors, oncogenes, and cell replication markers, in normal endometrium (NE), endometrial polyps (EP) and RE specimens.

This was an experimental study examining endometrial tissue expression of estrogen receptors (ER1 and 2), progesterone receptors (PR-A+B), androgen receptor (AR), insulin receptor (Insulin-R), insulin-like growth factor receptor 1 (IGFR-1), thyroid hormone receptor (TH-RB), B-cell lymphoma 2 (Bcl-2), Ki67, HOXA10, in women with NE, EP and RE, of women undergoing hysteroscopy for benign gynecologic pathology. Specimens were separated in 3 groups: NE, EP, RE. Endometrial samples were processed for real-time RT-PCR analyses. Main outcome measure was tissue expression of the markers in the three groups.

Of the 16 patients, 2 had NE, 8 had RE, 5 had EP, 1 had both, RE and EP. Compared to NE, RE and EP showed significantly increased Bcl-2, Insulin-R, ER-ß, PR-A+B, and TRB expression (P<0.044), with EP showing significantly increased PR-A+B, compared to RE (3.29±0.47 fg/µg RNA versus 1.86±0.34 fg/µg RNA; P=0.023). The other markers were not significantly different across the three groups: Ki67 appeared non-significantly decreased, while HOXA10, IGF-R1, AR, and ER-α, were non-significantly increased.

RE showed biochemical characteristics different from NE. Similar to endometrial polyps, RE showed enhanced cell differentiation, but not cell replication. These changes in RE could be detrimental for embryo implantation and should be of consideration in women undergoing fertility treatments.