Objective: This study was conducted to examine HOXA11 gene expression in the human endometrium during normal menstrual cycle.
Study design: Expression of HOXA11 was examined in the endometrium by in situ hybridization and semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR).
Results: In the proliferative and early secretory endometrium, both glandular and stromal cells expressed HOXA11 after hybridization. It is interesting to note that the expression in glandular epithelium was dramatically decreased or disappeared in the midsecretory phase at the time of implantation. This expression patterning was kept in the late secretory endometrium and decidua of early pregnancy, whereas in stromal cells, a high-level expression was found and no variations were detected during the menstrual cycle. Semiquantitative RT-PCR analysis demonstrated that total HOXA11 messenger RNA levels were markedly increased in the midsecreatory endometrium.
Conclusion: This study reveals a novel expression pattern for HOXA11 gene in human endometrium and the downregulation of HOXA11 in glandular epithelium may be necessary for the differentiation and receptivity of endometrium.