Expression of tyrosine kinase receptor B in eutopic endometrium of women with adenomyosis

Our study is to investigate whether tyrosine kinase receptor B (TrkB) is expressed in eutopic endometrium of women with adenomyosis and its association with clinical characteristics. We collected endometrial tissues from 31 women with adenomyosis and 30 adenomyosis-free women undergoing surgery for benign indications. TrkB expression was assessed by immunohistochemistry and reverse-transcription polymerase chain reaction. Immunoreactive staining for TrkB was present as brown flocculent precipitate in the endometrial cells. The average level of TrkB protein (quantitation of immunostaining intensity) in secretory endometrial samples of women with adenomyosis was significantly higher than that in controls (p < 0.01). The average level of TrkB messenger RNA (mRNA) expression of women with adenomyosis was significantly higher than that of controls at secretory phase (p < 0.01). In addition, the immunostaining quantitation of TrkB protein was positively correlated with the serum CA125 (r = 0.308, p = 0.016) and dysmenorrhea (r = 0.393, p = 0.002). Our study revealed elevation of TrkB protein and mRNA expression in the secretory endometrium of women with adenomyosis. Moreover, TrkB protein expression in human endometrium was positively correlated with the serum CA125 and dysmenorrhea. TrkB might contribute to the pathogenesis and progression of adenomyosis.