LAUSR

Purpose Adenomyosis has been studied throughout the years, however, its aetiology and physiopathology are still unknown. The aim of this study was to identify the presence of PIWI proteins in women with adenomyosis. Methods We included 72 participants to be part of this study and were divided into two groups based on their anatomopathological diagnosis, control ( n  = 36) or adenomyosis ( n  = 36). All samples were tested for PIWIL1, PIWIL2 and PIWIL4 proteins by immunohistochemistry. The evaluation of protein expression was performed by the digital histological score (DHSCORE) and by the pathologist’s analysis. Results The participants had a mean age of 44.28 ± 5.76 years and 45.81 ± 4.86 years in the control and adenomyosis groups, respectively ( p  ≥ 0.05). Other clinical characteristics of the participants showed no statistical difference as well. PIWIL2 is highly expressed in the adenomyosis in comparison to the control group ( p  = 0.0001). The PIWIL1 is downregulated in the adenomyosis ( p  = 0.003) and PIWIL4 showed no difference in its expression ( p  = 0.05). Conclusion PIWIL2 might be involved in cellular survival and PIWIL1 may be downregulated due to the loss of tissue’s function and response to the hostile environment of the myometrium. This is the first time that PIWI proteins are studied in the adenomyosis.