Background. Endometriosis is distinguished by its high prevalence and significant impact on the quality of life and reproductive health of women; however, its etiology and essential pathogenesis of remain uncertain so far. Modern research is increasingly focusing on immune, hormonal and genetic factors that share a common structure and participate in common metabolism — so-called single nucleotide polymorphisms (SNPs), including stress-induced phosphoprotein 1 (STIP1), which participates in tissue and cellular metabolism through transcription splicing and folding of RNA. The role of this protein, known as heat shock protein (HSP)-organizing protein, is being actively studied in cancer and hyperproliferative diseases. The role of the STIP1 gene and its product in the pathogenesis of adenomyosis appears to be studied insufficiently, thereby determining the relevance of the present study.Objectives. To evaluate the expression of stress-induced phosphoprotein 1 in eutopic endometrium and myometrium in women with isolated adenomyosis, as well as in combination with other benign hyperproliferative diseases of the reproductive system.Methods. Clinical study site: Clinical and Diagnostic Department of Ott Research Institute of Obstetrics, Gynecology and Reproductology. Design: an observational case-control study of patients with verified diagnoses of diffuse adenomyosis, uterine fibroids, and external genital endometriosis (main group — n = 55). The study group (n = 43) was divided into three subgroups: patients with isolated diffuse adenomyosis (AM, n = 16), adenomyosis in combination with uterine fibroids (AM + UF, n = 16), adenomyosis in combination with external genital endometriosis (AM + EGE, n = 11)), a comparison group — patients with uterine fibroids (n = 12) and a control group (n = 17) — women of reproductive age without gynecological diseases. The study was conducted from November 1, 2022 to September 30, 2023. The target indicator of the study was the level of relative mRNA (mRNA) expression of STIP1 gene (in RQ (Relative Quantity) units) in the uterus — adenomyosis glands, surrounding myometrium and endometrium. Histological evaluation of the endometrium served as an additional indicator. Statistical analysis of the results obtained, namely the relative level of mRNA expression, was carried out by the ΔΔСt method using the Expression Suit V1.0.3 program. (https://www.thermofisher.com/ru/ru/home/technical-resources/software-downloads/expressionsuite-software.html). The data analysis was performed using the GraphPad Prizm program (Insight Partners, USA). Differences between groups were evaluated by means of single factor ANOVA analysis (followed by post-hoc pairwise comparisons (Tukey test) of the values in each group. The differences were considered statistically significant at p < 0.05.Results. A high level of STIP1 gene expression was reported in myometrium of patients with isolated adenomyosis (more than 3-fold increase in relation to the comparison group — patients with uterine fibroids). In addition, myometrium of women with adenomyosis combined with uterine fibroids demonstrated a higher expression of STIP1 gene, compared to patients with isolated uterine fibroids (p < 0.01). The evaluation of the expression of mRNA of the STIP1 gene in the eutopic endometrium of patients with adenomyosis and women in the control group revealed no significant differences; however, STIP1 in the endometrium of women with adenomyosis was significantly lower than in the endometrium of both patients with uterine fibroids and women with adenomyosis combined with external genital endometriosis.Conclusion. Increased mRNA expression of STIP1 gene in myometrium in adenomyosis confirms its role in the pathogenesis of this disease. The role of the expression of the STIP1 gene and the corresponding protein is to be further clarified in order to assess its specificity and sensitivity as a diagnostic marker and to identify new approaches to the treatment of adenomyosis.
