ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 we compiled the clinicopathologic features of cases diagnosed with endometriosis within a year in our department. Methods: The biopsy materials evaluated in our clinic in 2021 were retrospectively analysed. Clinicopathologic data, in terms of age, localization, recurrence, operation type, comorbidity, parity were gathered. Gynaecological and non-gynaecological materials were classified. Type of the comorbidity were listed. Results: There were 78 materials of 70 cases. The mean age of the patients was 39 years. Recurrence was seen in 4 patients. The most common pelvic location was ovary. Vaginal cuff involvement was observed in only 1 case. Eight cases were located in the extrapelvic region. 13 patients had multifocal disease and 4 patients had atypi- cal endometriosis. There were ovarian neoplastic lesions accom- panying ovarian endometriosis in eight cases. Endometrioid carci- noma of the uterine cavity was present in 3 cases. Benign uterine lesions such as adenomyosis, adenomyotic nodule and leiomyoma uteri were present in 34 cases. Conclusion: As a result, 5,7% of the cases were recurrent. Endo- metriosis associated carcinomas accompanied 2,9% of the cases, and 5,7% of the cases were diagnosed with atypical endometriosis, which is accepted as precursor of the endometriosis associated carcinomas. 92,8% of the cases presented in pelvic location, and multifocal disease at diagnosis occurred in 18,5% of the patients. Careful microscopic examination, detection of multifocal dis- ease, and identification of accompanying neoplastic lesions will enable endometriosis cases to be correctly diagnosed and treated appropriately. PS-08-015 Trend analysis as a quality measurement for biomarkers - mis- match repair application A. Plotkin* *Sunnybrook Health Sciences Centre; University of Toronto, Canada Background & objectives: Universal screening of endometrial cancer (EC) for Lynch syndrome using mismatch repair (MMR) immunohistochemistry is becoming standard of care in many countries. We defined MMR-deficiency (MMRd) rates in EC and examined steadiness over time to identify trends and benchmark measurements. Methods: Pathology reports of EC biopsy and curettage (2018- 2021) and MMR immunohistochemical biomarker reports from Life Labs, Canada were audited. Two-sided logistic regression was used for sample size analysis and generalized linear models were used for trend analysis. 60 patients quarterly were identified as minimum case volume by sample size calculations required to establish benchmarks for testing proficiency (P≤0.05, 80% power). Results: Our cohort reached case volume ≥60 cases starting from the fourth quarter of 2019, thus meeting this requirement. The 1181 ECs included in the study were classified into MMR-d (n=313, 26.5%) or proficient (n=868, 73.5%). MMRd was highest in high-grade and mixed EC that included endometrioid EC (EEC, n=34/63, 54%) compared to low-grade EEC (n=256/919, 28%) and high-grade non-EEC (n=23/209, 11%), P<0.001. Proportion of MLH1/PMS2 loss was 22.1% (95% CI: 19.8-24.6%), MSH2/ MSH6 1.8% (95% CI: 1.1-2.7%), MSH6 2.2% (95% CI: 1.4-3.2%) and PMS2 0.8% (95% CI: 0.3-1.4%). For each protein, the pro- portion of MMRd cases was quarterly steady over the entire time period (P>0.05). Conclusion: Large laboratories may have the minimum volume to establish benchmarks for internal MMR immunohistochemistry quality control, and follow up trends over time, but this volume is not attainable for smaller laboratories. This study underscores the importance of trend analysis and the need to ensure that patholo- gists have sufficient expertise in biomarkers reporting. PS-08-017 Expression patterns of the gonadotropin and sex hormone receptors in various cell types of human endometrium during the menstrual cycle A. Magnaeva*, M. Shamarakova, A. Tsitrina, A. Asaturova, G. Tabeeva, A. Tregubova, L. Ezhova, V. Bozenko *National Medical Research Center for Obstetrics, Gynaecology and Perinatology named after Academician V.I.Kulakov, Russia Background & objectives: Expression alterations of oestrogen and progesterone receptors as well as follicle-stimulating and luteinizing hormone receptors lead to a number of reproductive issues. Therefore, understanding the physiological features of their expression and topical distribution is important for a endometrium comprehensive assessment. Methods: Endometrial tissue samples of 7 healthy females, who participated in IVF programs at the Research Center for Obstet- rics, Gynaecology and Perinatology (Moscow, Russia) due to male infertility were recruited. Fluorescent immunohistochemistry was used for Q-score evaluation of ER, PR, FSHR, and LHR expres- sion levels during menstrual cycle in endometrial glands, stoma, endotheliocytes, and macrophages. Results: The increased immunoreactivity of ER, PR, FSHR, and LGHR in the endometrial glands and stroma was initiated at the stage of early proliferation and reached its maximum level at the stage of late proliferation. Then, the expression of ER in the glands and stroma decreased during the early and middle stages of secre- tion, the immunoreactivity of PR in the stroma persists throughout the all stage of secretion, increased immunoreactivity of FSHR and LGHR in each component of the endometrium was observed in all secretion stages. Conclusion: It was shown that there is a connection between studied receptors immunoreactivity and endometrial structural features during menstrual cycle. Increased ER, PR, FSHR and LGHR expression in proliferative phase occurs according to endometrial growth, while increased PR, FSHR and LGHR expression in secretory phase is associated with endometrial decidual transformation and optimal condition for embrio implantation in case of pregnancy. Funding: State Assignment number 122020900122-7 The research was funded by RFBR and Moscow city Government, project number 16-29-07434 PS-08-018 An EMT-based score model identifies poor prognosis endometrial cancer (EC) patients and highlights COL11A1 as an independent risk factor of adverse events A. Mascaros Martinez*, A. Arroyo-Alvarez, E. Gonzalez, S. Tomas-Perez, B. McCormack, A. Herreros-Pomares, I. Marin- Ajado, J. Mari-Alexandre, J. Gilabert-Estelles, N. Santonja-Lopez *Department of Pathology Hospital General Valencia, Spain Background & objectives: Increasing evidence points to COL11A1 as a poor prognosis biomarker in several malignancies but not yet in EC. We aim to investigate the role of COL11A1 as a biomarker in EC and to study their relationship with epithelial-to- mesenchymal transition-related genes. Methods: We included 82 tissue biopsies from patients with a his- tological diagnosis of EC who underwent surgery at our institution (2014-2017). For normalization purposes, a control group con- sisted of endometrial tissues from 16 non-cancer hysterectomized S110