ECP 2023 Abstracts

S263 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 cases of serous endometrial carcinomas (SEC), and 10 cases of clear- cell endometrial carcinomas (CCEC). The expression of COX2 was detected by immunohistochemistry using rabbit polyclonal anti-COX2 antibodies from Diagnostic Biosystems (Pleasanton, CA, USA). Results: The EC tissue exhibited variable membranous-cytoplasmic expression of COX2, which did not differ significantly between its histological types (p=0.15). It is important to note that high-grade EC showed only moderate to strong expression of COX2, which differed significantly from low-grade EC where expression varied from weak to moderate to strong (p=0.0054). In grade 1 EEC, COX2 was mainly localized in the apical part of the cytoplasm. In EEC tissue with solid growth and grade 3 nuclear atypia, as well as in SEC and CCEC tumour cells, COX2 was detected around the perimeter of the cytoplasm and membrane. Conclusion: The levels of COX2 in EC tissue are higher compared to the normal endometrium, and this elevation depends on the histological features and differentiation of the tumour. This can serve as an indicator of neoplastic transformation of endometrial cells and the progression of carcinomas. The availability of selective COX2 inhibitors and pre- liminary data on their effectiveness in some carcinomas suggest that it may be a promising adjunct in the treatment of EC. E-PS-10-042 Features of ER and COX2 expression in endometrial polyps Y. Lуndіna*, N. Tsyndrenko, N. Hyriavenko, K. Sikora, O. Romaniuk, Y. Sikora, M. Lyndin, A. Romaniuk *Sumy State University, Ukraine Background & objectives: Endometrial polyps (EPs) are a variant manifestation of endometrial hyperplastic processes that can progress to endometrial cancer. The rate of malignancy depends on the mor- phological characteristics (presence or absence of nuclear atypia) and immunohistochemical features of the endometrial epithelium. Methods: The research was conducted on samples of EPs obtained after surgical treatment (hysteroresectoscopy) at the Sumy Regional Clinical Oncology Dispensary (Sumy, Ukraine). The expression of proteins was detected using immunohistochemistry with rabbit poly- clonal anti-COX2 antibodies from Diagnostic Biosystems and rabbit monoclonal antibodies against ER (clone SP1). Data processing was performed using SPSS Statistics 29.0 for Windows. Results: The expression of ER and COX2 was detected in all of the studied samples. The glandular EPs showed strong expression of ER in 86% and median expression in 14%. In glandular-fibrous EPs, ER expression was strong in 72% and median in 28%. COX2 expression was mainly found in the apical part of the cytoplasm of the prismatic epithelium. We did not find a statistically difference in the expression of COX2 and ER between the two groups of tissues (p>0.05). However, their expression significantly exceeded the indicators of intact endome- trial tissue. A direct correlation was found between the expression of COX2 and ER in the epithelium of the endometrial glands (p<0.05). Conclusion: The tissue of endometrial polyps is characterized by variability in the expression of ER and COX2. The direct correlation between ER and COX2 in the endometrial epithelium may indicate their synergistic involvement in the initiation and progression of endo- metrial hyperplastic processes and possible involvement in subsequent tumour transformation. The results of immunohistochemical studies of ER and COX2 expression can serve as criteria for a differentiated approach in choosing treatment strategies. E-PS-10-043 Immunohistochemical evaluation of microsatellite instability in endometrial cancers and its relationship with clinicopathological variables B. Malkoc*, B. Dogan Gun *Ardahan State Hospital Pathology Division, Turkey Background & objectives: Endometrial cancer is the most common invasive cancer of the female genital tract. In this study, we aimed to analyse the microsatellite instability of the endometrial cancer materi- als, by applying immunohistochemistry method and their relationship with clinicopathologic features are investigated. Methods: Tumour materials of 140 patients who were diagnosed with endometrial cancer were included in the study of which were all total abdominal hysterectomy materials extracted between 2016 and 2021 in Zonguldak city. We chose to use the immunohistochemical evaluation of MMR genes, which is also the most cost-effective method for this study and we’re experienced in colon cancers before. Results: 73,6% were found to be MSS and %26,4% were found to be MSI. A significant statistical relationship was found between FIGO grade and the comparison between the MSI and MSS groups (p=0,03). A significant difference in the MSI group(48.6%), and the MSS group(29,1%) was related to the MSI condition. There was no significant statistical relationship between TILs score and MSI and MSS status (p=0,928). However, in the group of where TILs score was 1 or more, the rate of MSI was greater. Even though, this finding doesn’t carry a statistical significance, a strong clinical relationship could be proven with more detailed survival analysis on larger patient groups in future studies. Conclusion: According to the findings in our study, there is a signifi- cant statistical relationship between the FIGO grade and MSI status (p=0,03). We believe that using the most practical and easily accessible immunohistochemistry method to analyse the MMR gene expressions in those patients who were diagnosed with endometrial cancer, could become one of the current protocols for the diagnosis and treatment of the cancer and the post-operative management of the patients in gynaecological oncology daily practice. E-PS-10-044 Confocal microscopy in the initial evaluation of vulva biopsies. Preliminary results L. Marimón*, S. Lopez-Prades, C. Marti, C. Miralles, L. Sisuashvili, A. Saco, M. Del Pino, N. Carreras, P. Fuste, A. Torne, J. Ordi, N. Rakislova *Hospital Clínic, Barcelona, Spain Background & objectives: Ex-vivo fusion confocal microscopy (FuCM) provides haematoxylin and eosin-like digital images from fresh tissue specimens minutes after sampling without wasting mate- rial. The aim of this study was to assess the usefulness of this technique in the evaluation of vulvar biopsies. Methods: Prospective study including 35 vulvar biopsies, which were processed immediately after sampling (10”, 70º alcohol and 20” acri- dine orange) and scanned using a VivaScope 2500-G4 device. After scanning, the specimens were routinely processed for conventional microscopy. FuCM images were evaluated by a pathologist. This diagnosis was compared with the diagnosis of the routinely processed biopsies blindly evaluated by another pathologist. Results: The final diagnoses were inflammatory diseases (12 biop- sies); melanocytic nevus (1); condyloma acuminata (5); high-grade squamous intraepithelial lesion/vulvar intraepithelial neoplasia (HSIL/ VIN, 12) and squamous cell carcinoma (5). The agreement between FuCM and final diagnosis was complete in 24/35 biopsies (69%: 9/12 inflammatory diseases; 0/5 condylomas; 0/1 nevus; 10/12 HSIL/VIN and 5/5 carcinomas). FuCM mistakes were due to technical problems (difficult orientation with absence of epithelium in the FuCM image, 3 cases) and misdiagnosis due to limited experience (3 cases), or absence of immunohistochemical support (5 cases). The accuracy of FuCM evaluation increased from 9/17 (53%) in the first set of biopsies to 15/18 (83%) in the second set (p=0.07). Conclusion: FuCM is a promising tool that allows providing histologi- cal information a few minutes after sampling without altering the tissue