ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 patients. Tissue specimens were obtained at surgery. Expression of genes of interest was assessed by RT-qPCR. Statistical analyses were performed with R (v.4.0.3) software. Results: Results from the TCGA cohort (n=232) demonstrated that COL11A1 expression significantly associates (p<0.05) with that of cancer-related extracellular proteoglycans (VCAN), EMT triggers (POSTN), EMT-inducing transcription factors, (SNAI1, SNAI2, ZEB1) and mesenchymal markers (FN1). One step further, we developed an EMT-based prognostic algorithm: (SNAI1x0.0984) + (COL11A1x0.5535) + (CDH2x0.0297) + (FN1x0.0008) + (VIMx-0.0014) COLL11A1 predominantly contributes to the EMT-score model. Further analyses by RT-qPCR on a validation cohort (n=82) deter- mined that COL11A1 expression is significantly elevated in Type 2 vs Type 1 EC (p=0.006), G2-G3 vs G1 EC (p=0.011 and p=0.025), metastasis (p=0.043), progression (p=0.017), relapse (p=0.034) and EC-related exitus (p=0.007). Additionally, we obtained the same results with the EMT-score. Conclusion: In light of these results and in agreement with the literature, it seems that diverse EMT biomarkers have prognostic connotations in different types of tumours. We have found that, in EC, COLL11A1 is related to EMT markers and tumours expressing COLL11A1 are usually more aggressive. Currently, these results are being validated by immunohistochemical staining. Funding: This research was funded by the “Instituto de Salud Carlos III- Fondo Europeo de Desarrollo Regional” (ISCIII-FEDER), Spain (Grant number: PI17/01945), the “Generalitat Valenciana”, Spain (Grant num- ber: GV/2020/200), the “Fundación para la Investigación del Hospital General Universitario de Valencia” (FIHGUV), Spain (Grant numbers: Prize FIGHUV 2019, 2020 and 2021) and the “Sociedad Española de Trombosis y Hemostasia” (SETH), Spain (Grant Number: Prize SETH) and E.G.-C. and J.M.-A. are supported by grants from Generalitat Valenciana ACIF/2020/216 and APOSTD/2019/087, respectively. PS-08-019 Mesonephric-like adenocarcinomas of the ovary: pathological and molecular characterisation of a case series A. De Leo*, A.G. Corradini, F. Rosini, L. Di Sciascio, A. Orsatti, R. Ciudino, F. Chiarucci, M. Grillini, S. Coluccelli, T. Maloberti, G. Tallini, D. Santini, D. de Biase *Pathology Unit, University of Bologna Medical Center, Italy Background & objectives: Mesonephric-like adenocarcinoma (MLA) of the ovary is a rare malignant tumour of the female gen- ital tract. In this study, we investigated the clinicopathological, immunohistochemical, and molecular features of 9 ovarian MLAs. Methods: Clinical data and history were extracted from the patient’s medical records (from January 2019 to December 2021). Immunohistochemistry (IHC) and targeted Next-Generation sequencing analysis were performed. Results: MLA accounted for 1.9% of cases (9/269). In 6 cases, MLA was associated with coexisting ovarian lesions: seromucinous borderline tumour (3), polypoid endometriosis (1), endometrioid carcinoma (2). Synchronous endometrial MLA was found in 2 cases. Diffuse endometriosis was present in all cases. Microscopically, tumours showed varying proportions of architectural patterns: glan- dular 9/9; papillary 7/9; glomeruloid 8/9; sex cord-like 7/9; solid 5/9; and spindle cell 6/9. All cases were positive for PAX8 and GATA3 with heterogeneous expression of CD10 and TTF1. MMR proteins were preserved in all cases. NGS analysis revealed patho- genic variants of KRAS in 8 cases and BRAF in 1 case. Mutations in TP53, POLE, BRCA1/2 were not identified. Conclusion: In our study, 8 patients presented with advanced dis- ease, and in 2 cases early disease recurrence was observed after chemotherapy treatment. MLA represents a rare and novel histo- type of ovarian carcinoma with distinct pathologic, immunohisto- chemical and molecular features and it can be added to the list of endometriosis-associated ovarian neoplasms. In consideration of the propensity for recurrence/metastasis MLA may be considered a potentially aggressive histotype despite its apparent low-grade morphology. PS-08-020 Neuroendocrine neoplasms of the female genital tract: correla- tion of molecular, immunohistochemical and clinical features in 24 cases M. Testa*, C. Amaglio, R. Maragliano, E. Leoni, F. Sessa, D. Fur- lan, S. Uccella *Pathology Unit, Dept. of Medicine and Surgery, University of Insubria, Varese, Italy Background & objectives: Neuroendocrine neoplasms (NENs) are uncommon in the female genital tract. Due to their rarity, little is known about them. Aim of this study is to correlate their molecular and immunohistochemical features with clinical data and to inves- tigate their prognostic value. Methods: The electronic medical record of our Pathology Insti- tute was utilized to identify women diagnosed with gynaecological NENs from 1983 to 2019. All cases underwent histological and immunohistochemical review. Patients’ clinical, demographic and treatment characteristics were searched. Molecular analyses were performed (including Next-generation Sequencing, real-time PCR, microsatellite instability evaluation). The association between tumour histology and survival was examined using Kaplan-Meier analyses. Results: A total of 24 cases were identified. 42% of the NENs were cervical, 25% endometrial and 33% ovarian. Median age was 62 years (range 39–78 years), with site-specific differences. Only high-grade NENs were retrieved on cervix and endometrium: 1 Neuroendocrine-tumour (NET) G3, 8 Neuroendocrine-carcinomas (NECs) and 7 Mixed-Neuroendocrine-non-neuroendocrine-neo- plasms (MiNENs), whereas the most common histological subtype in ovary was NET. 20/22 cases (91%) expressed Chromogranin-A and/or Synaptophysin and 17/23 cases (74%) expressed INSM1. Most of the cases didn’t show immunoreactivity for site-specific antibodies. HPV-infection and concomitant p16 overexpression was found in 8 cervical and 2 endometrial cases. 4 cases had altered immunohistochemical expression of DNA-mismatch-repair-pro- teins and associated microsatellite instability (MSI). Conclusion: Gynaecological NENs represent a rare tumour entity and constitute a diagnostic challenge. They usually show immunoreactivity for traditional neuroendocrine markers (Chromogranin-A and Synaptophysin), but we recommend caution in INSM1 reliability, since it showed a minor sensitivity in our study; NENs resulted mainly negative for site-specific markers, therefore they cannot be used to rule out metastases. Limited data regarding gynaecological NENs pathogenesis are available; our study highlighted NENs might follow site-specific molecular pathways, like HPV-related infection, or NEN-specific pathways, like MSI. PS-08-021 Contribution of β-catenin in endometrial cancer progression Z. Greally*, E. O’Regan, P. Lewitowicz, O. Adamczyk-Gruszka, A. Horecka-Lewitowicz, J. Gruszka, A. Strzelecka *Student Science Club at Collegium Medium Jan Kochanowski University, Poland S111