ECP 2023 Abstracts

S92 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 Most patients underwent concurrent chemoradiotherapy. Silva pat- tern C was commonest (68/89,76.4%), was frequently associated with lymphovascular emboli(LVE)(85.7%) and nodal metastases (81.8%). On univariate analysis, larger tumour size, higher stage and lack of HPV- associated features were significantly associated with lower progression-free survival(PFS) (p<0.001, p=0.003, p=0.011). Nodal metastases and higher tumour stages led to lower overall survival (OS) (p=0.049, p=0.017). Conclusion: Histopathologic features of HPV and block-like p16INK4a staining were useful in subtyping ECAs into HPV-depend- ent vs. non-HPV dependent. Tumours with HPV-associated features displayed improved PFS. Larger tumour size and higher stage were also associated with lower PFS. Funding: Intramural, Institutional funding. PS-10-027 DNA NGS and immunohistochemical analysis of a large cohort of adult granulosa cell tumours focusing on predictive aberrations. A. Safanda*, P. Dundr, N. Hájková, J. Hojný, E. Krkavcová, R. Michálková, J. Laco, J. Škarda, J. Drozenová, R. Matěj, M. Hácová, K. Němejcová *Department of Pathology, First Faculty of Medicine, Charles Uni- versity and General University Hospital in Prague, Czech Republic Background & objectives: We analysed a large cohort of adult granu- losa cell tumours of the ovary (AGCT) with aim to perform a com- plex DNA analysis and reveal potentially clinically relevant altera- tions and immunohistochemical analysis of selected predictors of immunotherapy. Methods: Paired-end capture DNA NGS analysis (KAPA HyperPlus kit; 788 genes, 2044 kbp; Roche) using NextSeq500 (Illumina) was performed with 87 FFPE AGCTs. The constructed pipeline in CLC Genomics Workbench (Qiagen) were used for evaluation of muta- tions, tumour mutation burden (TMB; TMB≥10 mut/Mb were con- sidered as TMB-High) and microsatellite stability. Immunohistochemi- cal analysis of HER2 and PD-L1 were performed on 120 samples. Results: TMB in AGCTs ranged between 2-20 mut/Mb (median 6). 7/87 (8%) were TMB-High, and two of these were MSI-High. FOXL2 recurrent mutation (C134W) was found in 81/87 (93%) AGCTs. More- over, in 8 of those was detected also second FOXL2 mutation (V261fs, *377fs, P332A, G240S, M220fs or K366fs). Other detected mutations included TERT, CHEK2, and TP53 (all found in ≥3 cases). The expres- sion of HER2 was negative in the entire cohort. The expression of PD-L1 showed a similar result, with a single exception of a case with CPS slightly above 1. Conclusion: Our complex DNA analysis of AGCT revealed potentially significant genetic alterations with possible impact on clinical practice. Regarding predictive immunohistochemical markers, our results may provide valuable knowledge for future immunotherapy research. Supported by Ministry of Health of the Czech Republic (project no. NU21-03-00238 and RVO64165, General University Hospital in Prague) and by Charles University (Project UNCE204065). PS-10-028 Association of PD-L1 expression with clinicopathological and prog- nostic characteristics in cervical cancer: a single-institution study G. Sahraoui*, F. Sassi, M. Manai, R. Mchiri, R. Doghri, L. Charfi, K. Mrad *Salah Azaiez Institute, Tunisia Background & objectives: The immune checkpoint PD-L1 plays a crucial role in immunosuppression in cervical cancer (CC). This study aimed to determine the expression profile of the PD-L1 protein in CC and investigate the correlations between PD-L1 status and clinicopathological and prognostic characteristics. Methods: This retrospective descriptive study collected 146 cases of CCs from medical records and pathological reports. The expres- sion of PD-L1 was assessed through immunohistochemistry using the laboratory’s protocol. The mean age of the patients was 54 years (23-87 years), and the average tumour size was 40.7 mm (5-90 mm). Results: Squamous cell carcinoma was the most common histological type (88.3%). CCs were well-differentiated in 62.6% of cases, and stage 2B was observed in 49% of cases. Vascular emboli were seen in 7.1% of cases. Concomitant radio-chemotherapy was recommended in 86.8% of patients, and brachytherapy was indicated in 79.7% of patients. More than half of the patients underwent surgery. Distant recurrence occurred in 17.3%, while pelvic recurrence occurred in 20.4% of cases. The evolution was favourable in 39.3% of cases. Immunohistochemi- cal analysis revealed PD-L1 expression in 32.4% of tumour cells and 47.1% of immune cells. The expression of PD-L1 in tumour cells was associated with endometrial invasion (p=0.014). Conclusion: PD-L1 is expressed in CCs, and the expression of PD-L1 in tumour cells was associated with endometrial invasion. Larger stud- ies with a higher number of samples are required to evaluate the cor- relation between PD-L1 and histoprognostic factors to support the role of this biomarker in the progression of CCs. PS-10-029 TLR4 down-regulation identifies high risk HPV infection and inte- gration in cervical squamous cell carcinomas A. Santoro*, M.C. Pedicillo, I.S. De Stefano, G. Aquino, M.L. Tornesello, F. Miele, N. D’Alessandris, G. Scaglione, F. Addante, G.F. Zannoni, G. Pannone *Pathology Unit, Department of Woman and Child’s Health and Pub- lic Health Sciences, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy Background & objectives: There are few studies on TLRs mediated HPV-clearance in cervical oncology. We evaluated whether TLR4 expression identifies HPV infection and HR-HPV integration in 40 bioptical samples of cervical squamous cell carcinoma (CSCC) and 20 HSIL bioptical samples. Methods: TLR4 levels was studied by IHC, HR-HPV integration by ISH, and viral typing by RT-PCR-based assay. TLR4 staining intensity (TLR4-SI), TLR4 percentage of expression and Combo Score (TLR4- CS) has been evaluated. Similarly, by IHC also CK19 and p16 expres- sion were studied. Results: TLR4-SI and TLR4-CS are downregulated in HSIL and CSCCs, compared to normal cervix (p=.001, ANOVA; p=.004; Kruskal-Wallis test). Significant differences have been observed between TLR4 % expression in normal epithelium and HSIL and between HSIL and CSCCs (p<0.05; ANOVA). ISH HPV+ samples reported TLR4-SI lower levels than negative samples (p = .002). Point- biserial correlation revealed association between TLR4 expression and HR-HPV integration (p = .0001) and between TLR4 expression and HPV16 infection (p = .001). An inverse significant relationship between TLR4-SI, CK19 (R=-0.4906; p=0.0001, ANOVA) and p16 has been observed. A correlation between TLR4 downregulation and inflammatory microenvironment has been demonstrated (R=0.5341; p=0.001, ANOVA). Conclusion: TLRs are main actors of the immune-response against HPV transformed cancer cells. In the present study, TLR4 down- regulation is strongly associated with HR-HPV (HPV16+) integra- tion in CSCCs, CK19 and p16 over-expression, in this way acting as an important biological actor for immuno-escape. This study reveals important implications for diagnostic approach, immunotarget therapy, and vaccination strategies.