ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 primary or metastatic RCC (p < 0.05). We observed moderate posi- tive correlation between expressions of TOLLIP in the primary tumour and its metastases (p < 0.05; k=0.48). Elevated TOLLIP expression correlated with worse overall survival (OS) (median OS, 64 vs. 101 months, p < 0.05). Conclusion: High TOLLIP expression predicts poor prognosis in RCC patients. The enhancement of TOLLIP expression probably occurs in the early stages of RCC, before the development of metastatic competence. While TOLLIP reduces immune surveillance and increases autophagy, our results suggest that it could drive the escape phase of immunoediting and compromise both immuno and targeted therapy. Funding: This research was funded by The National Centre for Research and Development, grant number POWR.03.02.00-00-I019/16. PS-26-010 Role of epithelial-mesenchymal transition in clear cell renal cell carcinoma J. Jeruc*, T. Čugura, S. Uhan, N. Zidar, E. Boštjančič *Institute of Pathology, Faculty of Medicine, University of Lju- bljana, Slovenia Background & objectives: Epithelial-mesenchymal transition (EMT) is believed to be the key process in development and progression of cancer, including renal cell carcinoma (RCC), with miR-200 family and miR-205 being key regulators. The exact role of EMT in RCC is not fully understood. Methods: We analysed the expression of miR-200 family and miR- 205 and their targets, ZEB1 and ZEB2, using qPCR and ZEB2 using IHC. Twenty cases (in total 50 samples) of formalin-fixed paraffin-embedded tissue were included, 10 RCC without and 10 with sarcomatoid differentiation (RCC-Sa). In RCC-Sa, sarcoma- toid and clear cell component were investigated separately. Micro- scopically normal renal tissue was used as control. Results: Interestingly, miR-200 family and miR-205 were down- regulated (hallmark of EMT) in both, clear cell component and sarcomatoid differentiation of RCC-Sa when compared to corresponding normal renal tissue. Moreover, they were down- regulated even in clear cell component of RCC without sarcomatoid differentiation. Their target genes transcription factors (TFs) of EMT also showed interesting expression: ZEB1 was not expressed, whereas ZEB2 showed variable pattern of expression, being either up- or down-regulated when compared to normal renal tissue irrespective of analysed component. Results of IHC support this information. Conclusion: Our result on miR-200 family and miR-205 expression suggest that EMT is involved not only in development of RCC-Sa but also in development of RCC. However, their target genes, ZEB1 and ZEB2 seems to have minor role in this process. Our results further confirm that although ZEB1 and ZEB2 are highly related, they may have opposing effects and expression patterns in tumour biology. miR-200 family and miR-205 are probably involved in EMT regulation trough other targeted EMT-TFs. Funding: Slovenian Research Agency, grant number P3-0054. PS-26-011 Spontaneous regression - scars of testicular germ cell tumours: association with clinicopathological features - institutional experience B. Jovanović*, B. Kovačević, I. Nikolić *Military Medical Academy, Serbia Background & objectives: Scars in testicular parenchyma as a his- tological element of GCT spontaneous regression is a rare but well- recognized phenomenon. We analysed the presence and frequency of complete or partial/focal scarring of GCT and their association with clinicopathological features of GCT. Methods: A surgical pathology archive between 2007 and 2022 has been searched for cases of GCT that had reported in the final diagnosis partial/focal or complete scarring of GCT. The associa- tion of scars and following clinicopathological features (patients’ age, tumour size, GCT type, lymphovascular invasion, tumour stage, germ cell neoplasia in situ (GCNIS), peritumoral atrophy, and microlithiasis) were analysed. Results: A total of 322 patients underwent radical inguinal orchi- ectomy for GCT. Complete GCT regression was reported in 6 cases (1.86%). In 3 of these 6 cases, metastases of mixed GCT were pre- sent, whereas GCNIS was diagnosed in 5 cases. Of a total of 316 GCTs, those with partial/focal scars were diagnosed in 68 cases (21.52%). GCTs without scars were diagnosed in 248 (78.48%) cases. Statistical significance in the occurrence of scars in GCT was found in older patients (34.0±8.2 vs 31.0±8.0 without scar; p=0.001) and in the seminomatous GCTs in comparison with mixed GCTs (p=0.027). Other clinicopathological features were not statistically related to the focal presence of the scar. Conclusion: Complete GCT regression is a rare event that occurs in GCTs and it is associated with the presence of metastasis and/or associated with the presence of GCNIS at the time of testicular sur- gery. Partial/focal regression - scarring of GCT is not uncommon. The meaning of focal scars in GCTs is unknown, but in the present study, it looks like it does not have any significant clinical mean- ing, namely to the lack of their association with the tumour stage. PS-26-012 Human epidermal growth factor receptor 2 (HER2) expression in urothelial carcinomas of the bladder A. Nalwa*, A. B S, P. Elhence, J. Naresh Bharti, M. Rao, G. Ram Choudhary *All India Institute of Medical Sciences, Jodhpur, India Background & objectives: HER2 is highly expressed in multiple malignancies and associated with patients’ prognosis, but its role in urothelial carcinomas remains elusive. To evaluate Her2 expression in urothelial non-muscle-invasive(NMIUC) and muscle-invasive bladder carcinomas(MIUC) by immunohistochemistry (IHC) and gene ampli- fication by insitu hybridization. Methods: This study involved total of 89 cases (39 muscle-invasive urothelial carcinomas and 50 non-muscle-invasive urothelial carci- nomas). Histopathological grading was done as per WHO 2022. All cases were subjected to IHC by HER2 and all equivocal (2+) cases were subjected to FISH using HER2/CEN17 dual colour probe. IHC and FISH analyses were scored per 2018 updated ASCO/CAP recommendations for breast carcinomas Results: Her2 overexpression (3+) was seen in 11 of 50 NMIUC cases (22%) and 7 of 39 MIUC cases (17.9%). 3 cases of MIUC and 2 of NMIUC showed equivocal (2+) positivity by IHC and were subjected to FISH analyses. None of these cases showed amplifi- cation on the dual-probe assay. There was no association between gender of patients and HER2 protein expression. HER2 positivity was associated with a higher tumour grade irrespective of deep muscle invasion. No significant correlation between HER2 expres- sion and lymph node status was found. Conclusion: The present study shows overexpression of HE2 in high-grade urothelial carcinomas both muscle-invasive and non- muscle-invasive urothelial carcinomas’ indicating it has the poten- tial to become an ideal target for bladder cancer therapy. However, S170