ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 Background & objectives: Complex renal cysts are a diagnostic chal- lenge for radiologists and urologists. Bosniak classification uses imag- ing features to establish the malignant potential of these lesions. Our objective is to describe the pathological findings of Bosniak III and IV cysts. Methods: We retrospectively reviewed the Bosniak III and IV lesions that were surgically resected at our institution between 2018 and 2021. Two genitourinary pathologists analysed the gross pictures and microscopic slides of the surgical specimens. We also searched our database to find the incidence of the different renal tumours in 2021 and compare it with the diagnosis of complex cysts. Results: 27 lesions in 26 patients 14 males and 12 females, median age 60 years (41-77). Median size was 26 mm (12-70). 8(30%) were Bosniak III, 19(70%) Bosniak IV. 19 (70%) were malignant and 8 (30%) benign lesions. 79% of Bosniak IV and 50% of Bosniak III were malignant. 7(26%) lesions were solid, 14(52%) solid-cystic and 6(22%) cystic. 86% (6/7) of the solid and 17 % (1/6) of the cystic nodules were malignant. When <20mm, malignant lesions were encapsulated (5/5). 42% (8/19) were papillary carcinomas while these carcinomas represent 17% of our renal tumours. Benign lesions were 3 cystic nephromas, 2 simple cysts, 1 haemangioma, 1 pseudoinflammatory tumour and 1 oncocytoma. Conclusion: Our results show a high incidence of papillary renal cell carcinoma in complex renal cysts compared to the incidence in overall malignant renal lesions. In lesions <20 mm the presence of a capsule is highly suspicious of malignancy. The Bosniak classifi- cation is useful to determine the malignancy probability of complex renal cysts. However, it still has numerous pitfalls, so we’ll need more radio-pathological correlation studies in the future. PS-26-018 P53 overexpression in prostate carcinoma A. Dhaoui*, S. Ben Rejeb, M. Aloui, D. Aloui, R. Boulma *Forces de Securité Interieure, Tunisia Background & objectives: Somatic TP53 mutations are found in up to 20% of patients with localised prostate cancer and have been associated to disease aggressiveness and progression. The aim of this study was to assess p53 overexpression in prostate carcinoma. Methods: We have retrospectively collected 24cases of pros- tate carcinoma diagnosed in our pathology department between 2012-2022.We have evaluated the archival formalin-fixed, par- affin-embedded cases to detect abnormal p53nuclear protein accumulation using immunohistochemistry. For each cases, we assessed the percentage of positive cells and the intensity of staining comparing with normal adjacent prostate tissue. A cut-off of 50% of positive tumour cells was considered for p53 overexpression. Results: Mean age of patients was 70years old. The gleason score was 6 in 4cases,7 in 9cases,8 in 4cases,9 in 4cases and 10 in one case. ISUP grade was 1 in 4 cases,2 in 5 cases,3 in 4 cases,4 in 4cases and 5 in 5cases.Perineural invasion was described in 4 cases. Positive staining for p53 was found in 19 cases, however in 12 cases, less than 5% of cells were positive. Overexpression of p53 was found in 16,7. Gleason score was high (>=8) in 3 cases and ISUP grade was high (>=3) in 4cases. All patients with p53 overexpression developed resistance to hormonal therapy and 2 patients passed away because of distant metastasis. Conclusion: In the present study, high protein p53 levels of expres- sion was found in 16,7% and patients with p53 overexpression are more likely to develop hormone therapy resistance and poor out- come. However, p53 could be a potential marker for target therapy in the future mainly. PS-26-019 The potential of tumour microenvironment markers in the onset and progression of prostate cancer A.C. Ionescu*, M. Aschie, G.C. Cozaru, M. Deacu, E. Matei, G. Baltatescu, A. Nicolau, I.C. Iorga, I. Burlacu, I. Dode, C.I. Oras- anu, M. Enciu *Faculty of Medicine, “Ovidius” University of Constanta/ Insti- tute of Oncology „Prof. Dr. Alexandru Trestioreanu", Bucharest, Romania Background & objectives: The aim of the study was to study the potential of a selected panel of prostate tumour micro-environment markers to define molecular subgroups of prostate cancer and to predict progression of prostate cancer. Methods: We included 60 cases (prostate adenocarcinoma, benign prostatic hyperplasia and atypical lesions). Cases of adenocarci- noma showed a Gleason score ranging from 7 to 10, with a group grade of 3, 4 and 5. Three categories of immunohistochemically markers were used: for cancer activating fibroblasts (CAFs: CD34, Alpha SMA, Caveolin), vascular markers (CD31) and steroid hor- mone receptor markers (AR, PR, ER). Results: Hormone markers were expressed, to varying degrees, nuclear, epithelial and stromal cells, progesterone became nuclear positive only in stromal cells, while the expression of alpha SMA, Caveolin and CD 34 was quantified stromal, cytoplasmic and mem- brane. Statistically significant results were obtained for CD31, CD34 and progesterone. Conclusion: The research highlights a promising prognostic poten- tial for some of the evaluated markers, with an important role in their subsequent validation as biomarkers, and in developing new therapies based on their stratification into risk groups. Funding: This work was supported by the PROMETEU project, in the framework of Ovidius University of Constanta biomedical grant competition, contract no. 6 / 20.10.2021. PS-26-020 Defining the most concordant basal and luminal urothelial markers using transcriptomic data E. Olkhov-Mitsel, E. Slodkowska, Y.H. Yu, C. Sherman, M. Downes* *Sunnybrook Health Sciences Centre, Canada Background & objectives: Transcriptome expression profiles allow for prognostically significant stratification of urothelial carcinomas into basal and luminal subtypes. In this study, we used NanoString mRNA data to correlate with CK20, GATA-3, CD44 and CK5/6 immunohistochemistry to identify the most appropriate basal/luminal immunomarkers. Methods: A triplicate core tissue microarray of muscle invasive urothelial carcinomas was stained with known luminal (GATA3, CK20) and basal (CK5/6, CD44) markers. A subset were profiled for signature luminal and basal genes using a 23-gene NanoString chip. The area under the curve (AUC), sensitivity and specificity for each stain was calculated using SPSS. Results: 243 chemotherapy naïve cases were stained and 91 (37%) had transcriptomic profiling performed. Hierarchical clustering of the Nanostring data segregated cases into a luminal or basal cat- egory. CD44 positivity was significantly higher in CK5/6 posi- tive vs. negative cases (81.5% vs. 22.4%, p<0.001) and in basal vs luminal (89.8% vs. 43%, p< 0.001). CK20 positive cases were significantly more prevalent in GATA3 positive vs. negative cases (35.4% vs. 2.8%, p<0.001) as well as in luminal vs basal (35.2% vs. 0%, p < 0.001). There was a significant (p<0.001) correlation between the RNA expression levels and IHC measurements for S172