ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 Background & objectives: PI3K/Akt pathway in renal cell carcinoma progression, metastasis, resistance to therapies has not been investi- gated clearly. TFE3 expression is related to worse prognosis in renal cell carcinoma in several studies. We tried to find relation between TFE3 and PI3K/Akt pathway. Methods: Human renal cell carcinoma cell lines UOK146, Caki- 1, and Caki-2 were maintained in DMEM supplemented with 10% foetal bovine serum. TFE3 down regulation was done by small interfering RNA transient transfection in UOK 146 cells. TFE3 overexpression was don by transient transfection in Caki-1 and Caki-2 cells. Western blot analysis was done for TFE3 and phos- pho-Akt, and Akt. Results: The PI3K/Akt signalling pathway serves an important role in renal cell carcinoma for the regulation of cell proliferation, differentiation and survival. When TFE3 was down regulated with TFE3 specific siRNA, phospho Akt was decreased, significantly (p<0.001). When TFE3 was upregulated with TFE3 transfection, phosphor Akt was increased, significantly (p<0.001). Conclusion: TFE3 was related with PI3K/ AKT pathway in renal cell carcinoma. Our result suggest an important role for PI3K/Akt inhibitors as a potentially useful treatment for patients with renal cell carcinoma. PS-MD-01 | Poster Session Molecular Diagnostics Pathology Symposium PS-MD-01-001 EIF1AX mutations in thyroid nodules: analysis of a series of 1095 consecutive cases F. Chiarucci*, D. de Biase, A. De Leo, A.G. Corradini, M. Sirolli, G. Simoncini, A. Orsatti, L. Di Sciascio, T. Maloberti, S. Coluc- celli, G. Tallini *Department of Experimental, Diagnostic and Specialty Medicine, Alma Mater Studiorum—University of Bologna, Italy Background & objectives: EIF1AX, on X chromosome (Xp22.12) encodes an essential eukaryotic translation initiation factor (eIF1A). EIF1AX mutations are RAS-like genetic changes found in a minority of thyroid nodules. Little is known about their prevalence and correlation with thyroid pathology in Europe. Methods: Between February 2019 and December 2021 we analysed 1095 samples (709 cytology and 386 FFPE histology specimens) using a NGS panel including 330 genomic regions and comprising EIF1AX (exons 1, 2, and chrX intronic region g.20148634–20148745). Results: Amplifiable DNA was obtained in 1029 of 1095 samples (cytology: 654/709, 92.24%; FFPE histology 375/386, 97.15%). EIF1AX mutations were found in 15/1029 cases (1.46%). Mutated cytology specimens: 1/48 (2.08%) BETHESDA-I (histology: hyperplastic nodule); 2/125 (1.60%) BETHESDA-II (histology: one follicular adenoma, one hyperplastic nodule); 4/234 (1.71%) BETHESDA-III (all without histology follow-up); 1/100 (1.00%) BETHESDA-IV (histology: hyperplastic nodule); 1/61 (1.64%) BETHESDA-VI (histology: undifferentiated thyroid carcinoma; PIK3CA and TERT promoter were also mutated). Mutated histol- ogy specimens: 1/38 (2.63%) hyperplastic nodules; 5/79 (6.33%) follicular adenomas. In addition to the undifferentiated carcinoma, EIF1AX mutations co-existed with additional mutations (NRAS- p.Q61R: two cases; HRAS-p.Q61K, GNAS-p.A201H, TSHR-p. F631L: one case each) in 5/1029 (0.48%) cases, all with benign diagnoses. Conclusion: EIF1AX mutations are RAS-like alterations found in benign follicular-patterned thyroid nodules (hyperplastic nodules and follicular adenomas) where, in a small minority of cases, they may co-exist with other RAS-like mutations. No EIF1AX mutations were found in 172 papillary, 14 follicular, 12 oncocytic, 10 medullary carcinomas. The only malignant tumour with EIF1AX mutation in the series was an undifferentiated carcinoma with co-mutated highly pathogenic alterations (PIK3CA and TERT promoter). Isolated EIF1AX mutations are not a marker of malignancy in thyroid nodules. PS-MD-01-003 First steps in molecular classification in endometrial carci- noma: experience in a low income country H. Douik*, R. Doghri, G. Sahraoui, M. Ghalleb, M.N. Rajoua, O. Azaiez, M. Hechiche, M. Kharrat, K. Mrad, L. Charfi *Salah Azaiz Institute of Cancer, Tunisia Background & objectives: The Cancer Genome Atlas (CGA) catego- rized endometrial cancer into four genomic groups combining POLE mutational analysis with immunohistochemical analysis of p53 and mismatch repair (MMR) proteins. We aimed to evaluate feasability of this new classification of endo- metrial carcinoma in routine. Methods: Searching POLE mutations in exons 9 to 14 was performed by SANGER sequencing on frozen tumoral material. Mismatch repair genes deficiency (MSH2, MSH6, MLH1, PMS2) was assessed by either immunohistochemistry and/or MSI statement using the PCR real-time based molecular idyllaTM system testing, on formalin fixed and paraffin embedded (FFPE) tumoral tissue. P53 was evaluated by immunohistochemistry on FFPE. Results: We achieved molecular classification in twenty endome- trial carcinoma cases. Our first results revealed 3 new silent mutations in exons 9 and 10 and a novel stop mutation at exon 13 of POLE gene: One patient carries two silent mutations in respectively exon 9 and 10 with and MSS status and a normal expression of P53; a second patient with a silent mutation at exon 9, is deficient in MLH1 and PMS2 protein and normal expression of P53; the functional mutation at exon 13 concerned a woman with proficient MMR protein and a focal immunostaining of P53. 50% of patients without any mutation in POLE gene were MSI and P53+. Conclusion: Our first step in molecular classification of endome- trial cancer highlighted new mutations in POLE gene. Our expe- rience showed that molecular classification is quite complex in routine. Pole mutation is somewhat tedious because of the need of frozen tissue and the technique is long. Immunohistochemis- try needs good practice in pre-analytical step and idylla technique could be an alternative solution. PS-MD-01-004 Genomic landscape of 63 samples of 29 Hungarian breast can- cer patients A.M. Tőkés*, O. Pipek, D. Alpár, O. Rusz, Z. Udvarnoki, I. Csabai, C. Bödör, L. Madaras, Z. Kahán, B. Kővári, J. Kulka *Semmelweis University, Hungary Background & objectives: Incidence of breast cancer (BC) in Hun- gary is similar to neighboring Central European countries, however, BC mortality is much higher. It is of importance to characterize commonly affected genes in specific patient populations in order to efficiently aid targeted therapies. Methods: We performed whole genome sequencing of 63 sam- ples of 29 Hungarian BC patients using the Illumina NovaSeq S185