ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 E-PS-15-006 Novel diagnostic value of driver gene transcription signatures to characterise clear cell renal cell carcinoma, ccRCC Z. Ujfaludi*, L. Kuthi, G. Pankotai-Bodo, S. Bankó, F. Sükösd, T. Pankotai *University of Szeged, Faculty of Medicine, Institute of Pathol- ogy, Hungary Background & objectives: Describing and explaining cancer pheno- types manifestation of mutation in marker genes should be examined by comparative tools. The approach of this study was a first attempt to use genetic markers to predict transcription related alteration for diagnostics purposes. Methods: Subsequent to extraction of total RNA from snap-frozen normal and ccRCC tumour sections and reverse transcription, gene doses and expression of the main oncogenic drivers of ccRCC were measured by quantitative real-time PCR method, followed by cal- culation of absolute and relative quantities of 5 genes. Diagnostic value of the approach was examined by descriptive statistics using SigmaPlot 12.5 software package. Results: Determining the copy numbers of four tumour suppressors, VHL, SETD2, PBRM1 and BAP1, ccRCC tumorous and normal adjacent kidney tissues did not significantly differ. Moreover, the relative gene expressions of these genes did not correlate with the gene dosages. Our data revealed that the absolute mRNA levels and also the combined transcription profiles of the four aforementioned driver genes, supplemented by p14ARF, were significantly different in the tumorous samples than in normal ones. Using gene expression signature of four driver genes, ccRCC and normal kidney samples can be discriminated with 87 per cent sensitivity and 77% specificity. Besides, the expression of p14ARF can be used as an independent indicator. Conclusion: We showed that by calculating the median transcription values of the four ccRCC tumour suppressors of 3p25 and 3p21 chromosomal loci – VHL, SETD2, PBRM1, and BAP1 –, complemented that of the p14ARF, normal, and ccRCC tissues can be distinguished. However, proving that these markers can be suitable in the staging of the disease has not been inspected yet. Our results also highlight the importance of examining the manifestation of the genetic alterations lying behind tumour progression. Funding: This research was funded by the National Research, Development and Innovation Office grant GINOP-2.2.1-15-2017- 00052, NKFI-FK 132080 and 2019-1.1.1-PIACI-KFI-2019-00080, the János Bolyai Research Scholarship of the Hungarian Academy of Sciences BO/27/20, ÚNKP-20-5- SZTE-265 and UNKP-21- 5-SZTE-563. The work of LK was founded by the University of Szeged, Faculty of Medicine Research Fund-Hetényi Géza Grant (Grant No. 5S 340 A202) and the New National Excellence Programme (Grant No. UNKP-21-4-SZTE-131). E-PS-15-007 Pulmonary Adenocarcinoma: RET mutation in cfDNA NGS interpretation - case report L. Carvalho*, A. Ladeirinha, A. Alarcão, M.R. Silva, T. Ferreira, A. Rodrigues, C. Vilasboas, V. Sousa *1 Anatomical Pathology Department, Hospitais da Universidade de Coimbra, Centro Hospitalar e Universitário de Coimbra. 2 Insti- tute of Anatomical and Molecular Pathology, Faculty of Medicine of the University of Coimbra, Portugal Background & objectives: RET fusions through FISH/IHC/RT- PCR limit fusion partners recognition. NGS DNA/RNA allows fusion genes and splicing isoforms discrimination and fusion transcripts quantification. Liquid biopsies are FDA-approved/validated for cir- culating cell-free DNA (cfDNA) testing in advanced-stage solid sequences/acquired resistance to molecular therapy. Methods: A 70-years-old woman with Acinar Adenocarcinoma (CK7/TTF1+) dignosis in RU Lobetomy (2018). New lesions on PET-CT in 2019. Biopsy was performed: pulmonary Adenocarcinoma with EFGR mutated - c.2573T>G;p.(Leu858Arg). Erlotinib induced partial response; May 2021 started osimertinib therapy. In 2022, tissue re-biopsy and liquid biopsy were both analysed by NGS. Results: Tissue biopsy DNA and RNA analysed by NGS showed the following genetic alterations: EGFR (exon 21): c.2573T>G;p. (Leu858Arg) (17%) and MET Amplification (copy number 7,97). Analysis of liquid biopsy by NGS showed the following genetic changes: EGFR: c.2573T>G;p.(Leu858Arg)(1,5%); KRAS: c.175G>A;p.(Ala59Thr)(0,3%) and RET: c.2647G>T;p.(Ala- 883Ser)(0,1%). Conclusion: RET fusion occurs in 1–2% of NSCLC, particularly in younger non ‐ smokers and high risk for brain metastasis is established. MEN2B/MEN1/MEN2A germline mutations have to be considered when RET mutations present low allele frequency; tumoral heterogeneity will always be considered if RET mutations in follow up with higher frequency. NGS cfDNA potentiality for actionable RET mutations, identification, as well as resistance mechanisms after initial response/resistence rearranged RET. Non- invasive cfDNA testing simplifies RET-rearranged determination for TKIs follow up, preceding clinical imaging. E-PS-15-008 Predictive testing in stage-IV NSCLC within a network of collaborating hospitals B. Cajiao Garcia*, A. van der Wekken, S. Willems, L.C. van Kem- pen, E. Schuuring *University of Groningen, University Medical Center Groningen, Department of Pathology and Medical Biology, Groningen, The Netherlands Background & objectives: Molecular diagnostics is not performed for all eligible NSCLC patients. A better understanding of the hurdles that are encountered by healthcare professionals within the care chain is of pivotal importance to improve outcome for lung cancer patients. Methods: Pulmonary oncologists, pathologists and clinical sci- entists in molecular pathology in a collaborating network of 4 regional hospitals that submit predictive testing to an academic centre received a questionnaire addressing aspects of tissue avail- ability, turn-around-time, costs and logistics related to predictive testing. Results were discussed with the participating hospitals in a virtual meeting. A written report was returned to the participants. Results: Interviewed health care professionals were satisfied with the organization of predictive testing, but also identified room for improve- ment. When a tissue biopsy cannot be obtained (~10% of all stage 3b-4 lung cancer patients), access to comprehensive testing on a liquid biopsy needs to be organized. Molecular testing is preferred over PDL1 and ALK immunohistochemistry when tissue is limited. Although turn- around times for comprehensive analysis of mutations and gene fusions is acceptable (10-15 business days), sample flow and reporting could be further improved to expedite the results. To identify patients who may benefit from adjuvant targeted therapy, predictive testing should be expanded to stage 1-2 in lung cancer patients. Conclusion: Active discussions between health care professionals are essential to find opportunities to further improve care for lung cancer patients. This study have led to proposals for improvement that will be evaluated in Q4 2022. S306