ECP 2023 Abstracts

S315 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 Methods: We compared the data resulting from fast (Ion S5) and ultra- fast NGS (Genexus) in the evaluation of non-small cell lung carcinoma (NSCLC) with HER2 (ERBB2) mutations identified for both platforms. The cases were analysed in order to verify a correlation between the morphological assessment of the percentage of tumour cells (PTC) and the allelic fraction detected by each of the methods. Results: The study was performed on a sample of 29 NSCLC, with 75.8% primary lung cancer and 93% FFPE tissue block material. The estimated average tumour cell content (PTC) of the sample used in both tests was 41.7%. Small samples with limited estimated tumour cell content (30%) corresponded to 38% of the cases. On the ultra-fast NGS platform, we observed a correlativity of 55% between PTC and AF for the detected variant. For fast-NGS, in 65.5%, there was a correlation between PTC and the allelic fraction (AF) detected. In the discordant group, the ultra-fast NGS analysis showed a greater AF detected compared to the fast method (3.6-10.1 points higher). Conclusion: The development of ultra-fast NGS tests has been imple- mented to expand molecular assays. Our study showed that in the majority of the cases there is a good agreement between the estimation of PTC and the AF for a rare mutation in lung cancer, detected by the ultra-fast and fast-NGS platforms. The greater agreement observed in the fast-NGS method can be explained by the need for adjustments in the emergent method’s workflow in order to enable its use in clinical practice. E-PS-15-040 PIK3CA hotspot mutations in circulating tumour cells in breast cancer G. Smagulova*, S. Yessentayeva, G. Kalmursayeva, A. Tulepbayeva, S. Kaus *Diagnostic laboratory, Gamma Lab, Kazakhstan Background & objectives: BC in terms of incidence ranks first among oncology diseases in women in Kazakhstan. Of these, more than 70% are women under the 60. PIK3CA mutations are often found in hor- mone-dependent,HER2-negative types of BC and can used for CTC identify. Methods: In total, 48 samples of BC were studied. 30 patients with luminal type A and B after therapy, 18 patients before therapy. Total 6 ml peripheral blood were used for LB. CTCs were isolated in a density gradient followed by morphological and molecular identification. DNA extraction kit for ctDNA and primary tumour DNA analysis was used. PIK3CA test kit real-timePCRkit was used. Results: PIK3CA tests performed for 48 patients with BC on primary tumour. Activating mutations in the PIK3CA gene were found in 20/48(41%) of cases in hormone-dependent and HER2-negative breast cancer. 16(80%) of which were due to E542K and E545K mutations. Liquid biopsy was performed for 7cases with PIK3СА positive primary tumour . PIK3CA positive CTC were found in all 5/7 cases BC with progression after hormone therapy. For that patients plasma ctDNA analysis also were PIK3CA positive. In 2/7 cases of oestrogen- and PIK3CA positive primary patients, PIK3CA-positive CTCs and cell free DNA were not detected. Primary patients underwent IHC testing for oestrogen, progesterone, Her2neu, and Ki67 concomitantly with PIC3CA tests. Conclusion: During CTC isolating in density gradient PIk3СA- positive DNA concentration in the Mononuclear cells fraction is less than in the cell free DNA fraction. Since targeted therapy with a selective inhibitor of the alpha isoforms of PIK3 is recommended for patients with mutated PIK3CA gene, it is advisable to include this genetic testing in the domestic Protocol for the diagnosis and treatment of breast cancer to determine the status of the PIK3CA gene simultaneously with the detection of the tumour immunophenotype. E-PS-15-041 EML4-ALK fusion variants and NTRK1 fusion in lung adenocar- cinoma – case report V. Sousa*, A. Alarcão, A.F. Ladeirinha, M.R. Silva, T. Ferreira, C. Eliseu, M. Viseu, V. Almeida, R. Almeida, G. Fontinha, A.L. Alves, L. Carvalho *IAP-PM - Universidade de Coimbra, CHUC, Portugal Background & objectives: According to published data, lung cancer continues to increase every year. It is important to study the new data obtained through the use of technologies that allows us to have greater knowledge of the changes that occur on these tumours. Methods: Authors present a case of a woman diagnosed with a lung adenocarcinoma. Mutation research was performed by next-genera- tion sequencing (Genexus, Oncomine Precision Assay Panel, Thermo Fisher Plataform). Manual macrodissection was performed and nucleic acid extraction was carried out with the MagMAX FFPE DNA/RNA Ultra Kit. Results: Several molecular alterations were detected. We found three different EML4-ALK fusion gene (EML4-ALK.E6aA20.AB374361.1; EML4-ALK.E6bA20.AB374362.1; EML4ALK.E6ins18A20.1), and one TPM3-NTRK1 fusion gene. ALK and NTRK1 gene fusion are associated with response with tyrosine kinase inhibitor therapy anti ALK and NTRK1 respectively. According to the last Non-small Cell Lung Cancer NCCN Guidelines, the presence of fusions in the ALK gene are associated with response to Lorlatinib and the presence of fusions in the NTRK1 gene are asso- ciated with response to Larotrectinib. There are ongoing clinical trials for each of the fusions in these two genes, but no ongoing clinical trials were found where the two fusions, EML4-ALK and TPM3-NTRK1, were present simultaneously. Conclusion: Patient started Brigatinib therapy for ALK rearrangement in August 2022. Molecular Tumour Board are important in complex molecular cases in order to identify the best therapeutic or clinical trials available. Studies show that the “short” and “long” forms of ALK fusions leads to differential responses to ALK TKIs, demonstrating that “shorter “ variants are associated with poor outcomes. It is important to under- stand the meaning of the various variants of mergers and to study the meaning of concomitant mergers. E-PS-15-042 Complex MET gene alterations in a lung adenocarcinoma – case report V. Sousa*, A. Alarcão, A.F. Ladeirinha, M.R. Silva, T. Ferreira, C. Eliseu, M. Viseu, V. Almeida, R. Almeida, G. Fontinha, A.L. Alves, L. Carvalho *IAP-PM - Universidade de Coimbra, CHUC, Portugal Background & objectives: MET mutations and/or amplifications are primary oncogenic drivers, in lung cancer with amplification being mechanisms linked anti-EGFR/ALK therapies resistance. Among MET mutations METex14 skipping is one the most frequent. A broad range of molecular alterations lead to METex14 skipping. Methods: Authors present the case of a woman with lung solid adeno- carcinoma. Mutation analysis was made by NGS (Genexus, Oncomine Precision Assay Panel, Thermo Fisher Plataform). Macrodissection was performed and nucleic acid extraction was carried out with the MagMAX FFPE DNA/RNA Ultra Kit. For MET gene the Oncomine Precision Assay Panel search: DNA Hotspots (SNVs/Indels), CNVs (polysomy/amplification), inter-genetic and intra-genetic fusions. Results: MET-MET.M13M15.1 variant was identified, which corresponds to MET exon 14 skipping. Two other muta- tions were also identified, c.3082+1G>A;p.? (47,5%) and c.3082+1_3082+2insA;p.? (25,8%), not knowing which protein