ECP 2023 Abstracts

S37 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 agreement (Fleiss’s κ; 95% confidence interval, CI) were performed by R Software (v 4.2.2) and irr (interrater reliability package). Results: Both assays have demonstrated a significant ICC (p<0.001) using CPS≥10 as a cut-off value: 22C3=0.939 (CI:0.913-0.96); SP263=0.972 (CI:0.96-0.982); combined 22C3-SP263=0.909 (CI:0.874-0.938). Fleiss’s κ confirmed an almost perfect agreement among pathologists and assays: 22C3=0.938 (CI:0.857-1.018); SP263=0.972 (CI:0.890-1.052); combined 22C3-SP263=0.907 (CI:0.869-0.945). Conclusion: Both 22C3 pharmDx, which was used in the KEYNOTE studies, and SP263 are approved in Europe and can be reliably per- formed in mTNBC, providing that each assay is used on the dedi- cated platform (Dako and Ventana, respectively). The inter-observer reproducibility ranges from perfect to almost perfect in both assays, confirming that PD-L1 with CPS should be assessed by specifically trained pathologists. The validation and harmonization of the assays is warranted to provide a high-quality PD-L1 CPS test in mTNBC. This work was partially supported by the Italian Ministry of Health with Ricerca Corrente 5 x 1000 funds Mariia Ivanova was supported by Fondazione Umberto Veronesi. Konstantinos Venetis was supported by Fondazione IEO – MONZINO. OFP-09-014 Tumour infiltrating lymphocytes and neutrophil-to-lymphocyte ratio before neoadjuvant therapy in relation to prognosis of triple negative breast cancer Y. Liu*, M. Zhao *The Fourth Hospital of Hebei Medical University, China Background & objectives: To explore the correlation between the peripheral blood neutrophil-to-lymphocyte ratio (NLR) and tumour infiltrating lymphocyte (TIL) before neoadjuvant therapy (NAT) and the prognosis of patients with triple negative breast cancer. Methods: A total of 126 patients with TNBC who received NAT were screened out. PD-L1 (22C3), TILs, CD8+TIL and FOXP3+TIL were detected by immunohistochemistry in core needle biopsy specimens before treatment, and NLR was calculated. Kaplan-Meier analysis was used to estimate survival rates. Univariate and multivariate analyses were performed using Cox proportional hazards regression. Results: Univariate analysis showed that high T stage, lymph node involvement, lymphovascular invasion, high NLR, low TILs density and high CD8+ TIL were associated with poor overall survival (OS) and breast cancer-specific survival (BCSS). Multivariate Cox regres- sion analysis showed that high NLR (HR= 36.182, 95%CI: 4.120- 317.759, P=0.001) and high CD8+ TIL density (HR=0.182, 95%CI: 0.044-0.754, P=0.019) were independently associated with poor OS. Similarly, high NLR (HR=23.989, 95%CI: 2.275-252.131, P = 0.008) was independently associated with worse BCSS. Conclusion: NLR may be able to predict the prognosis of patients with triple negative breast cancer after neoadjuvant therapy. OFP-09-015 Frozen section vs touch imprint for intraoperative evaluation of sentinel lymph nodes of breast cancer patients in neoadjuvant set- ting: a systematic review and meta-analysis M. Huerta-Rosario*, C. Quispe-Vicuña, D. Julca-Marin, L.M. Acuña- Chavez, F. Medina-Navia, H.K. Baltazar-Ñahui, C.J. Zumarán-Nuñez *Universidad Señor de Sipán, Red de Eficacia Clínica y Sanitaria, REDECS, Lima, Peru Background & objectives: Evaluation of frozen section (FS) or touch imprint (TP) in neoadjuvant setting is challenging due to therapy effect. Some studies suggested that TP may not be the appropriate method. Our objective is summarizing evidence on these techniques after neo- adjuvant therapy. Methods: PubMed, Embase, Scopus and Web of Science were sys- tematically searched until September 2022 for studies evaluating the diagnostic accuracy of FS and TP in BC patients who underwent neo- adjuvant therapy. A meta-analysis was planned using a random-effects model to estimate pooled effects. Study quality was assessed using the QUADAS-2 tool. GRADE criteria were used to identify the certainty of evidence. Results: 17 studies were included. Regarding TP, at lymph node level the pooled sensitivity and specificity was 0.55 (96% CI) (0.33-0.76) and 1.0 (0.98 -1.0), respectively. At patient level, TP had a pooled sensitiv- ity and specificity of 0.74 (0.50 - 0.89) and 0.99 (0.82-1.00), respec- tively. Regarding the FS, at lymph node level, the pooled sensitivity and specificity was 0.86 (0.81- 0.90) and 1.00 (0.94 -1.00), respectively. At patient level, FS reports a sensitivity and specificity of 0.79 (0.72-0.84) and 1.0 (0.0-1.0), respectively. For most studies, risk of bias was low. Also, for both techniques, the sensitivity had a very low to moderate certainty and the specificity had a high certainty. Conclusion: Both diagnostic techniques showed very high specific- ity. Although at lymph node TP had a low sensitivity, at patient level the sensitivity was comparable for both technics. The low certainty in some results would indicate the need for future methodologically better studies. OFP-10 | Joint Oral Free Paper Session Digital and Computational Pathology and Other Topics (EM / DEVEL / CARD) OFP-10-001 Diagnostic electron microscopy of endomyocardial biopsies V. Papa*, C. Baldovini, M. Riefolo, O. Leone, G. Cenacchi *Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy Background & objectives: Endomyocardial biopsy is an impor- tant invasive procedure in suspected non-ischemic cardiomyopathy patients. Histological data can need ultrastructural examination for a more detailed differential diagnosis. We aimed at clarifying the diag- nostic role of Electron Microscopy (EM) in primary and secondary cardiomyopathies. Methods: Endomyocardial biopsies obtained from patients with sus- pected non-ischemic cardiomyopathy between January 2001 and March 2023 at S. Orsola Hospital were studied. For EM analysis, the sam- ples were fixed in 2.5% glutaraldehyde and post-fixed in 1% osmium tetroxide, then dehydrated in ethanol and embedded in epoxic resins. Ultrathin sections were examined under a transmission EM Philips 410. Results: Altogether 466 biopsies were analysed, 123 of which revealed non-specific changes as presence of glycogen, lipid and mitochondrial accumulations. In 122 cases EM confirmed the his- tological signs of amyloidosis showing extracellular 7-10 nm non- branched fibrils, while in 34 cases the diagnostic ultrastructural markers were useful for the differential diagnosis as follows: mito- chondrial paracristalline inclusions and/or shape and size abnor- malities (mitochondrial cardiomyopathy); lysosomal lamellated zebra-bodies inclusions in cardiomyocytes (Fabry disease); basal membrane in the inner side of autophagic vacuoles (Danon dis- ease); ovoidal/polygonal extracellular deposits (cardiac ochronosis); many electrondense iron-containing particles (sized <12 nm) free in the cytoplasm or in single-membrane-bound lysosomal bodies (haemocromatosis); curvilinear bodies and concentric mielin figures (hydroxychloroquine cardiotoxicity). Conclusion: The diagnostic role of EM was especially evaluated in the vacuolar degeneration of cardiomyocytes, commonly encountered during routine histological examination, in which EM can often reveal their content to differentially diagnose various lysosomal storage dis- eases, mitochondrial cardiomyopathy or autophagic degeneration; moreover EM can be useful in overcoming histological sensitivity