ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 PS-24-007 Influence of tobacco cigarettes on the oral mucosa V. Gargin*, R. Nazaryan, L. Kryvenko, Y. Zakut, T. Popova *Kharkiv National Medical University, Ukraine Background & objectives: Despite well-documented adverse effects of tobacco consumption, mechanism of its influence on oral mucosa is not clear. The objective of the performed research was to assess the effect of smoking on the morphofunctional state of periodontal tissues in young animals. Methods: 30 ten-week-old WAG rats were randomly distributed in two groups, as follows: control animals and tobacco exposed. Smoking was generated using the Boyarchuck chamber operated in a one-pass mode with the smoking feed controlled externally by a metering pump. Morphologic study with morphometry was performed. Results: Morphological study of oral mucosa was carried out after removing the animals from the experiment on the 90th day. The study of histological specimens of the experimental group showed moderate hyperkeratosis of the epithelium. Own plate was found with acanthotic cords with increased number of fibroblasts, single leukocytes, sclerosis of the reticular layer. The vessels of microcir- culatory bed have been characterized by uneven blood filling with background of isolate vessels that have fallen lumens and presence of blood-empty arterioles and capillaries with signs of constriction. Endotheliocytes are flattened with signs of desquamation in focus of ischemia in slides stained according to Rego. Conclusion: Morphometric study proves reducing vascular density from 19,44±1,97% to 10,01±1,33 %, increasing area of connective tissue from 18,33±2,71% to 29,54±1,87%, spreading area of tissue with ischemia from 1,14±0,70% to 7,44±1,60%. Morphofunctional changes in the periodontium with damage to the structure of the epithelial membrane and changes in its permeability, microcirculatory disorders, sclerotic changes are a manifestation of the initial inflammatory and dystrophic processes that can lead to persistent chronic process in oral mucosa. Funding: This study is the part of scientific research work “Opti- mization of early diagnosis, prevention and treatment of oral tis- sue diseases with smoking addiction”, № 0120U102057, Kharkiv National Medical University, and is funded by Ministry of Health of Ukraine. PS-24-008 Prevalence of vessels encapsulating tumour clusters (VETC) in human cancers S.L. Renne*, R. Akpinar, M. Coto-Llerena, L. Terracciano, L. Di Tommaso, S. Piscuoglio *Humanitas Clinical and Research Center – IRCCS, Humanitas University, Department of Biomedical Sciences, Rozzano, Italy Background & objectives: VETC shields tumour-cell clusters, pro- moting free circulation in the bloodstream. This mechanism of metas- tasization is an alternative to the epithelial-to-mesenchymal transition process, and has been recently described in hepatocellular carcinoma (HCC), however the prevalence of VETC among cancers is unknown. Methods: We assessed the VETC prevalence on a retrospective series of 1861 neoplastic samples from 1796 patients comprising 24 different histologies. VETC was defined as continuous endothe- lial covering of neoplastic clusters and highlighted by CD34 immu- nohistochemistry. Analysis was performed on a tissue microarray by experienced pathologists blinded to clinical and pathological data. Results: VETC was present in 73/1769 cases (4%) and in 10/23 histotypes (44%). The histotypes that had VETC+ cases were renal cancer (RCC) 29/115 (25%), HCC 23/102 (23%), prostate cancer (PRC) 7/42 (17%), mesotheliomas 2/17 (12%), pancreatic cancer 4/84 (5%), oesophageal cancer 2/72 (3%), and gastric cancer 3/158 (2%). Colorectal, extrahepatic bile duct, and urinary bladder can- cer had one VETC+ case each. Cases with VETC+ tended to be associated to the intermediate histologic grade (G2; p<0.0001). Age, size, survival, and status were similar between the two groups. Conclusion: VETC is present across different histotypes and might represent an alternative mechanism of metastasis. Even if present in a minority of cases, VETC was peculiar of some histotypes (especially HCC, RCC, PRC), possibly representing a histotype- specific angiogenetic mechanism. Since VETC predicts response to tyrosine kinase inhibitors, further studies are warranted to assess the prognostic and predictive value of this peculiar vascularization type. PS-24-009 FABP1 expression in human tumours: a tissue microarray study on 17,071 tumours D. Dum, C. Bernreuther, A. Luebke, V. Reiswich, R. Simon, D. Höflmayer, A. Marx, S. Minner, T.S. Clauditz*, T. Krech *University Medical Center Hamburg, Germany Background & objectives: Fatty acid binding protein 1 (FABP1) is a key protein for the metabolism of fatty acids. It is abundantly expressed in the liver (10%of cytosolic proteins). Because of its high tissue specificity, immunohistochemical FABP1 is thought to have diagnostic utility. Methods: A set of tissue microarrays containing 17,071 samples from 150 different tumour types and subtypes as well as 608 samples of 76 different normal tissue types was analysed by immunohistochemistry, to comprehensively determine the patterns of FABP1 expression in normal and neoplastic tissues. Results: Among normal tissues, strong FABP1 immunostaining occurred in hepatocytes, proximal tubuli of the kidney and in epithelial cells of the small intestine, appendix, and the colorec- tum. FABP1 positivity was found in 24 of 150 tumour categories, including 17 with ≥1 strongly positive case. The highest FABP1 positivity rates were seen in colorectal adenomas (86%), colorec- tal adenocarcinomas (71.1%) and in hepatocellular carcinomas (65.3%), followed by mucinous carcinoma of the ovary (34.6%), cholangiocarcinoma (21.6%), and various adenocarcinomas from the digestive tract (10-23%). In colorectal cancer, reduced FABP1 expression was linked to microsatellite instability, right-sided tumour location (p<0.0001 each), and absence of BRAF V600E mutations (p=0.001), but unrelated to pT and pN status. Conclusion: FABP1 immunostaining has considerably high tumour specificity. As FABP1 expression is virtually absent in adenocar- cinomas of the lung, FABP1 immunohistochemistry might be par- ticularly helpful to assist in the identification of metastatic adeno- carcinoma to the lung. PS-24-010 The impact of display variability in digital pathology J. Rostang*, B. Diricx, J. De Vylder, T. Bisson, R. Carvalho, M. Franz, P. Hufnagl, T. Kimpe, N. Zerbe *Barco N.V., Kortrijk, Belgium Background & objectives: Digital visualization should enable accu- rate clinical diagnosis in line with conventional pathology. Therefore, the display plays a crucial role. In this research project we evaluate S166