ECP 2023 Abstracts

S27 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 Background & objectives: Keloids are hyper-proliferative scars whose mechanism is still poorly understood. The aim of this study was to investigate the regulatory role of microRNAs (21 and 199) in the synthesis of collagen V (Col V) related to the progression of keloid. Methods: Skin biopsies from 14 patients and 6 healthy controls were studied. Keloid histologic assessment was performed with a graduation score from zero to 4. Semi-automated microscopic evaluation of keloid, immunohistochemistry, immunofluorescence, and quantitative RT-qPCR were performed. Results: Col V was overexpressed in keloid, mainly in Grade 4 compared to normal subjects and the remaining grades. A posi- tive association was found between Col V and thickened basement membrane of the dermo-epidermal junction and the number of der- mal immune cells. Significant association (ρ>0.50, P<0.01) was found between Col V in the papillary dermis, miR21, miR199, and lymphatic vessels; Col V in the reticular dermis and miR21. When correlated with the clinical-pathological characteristics, there was a significant association (ρ>0.45, P<0.05) between Col V in the pap- illary dermis and gender, fibrosis follow-up, and ethnicity; between Col V in the reticular dermis and ethnicity. Conclusion: Increased deposition of Col V and its correlation with histological graduation, miR21, and miR199 expression, suggest that Col V may affect the regulatory pathway of keloid through the control of miRNAs. These findings highlight the pathogenesis of keloid scars and the perspective of future treat- ment options. This work was supported by the Sao Paulo Research Foundation - FAPESP [Process numbers: 2018/20403-6, 2018/00415-0, and 2021/13220-5] and Foundation Faculty of Medicine. OFP-07-003 Hypoxia and ezrin expression in primary melanoma have high prognostic relevance U. Maccio*, A. Mihic, D. Lenggenhager, I. Kolm, C. Mittmann, M. Heikenwälder, A. Lorentzen, D. Mihic-Probst *Universitätsspital Zürich, Institut für Pathologie, Switzerland Background & objectives: Hypoxia affects tumour aggressive- ness and activates pathways associated with epithelial mesenchy- mal transition (EMT) which are crucial for tumour progress. The study investigates the correlation of hypoxia and EMT with sen- tinel lymph node status and tumour-specific survival in primary melanomas. Methods: CD34 for capillary count and Hypoxia inducible factor-1α (HIF-1α) as hypoxia indicators as well as Ezrin and L1-Cell Adhesion Molecule (L1CAM), both critical proteins con- tributing to EMT, were analysed using immunohistochemistry in 49 melanoma patients with long follow-up (F/U, mean 110 months; range 12-263 months). Results: We found a significant correlation between Breslow tumour thickness and Ezrin expression (p = 0.018). L1CAM expression in primary melanoma was significantly associated with HIF-1α expres- sion (p<0.0001) and sentinel lymph node metastasis (p=0.011). Fur- thermore, low capillary count, reflecting hypoxic condition, was sig- nificantly associated with Ezrin expression (p=0.047) and decreased tumour-specific survival (p=0.035). In addition, patients with high Ezrin expression in their primary melanoma had a dramatic loss of life early in their F/U period (mean survival time 29 months; range 15-44 month). Conclusion: Our results highlight the relevance of Ezrin, L1CAM and HIF-1α as prognostic markers in melanoma patients. Additionally, we demonstrate that hypoxia in primary melanoma affects epithelial mes- enchymal transition and is at least partly responsible for early metastatic dissemination. OFP-07-004 Does size matter in positive sentinel lymph nodes in melanoma? C. Lightner Ferrer*, C. Heffron *Cork University Hospital, Ireland Background & objectives: Sentinel lymph node (SLN) in melanoma is a core part of management of cutaneous malignant melanoma. Tumour burden within the SLN has been the subject of much debate. Our aim was to assess impact of tumour burden in our cohort. Methods: SLN received in our laboratory over a 10 year period were retrieved from our files. Data including size of metastases, Breslow thickness of original melanoma, subsequent completion lymphad- enectomy, recurrence (local or distal), metastases (local or distal) was recorded and analysed. Any pathologically documented follow up was also noted. Results: A total of 380 cases were retrieved, 296 (77.9%) were negative while 84 (22.1%) were positive with the size of the metastatic deposits ranging from isolated tumour cells to a 13mm deposit. As expected, positive cases had a higher average Breslow thickness (4mm v 2.4mm), higher stage (pT4 35.7% v 15.2%) as well as higher rate of recurrence or metastases (46.9% v 13.5%). A comparison of metastatic deposit size >1mm v 1mm or less (53.1% v 46.9%) showed both groups to have a similar rate of documented recurrence or metastases, 46.5% v 47.4% with an average Breslow thickness of 4.6mm and 3.4mm respectively. Both had similar rates of completion lymphadenectomy. Conclusion: Size >1mm has been used as cut off to determine further management decisions eg completion lymphadenectomy. Our data does not show any major differences when this cut off is used. There is now data suggesting giving adjuvant immunotherapy to patients with a deposit >0.3mm. It is clear that careful recording of the size of metastatic deposits in SLNs will be vital in determining the next stage of treatment in melanoma and thus analysis of any follow up data is merited. OFP-07-005 Immunohistological study of melanocyte stem cells A.A. Khan*, A.K. Yadav *Vardhman Mahavir Medical College, India Background & objectives: Vitiligo is characterized by marked reduc- tion of melanocytes. Re-pigmentation in vitiligo depends on the viable melanocyte stem cells (MelSCs) in lesional and perilesional skin. The objective was to evaluate the presence of MelSCs using CD34 and C-kit immunohistochemical markers. Methods: It’s a cross-sectional study in a tertiary care hospital. A 3mm punch biopsy from lesional and perilesional skin from 33 clinically diag- nosed vitiligo patients were sent for histopathological examination. The spec- imens were formalin fixed and paraffin processed. Sections of 3-4 micron were taken and stained with haematoxylin and eosin for vitiligo histological scoring and immunohistochemistry was performed for MelSCs evaluation. Results: In this study, male to female ratio was 0.83:1 with mean age at appearance of first lesion being 22.09 years. Mean histological score in lesional and perilesional skin in study subjects was 2.7 and 1.18 respec- tively. Vitiligo histological score was significantly higher in lesional skin as compared to perilesional skin ( p < .0001) suggesting an increased disease activity in lesional skin. Histological examination revealed presence of melanocytes and melanin pigment in many of the vitiliginous lesion but in significantly less number and concentration. We were unable to observe MelSCs due to decreased expression of CD34 and c-kit in lesional and perilesional skin and hence no correlation was established. Conclusion: Detection of melanocyte stem cells in vitiliginous lesion is important in understanding the pathogenesis and development of novel therapeutic models in this cell based era. The current study high- lights the importance of histopathology and immunohistochemistry in the assessment of disease activity in vitiligo. However, CD34 and C-kit