ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 Conclusion: In colorectal carcinoma, NK cells are present in very low density in tumour tissue. Their number in situ does not signifi- cantly impact overall survival. PS-07-027 Prognosison the pre-treatment immunological characteristics of neoadjuvant therapy in oesophageal squamous cell carcinoma Y. Liu*, J. Li *The Fourth Hospital, China Background & objectives: The expression of PD-L1 and tumour- infiltrating lymphocytes (TILs) in tumour microenvironment can predict the prognosis in oesophageal squamous cell carcinoma (ESCC). This study aims to explore the prognosis of pre-treatment immunological characteristics in ESCC before the neoadjuvant therapy (NAT). Methods: A total of 205 patients who receive 2-3 cycles of NAT and was surgically resected between 2015 and 2020.The expression levels of PD-L1, CD4+, CD8+, FOXP3+ and CD20+ cells before the NAT were observed. The patients were randomly divided into the training set and the validation set, and then the nomograms were drawn to predict the patient prognosis. Results: The expression of PD-L1 before the NAT was positively correlation (P <0.05)with different types of TILs, with a posi- tively related trends to the level of histological grade and lymph node metastasis status. The expression levels in TILs are positively correlated with postoperative histological grading, negatively con- nected to postoperative tumour size( P <0.05). We build two prog- nostic models and further verify it, results show that the predictive lymph node metastasis status model and the predictive depth of tumour infiltration model based on the expression level of PD-L1 and TILs of pre-NAT show a good consistency and have good predictive capabilities compared with ideal models. Conclusion: The higher of TILs expression in ESCC, the higher of the expression of PD-L1, CD4+, CD8+, FOXP3+ and CD20+ cells. There is a raising trend of histological grade with a high-TILs in the pre-NAT ESCC patients, and the higher the chance of lymph node metastasis. Two predicted models have a moderate to good discrimination and consistency, which can provide the predictive value for the ESCC patients before the NAT, and it also can provide references for clinical precision treatment. PS-07-028 Adding a zero Buds group (BD0) in the tumour budding scoring system in colorectal carcinomas: is it relevant? I. Helal*, M. Ben Thayer, F. Khanchel, S. Fkih, R. Hedhli, E. Ben Brahim, R. Jouini, A. Chadli *Habib Thameur Hospital, Tunisia Background & objectives: The validated Budding scoring system is made up of 3 groups: BD1(0–4 buds), BD2(5–9 buds), BD3(≥10 buds). A recent study suggested adding a fourth group with zero Buds(BD0). We aim to study the accuracy of the onset of BD0 category Methods: Our study included retrospectively patients who were operated on for CCR during a four-year-period from 2013 to 2016. Patients who received neoadjuvant treatment were excluded. We performed conventional BD scoring for all cases. We divided the BD1 group into two groups BD0 (0 buds/0.785 mm2) and BD1*( 1–4 buds/0.785 mm2 ). We studied the differences between these two groups. Results: Our sample of 133 patients consisted in 75 men and 58 women. According to the conventional BD scoring system, 67carci- nomas were BD1, 33 were BD2 and 33 were BD3. The BD1 group was divided into two groups: 22 BD0 and 45 BD1*. Comparing the two groups, we found no statistically significant difference between BD0 and BD1* groups regarding age(p=0.5), tumour size(p=0.5), tumour grade(p=0.6), T stage, N stage(p=0.5),M stage(p=0.1), AJCC stage (p=0.2), vascular invasion(p=1), peri- neural invasion(p=0.7) and overall survival( p=0.9). However, when we compared the four groups(BD0, BD1*,BD2,BD3), there was a statistically significant association between BD and perineu- ral invasion(p=0.02) , M stage (p=0.05), AJCC stage (p=0.03) and overall survival(p=0.02). Conclusion: BD is ever arousing pathologists’ interest in the latest years. The onset of a BD0 category has recently been proposed. Our study revealed that there were no statistically significant dif- ference between the two groups BD0 and BD1* regarding the main histoprognostic factors and the overall survival. These findings suggest that adding a fourth group BD0 wouldn’t have an additional relevance. However, further and larger studies are needed to assess the accuracy of adding the BD0 group. PS-07-029 Microsatellite instability (MSI) immunohistochemistry (IHC), colorectal cancer and Lynch syndrome (LS) genetic testing – one year experience at UK District General Hospital A. Bommana*, R. Swamy *Lister Hospital, United Kingdom Background & objectives: BRAFV600E mutation followed by MLH1 promoter hypermethylation to identify LS in colorectal can- cer is practised at our centre. This algorithm is followed for cases with loss of MLH1 IHC expression. We audited our practice to identify LS in colorectal cancers. Methods: 209 colorectal cancers with their MSI IHC results reported during 2021 at our department were retrieved. Cases with loss of MLH1 IHC expression were identified. BRAF status ana- lysed by New Genomic Sequencing (NGS) DNA panel and MLH1 promoter hypermethylation test results were recorded. Results: 43 cases with loss of MLH1 and PMS2 IHC expression were identified. NGS showed wild-type BRAF in 9 cases. MLH1 promoter hypermethylation was present in 2/9 but absent in 4/9 cases with wild type BRAF. Thus 4/43 cases with loss of MLH1 IHC expression, wild type BRAF and no MLH1 promoter hypermethylation were identified as LS colorectal cancers. The subsequent results following MLH1 IHC testing were not available in time for discussion of treatment options at colorectal Multidisciplinary meeting (MDM) in 7 of these cases. Pathologist did not request MLH1 hypermethylation test in time for 3 cases and negative MLH1 hypermethylation result became available in 4 cases, after MDT discussion. Conclusion: NICE and Royal College of Pathologists recommend MSI IHC testing in colorectal cancer to detect LS but awareness of its value to guide treatment decisions is lacking. People with LS have colorectal cancers that respond more favourably to immuno- therapy and unfavourably to conventional chemotherapy regimens that include 5-Flurouracil. Pathways to facilitate timely MSI testing for district general hospitals which rely on external genomic labora- tories for cancer molecular work-up needs to be addressed. PS-07-031 Morphological spectrum and clinicopathological correlation in appendiceal mucinous neoplasms (AMN) and pseudomyxoma peritonei (PMP): retrospective histopathology review of cases seen at a tertiary care institution between Jan 2012-June 2019 K. Deodhar*, A. Jadhav, S. Mokal, R. Kaushal, M. Bal, M. Ramadwar S98