Background ESD is the gold standard treatment for large sessile adenomas yet US adoption rates are low. In ESD, tissue is cut only when the scope tip, with hot knife extended, is moving; this requires different skills than needed for snare polypectomy (scope tip held still). Scope tip control and ESD training methods are needed. A program including an inanimate figure tracing model (FTM; Model1), ex vivo pig stomach model (PSM; Model2) and bovine colon model was devised. This paper concerns preliminary results for models 1 and 2.Methods A straight hollow plastic tube with a window cutout 15cm from its end was used for both models (slotted sponge = “anus”). For the FTM a paper with a line figure is placed in the window. After endoscope insertion and positioning the figure is traced with a catheter "pen"; 8 tracings (4 figure types) and 1 pig ESD were done per session. In the PSM a piece of pig stomach and Bovie pad was placed over the window. After “lifting” the mucosa ESD resection of a "polyp" was done. Time/accuracy were tracked for both models as were bowel wall injuries in the PSM.Results A total of 30 FTM sessions and PSM cases were done (2 trainees). Completion times and accuracy improved over 8 FTM sessions for less experienced trainee A but not for trainee B. A total of 29/30 PSM cases were completed. The number of deep muscle injuries decreased with time, however, case length correlated with tissue quality and not number of cases. Lifting and tissue conductivity problems were noted in poor quality tissue.Conclusions Despite model related issues, both models are feasible and allow trainees to learn scope tip control and ESD; clearly, more study is needed. A smaller diameter tube and use of fresh stomach are advised.

Introduction: Expression of Osteopontin (OPN) and Matrix Metalloproteinase 2 (MMP 2) are elevated in CRC. OPN is an integrin binding phosphorylated glycoprotein implicated in cell-mediated immunity, inflammation, tumor progression, and cell viability. OPN is secreted by macrophages and leukocytes. OPN activity is associated with the PI3K/AKT and ERK pathways and VEGF mediated tumor angiogenesis. MMP-2 degrades type IV collagen and facilitates tumor cell invasion and metastasis. MMP-2 also promotes tumor angiogenesis. This study’s first purpose was to compare preoperative (PreOp) plasma OPN and MMP2 levels in CRC and benign pathology (BP) patients (pts); the 2nd purpose was to assess the combination of these proteins for diagnosis. Method: PreOp plasma samples obtained from consenting CRC and BP pts undergoing surgery were used for this study. Prospectively gathered demographic, clinical and pathologic data were analyzed. Plasma levels of OPN and MMP2 (ng/ml) were measured via ELISA and reported as median + 95% CI. The receiver operating characteristic (ROC) curve and area under the ROC curve (AUC) were used to evaluate the diagnostic value of each protein alone and in combination. Expression levels of OPN and MMP2 were determined in tumor and normal tissue for a subset of pts by QRT-PCR. The Mann-Whitney test was used for analysis. Results: Plasma from 156 CRC (73% colon, 27% rectal) and 102 BP (polyp 32%, diverticulitis 56%, other 12%) pts was studied. CRC stage breakdown was: 1, 26%; 2, 33%, 3, 29%, 4, 12%. CRC median preop plasma levels were significantly higher vs. the BP group for both proteins [OPN; 82.4,CI:75.4, 89.5 vs 59.2, CI:53.8,63.3;MMP2; 203.6,CI:195.0,214.5 vs 160.2,CI:151.9,172.2; P<0.0001). Higher OPN levels were noted in stg 3(p=0.04) and Stg 4(p=0.01) vs stg 1 pts. The AUC value for the ROC curve for OPN and MMP2 were 0.73 and 0.73 respectively with 61% and 70% specificity. The AUC for the 2 protein combination was 0.80 with 65% sensitivity and 80% specificity. OPN and MMP2 expression was elevated in 75% and 50% of CRC tumors tested, respectively (n=12). Conclusion: Median CRC OPN and MMP2 levels were significantly higher (39% and 27%) than BP levels. OPN and MMP2 expression was confirmed in a subset of pts. This 2 protein combination improved the AUC and specificity for CRC diagnosis. Further study with more protein combinations is warranted. Citation Format: Chandana S. k. Herath Mudiyanselage, Hiromichi Miyagaki, Neil Mitra, Yanni Hedjar, Xiaohong Yan, Vesna Cekic, Joseph Martz, Jennifer Agnew, Richard L. Whelan. Osteopontin and matrix metalloproteinase 2 plasma levels are elevated in colorectal cancer (CRC) vs benign disease; The 2 protein combination improves specificity as regards CRC diagnosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1415.

Introduction: Cancer-Testis antigens (CTA’s) are normally expressed in germline tissue, however, aberrant expression occurs in some cancers. Restricted CTA expression in normal tissues make CTA’s potential vaccine targets. CTA’s have been associated with tumor cell proliferation and invasion. The CTA A-kinase anchor proteins 4 (AKAP 4) plays a role in cancer development and progression. The expression pattern of AKAP4 gene in CRC is not well characterized. This study’s aim was to assess AKAP4 expression in CRC and to assess this CTA’s potential as a vaccine target. Methods: CRC patients (pts) undergoing surgery who donated tissue to an IRB approved tissue/data bank comprise the study group. Demographic and pathologic data were assessed. Tissues were OCT embedded and stored at -800C. Total purified RNA was isolated from tissue samples and cDNA synthesized. AKAP4 expression was analyzed by quantitative PCR (QPCR) using EXPRESS qPCR universal Supermix and Taqman assay. Comparative quantitative analysis was performed based on the delta-delta Ct method with GAPDH as internal control. Tumor and testis AKAP4 expression levels were determined; tumors with levels 0.1% or more than the testis was considered positive. Immunohistochemistry (IHC) was performed on a subset of tumor and normal tissue. The impact of tumor location and cancer stage on AKAP4 expression was determined and assessed (Wilcoxon signed rank test). Results: 70 paired CRC and normal tissue specimens (35 M/36 F, age 67.8±14) were studied (86% colon,14% rectal; cancer stage: 1, 24%; 2,37%; 3, 31.%;stg 4, 7%). The percent of pts with a relative Malignant to Normal tissue AKAP4 expression ratio (MN) over 1 was 17%; the percent with both MN ratio over 1 and expression levels above 0.1% of testis levels was 16%. IHC demonstrated AKAP4 in a subset of CRC tumor samples. No significant difference was noted between colon vs rectal, or cancer stage groups. No expression was found in 21 normal samples. Discussion: In a tumor subset the relative expression of AKAP4 was above that of normal colon and more than 0.1% of testis expression. IHC study demonstrated the antigen in CRC tumors. A larger study is needed determine if AKAP4 expression correlates with T, N, or final tumor stage. AKAP4 holds some promise as a vaccine target. Citation Format: Chandana S. K. Herath Mudiyanselage, Neil Mitra, Otavia L. Caballero, Dasuni N. Gamage, Xiaohong Yan, Vesna Cekic, Joseph Martz, Richard L. Whelan. Assessment of the Cancer Testis antigen AKAP4, via tumor expression analysis and IHC, as a potential vaccine and immunotherapy target for colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1414.