Thyparambil, Sheeno

INTRODUCTION: Esophageal adenocarcinoma (EAC) is an aggressive cancer with poor prognosis. Barrett's esophagus (BE) is a critical precursor of EAC. Patients with BE undergo endoscopic surveillance to monitor disease progression although only a small fraction develop EAC. These procedures are invasive and have limited accuracy in predicting BE progression. We evaluated the utility of an 8-protein mass spectrometry panel in predicting progression in patients with BE. METHODS: Eighty untreated controls and 20 cases were selected from our institutional tissue registry. Quantitative mass-spectrometry was performed on microdissected tissue sections. Data were split into 80% training and 20% test sets. We used Least Absolute Shrinkage and Selection Operator-regularized regression to train a logistic classifier on training data. Classifier performance was evaluated in test data. RESULTS: Ninety-two samples had sufficient tissue for mass spectrometry analysis (18 progressors, 74 nonprogressors). The multivariable regression model produced a sensitivity of 100% and a specificity of 39% in the overall cohort, with AUCs of 0.75 and 0.89 in the overall and test cohorts, respectively. Cox proportional hazards time-to-progression (TTP) showed a hazard ratio of 66.1 (95% CI 7.79–561, P = 0.00012) for the model prediction. DISCUSSION: The promising performance of the model generated here suggests that the test may aid in selecting patients most likely to benefit from active BE surveillance. Moreover, the association of this model's prediction with time-to-progression may offer decision support for management of patients likely to progress quickly. These results support continued development of this proteomic panel as a risk stratification tool for patients with BE.

343 Background: Esophageal adenocarcinoma (EAC) continues to have extremely poor prognosis despite advances in surgical and oncological regimens. Targeted and immune therapy hold promise to improve outcomes in solid tumors including EAC. At present HER-2 and anti-PD-L1 therapies are approved by the FDA for EAC. Additionally, off-label use of EGFR directed therapy has been reported. The aim of this study is to measure expression of 80+ oncoproteins in EAC using multiplexed mass spectrometry to elucidate expression of currently approved-drug targets and explore promising new targets for drug development. Methods: After Institutional Review Board approval (Mayo Clinic and KUMC), EAC patients whose tumors were resected via esophagectomy before chemotherapy and/or radiation were identified. Normal esophageal mucosa samples with no history of EAC were also retrieved for analysis. Tissue sections were microdissected to exclude stroma from adenocarcinoma cells. Isolated EAC cells were solubilized for mass spectrometry-based quantitation of more than 80 clinically relevant tumor markers. Results: 55 EAC tissues were analyzed. HER2, PD-L1 and EGFR were overexpressed only in 16.3%, 0%, and 0% of patients, respectively. New oncoproteins #2 and #6 were noted to have high (7,634.0 and 27,222.6 attomoles/ug) and consistent (98.1% and 94.5%) overexpression in EAC samples. Expression of HER2, oncoproteins #2 and #6 were significantly higher in EAC compared to normal esophageal mucosa. There was no statistical difference in the expression of PD-L1 and EGFR between EAC and normal samples. Conclusions: Mass spectrometry revealed a very low prevalence of target oncoproteins in EAC for currently used drugs. Our study potentially reveals alternate markers which are near universally present at high levels and should be further explored for targeted treatment.[Table: see text]

249 Background: Since 1975, Esophageal adenocarcinoma (EAC) incidence has increased more than any other cancer (̃700%). Pre-malignant metaplastic tissue, or Barrett's Esophagus (BE), is the only known precursor for EAC. Periodic histological assessment of endoscopic biopsy along dysplasia-carcinoma sequence is used to assess progression risk. Current surveillance protocols have clinical limitations as 80% of patients still present with stage II-IV EAC. The aim of this study is to compare novel proteomic expression patterns to distinguish stable BE patients from those who developed EAC using the STLA101 assay. Methods: After Institutional Review Board approval patients with BE/GERD were identified. Two cohorts were selected: progressors (progressed to EAC at subsequent interval of 0.5-3 years) and non–progressors (̃10 yrs of f/u surveillance without progression along dysplasia/carcinoma path). 24 normal esophageal mucosa samples with no h/o of BE were also retrieved for baseline expression levels. Tissue sections were microdissected to isolate pure BE cells from surrounding stromal cells. BE cells underwent a multi-step process where tissue was heated and digested to produce a liquid biopsy for mass spec. Isotopically labeled control peptides representing the STLA101 panel were spiked in with digested tissue samples to quantify all of the markers simultaneously using a Triple-quad mass spectrometer. Results: A total of 95 tissues were analyzed. 29 BE biopsies progressed to EAC within a mean of 380 days while the remaining 28 BE and 14 GERD specimens did not progress over a 10-yr period. All 8 biomarkers were expressed at a higher level in BE tissue that progressed to cancer when compared to BE/GERD tissue that remained stable over 10 years. The assay had a 100% technical success rate as no samples yielded “non-detectable” data points. Conclusions: The differential overexpression of the STLA101 panel on progressive and non-progressive BE tissues demonstrates the clinical utility of STLA101 as a predictive biomarker panel for early detection of esophageal carcinogenesis. Non-progressive BE tissues were similar to normal mucosa, therefore, patients whose BE tissue samples resemble this profile may receive a reduced screening cadence. On the other hand, patients with overexpression of the STLA101 panel may be eligible to receive more frequent screening or therapeutic intervention.