Abstract 2098: Molecular based blood screening assay for metastatic adenoid cystic carcinoma

Abstract

Abstract Adenoid cystic carcinoma (ACC) is a rare, yet highly lethal, tumor that originates in the excretory glands of the head and neck. It is a locally aggressive disease, with more than half of patients presenting with perineural invasion and/or bone erosion. The current standard of care consists of surgical excision followed by radiation. Many healthy patients are left with positive margins after surgery and receive systemic therapy in addition to adjuvant radiation without evidence showing added benefit for that approach. Despite extensive surgery, long-term survival rates remain low due to a high incidence of locoregional disease progression and metastatic disease to the lung, liver, brain, or bones, sometimes several years after definitive treatment. Extensive genome analysis of ACC has uncovered a high mutation rate of the proto-oncogene MYB, typically as a genomic translocation resulting in an MYB fusion event with one of the following gene loci: nuclear factor I/B (NFIB), transforming growth factor beta 3 (TGFBR3) or RAD51B. The translocation approximates an enhancer to the MYB regulatory element which can be transactivated by the MYB fusion product, thus leading to the overexpression of MYB via a positive feedback mechanism. Currently, detection of systemic disease relies on diagnostic imaging, which can be imprecise, costly and time-consuming. Years of routine imaging is very impractical, attrition rates are high, and patients often present years later with symptomatic metastatic disease. A rapid and sensitive molecular-based blood screening tool would allow for continuous monitoring and earlier detection of metastatic ACC, ideally improving survival outcomes for these patients. In this study, we hypothesized that the dysregulation in MYB, and the reliance of ACC cells on MYB for survival and progression could be harnessed to develop a molecular screening tool to monitor for metastatic disease of ACC. We developed a blood-based PCR screening probes for metastatic disease in patients with a history of ACC. By analyzing blood samples from four cohorts: healthy individuals (no history of cancer) (n=6), patients with a history of ACC but with no evidence of disease for longer than 3yrs (NED) (n=16), patients with newly diagnosed local disease (n=8), and patients with confirmed metastatic disease (n=7), we demonstrate that our assay was able to detect significantly elevated levels of aberrant MYB expression in all blood specimens from our metastatic disease cohort (p < 0.01). Additionally, our probes were able to detect aberrant levels of MYB in the blood of a patient 11 months before imaging techniques identified metastatic lung lesions. These findings indicate that we can harness a specific ACC genetic trait to develop a sensitive, rapid, and inexpensive molecular screening assay from blood to detect metastatic ACC. We continue to expand and validate these findings by screening existing and new ACC patients every 6 months. Citation Format: Acadia H. Moeyersoms, Ryan A. Gallo, Zoukaa B. Sargi, Jason M. Leibowitz, Andrew J. Rong, David T. Tse, Daniel Pelaez. Molecular based blood screening assay for metastatic adenoid cystic carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2098.