Abstract 4537: Cryogenic biopsy device for preservation of labile biomarkers

Background: Preanalytical factors such as the handling of biospecimens between resection and analysis can have a significant impact on assay results which may adversely affect patient care. Global phosphoprotein analysis indicates that a 5 minute delay in time-to-stabilization (ischemia time) can impact 20% of phospho-serine and 50% of phospho-tyrosine residues in kinases. Consequently, inadequate tumor biopsy processing is a significant impediment to the use of phosphorylated biomarkers in oncology. We aim to develop new biopsy devices and methodologies to stabilize highly dynamic biomarkers and minimize the influence of preanalytical factors. Methods: A cryobiopsy device (CBD) was developed by integrating a 19G cryoablation needle with a 16G cutting cannula of a clinical biopsy device. The device enables in-situ freezing of the tissue sample before it is cut and removed from the tumor. We measured the stabilization of a highly labile biomarker, phosphorylated-MET (pMET), to compare between percutaneous biopsy samples acquired by the CBD (zero ischemic time) and by a clinical grade 18G biopsy device (Temno) (10-20 second ischemic time). The animal protocol was approved by the FNLCR9s IACUC. Athymic nude mice (nu/nu NCr) were implanted with human gastric carcinoma cell line SNU-5. Tumors were biopsied 3 weeks after implantation (tumor size range 150-250mm 3 ). The needle was passed through the skin into the tumor, a tissue sample was collected, and the biopsy needle was retracted. The tissue sample of the Temno device was rapidly frozen in a cryovial that was precooled in liquid nitrogen [1]. The already frozen tissue sample of the CBD was rapidly transferred to a second precooled cryovial. The vials were sealed and returned to liquid nitrogen. Frozen specimens were stored at −80°C until processing. Each tumor was biopsied once and the animal was euthanized. The methodology to determine the pMET/MET levels in the biopsy samples is detailed in [2]. Results: The pMET/MET ratio was not significantly different between samples acquired by the CBD and by the Temno device (mean±st dev): pY1234/35-MET/MET ratio: CBD 0.75±0.11; Temno 0.71±0.10 pY1356-MET/MET ratio: CBD 0.56±0.08; Temno 0.50±0.06 pY1235-MET/MET ratio: CBD 0.90±0.15; Temno 0.83±0.14 Conclusions: Past studies showed that tissue levels of highly labile biomarkers like pMET can change significantly in 1-2 minutes from the time of tissue harvesting [2]. The current study demonstrates that rapid freezing of the tissue within less than 20 seconds from tissue harvesting maintains the in-vivo levels of pMET similarly to tissue freezing before tissue harvesting. This result suggests that devices that rapidly freeze tissue samples after removal from the body, which are more suitable for clinical use, may be sufficient for preservation and accurate quantitation of highly labile biomarkers. 1. PMID: 18980982 2. PMID: 27001313 Supported by NCI Contracts HHSN261200800001E and HHSN261201200050C Citation Format: Erez Nevo, Melinda G. Hollingshead, Katherine Ferry-Galow, Jeevan P. Govindharajulu, Shoshan Nevo, Kay D. Gray, Ralph E. Parchment, James H. Doroshow, Apurva K. Srivastava. Cryogenic biopsy device for preservation of labile biomarkers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4537.