Point-of-Care Immunoassay for Rapid Analysis of Tumor Biopsies: Proof-of-Principle
Brian Currie MD1, James Chen MD1, Daniel Ackerman PhD1, Stephen Hunt MD PhD1, Gregory Nadolski MD1, Nick Siciliano PhD2, Terence Gade MD PhD1
Percutaneous biopsies play a central role in the profiling of malignancies for precision medicine. The success of this strategy hinges on high quality samples, a task complicated by tumor cell heterogeneity and impurity of biopsy specimens. Inaccurate biopsies lead to repeat procedures and can stagnate both treatment and clinical translation of evolving therapies, all of which negatively impact patient care. A method that confirms the acquisition of cancerous cells at the point-of-care (POC) in the procedural suite while minimizing specimen damage would mitigate these limitations. We demonstrate proof-of-principle for a POC biopsy test that can detect secreted proteins specific to tumor cells.
This was a preliminary study employing a preexisting IRB-approved observational clinical trial. The protocol was developed for the genomic, proteomic, metabolomic and immunologic profiling of HCC prior to and following TACE and therefore provides an ideal vehicle for the development of a POC test designed to enable these analyses. As part of this prospective cohort study, patients meeting inclusion criteria undergo biopsy prior to TACE. Following biopsy of HCCs from patients (n=4), samples were incubated in 1 mL of biopsy buffer for 5-10 minutes and vigorously shaken and then removed for processing. 50 μL biopsy buffer was applied to a commercial enzyme-linked immunosorbent assay (ELISA) for alpha fetoprotein (AFP).
A retrospective analysis was also performed of the operations data related to all interventional radiology procedures from April 2016 to April 2017 at our institution. The total time for the completion of the biopsy protocol and subsequent TACE (n=13) was compared to the total time for TACE only (n=12) procedures. The TACE only cohort was selected to match the TACE + biopsy cohort to limit factors that could influence differences in procedure time. Statistical analysis was performed with an unpaired Student’s t-test, with a p value <0.05 used as the threshold for statistical significance.
No significant difference was observed in the procedure time for patients undergoing TACE + biopsy when adjusted to include readout time required for the proposed immunoassay (104 ± 7.9 min) as compared to TACE alone (88.9 ± 11.4 min, p=0.285).
Measurable levels of AFP were only detected in those patients with HCCs staining positive for AFP on immunohistochemistry as assessed by a pathologist (2.6 ± 0.13 vs 0.18 ± 0.024, p < 0.001).
This proof-of-principle study demonstrates the feasibility of integrating the proposed biopsy algorithm into the clinical workflow in terms of procedural time and the ability to accurately identify secreted proteins from HCC as an indication of adequacy.