Abstract 3280
Background
Colorectal cancer (CRC) is one of the leading cancer with the 55% survival rate. The analysis of tumor microenviroment in fresh surgical samples by flow cytometry focuses on the presence of immune cells. However, no direct access to fresh tumor sample is always possible. Moreover, transport of interesting fresh tumor tissue specimens to distant labs is sometimes neccesary. Therefore, we analyzed both fresh and frozen cells isolated from tumor tissue, stored in hibernation buffer for 1 to 3 days and compared the percentage of EpCAM+, CD45+ and CD3+ cells. We analyzed 26 surgical samples of primary CRC and metastatic samples.
Methods
Surgical samples were obtained from patients with CRC and processed for an isolation of a single cell suspension (SCS) prepared using standard protocol with collagenase. After washing and blocking with mouse serum, cells were stained with fluorescently labeled antibodies (EpCAM-PE, CD45-FITC, CD3-APC). The cells were phenotyped using the FACS ARIAII instrument. Samples were obtained from freshly prepared (n = 19) and frozen cells, stored in DMSO supplemented medium (n = 8). 1 sample was phenotyped both from freshly prepared and frozen cells.
Results
From freshly prepared SCS, the average amount of EpCAM+ and CD45+ cells was 78.7% and 14.7%, respectively. In 12 out of 19 cases we also used anti CD3 antibodies. 2% of infiltrated cells were found to be positive for CD3. When using frozen SCS, we detected a higher positivity for EpCAM (92.85%), CD45 (62%) and CD3 (6%) compared to freshly prepared SCS.
Conclusions
We phenotyped human CRC samples for EpCAM, CD45 and some samples for CD3 marker. We found that for the FACS analysis, the stability of tumor tissue samples seems to be acceptable for isolation of SCS from CRC if stored in hibernation buffer, at 4 °C for 1 to 3 days. When isolated SCS from frozen stocks were used, we detected higher percentages of positive cells for EpCAM, CD45, CD3 markers. Therefore, we do not recommend to compare freshly isolated cells with previously frozen cells in FACS experiments.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
grants APVV (no.16–0066), VEGA (no. 1/0380/18).
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
2963 - Analytical performance of the Resolution-HRD plasma assay used to identify mCRPC patients with biallelic disruption of DNA repair genes for treatment with niraparib
Presenter: Ira Pekker
Session: Poster Display session 3
Resources:
Abstract
3523 - Results of a global external quality assessment scheme for EGFR testing on liquid biopsy
Presenter: Nicola Normanno
Session: Poster Display session 3
Resources:
Abstract
3295 - Clinical impact of plasma Next-Generation Sequencing (NGS) in advanced Non-small cell lung cancer (aNSCLC)
Presenter: Laura Bonanno
Session: Poster Display session 3
Resources:
Abstract
5632 - Feasibility study of a ctEGFR prototype assay on the fully automated Idylla™ platform
Presenter: Martin Reijans
Session: Poster Display session 3
Resources:
Abstract
3614 - Enhanced Access to EGFR Molecular Testing in NSCLC using a Cell-Free DNA Tube for Liquid Biopsy
Presenter: Theresa May
Session: Poster Display session 3
Resources:
Abstract
5664 - Analysis of circulating tumor DNA in paired plasma and sputum samples of EGFR-mutated NSCLC patients
Presenter: Christina Grech
Session: Poster Display session 3
Resources:
Abstract
4945 - Liquid biopsy and Array Comparative Genomic Hybridization (aCGH)
Presenter: Panagiotis Apostolou
Session: Poster Display session 3
Resources:
Abstract
5746 - Next-generation sequencing panel verification to detect low frequency single nucleotide and copy number variants from mixing cell line studies
Presenter: Rocio Rosas-Alonso
Session: Poster Display session 3
Resources:
Abstract
5901 - Automated rarefaction analysis for precision B and T cell receptor repertoire profiling from peripheral blood and FFPE-preserved tumor
Presenter: Luca Quagliata
Session: Poster Display session 3
Resources:
Abstract
2027 - A Heptamethine cyanine dye is a potential diagnostic marker for Myeloid-Derived Suppressor Cells
Presenter: Chaeyong Jung
Session: Poster Display session 3
Resources:
Abstract