Table 1.
Advantages and limitations of methods that have been established in ovo.
| Readout | Purpose (examples) | Requirements | Advantages | Limitations | Reference (DOI) | |
|---|---|---|---|---|---|---|
| macroscopic | ||||||
| weight | - tumor mass - tumor volume |
- precision scale | - easy feasibility - high throughput - low costs |
- unprecise and volatile (surrounding stroma) - insensitive |
(9–12) | |
| TIVITA | - angiogenesis - health status - tissue oximetry |
-TIVITA camera and computer | - easy feasibility - noninvasive - monitoring at multiple timepoints - assessment and quantification of tissue-specific parameters (e.g. StO2, THI) in vivo |
- time-consuming evaluation - manual evaluation imprecise |
(13) | |
| stereo microscope | - tumor growth - tracking of labeled cells - angiogenesis |
- stereomicroscope | - easy feasibility - noninvasive - monitoring at multiple timepoints in vivo |
- costly equipment | (14–16) | |
| microplate reader | - tumor growth - viability/metabolic activity - cell death kinetics - gene expression via reporter genes |
- luciferase-transduced/fluorescent cells - Resazurin/WST-1/MTT - microplate reader |
- precise determination of (viable) tumor mass ex vivo
- high throughput |
- requires inoculation of luciferase-transduced/ fluorescent cells |
– | |
| luminescence | - tumor growth - gene expression via reporter genes |
- luciferase-transduced cells - chemiluminescent substrate - imager |
- monitoring of tumor growth at multiple timepoints - noninvasive - precise determination of viable tumor mass in vivo |
- requires inoculation of luciferase-transduced cells - costly equipment |
(12, 13, 17–19) | |
| MRI | - tumor growth | - MRI and equipment | - noninvasive - monitoring of tumor growth at multiple timepoints - assessment of biodistribution of labelled compounds |
- time-consuming - costly equipment |
(11, 20–22) | |
| ultrasonography | - repetitive visualization of tumor growth and vascularization - evaluation of anti-angiogenic therapy response |
- ultrasonographic scanner/ultrasound devicetab | - cost efficient - longitudinal monitoring of tumoral development - easily applicable |
- interpretation depends on operator and manually adjusted machine settings | (23–25) | |
| cellular | ||||||
| FACS | - toxicity - differentiation - ICD - ROS levels |
- cytometer - tissue dissociator - lysis buffer - strainer - antibodies |
- enables broad range of downstream assays - analysis of intra- and extracellular marker expression - high throughput - examination of cancer-immune cell interactions |
- samples are sticky - sample heterogeneity - requires equipment for tumor digestion |
(13) | |
| sections | - apoptosis - EMT - differentiation - immune landscape - invasion of cancer cells |
- kryotome/microtome - antibodies - microscope |
- enables visualization of immune cell infiltration | - time consuming sample preparation - quantitative image analysis time consuming and high knowledge level |
(26–29) | |
| subcellular | ||||||
| ELISA | - growth factors - immunogenicity - angiogenesis |
- ELISA - bead-based multiplex assay |
- species specificity - high-throughput - examination of cancer-immune cell interactions |
- multiplex assay costly - tissue sampling after tissue dissociation? |
– | |
|
PCR/
transcriptomics |
- underlying molecular mechanisms - metastatic potential - spread of oncolytic viruses |
- tissue dissociator - RNA isolation kit |
- underlying mechanisms | - tissue sampling - low DNA/RNA yield |
(30–32) | |
|
proteomics/
lipidomics |
- protein expression analysis - metabolomics profiling |
- tissue dissociator - mass spectrometer - protein profiler array |
- sensitivity | - low protein yield - high cost and technical demand (MS) - time-consuming (MS) |
(33, 34) | |
| WB | - protein expression analysis | - tissue dissociator - western blot equipment |
- underlying mechanisms - sensitivity and specificity |
- low protein yield - prone to false/subjective results - high cost and technical demand |
(33, 35) | |