Table 1.
Comparison of different tumour biomarker detection methods for clinical applications
| Biomarker | Modality | Strengths | Limitations | Ref. |
|---|---|---|---|---|
| Imaging‐based methods | ||||
| CT, MRI, PET, etc | High accuracy, displaying solid tumour visually | High ionizing radiation, unable to detect minimal tumours | 183 | |
| Solid biopsy | ||||
| IHC staining, etc | Reflecting histological situations | Invasive detection methods, cannot cover all heterogeneity | 124 | |
| Body fluids biopsy | ||||
| miRNAs | Altered level of tumour‐specific miRNAs, such as miR‐21 and miR‐155. | Non‐invasive, high sensitivity, allowing for early detection | Unstable, limited by individual difference | 50‐52 |
| ctDNAs | Tumour‐specific mutations, such as EGFR and BRAF. | Non‐invasive, high sensitivity, reflect individual difference, allowing for early detection | Lack of functional studies | 199‐122 |
| DNA methylations, such as ALX4. | ||||
| Proteins | Elevated level of proteins, such as AFP and CA‐125. | Non‐invasive, high sensitivity, allowing for early detection | Limited by individual difference | 116 |
| Different expression profiles, such as ER, PR, HER2, etc | ||||
| Exosomes | Increased exosome number | Non‐invasive, relatively stable in exosome, allowing for early detection | Limited isolation efficiency, lack of large scale studies | 166‐168 |
| Different exosomal nucleotides and proteins | ||||
| CTCs | Increased CTC number | Non‐invasive, reflecting the evolutions of tumour cells timely during tumour development and treatment | Affected by isolation and selection methods, lack of large scale studies, can only be detectable during metastasis but can hardly be detected at an early stage | 194‐196 |
| Altered nucleotides and proteins in CTCs | ||||
The table shows the classification of currently used tumour biomarker detection methods and compared their strengths and limitations considering whether it is less harmful to patients, convenient to detect, with a high accuracy, high stability, can be detectable at an early stage, reflecting individual difference and indicating tumour evolution during development and treatment.
CT, computed tomography; IHC, immunohistochemistry; MRI, magnetic resonance imaging; PET, positron emission tomography.