Table 2.
Some current biomarkers of irAEs.
| Category | Biomarker | Specific irAE | Specific cancer type |
|---|---|---|---|
| Serum factors | IL-6 (32–34) | Non-specific | Non-specific |
| IL-17 (25, 35) | ICIs-induced colitis, | Melanoma | |
| C reaction protein (36–38) | Non-specific | RCC, NSCLC | |
| Preexisting auto-antibody (39–41) | Endocrine irAEs | Non-specific | |
| Serum neurofilament light chain (42) | Neuro irAEs | Non-specific | |
| Cells | Neutrophil to lymphocyte ratio (43) | Non-specific | Non-specific |
| Platelet-to-lymphocyte ratio (44) | Non-specific | NSCLC | |
| IgG4+/PD-1+ MFI ratio (45) | Non-specific | Non-specific | |
| Tumor Infiltrating Lymphocytes (46) | Cutaneous irAEs | Melanoma | |
| Others | TMB (47) | Non-specific | Non-specific |
| Circulating tumor DNA (48, 49) | Non-specific | Non-specific | |
| Indoleamine 2,3-dioxygenase 1 (50) | Immune-mediated hepatotoxicity | Non-specific |
RCC, renal cell carcinoma; NSCLC, non-small cell lung cancer; IL-6, interleukin-6; IL-17, interleukin-17; TMB, tumor mutation burden; MFI, mean fluorescence intensity.