Table 1.
Summary of biomarkers in triple negative breast cancer.
| Biomarker | Main Function | Assay | Prognostic/Predictive Significance | Target Therapy | Ref. |
|---|---|---|---|---|---|
| BRCA1 and BRCA2 genes | DNA-double strand break repair | BRACAnalysis CDx test HRDetect assay HRD assay myChoice CDx |
Poor prognostic factor. High response to platinum-based therapy and predictor for response to PARP inhibitors | PARP inhibitors | [9,10,30,55,58,59,60,63,64,65] |
| HRR genes | Homologous recombination repair of DNA | Predictor of response to platinum therapy in neoadjuvant setting | ATR inhibitor * WEE1 inhibitor * |
[41,47,56,57,59,60,61,62] | |
| Stromal TILs | Tumor infiltrating lymphocytes involved in immune response against the tumor | Tissue Immunohistochemistry | High TILs correlates with more favorable survival outcomes and are predictive for increased response to neoadjuvant CT | NA | [92,93,94] |
| PD-L1 protein | Tumor immune evasion process | VENTANA PD-L1 (SP142) Assay | High expression correlates with higher survival rates in trials with ICI | Immune checkpoint inhibitors | [11,117,118,119,120,121,122,123,124,125] |
| Microsatellite instability (MSI) | High Immunogenic activity | Histologically/cytologically confirmed MSI-H/dMMR | Predictor of response to Pembrolizumab | Pembrolizumab | [126] |
| PI3-kinase pathway | Cell proliferation | Tissue Immunohistochemistry of PI3KCA/PTEN or PI3k pathway genomic sequencing by NGS | Higher sensitivity to AKT inhibitors and to combination therapy of PI3K and androgen receptor inhibitors in LAR tumors | PI3K inhibitor * AKT inhibitor * |
[163,168,169,170,171,173] |
| GPNMB | Cell migration, invasion, angiogenesis, epithelial-mesenchymal transition | Tissue Immunohistochemistry | Poor prognostic factor | Glembatumumab vedotin (Antibody-drug conjugate) * | [179,181,182,183] |
| Trop-2 | Cell cycle progression, migration, proliferation, metastasis | Tissue Immunohistochemistry | Poor prognostic factor | Sacituzumab Govitecan-hziy (Antibody-drug conjugate) * | [189,190] |
| LIV-1 | Cell adhesion, epithelial-mesenchymal transition | Tissue Immunohistochemistry | Under investigation | Ladiratuzumab vedotin (Antibody-drug conjugate) * | [196] |
| CA6 | Tumor cell survival and proliferation | Tissue Immunohistochemistry | Under investigation | SAR566658 (Antibody-drug conjugate) * | [197] |
* Under clinical investigation; ICI: immune checkpoint inhibitors.