Predictive biomarkers for EGFR MoAb treatment in mCRC
| Biomarker | Frequency of alteration in CRC | Most frequent alterations | Predictive value for EGFR MoAbs |
|---|---|---|---|
| KRAS | 30-40% with recent studies suggesting several novel mutations outside of the known hotspots in codons 12 and 13 of exon 2 | Activating mutation in codons 12 and 13 of exon 2 | Negative predictor |
| BRAF | 10-20% | Activating mutation V600E in exon 15 | Unclear, but possibly little predictive value |
| PTEN | 20-40% | Loss of protein expression measured by IHC | Unclear, secondary to lack of standardized IHC scoring |
| PIK3CA | 15-25% with several mutations scattered outside of the known hotspots in exons 9 and 20 | Mutations in exons 9 and 20, with constitutive activation of PI3K pathway | Unclear, but PI3K pathway activation by PTEN loss or PIK3CA mutations appears to be negative predictor |
| Amphiregulin, epiregulin | NA | Overexpression of ligands | Higher values likely positive predictor |
| FcR polymorphisms | About 40% | FcγRIIa-FcγRIIIa H131H and/or V158V polymorphism | Unclear but FcγRIIIa alone may have positive predictive value |
Abbreviations: NA, not applicable, continuous variable.