Table 2.
Summary of predictive biomarkers for colorectal cancer treatment
| Biomarker | General comments |
|---|---|
| Microsatellite instability | Several studies have shown that 5-FU adjuvant chemotherapy does not benefit patients with MSI-H or dMMR tumors. However, there are a few notable studies which demonstrate contrasting results, including a secondary analysis of a trial which suggested that irinotecan + 5-FU treatment may be of greater benefit to patients with MSI-H or dMMR tumors. |
| KRAS | Prospective studies have shown longer PFS and OS in KRAS WT mCRC treated with EGFR inhibitors alone or combined with 5-FU-based adjuvant therapy. NCCN and ASCO guidelines recommend KRAS mutation testing in all mCRC patients prior to EGFR inhibitor therapy. |
| BRAF | There are limited studies on the predictive nature of BRAF mutation status with CRC treatment. Currently, BRAF mutation status is an active area of investigation as a predictive marker of response for EGFR inhibitors. |
| Loss of heterozygosity 18q | There are limited studies on the predictive nature of LOH 18q with CRC treatment. The E5202 trial is currently investigating the role of LOH 18q as a predictive biomarker. |
| TP53 | Several prospective studies have failed to demonstrate any correlation between TP53 mutation status and response to adjuvant therapy. EGTM and ASCO recommend against TP53 mutation analysis for predicting response to adjuvant therapy in CRC. |
| Thymidylate synthase | Prospective studies regarding the predictive value of thymidylate synthase overexpression are inconsistent. |
| VEGF | There are limited studies on the predictive nature of VEGF expression with CRC treatment. The predictive value of VEGF expression remains to be determined. |
5-FU 5-fluorouracil; ASCO American Society of Clinical Oncology; CRC colorectal cancer; dMMR defective mismatch repair; EGFR epidermal growth factor receptor; EGTM European Group of Tumor Markers; LOH loss of heterozygosity; mCRC metastatic colorectal cancer; MSI-H microsatellite instability-high; NCCN National Comprehensive Cancer Network; OS overall survival; PFS progression-free survival; WT wild type