Infusional fluorouracil/leucovorin plus irinotecan-based regimen (FOLFIRI) with bevacizumab has been widely used as first-line treatment for patients with metastatic colorectal cancer (mCRC). Recently, the investigators have shown that prospective analysis of uridine diphosphate glucuronosyl transferase 1A1 (UGT1A1) genotyping for irinotecan dose escalation (FOLFIRI regimen) with combination of bevacizumab biweekly as the first-line setting in mCRC patients (ASCO Abstract #491 - 2013 Gastrointestinal Cancers Symposium).