This study involves standard combination chemotherapy treatment for colon cancer, 5-Fluorouracil (5FU), leucovorin and irinotecan (known as FOLFIRI), plus bevacizumab (Avastin). The study is designed to test the FOLFIRI regimen based on certain characteristics of a person's genetic makeup or "genes". Genes are made of DNA and determine not only inherited traits or appearance (hair and eye color, height, body type, etc.) but also play an important role in health and how the body responds to illness and treatments for those illnesses.