Gene Expression in Patients With Advanced or Metastatic Colorectal Cancer Receiving Bevacizumab

RATIONALE: Studying samples of tumor tissue from patients with cancer in the laboratory may help doctors learn more about changes that occur in DNA and identify biomarkers related to cancer. It may also help doctors understand how patients respond to treatment. PURPOSE: This laboratory study is looking at gene expression in patients with advanced or metastatic colorectal cancer receiving bevacizumab.