EGFR and metastatic colorectal cancer: The objectives of the study were (1) to assess the efficacy (response rate and duration of stable disease (s.d.)) of erlotinib given daily in patients with recurrent or metastatic colorectal cancer, (2) to assess the toxicity, time to progression and (3) to investigate the effect of erlotinib on EGFR inhibition and downstream signalling pathways.