The purpose of the study was to prospectively explore the role of serum MMP-7 as a predictive and prognostic marker of anti-epidermal growth factor receptor (EGFR) therapy and irinotecan efficacy in third-line advanced colorectal cancer therapy. One hundred patients were recruited prospectively from six Spanish hospitals. Patients were treated with biweekly irinotecan 180 mg/m(2) and cetuximab 400 mg/m(2) (loading dose) and weekly cetuximab 250 mg/m(2) until progressive disease or unacceptable toxicity. Baseline MMP-7 was determined using a quantitative solid-phase sandwich ELISA. KRAS and BRAF mutational status were also assessed. The clinical endpoints examined were overall survival (OS), progression-free survival (PFS), and response rate. No association between serum MMP-7 and neither KRAS nor BRAF mutational status was found. The multivariate analysis revealed that MMP-7 predicts PFS both in wild-type (WT) KRAS patients (HR 1.03, 95% CI 1.00-1.06; p = 0.046) and in mutant KRAS patients (HR 1.18, 95% CI 1.01-1.35; p = 0.036). The presence of mutant BRAF was associated with shorter PFS (HR 8.49, 95% CI 2.88-25.0; p < 0.001) and worse OS (HR 3.55, 95% CI 1.39-9.09; p = 0.008) in the subset of WT KRAS patients. Serum MMP-7 is associated with PFS in colorectal patients treated with anti-EGFR therapy as third-line treatment independently of KRAS status.