['Tissue inhibitor of metalloproteinase-1 (TIMP-1) is known to protect cells against apoptosis. We raised the hypothesis that elevated tumor tissue levels and thereby plasma levels of TIMP-1 would predict resistance to apoptosis-inducing chemotherapy.', 'Ninety patients with metastatic colorectal cancer were included in the study. Plasma TIMP-1 and serum carcinoembryonic antigen (CEA) were measured in samples obtained before the first cycle of chemotherapy.', 'Analysis of best objective response (complete or partial response versus stable or progressive disease) showed that patients with low plasma TIMP-1 had higher probability of obtaining an objective response [odds ratio (OR), 3.5; 95% confidence interval (95% CI), 1.4-8.5, P=0.007]. CEA treated as a continuous variable was also a statistically significant predictor of no response (OR, 1.3; 95% CI, 1.0-1.7, P=0.02, area under the curve 0.66) but much less so. Plasma TIMP-1 was the only significant covariate in a multivariable analysis of best objective response (OR, 3.6; 95% CI, 1.4-9.5; P=0.001). Plasma TIMP-1 scored as a continuous variable on the log scale (log(e)) was significantly associated with overall survival [OS; hazard ratio (HR), 3.8; 95% CI, 2.4-5.9; P<0.0001] and with time to progression (TTP; HR, 1.5; 95% CI, 1.0-2.3; P=0.048). Multivariable analysis showed that plasma TIMP-1 was significant for OS when including routine clinical baseline covariates (HR, 3.5; 95% CI, 2.1-5.8; P<0.0001). A multivariable analysis including TTP instead of OS showed that only plasma TIMP-1 was retained in the model (HR, 1.5). CEA was not significantly associated with TTP or OS when TIMP-1 was included in the model.'] Is tIMP-1 significantly associated with objective response and survival in metastatic colorectal cancer patients receiving combination of irinotecan , 5-fluorouracil , and folinic acid?