Rhodes et al. analyzed 11 polymorphisms in 54 patients with metastatic colorectal cancer, and reported significant associations with grade 3–4 toxicity and grade 3–4 neutropenia when combining ABCB1, C1236T, and SLCO1B1 T521C polymorphisms (Rhodes et al., 2007). Here, SLCO1B1 is linked to metastatic colorectal cancer.