Recently, in patients with stage II–III colorectal cancer treated 5-FU (fluorouracil)-based adjuvant chemotherapy, positive AQP1 expression was associated with an increased disease free survival (DFS) rate compared with that of AQP1-negative ones [35]; therefore, it has been suggested that AQP1 may be a candidate biomarker predictive of response to 5-fluorouracil-based adjuvant chemotherapy [33]. This evidence concerns the gene AQP1 and colorectal cancer.