In this review we focus on the roles of the calcium (Ca<sup>2+</sup>), sodium (Na<sup>+</sup>), potassium (K<sup>+</sup>), chloride (Cl<sup>-</sup>) and zinc (Zn<sup>2+</sup>) transporters in GI cancer, with a special emphasis on the roles of the KCNQ1 K<sup>+</sup> channel and CFTR Cl<sup>-</sup> channel in colorectal cancer (CRC).
Finally we analyzed expression of CFTR in early stage human CRC patients stratified by risk of recurrence and found that loss of expression of CFTR was significantly associated with poor disease-free survival.
The CFTR 5T polymorphism was identified in 31 of 334 (9.3%) patients of sporadic pancreatic cancer, in 5 of 43 (11.6%) patients with familial pancreatic cancer and in 10 of 112 (8.9%) controls with colorectal cancer.