Given the above, the purpose of this study was to investigate whether the stimulation of intestinal epithelial cancerous cells by ATP leads to a modulation of MRP2 expression, which we postulate would entail an increased resistance of tumor cells to certain chemotherapeutic drugs and hence be detrimental to the treatment of colorectal cancer by enhancing the survival of cancer cells. The gene discussed is ABCC2; the disease is colorectal cancer.