A clinical study based on metastatic colorectal patients revealed that the group that received low-dose, subcutaneous IL-2 with melatonin after a first-line therapy of 5-FU had a higher percentage of survival at 1 year compared to those who only received 5-FU treatment, which suggested that the low-dose, subcutaneous IL-2 and melatonin can be used as a second-line therapy for colon cancer therapy [86]. Here, IL2 is linked to malignant colon neoplasm.