NOTCH2 and digestive system neoplasm: Based on our data, activated forms of Notch1, Notch2, Notch3, and Notch4 (N1ICD, N2ICD, N3ICD, and N4ICD) in stomach-cancer cells were all upregulated, especially N1ICD and N2ICD, after the co-culture of cancer cells and macrophages.