It was found that MSC‐DF Notch1-/- promoted the formation of spheroids in co-cultured melanoma cells, while MSC‐DFN1IC+/+ (N1IC: Notch1 intracellular domain, an active form of Notch1) suppressed melanoma cell sphere formation capacity, thereby diminished tumor initiation properties. Here, NOTCH1 is linked to neoplasm.