RIPK1 and medical procedure: Because AQP1 is expressed in both membrane and cytoplasm of breast cancer cells6,30, but RIPK1 is exclusively localized in the cytoplasm, the localization of AQP1 and RIPK1 in MDA-MB-231, a human TNBC cell line, and 4T1, a mouse TNBC cell line, was assessed respectively by immunofluorescence staining.