CLDN1 and gastrointestinal stromal tumor: This is in concordance with the increased expression of total CLDN1 in GIST T-1R cells, as shown in Figure 1A. The fractionation data were in concordance with the immunofluorescence staining data, shown in Figure 8A, revealing that, besides the increased expression of CLDN1 in the membranes, this protein is also significantly increased in the cytoplasmic compartment.