KPNB1 and cancer: While it is possible that these proteins only bind Kpnβ1 when cells are in the cancer state, we propose that the presence of these proteins in the cancer only group could also be due to their (1) increased expression, (2) higher affinity binding to Kpnβ1 due, for example, to a post-translational modification on one or other binding partner, or (3) increased duration of interaction with Kpnβ1 in the cancer cell lines.