Similar changes were also observed in metastatic group A; however, in contrast to CM samples from primary tumours, some components of the base (PSMD2 and ADRM1) and lid (PSMD8) were expressed at higher levels in metastatic group A, possibly as part of a compensatory mechanism for the lower expression of the other PN components identified here (Supplementary Fig. 4d–g). Here, PSMD2 is linked to neoplasm.