PPIA and neoplasm: Proteins that decreased in abundance with increasing tumor severity were mainly associated with cytoskeleton remodeling, intracellular transport, and cell–cell adhesion (ARFIP1, ANXA2, CCT2, CCT5, EZR, LYPLA1, PPIA, RDX, SEPTIN8, 14-3-3ε, and VCL)—mechanisms well known to contribute to tumor growth, tissue invasion, and subsequent detachment of cancer cells for metastasis [22].