In the present work, we have developed a novel electrochemical immunosensor based on modified disposable ITO-PET (indium tin oxide - polyethylene terephthalate) electrodes for PAK-2 (p21-activated kinase 2) early detection. An ITO-PET electrode surface was modified with 3-cyanopropyl trimethoxysilane (3-CPTMS), which formed self-assembled monolayers (SAMs). PAK2 immunosensing was performed by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) techniques, square wave voltammetry (SWV) and a single frequency impedance (SFI) technique utilized for specific interaction between the anti-PAK2 and PAK2 antigen. Further, the morphological characterization of each ITO electrode surface was observed by scanning electron microscopy (SEM). All parameters such as 3-CPTMS concentration, antibody concentration and antibody incubation time were optimized. Analytical characteristics of the proposed immunosensor such as linear determination range, repeatability, reproducibility, regeneration, storage life and surface coverage of immunosensors were determined. The PAK2 electrochemical immunosensor performed flawlessly with a wide determination range (from 0.05 pg mL(-1) to 2.5 pg mL(-1)) and low limits of detection (0.0252 pg mL(-1)) and of quantification (0.0842 pg mL(-1)) The artificial and human serum samples were tested to verify the viability of the proposed immunosensor. (C) 2019 Elsevier B.V. All rights reserved.