PACAP Immunoreactivity in Human Malignant Tumor Samples and Cardiac Diseases Z. Szanto & Zs. Sarszegi & D. Reglodi & J. Nemeth & K. Szabadfi & P. Kiss & A. Varga & E. Banki & K. Csanaky & B. Gaszner & O. Pinter & Zs. Szalai & A. Tamas Received: 30 March 2012 / Accepted: 15 May 2012 / Published online: 31 May 2012 # Springer Science+Business Media, LLC 2012 Abstract Pituitary adenylate cyclase activating polypeptide (PACAP) is a pleiotropic and multifunctional neuropeptide having important roles in various physiological processes. Recent trends in PACAP research point to the clinical intro- duction of PACAP or its analogs/fragments possibly in the near future. Recently, we have shown the presence of PACAP in human plasma, milk, placenta, and follicular fluid samples. However, relatively few data are available on PACAP in human tissues from patients with different disorders. The aim of the present study was to determine, by radioimmunoassay, the tissue level of PACAP38-like immu- noreactivity (LI) and PACAP27-LI in different primary non- small cell lung cancer, colon tumor samples, and in cardiac muscle samples from patients suffering from ischemic heart disease and valvular disorders. We also labeled the PAC1 receptors in human cardiac cells. All samples showed sig- nificantly higher PACAP38-LI compared with PACAP27- LI. We found significantly lower levels of PACAP38-LI and PACAP27-LI in tumoral and peripheral samples compared with normal healthy tissue in both lung and colon cancers. Further investigations are necessary to describe the exact function of PACAP in oncogenesis. We showed that PACAP38-LI and PACAP27-LI are significantly higher in ischemic heart diseases compared with valvular abnormali- ties, suggesting that PACAP might play a role in ischemic heart disorders. Keywords PACAP . Colon cancer . Lung cancer . Heart disorder . PAC1 receptor Introduction Pituitary adenylate cyclase activating polypeptide (PACAP) was isolated from ovine hypothalami in 1989, based on its activating effect on adenylate cyclase in the pituitary gland. PACAP is a member of the secretin/glucagon/vasoactive in- testinal peptide (VIP) family and exists in 27 and 38 amino acid form, the latter being the predominant peptide in mam- malian tissues. PACAP is a pleiotropic and multifunctional neuropeptide having important roles in various physiological processes (Vaudry et al. 2009). Since its discovery, a large number of studies have shown its neurotrophic, neuroprotec- tive, general cytoprotective, and anti-inflammatory effects both in vitro and in vivo (Delgado and Ganea 2001; Z. Szanto Surgery Clinic, University of Pecs, Pecs, Hungary Z. Sarszegi : B. Gaszner : O. Pinter Heart Institute, University of Pecs, Pecs, Hungary D. Reglodi : P. Kiss : A. Varga : E. Banki : K. Csanaky : A. Tamas (*) Department of Anatomy, PTE-MTA “Lendulet” PACAP Research Team, University of Pecs, 7624 Pecs Szigeti ut 12., Hungary e-mail: andreatamassz@gmail.com J. Nemeth Department of Pharmacology and Pharmacotherapy, University of Debrecen, Debrecen, Hungary K. Szabadfi Department of Experimental Zoology and Neurobiology, University of Pecs, Pecs, Hungary Z. Szalai Department of Pulmonology and Allergology, Karolina Hospital, Mosonmagyarovar, Hungary J Mol Neurosci (2012) 48:667–673 DOI 10.1007/s12031-012-9815-4