Journal of Environmental Pathology, Toxicology and Oncology, 33(4):339-347 (2014) 339 0731-9989/14/$35.00 © 2014 Begell House, Inc. www.begellhouse.com Hsp70 Is an Independent Stress Marker Among Frequent Users of Mobile Phones Karuppiah Balakrishnan, 1, * Vijayan Murali, 2 Chinniah Rathika, 1 Thirunavukkarasu Manikandan, 2 Ravi Padma Malini, 1 Ramanathan Aravind Selvin Kumar, 3 & Muthukalingan Krishnan 4 1 Department of Immunology, School of Biological Sciences, Madurai Kamaraj University, Madurai, Tamil Nadu, India; 2 Department of Biotechnology & Genetic Engineering, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India; 3 Department of Pediatric Nephrology, Institute of Child Health & Hospital for Children, Dr. M. G. R. Medical University, Chennai, Tamil Nadu, India; 4 Department of Environmental Biotechnology, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India * Address all correspondence to: Dr. Karuppiah Balakrishnan, Department of Immunology, School of Biological Sciences, Madurai Kamaraj University, Madurai 625 021, Tamil Nadu, India; Tel.: 0452-2458418; immunobala@mkuniversity.org. ABSTRACT: The aim of this study was to measure the serum concentrations of heat shock protein (HSP) 70 and C-reactive protein (CRP) and the expression levels of the hsp70 gene among frequent users of mobile phones (FUMPs). We enrolled 120 employees of information technology (IT)/IT enabled service companies (FUMPs; IT professionals) and 102 infrequent users of mobile phones (IFUMPs; people from non-IT professions) as con- trols. The serum concentrations of HSP70 and CRP were measured by enzyme-linked immunosorbant assay and hsp70 gene expression by reverse transcription polymerase chain reaction. Signiicantly higher concentrations of serum HSP70 (P < 0.00012) and CRP (P < 0.04) were observed among FUMPs than IFUMPs. A higher level of hsp70 gene expression (fold induction) was observed among FUMPs than IFUMPs (P < 7.06 × 10 –13 ). In contrast to the duration of exposure–dependent increase of serum concentration of CRP, the serum HSP70 concentration was found to be independent of the duration of exposure to mobile phones. Thus, the study convincingly demon- strated the role of serum HSP and CRP as systemic inlammatory biomarkers for mobile phone–induced radiation. KEY WORDS: RF-EMF, HSP70, gene expression, mobile phone, CRP, biomarker ABBREVIATIONS: cDNA, complementary DNA; CRP, C-reactive protein; ELISA, enzyme-linked immunosor- bent assay; EMF, electromagnetic ield; FUMP, frequent user of mobile phones; HSP, heat shock protein; IFUMP, infrequent user of mobile phones; IT, information technology; ITES, information technology–enabled service; PCR, polymerase chain reaction. I. INTRODUCTION The mobile phone is a modern invention that is used widely by people of all ages. The usage of mobile phones has increased dramatically over the past de- cade. Mobile phones are now considered an essen- tial part of society and commerce. Mobile phones transmit and receive radio waves of frequencies in the range of 900–1800 MHz. Worldwide, more than 6.8 billion people have mobile/cellular subscriptions (International Telecommunication Union, May, 2014). India is one of the most densely populated countries in the world and ranked second largest in terms of mobile phone usage; 933 million currently use mobile phones (Telecom Regulatory Authority of India, 2014). Mobile phone users’ health may be affected by the radiofrequency radiation from mo- bile phones. 1 The health effects of radiofrequency electromagnetic waves emitted from cell phones have been discussed previously. 2 The human body, especially the head, may serve as a lossy resonator, absorbing much of the energy emitted by cellular phones. 3 Of late, employees of information technol- ogy (IT)–enabled services (ITES) are voicing con- cerns about mobile phone–induced radiation. A member of the pentraxin family of proteins, C-reactive protein (CRP) is an acute-phase protein that is secreted by the liver in response to a variety