Saeed Hashemzadeh - Department of Psychology, Kish International Branch, Islamic Azad University, Kish Island.
Mahmoud Borjali - Assistant Professor, Department of Clinical Psychology, Kharazmi University, Tehran, Iran.
Peyman Hasani Abharian - Assistant Professor, Brain and Cognition Clinic, Institute for Cognitive Sciences, Tehran, Iran.

Background: Cancer is a disorder in the rate of cell proliferation and differentiation that can occur in any tissue of the body and at any age, and attacking healthy tissues of the body causes severe disease and consequently death. Objective: The aim of this study was to analyze the structural equations of biological indicators of stress based on perceived stress mediated by emotional regulation in patients with gastrointestinal cancer. Methods: In terms of research method, this research is descriptive-correlational research of structural equation type. The statistical population of the present study included all patients with gastrointestinal cancer who were referred to Reza Medical Center-Mashhad and Ibn Sina Hospital-Tehran and were diagnosed with this disease based on the patient's file. The sample of this study included ۲۵۰ people from the mentioned community, which was done using a non-random and available sampling method. Data in this study were obtained using the Perceived Stress Scale, Cognitive Emotion Regulation Questionnaire, and Biological Indicators of Stress. Data were analyzed by structural equation modeling and Pearson correlation using SPSS.۲۲ and AMOS.۲۲ software. Results: The results showed that perceived stress (β=-۰.۳۷, p <۰.۰۰۱) directly emotional regulation. Also, emotional regulation (β=۰.۵۴, p <۰.۰۰۱) had a direct effect on biological stress indices. Emotional regulation played a mediating role in the relationship between perceived stress and biological stress indices (RMSEA:۰.۰۰۱; AGFI:۰.۹۳). Conclusion: It can be concluded that the structural model of biological indicators of stress in patients with gastrointestinal cancer based on perceived stress mediated by emotional regulation has a good fit.

Gastrointestinal cancer, Biological indicators of stress, emotion regulation