Shaghayegh Saljooghi - Department of Clinical Biochemistry, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran.
Zahra Heidari - Department of Internal Medicine, Zahedan University of Medical Sciences, Zahedan, Iran.
Mohsen Saravani - Department of Clinical Biochemistry, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran & Cellular and Molecular Research Center, Resistant Tuberculosis Institute, Zahedan University of Medical Sciences, Zahedan, Iran.
Mahnaz Rezaei - Department of Clinical Biochemistry, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran & Cellular and Molecular Research Center, Resistant Tuberculosis Institute, Zahedan University of Medical Sciences, Zahedan, Iran.
Saeedeh Salimi - Department of Clinical Biochemistry, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran & Cellular and Molecular Research Center, Resistant Tuberculosis Institute, Zahedan University of Medical Sciences, Zahedan, Iran.

Background: A group of transcription factors involved in several cellular processes like cell growth, proliferation, cell cycle, differentiation and apoptosis which are critical to the cell biology of cancer is Forkhead Box O (FOXO) family. FOXOs are known as putative tumor suppressors. FOXO۱ is a member of FOXO family which its abnormal expression or function has been indicated to promote cell proliferation and tumorigenesis. The probable effects of FOXO۱ rs۱۷۵۹۲۲۳۶ polymorphism on Papillary thyroid carcinoma (PTC) and its clinical findings were evaluated. Methods: In total, ۱۵۶ PTC patients and ۱۵۸ healthy subjects were participated in the study. Genotyping of FOXO۱ rs۱۷۵۹۲۲۳۶ polymorphism was carried out using RFLP-PCR method.  Results: There was no association between the FOXO۱ rs۱۷۵۹۲۲۳۶ polymorphism and PTC in codominant, recessive, dominant, overdominant, and log-additive models. The frequency of rs۱۷۵۹۲۲۳۶A allele was ۱۳% in PTC and ۱۷% in control group and were not statistically significant (p= ۰.۱۵). The analysis of the relationship between FOXO۱ rs۱۷۵۹۲۲۳۶ polymorphism and clinical specifications of papillary thyroid carcinoma demonstrated no significant relationship between rs۱۷۵۹۲۲۳۶ polymorphism and PTC in different ages (< ۴۰ and≥ ۴۰), gender (male/female), extrathyroidal expansion, N stage, vascular invasion and capsular invasion in PTC patients. There was a relationship between FOX۱ rs۱۷۵۹۲۲۳۶ polymorphism and a larger tumor size (≥ ۱ cm) only in log-additive model (OR= ۲.۹۶, ۹۵% CI= ۰.۸۸-۹.۹۸; p= ۰.۰۴). Conclusions: FOXO۱ rs۱۷۵۹۲۲۳۶ polymorphism was not associated with PTC; however, this variant was associated with a larger tumor size (≥ ۱ cm) only in log-additive model.

FOXO۱, Papillary thyroid carcinoma, Polymorphism, Tumor size.