RT Journal Article SR Electronic T1 Increased FNDC5/IRISIN protein expression in breast cancer tissue is associated with obesity in postmenopausal women JF Journal of Clinical Pathology JO J Clin Pathol FD BMJ Publishing Group Ltd and Association of Clinical Pathologists SP 696 OP 701 DO 10.1136/jclinpath-2020-207249 VO 75 IS 10 A1 María Elena Tejeda A1 Patricia Canto A1 Alberto Tenorio-Torres A1 Letica Orozco-Arguelles A1 Ramón Mauricio Coral-Vázquez A1 Alejandro Zentella-Dehesa A1 Marcela Leal-García A1 Claudia Cecilia Vega-García A1 Verónica Bautista-Piña A1 Juan Pablo Méndez YR 2022 UL http://jcp.bmj.com/content/75/10/696.abstract AB Aim To analyse the fibronectin type III domain containing 5 (FNDC5)/irisin expression in tumour tissue of postmenopausal women presenting breast cancer and different body mass indexes (BMIs), proposing that obesity deregulates the expression of FNDC5/irisin at the breast tumour level. In addition, we investigated if different breast cancer cell lines are capable to synthesise this protein.Methods A total of 150 postmenopausal women (50 with a normal BMI, 50 presenting overweight and 50 having obesity) diagnosed with operable breast cancer were included. FNDC5/irisin expression was determined by immunohistochemistry or by immunocytochemistry. Qualitative analysis of protein expression was performed by the H-Score method, through ImageJ’s IHC Profiler software. Statistical analyses were carried out using STATA V.14.0 (Texas, USA); p value<0.05 was accepted as statistically significant. Statistical power of the study was >80% with a p<0.05.Results FNDC5/irisin expression in breast cancer tissue of postmenopausal women with obesity was significantly increased when compared with FNDC5/irisin expression in women with a normal BMI (p=0.001). Furthermore, three breast cancer cell lines studied were capable to synthesise and express FNDC5/irisin, being the BT-474 cell line the one that exhibited the highest intensity of expression.Conclusions Our results confirm that women with breast cancer and obesity exhibit an increased irisin expression in their tumorous tissue compared with women with breast cancer and normal BMI. Likewise, in vitro breast cancer cell lines have the capacity to synthesise and express FNDC5/irisin, without any extracellular stimuli, however the microenvironment surrounding these cells in vivo participates in its regulation.All data relevant to the study are included in the article.