June 2018 | Volume 9 | Article 306 1 ORIGINAL RESEARCH published: 06 June 2018 doi: 10.3389/fendo.2018.00306 Frontiers in Endocrinology | www.frontiersin.org Edited by: Rosamaria Lappano, University of Calabria, Italy Reviewed by: Fumihiko Hakuno, The University of Tokyo, Japan Barbara Belletti, Centro di Riferimento Oncologico di Aviano (IRCCS), Italy *Correspondence: Helena Jernström helena.jernstrom@med.lu.se Specialty section: This article was submitted to Cancer Endocrinology, a section of the journal Frontiers in Endocrinology Received: 26 March 2018 Accepted: 23 May 2018 Published: 06 June 2018 Citation: Björner S, Rosendahl AH, Tryggvadottir H, Simonsson M, Jirström K, Borgquist S, Rose C, Ingvar C and Jernström H (2018) Coffee Is Associated With Lower Breast Tumor Insulin-Like Growth Factor Receptor 1 Levels in Normal-Weight Patients and Improved Prognosis Following Tamoxifen or Radiotherapy Treatment. Front. Endocrinol. 9:306. doi: 10.3389/fendo.2018.00306 Coffee Is Associated With Lower Breast Tumor Insulin-Like Growth Factor Receptor 1 Levels in Normal- Weight Patients and Improved Prognosis Following Tamoxifen or Radiotherapy Treatment Sofe Björner 1 , Ann H. Rosendahl 1 , Helga Tryggvadottir 1 , Maria Simonsson 1 , Karin Jirström 1 , Signe Borgquist 1 , Carsten Rose 2 , Christian Ingvar 3 and Helena Jernström 1 * 1 Skåne University Hospital, Department of Clinical Sciences Lund, Oncology and Pathology, Faculty of Medicine, Lund University, Lund, Sweden, 2 CREATE Health, Department of Immunotechnology, Lund University, Medicon Village, Lund, Sweden, 3 Skåne University Hospital, Department of Clinical Sciences Lund, Surgery, Lund University, Lund, Sweden Coffee is associated with decreased breast cancer risk, but the impact of body mass index (BMI) in combination with coffee consumption on prognosis is unclear. The suppressive effect of coffee constituents on the insulin-like growth factor receptor 1 (IGF1R) levels in breast cancer cells may play a role. The aim was to investigate the prognostic impact of coffee consumption and possible associations with tumor- specifc IGF1R protein expression and BMI in a population-based cohort in Sweden, comprising 1,014 primary breast cancer patients without pretreatment enrolled 2002–2012 and followed for up to 13 years. Patients with higher coffee consump- tion had lower tumor IGF1R levels (P = 0.025), but only among the normal-weight patients (P = 0.005). Coffee did not impact the recurrence-risk overall. However, tamoxifen-treated patients with ER + tumors drinking ≥ 2 cups of coffee/day had lower recurrence-risk [adjusted HR (HRadj) 0.57, 95% CI, 0.34–0.97] compared with patients with lower intake, although only among normal-weight patients (HRadj 0.37, 95% CI: 0.17–0.78; Pinteraction = 0.039). Similarly, coffee consumption ≥ 2 cups/day was associated with signifcantly lower recurrence-risk among the 640 radiothera- py-treated patients irrespective of BMI (HRadj 0.59, 95% CI 0.36–0.98) and in the 296 normal-weight patients (HRadj 0.36, 95% CI 0.17–0.76) but not in the 329 overweight or obese patients (HRadj 0.88, 95% CI 0.42–1.82) although the interaction was not signifcant (Pinteraction = 0.093). In conclusion, coffee consumption was negatively associated with tumor-specifc IGF1R levels only among normal-weight patients. Though, IGF1R did not explain the association between coffee intake and improved prognosis among normal-weight tamoxifen- or radiotherapy-treated patients. Studies of IGF1R-targeting therapies may beneft from taking BMI and coffee consumption into account. Keywords: coffee, insulin-like growth factor receptor 1, body mass index, breast cancer, prognosis