Abstract 4282: Branched-chain amino acids in the urinary metabolic profile of colorectal cancer patients and associations with muscle mass, BMI, and physical activity in the ColoCare Study
Authors: Ose Jennifer , Liesenfeld David B. , Boehm Juergen , Habermann Nina , Owen Robert W. , Gigic Biljana , Skender Stefanie , Nattenmueller Johanna , Kauczor Hans-Ulrich , Ulrich Cornelia 
Published: July 2016

Abstract
Background
Branched-chain amino acids (BCAA; e.g., valine, leucine and isoleucine) have been previously linked with survival in colorectal cancer patients. It is unclear whether BCAAs are prognostic biomarkers or a surrogate endpoint for factors related to muscle mass. Thus, we investigated the correlation between BCAAs and muscle mass, physical activity and body mass index (BMI) at multiple time points during the course of disease in a prospective cohort of patients.
Methods
Patients with newly diagnosed colorectal cancer [n = 197; (stage I - IV)] from the ColoCare study in Heidelberg, Germany with baseline and follow-up data, and measurements of urinary BCAAs were eligible. Skeletal muscle mass of the dorsal muscle was quantified based on abdominal computed tomography (CT)-scans (vertebral body L3/4 and L4/5). BMI (kg/m2) and physical activity [metabolic equivalent (MET) hours/week] were reported by questionnaire. In addition, minutes of moderate and vigorous physical activity/week were measured by accelerometry. We prospectively monitored the urinary metabolome of these patients at multiple time points after surgery [baseline (n = 197), 6-month follow-up (n = 107) and 12 month follow-up (n = 75)]. BCAAs (valine, leucine and isoleucine) were identified using gas chromatography mass spectrometry (GC/MS). Metabolites were normalized based on the sum intensity of all annotated metabolites for statistical analyses. Pearson and partial correlation coefficients with parameters of energy balance/muscle mass were computed for each time point, adjusted for gender and age at diagnosis.
Results
As expected, urinary valine, leucine and isoleucine were highly correlated, independent of time point (r&gt;0.95, P&lt;0.01). There were no statistically significant correlations between BCAA and parameters of energy balance or muscle mass at baseline, 6 months, or 12 months (ranges of correlations for muscle mass: r = -0.17 to -0.04; for self-reported physical activity, MET hours/week r = -0.006 to -0.04, accelerometry-based moderate physical activity: r = -0.21 to-0.10; BMI: r = -0.05 to 0.09).
Conclusion
The present data suggests that urinary levels of BCAA in colorectal cancer patients do not reflect parameters of energy balance and muscle mass. Thus, they warrant further investigation as potential prognostic biomarkers.
Citation Format: Jennifer Ose, David B. Liesenfeld, Juergen Boehm, Nina Habermann, Robert W. Owen, Biljana Gigic, Stefanie Skender, Johanna Nattenmueller, Hans-Ulrich Kauczor, Cornelia Ulrich. Branched-chain amino acids in the urinary metabolic profile of colorectal cancer patients and associations with muscle mass, BMI, and physical activity in the ColoCare Study. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4282.