## 5 Conclusions  
The results of this study show that previously reported VOC biomarkers can be exploited to determine pitavastatin treatment efficacy. Through chemometric analyses, pitavastatin administered at high concentration was determined to have antitumor effects, as pita high trended towards healthy controls and displayed significant differences when compared to cancer week 1-3 samples. On the contrary, urinary VOC expression for pitavastatin administered at low concentration is highly reflective of cancer samples and showed considerable differences when compared to control samples; therefore, the VOC analyses indicated that the treatment is not effective in slowing tumor progression. The results from the VOC assays are highly reflective of the traditional analyses (micro-CT and X-ray analysis), which showed that pitavastatin administered at high doses inhibits tumor-induced bone damage, and pitavastatin at low concentrations does not. Upon validation of the results using humans with breast cancer, we found that urinary VOCs may be able to be used to accurately and noninvasively monitor the efficacy of breast cancer treatments in real time in the future, which would potentially decrease overtreatment and treatment-related morbidity without reducing survival rates.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/molecules27134277/s1](https://www.mdpi.com/article/10.3390/molecules27134277/s1)]([https://www.mdpi.com/article/10.3390/molecules27134277/s1](https://www.mdpi.com/article/10.3390/molecules27134277/s1)), Table S1. VOCs of interest identified using approach 1, with \(p\)-values when comparing each week for pita high (PH) samples and cancer (C) samples (ns--no significance, * \(p<0.05\), ** \(p<0.01\), *** \(p<0.001\), underlined asterisk--\(p<0.05\) by FDR, **name bolded--LDA**); Table S2. VOCs of interest identified using approach 2, with \(p\)-values when comparing each week for pita high (PH) samples to cancer (C) week 3 samples (ns--no significance, * \(p<0.05\), ** \(p<0.01\), *** \(p<0.001\), underlined asterisk--\(p<0.05\) by FDR, **name bolded--LDA**).  
Conceptualization, M.A. and H.Y.; methodology, P.G., L.W., S.L. and M.W.; data curation, P.G. and M.W.; validation, P.G. and M.W.; formal analysis, P.G. and M.W.; investigation, M.A., H.Y., B.-Y.L., A.P.S. and M.K.; resources, M.A., H.Y., A.P.S., B.-Y.L. and M.K.; writing--original draft preparation, P.G. and M.W.; writing--review and editing, P.G., M.W., L.W., S.L., H.Y., A.P.S., B.-Y.L., M.K. and M.A.; visualization, P.G. and M.W.; supervision, M.A., H.Y., A.P.S., B.-Y.L. and M.K.; project administration, M.A., H.Y., A.P.S., B.-Y.L. and M.K.; funding acquisition, M.A. and H.Y. All authors have read and agreed to the published version of the manuscript.  
This research was funded by U.S. National Institutes of Health (NIH)/National Institute of Arthritis and Musculoskeletal and Skin Diseases (grant # R01 AR052144) and the National Science Foundation (grant # 1659688 and 1502310).  
**Institutional Review Board Statement:** Experimental procedures followed the Guiding Principles in the Care and Use of Animals supported by the American Physiological Society and were approved by the Indiana University Animal Care and Use Committee (protocol code: SC292R; date of approval: 30 May 2019). No humans were utilized in this study.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** Data presented in this study is available upon request from the corresponding author.  
**Acknowledgments:** The authors would like to thank [PERSON] for helping with optimization of procedures and [PERSON] for assisting with analysis of urine samples via GC-MS QTOF. Finally, the authors would like to acknowledge the National Science Foundation (grant #1502310) and Agilent Technologies.  
**Conflicts of Interest:** The authors declare no conflict of interest.  
**Sample Availability:** No biological samples or volatile organic compound standards are available from the authors.