Monounsaturated fatty acids in serum triacylglycerols are associated with response to neoadjuvant chemotherapy in breast cancer patients

Changes in cellular lipid metabolism are a common feature in most solid tumors, which occur already in early stages of the tumor progression. However, it remains unclear if the tumor-specific lipid changes can be detected at the level of systemic lipid metabolism. The objective of this study was to perform comprehensive analysis of lipids in breast cancer patient serum samples. Lipidomic profiling using an established analytical platform was performed in two cohorts of breast cancer patients receiving neoadjuvant chemotherapy. The analyses were performed for 142 patients before and after neoadjuvant chemotherapy, and the results before chemotherapy were validated in an independent cohort of 194 patients. The analyses revealed that in general the tumor characteristics are not reflected in the serum samples. However, there was an association of specific triacylglycerols (TGs) in patients' response to chemotherapy. These TGs containing mainly oleic acid (C18:1) were found in lower levels in those patients showing pathologic complete response before receiving chemotherapy. Some of these TGs were also associated with estrogen receptor status and overall or disease-free survival of the patients. The results suggest that the altered serum levels of oleic acid in breast cancer patients are associated with their response to chemotherapy. What's new?: Up to 25% of breast tumors show pathologic complete response (pCR) following neoadjuvant chemotherapy. Identifying biomarkers that could predict pCR could help select those patients who would most benefit from therapy. Knowing that blood oleic acid concentration is increased in cancer patients and associated with breast cancer predisposition, here the authors explored how serum lipidomic profiles may be associated with pCR in patients receiving therapy. Lowered concentrations of oleic acid in serum triacylglycerols were found to be associated with pCR in breast cancer patients receiving neoadjuvant chemotherapy. This highlights the importance of systemic lipid metabolism status in response to chemotherapy.