Fig. 2

Endogenous FFAR4 ligand distribution in human breast tissues. a Representative gas chromatogram of breast cancer tissue samples. b Mass spectra of the FAME captured at retention time 27.010 min (top) shows excellent match (MF and RMF at 939 on a scale of 0 [no match] to 1000 [perfect match]) with the mass spectra of DHA methyl ester in NIST library (bottom). c Total fatty acid amount is significantly lower in cancerous compared to normal breast tissues (n = 19). d five FFAR4 ligands exhibited elevated proportions in cancerous compared to normal breast tissues (n = 19). e Detailed view of uniformly elevated proportions of SA, DGLA and DHA in cancerous compared to normal tissues (n = 19). Each line represents an individual subject. Bars represent mean ± S.D. *** P <  0.001. FAME: fatty acid methyl ester; MF: matching factor; RMF: reverse matching factor