Metabolic subtyping of luminal A samples using hierarchical clustering. The HR MAS MR spectra of the samples classified as luminal A (N = 31), cluster in three groups using hierarchical clustering with Spearman's correlation as the distance measure and complete linkage. The mean spectra of each luminal A group are shown. Selected metabolite allocations are indicated with abbreviations (β-Glc: β-glucose; Lac: lactate; Cr: creatine; m-Ino: myo-inositol; α-H: α-H of amino acids; Gly: glycine; α-Glc: α-glucose; Tau: taurine; Cho: choline; GPC: glycerophosphocholine; PCho: phosphocholine; Ala: alanine). The spectral chemical shift-scale is non-continuous due to deletion of signals from lipid residues at 2.8 ppm and 2.05 ppm.