Fig. 1: Plasma kisspeptin, c-Myc, and glutaminase are highly expressed in human triple-negative breast cancer (TNBC).

a Plasma kisspeptin (KP) levels (pmol/L; mean ± SEM) measured by radioimmunoassay in blood samples taken from healthy subjects (n = 26), nonmetastatic TNBC patients (i.e., early disease; n = 25), or metastatic TNBC patients (n = 27). Statistical analysis done using a nonparametric Kruskal–Wallis test. Error bars: SEM. b Representative images of immunostaining on formalin-fixed and paraffin-embedded human breast tissue biopsies showing the lack of expression of GLS or c-Myc in normal breast tissue, whereas these proteins are enriched in TNBC tumors; staining of epithelial markers cytokeratins 8/18 (enriched in normal breast tissue mammary glands) and cytokeratin 5 (enriched in basal tumors) shown below. Scale bar, 50 μM; n = 5/cohort. Representative western blots showing the expression of endogenous c-Myc and glutaminase (GLS1) in breast tissue lysates from (c) six healthy subjects and (d) 12 TNBC primary tumor biopsies, relative to expression of each protein in MDA-MB-231 cell lysates (positive control); see Supplementary Fig. 1a for the remaining six TNBC blots. Densitometric analysis of e c-Myc and f GLS1 blots from 12 TNBC biopsies and six normal breast tissue, conducted by normalizing to GADPH loading controls and protein expression in MDA-MB-231 cell lysates (internal control); Student’s unpaired t test, *p < 0.05.