CXCR4 and breast carcinoma: Figure 9 shows an example of a patient with luminal A molecular subtype breast cancer with very low avidity in the breast primary and skeletal disease using 68Ga-Pentixafor; the lesions are clearly visible using 18F-FDG. This is in agreement with a study by Vazquez et al. who demonstrated a higher CXCR4 expression in triple-negative samples compared to in luminals A and B and HER2-enriched in the molecular subtype analysis of breast cancer tissue RNA sequencing data from the Cancer Genome Atlas (TCGA) breast cancer cohort [33].