The heterogeneity of CXCR4 expression found within various types of cancers, including ACC, suggests that a method to detect and quantify CXCR4 on tumors non-invasively would be valuable in investigating CXCR4 in cancer biology, and in selecting and following patients in studies targeting CXCR4 as anti-cancer therapy. This evidence concerns the gene CXCR4 and adrenal cortex carcinoma.