MYC and Increased circulating prolactin concentration: The identification of SOX4-PRL-c-MYC signalling axis provides actionable insights for developing novel therapeutic strategies against this malignancy.<h4>Key points</h4>Retroperitoneal sarcoma cells can secrete prolactin into the bloodstream, inducing hyperprolactinaemia, which subsequently triggers metabolic reprogramming, such as glucose metabolism.