This technique was originally used to detect disseminated cancer cells, which were indicative of increased recurrence and poorer survival and therefore served as prognostic, metastatic markers.107 However, this technology was subsequently enriched to detect circulating CAFs, demonstrating that CAFs were present in 88% of breast cancer patients with metastases, 23% of patients with localised disease and 0% of healthy donors.113 Moreover, in oesophageal cancer, ADAM12 is the serum-borne marker for IL-6+ CAFs, and its presence predicts poor response to neoadjuvant chemoradiation.46 The gene discussed is IL6; the disease is cancer.