To date, metabolic profiling of serum or urine samples has been used, for example, to distinguish between cancerous and benign growth in pancreatic cancer patients [71], for staging patients suffering from colon cancer [72], for studying the effectiveness of bladder cancer treatments [73], and for distinguishing between ER+ and ER- breast cancer tumours [74]. The gene discussed is ESR1; the disease is pancreatic neoplasm.