Specifically in the area of cancer research, various BREs were developed to detect biological makers at physiological ranges, including carcinoembryonic antigen (CEA) detection in saliva showing promise for early oral cancer detection [1], measuring inflammation markers [2], detection of breast cancer marker Mucin1 in serum samples [3], and volatile organic compounds in breath-based biosensors [4] and biological fluids to detect cancers using odorant receptor-based biosensors [5]. The gene discussed is CEACAM5; the disease is breast carcinoma.