The sensing targets in this review are: H2O2, glucose, uric acid (UA), cholesterol, carcinoembryonic antigen (CEA), long non-coding RNA, carbohydrate antigen 19-9, cancer cells (human leukemia CCRF-CEM), dopamine, cardiac troponin I, human tissue polypeptide antigen (hTPA), cancer antigen 125 (CA-125), glutamate, lead, mercury, zearalenone (ZEA), organophosphates and 2-butanone. The gene discussed is CEACAM5; the disease is leukemia.