Development of electrochemical biosensors for tumor marker determination towards cancer diagnosis: Recent progress

According to the latest statistics, cancer is expected to account for nearly 1800000 new cases and about 607000 deaths in the US in 2019. Approximately 40% of people with cancer survive. This means that life expectancy is a little more than 1 in 3. Therefore, it is essential to detect this malignancy in early stage and predict therapeutic responses in patients in order to enhance the efficiency of treatment, decrease side-effects and optimize the cure process. One of the best solutions for early cancer diagnosis and management is tracking tumor markers. Cancerous or noncancerous cells produce these substances in response to cancer or some specific conditions. Although, onco-biomarkers are generated in normal situations, their concentration is much higher in the presence of tumors. These materials which most of them are proteins can be spotted in body fluids such as blood, serum and urine. An increased level of an oncobiomarker may be associated with the presence of cancer, however, it is not a definite indicator. For that reason, a combination of biomarkers and other diagnostic tests are always preferred. Due to the high cost, low speed and intricate instrumental requirements of existing assays such as enzyme linked immuno-sorbent assay, fluorescence and radiometric immunoassay for measurement of biomarkers, there is an extreme need for more inexpensive, swift, simple and portable detection methods. In recent years, the popularity of electrochemical biosensors are increasing in diagnostic fields. Significant improvements in electrochemical techniques, biological instrumentation and nanotechnology have paved the way for the emergence of novel platforms for detection of tumor markers. Importance of measurement of biomarkers by electrochemical-based affinity biosensors for early cancer diagnosis and monitoring have been emphasized by numerous articles. The main purpose of the present review is to give researchers a general idea of the recent studies about early cancer detection by EC-based biosensing devices, being pursued globally.