Some devices, such as an amperometric immunosensor based on a screen-printed (SP) chip for simultaneous quantification of carbohydrate antigen 19-9 (CA19-9), and cancer antigen 125 (CA125) [34], a photoresist-patterned microfluidic paper-based analytical device with amperometric detection system for α-fetoprotein (AFP), carcinoembryonic antigen (CEA), CA125, and cancer antigen (CA153) [87], successfully demonstrated their potential applicability in clinical practice to identify cancer biomarkers in serum samples taken from cancer patients. This evidence concerns the gene AFP and cancer.