Currently, research on CNT-based biosensors is focused on exploiting the development of CNT electrodes for the electrochemical detection of biological agents, such as glucose [19], immunoglobulin G (IgG) [20], immunoglobulin E (IgE) [21,22], thrombin [23], and total prostate-specific antigen (T-PSA) as a cancer marker [24]. This evidence concerns the gene KLK3 and cancer.