Developments in biosensor and bioelectronics technology have helped the biomedical profession with diagnosis and treatment. With an emphasis on cancer detection, this approach offers the potential to identify molecular targets as a new generation of diagnostics. Given that cancer is the second primary cause of death from all illnesses, more research is being done in this area with an emphasis on early detection. Traditional cancer screening techniques have low specificity and sensitivity and are expensive, unpleasant, and time-consuming. Recently, scientists have developed a range of biosensors to detect specific molecular markers of cancer. One kind of point-of-care device that patients may use at home is a biosensor. By incorporating nanocomposite (NC) into the electrochemical sensing interface, signal amplification is achieved, increasing detection accuracy and limits. PANI (polyaniline) and its composites found widespread usage in electrochemical (EC) sensors and bio-sensors due to their attractive properties and their ability to be modified by carefully choosing the suitable components. The concepts and detection limit that may aid in the early detection of cancer are described in this work along with a detailed examination of a number of biosensors based on PANI and tumor biological markers that have been developed to discover biomarkers.