TP53 and cancer: The proteins monitored by the NAPPA-based nanogravimetric biosensor, namely p53 and MDM2, are of fundamental importance in the molecular mechanisms leading to malignant cell transformation and cancer; p53 is in fact a 53-kiloDalton phosphoprotein oncosuppressor, encoded by a 20-kilobases gene situated on the short arm of human chromosome 17 and termed as the “guardian of the genome” and the “policeman of oncogenes” [13,14].