The highlighted methods have been developed for the determination of circulating biomarkers associated with cancer (mutations in the EGFR and p53 genes, DNA species related to ORAOV1, BRCA and HPV-16 genes, mRNA associated to IL-8 and many cancer related miRNAs), neurodegenerative diseases (PrPC proteins, Alzheimer-related DNA sequences, mutated apolipoprotein E gene), bacterial (E. coli, Porphyromonas gingivalis 16S rRNA, S. pneumoniae lytA gene Mycobacterium sp. This evidence concerns the gene PRNP and cancer.