It is expected that ddPCR may have good application prospects in molecular cancer diagnosis, for example in the study of phosphoinositide-3-kinase, catalytic subunit α (PIK3CA) (17), MET proto-oncogene (MET; hepatocyte growth factor) (18) and Kirsten rat sarcoma viral oncogene homolog (K-RAS) (19). The gene discussed is PIK3CA; the disease is cancer.