Cheng et al. developed a QD-based fluorescent nanobiosensor aimed at the early diagnosis of HCC, to enable the simultaneous quantitative detection of three major serum biomarkers, α-fetoprotein (AFP), dickkopf-related protein 1 (DKK1), and glypican-3 (GPC3), all within a single clinical sample. The gene discussed is GPC3; the disease is hepatocellular carcinoma.