CEACAM5 and neoplasm: Recentstudies showedthat Pd-NMs were designed as probes to recognize specific tumor biomarkerssuch as programmed cell death ligand 1 (PD-L1), α-fetoprotein(AFP), prostate-specific antigen (PSA), carcinoembryonic antigen (CEA),carbohydrate antigen 24–2 (CA-242), human epidermal growthfactor receptor 2 (HER2), and microRNAs (miRNAs), thereby achievinghighly sensitive tumor detection.