The detection limit for CEACAM5 in the multiplex assay was ≈100 CEACAM5 mRNA copies/μL, which is approximately the signal of 1 tumor cell (range: 30–400 CEACAM5 mRNA copies per cell).10,11,16 This, together with the previous finding that very low levels of CEACAM5 mRNA are detected in LNs of control patients,10,11 suggests that CEACAM5 mRNA concentrations <100 copies/μL are not relevant for LN classification. The gene discussed is CEACAM5; the disease is neoplasm.