Abstract: Objective To study the expressions of CK19 mRNA and CK20 mRNA in peripheral blood of patients with laryngeal squamous cell carcinoma before and after radical treatment，and its clinical significances.Methods The nested reverse transcription polymerase chain reaction (nested RT-PCR) was used to detect the expressions of CK19 mRNA and CK20 mRNA at different stages in 48 cases of laryngeal squamous cell carcinoma. Dynamic observation of the expressions of CK19 mRNA and CK20 mRNA was applied within 24 months after operation. Results The positive expressions of CK19 mRNA and CK20 mRNA in peripheral blood at prior-treatment stage of 48 cases were 37.5% (18/48) and 45.8% (22/48) separately.The positive expressions of CK19 mRNA and CK20 mRNA were decreased statistically within 24 months after treatment (P＜0.05)，but these phenomena did not show in the cases with local recurrence.The positive expressions of CK19 mRNA and CK20 mRNA at prior-treatment in the patient with local recurrence were statistically higher than that without local recurrence.Conclusion The dynamic detections by nested RT-PCR for CK19 mRNA and CK20 mRNA in peripheral blood of patients with laryngeal squamous cell carcinoma at prior-and post-treatment stages could be used to evaluate micrometastasis and clinic treatment，and to predict the risk of local recurrence in the level of molecular biology.

Key words: Laryngeal neoplasm, CK19, CK20, RT-PCR, Peripheral blood