Abstract: Objectives: To evaluate the short-term effects of neoadjuvant chemotherapy with pingyangmycin (PYM) in the treatment of laryngeal squamous cell carcinoma and to detect the changes in physiology and molecular biology in tumors compared with tissue specimens from the surrounding normal tissue after neoadjuvant chemotherapy. Methods: a). Fifty cases of laryngeal squamous cell carcinoma were treated with 16 mg of PYMevery other day with a total dose of 112 to 192 mg. before surgery. The short-term curative effect was evaluated and the side effects of the drug were observed. b). Twenty-four cases with laryngeal squamous-cell carcinoma were treated with PYMas neoadjuvant therapy, and the surgical procedures were conducted one week later. Pathology, flow cytometry and immunohistochemical staining for, PCNA, p53, Bcl-2, and CD44v6 were carried out on the tumor samples, specimens from the adjacent normal tissue and normal tissue. Results: a). The short-term curative rate of PYMin the cases with laryngeal squamous cell carcinoma was 80.2% (The curative rate with the recommended dose was 87.9%). The response rate to PYMwas related to the degree of cellular differentiation and drug dosage, but not to the clinical stage or primary location of the tumors. The side effects included fever, digestive reaction, skin symptoms and higher WBC. b). After chemotherapy, apoptosis was higher in the tumors and the surrounding area than before -chemotherapy. The G₁ and S-phase ratios after chemotherapy were higher than thos before chemotherapy, but the G₂- phase ratio was obviously lower compared to pre-chemotherapy. The expressions of PCNA, p53, Bcl-2 and CD44v6 in tumor samples after chemotherapy were lower than those before chemotherapy. There was no difference in PCNA, p53, Bcl-2 and CD44v6 expression in the area adjacent to the tumor compared to normal tissue, but there was a significant difference between the tumor-adjacent area and the tumor. Conclusion: a). Neoadjuvant chemotherapy with PYM is feasible for the treatment of laryngeal squamouscell carcinoma, and side effects are not evident. It is suggested that a total dose of 160 mg be recommended for preoperative chemotherapy. Senile patients or those with lung disease can reduce the dose befittingly. b). After neoadjuvant chemotherapy, large numbers of tumor cells died. Proliferation of tumor cells decreased and apoptosis increased after chemotherapy. The parameters evaluated for the areas surrounding the tumor were nearly normal after chemotherapy.