Abstract: Objective To investigate the expression of p53,ΔNp63 and ΔNp73 and their association with clinical pathology characteristics in different differentiated lung squamous cell carcinoma.Methods Expression of p53,ΔNp63 and ΔNp73 was detected by immunehistochemistry in 149 cases of different differentiated lung squamous cell carcinoma and 39 cases adjacent normal tissues.Results The positive rates of p53,ΔNp63 and ΔNp73 were 64.4%(96/149),85.9%(128/149),77.2%(115/149),respectively in lung squamous cell carcinoma.The positive rates and expression level in primary lung squamous cell carcinoma were remarkably higher than that in adjacent normal tissues(P ＜ 0.05).The expression of p53,ΔNp63 and ΔNp73 were not correlated with gender,age,clinical stage and metastasis in lymphoid nodes(P ＞ 0.05),however they were correlated with the degree of tumor differentiation(P ＜ 0.05).Conclusion p53,ΔNp63 and ΔNp73 is a group of valuable diagnostic markers of lung squamous cell carcinoma.p53,ΔNp63 and ΔNp73 may be as oncogenes to promote the progression of tumor.