目的：探讨鸟氨酸脱羧酶（ＯＤＣ）反义ＲＮＡ逆转人肺鳞癌细胞ＬＴＥＰ７８（Ｌ７８）恶性表型的分子机理。方法：核酸杂交，免疫细胞化学染色等。结果：在ＯＤＣ反义基因稳定整合、ＯＤＣ反义ＲＮＡ高效表达的转染细胞株中，ｃｍｙｃ及ｃＨａｒａｓｍＲＮＡ的表达比Ｌ７８亲本细胞显著下降；ｒａｓＰ２１蛋白的表达也受到明显抑制。结论：ＯＤＣ反义ＲＮＡ引起细胞内多胺耗竭，对ｃｍｙｃ及ｃＨａｒａｓ基因表达有明显的下调作用，这可能是其逆转人肺鳞癌细胞恶性表型的重要机制之一。 Objective: To investigate the molecular mechanism of antisense RNA of ornithine decarboxylase (ODC) reversed the malignant phenotype of human lung squamous cell carcinoma cell line LTEP78 (L78). Methods: Nucleic acid hybridization, immunocytochemistry, etc. Results: The expression of cmyc and cHaras mRNA in the transfected cell line with stable antisense ODC antisense gene and high expression of ODC antisense RNA was significantly lower than that of L78 parental cell. The expression of rasP21 protein was also significantly inhibited. CONCLUSION: ODC antisense RNA induces the depletion of polyamines in the cells, and significantly down-regulates the expression of cmyc and cHaras genes, which may be one of the important mechanisms for reversing the malignant phenotype of human lung squamous cell carcinoma.