Abstract: BACKGROUND ＆ AIM: To analyze the expression of RAP2B in lung cancer and adjacent tissue . MATERIALS AND METHODS: mRNA and protein expression level of RAP2B in 30 lung cancer and adjacent tissues were assessed by RT_PCR and Western_blot. RESULTS: ①The expression rate of RAP2B mRNA in lung cancer tissues was 73.3％(22/30)and 30.0％(9/30)in adjacent tissues. The difference between the two was statistically significant(P<0.05). Semi_quantitative results revealed that the relative expression of RAP2B mRNA was 0.155(0.000－0.530) in cancer tissues and 0.000(0.000－0.160) in adjacent tissues. The difference between the two was statistically significant(P<0.05). ②The detection rate of RAP2B protein in lung cancer tissues was 80％(24/30)and 60.0％(18/30)in adjacent tissues. The difference between the two was not statistically significant (P>0.05). Semi_quantitative results of Western blot demonstrated that the relative expression of RAP2B protein was 0.195(0.050－0.580) in cancer tissues and 0.030(0.000－0.180) in adjacent tissues. The difference between the two was statistically significant(P<0.05). CONCLUSION: Over_expression of RAP2B may play an important role in cancer development.

Key words: RAP2B, lung cancer, RT_PCR, Western blot