ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the expression of three different RASSF1 transcripts and its clinical significance in lung carcinomas.</p><p><b>METHODS</b>The mRNA expression of RASSF1A, RASSF1B and RASSF1C was detected by RT-PCR in 51 human lung cancer tissues and 51 matched normal tissues.</p><p><b>RESULTS</b>1. The mRNA expression of three RASSF1 transcripts was detectable in all non-cancer tissues. However, high rate of expression loss of RASSF1A and RASSF1B existed in lung cancer tissues, which was 53.2% (2851) and 37.3% (19/51), respectively. RASSF1C was expressed in all of the tumor tissues. 2. Loss or abnormal down-regulation of RASSF1A was positively related with lymph node metastasis and TNM stage (P < 0.05) and 3. RASSF1B and RASSF1C mRNA expression was not correlated with TNM stage, histological type, differentiation grade or smoking index.</p><p><b>CONCLUSION</b>There is a significant expression difference among the three RASSF1 transcripts in lung carcinoma. RASSF1A, closely associated with lymph metastasis and TNM stage of lung carcinoma, should be a new tumor suppressor gene.</p>