[The influence of promoter methylation of RASSF1A on RASSF1A mRNA and protein expression in gastric cancer tissues].
OBJECTIVE
To investigate RASSF1A expression in tissue of primary gastric cancer (GC) at mRNA and protein levels and analyze the relationship between DNA methylation status and RASSF1A expression in GC.


METHODS
RASSF1A mRNA expression was determined with RT-PCR in 54 specimens of cancer tissue and adjacent normal tissue. RASSF1A promoter methylation was detected with methylation-specific PCR. The expression of RASSF1A protein level was determined with Western blot in tissue of GC in 20 patients.


RESULTS
RASSF1A mRNA and protein expressions in GC were reduced significantly than those in corresponding normal tissue (A value: 0.2589 +/- 0.2407 vs 0.5448 +/- 0.2971, P < 0.0001; 0.1874 +/- 0.0737 vs 0.6654 +/- 0.2201, P < 0.0001, respectively). Methylation frequency of RASSF1A in primary GC was higher than that in corresponding normal tissue (66.7% vs 14.8%, P < 0.0001). Furthermore, RASSF1A mRNA expression in methylation group of GC was much reduced than that in unmethylation group of GC (0.1384 +/- 0.1142 vs 0.5018 +/- 0.2463, P < 0.0001).


CONCLUSIONS
Expression of RASSF1A is reduced in the tissue of GC at mRNA and protein levels. Low expression of RASSF1A is associated with hypermethylation of the promoter of RASSF1A gene.
Ye
Mei
M
Department of Internal Medicine & Geriatrics, Zhongnan Hospital, China.
Xia
Bing
B
Guo
Qiu-sha
QS
Zhou
Feng
F
Zhang
Xiao-lian
XL
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018899:CpG Islands; D019175:DNA Methylation; D006801:Humans; D008875:Middle Aged; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000473:pathology; D025521:Tumor Suppressor Proteins / Q000096:biosynthesis* / Q000235:genetics
C411762:RASSF1 protein, human; D012333:RNA, Messenger; D025521:Tumor Suppressor Proteins