Effect of promoter methylation of multidrug resistance 1 (MDR1) gene in gastric carcinogenesis.
BACKGROUND
The altered expression of multidrug resistance 1 (MDR1) contributes to various types of carcinogenesis and their disease progression. Hypermethylation of CpG islands located in the promoter regions is involved in gene silencing at the transcriptional level. The methylation status of MDR1 gene promoter was investigated in gastric cancer in relation to various clinicopathological features.


METHODS
The methylation of the MDR1 promoter was estimated in both antral non-neoplastic mucosa and cancer lesions in 83 patients with gastric cancer using a methylation-specific PCR method.


RESULTS
The methylation ratio (MR) of the cancer lesions (31.3 +/- 20.5) was significantly higher than that of non non-neoplastic mucosa (20.9 +/- 31.3, p = 0.0004). The MR was especially high in Lauren's intestinal cancer (p < 0.0001). A higher MR was also observed in more advanced stage (p = 0.005) and lymph vessel invasion-positive cases (p = 0.002).


CONCLUSIONS
The promoter methylation of MDR1 seems to have a significant role in carcinogenesis and tumor progression in the stomach.
Tahara
Tomomitsu
T
Department of Gastroenterology, Fujita Health University School of Medicine, Toyoake, Japan. tomomiccyu@yahoo.co.jp
Arisawa
Tomiyasu
T
Shibata
Tomoyuki
T
Yamashita
Hiromi
H
Yoshioka
Daisuke
D
Hirata
Ichiro
I