Genetic and epigenetic alterations of DLC-1, a candidate tumor suppressor gene, in nasopharyngeal carcinoma.
The DLC-1 gene, located at the human chromosome region 8p22, behaves like a tumor suppressor gene and is frequently deleted in diverse tumors. The deletion of 8p22 is not an uncommon event in nasopharyngeal carcinoma (NPC), therefore we explored the expression levels of the DLC-1 gene in NPCs and NPC cell lines by reverse transcription-polymerase chain reaction. The results showed the mRNA level of DLC-1 was downregulated. To identify the mechanism of DLC-1 downregulation in NPC, we investigated the methylation status of the DLC-1 gene using methylation-specific PCR, and found that 79% (31 of 39) of the NPC tissues and two DLC-1 nonexpressing NPC cell lines, 6-10B and 5-8F, were methylated in the DLC-1 CpG island. Microsatellite PCR was also carried out, and loss of heterozygosity was found at four microsatellite sites (D8S552, D8S1754, D8S1790 and D8S549) covering the whole DLC-1 gene with ratios of 33% (4 of 12 informative cases), 18% (2 of 11), 5% (1 of 18), and 25% (3 of 12), respectively. Taken together, our results suggest that DLC-1 might be an NPC-related tumor suppressor gene affected by aberrant promoter methylation and gene deletion.
Peng
Dan
D
Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha 410078, China.
Ren
Cai-Ping
CP
Yi
Hong-Mei
HM
Zhou
Liang
L
Yang
Xu-Yu
XY
Li
Hui
H
Yao
Kai-Tai
KT