Analyses of promoter hypermethylation for RUNX3 and other tumor suppressor genes in nasopharyngeal carcinoma.
BACKGROUND
Aberrant methylation of cytosine in promoter CpG islands is a recognized contributory process to carcinogenesis. This study explores the methylation profile of RUNX3 in combination with p16, RASSF1A, CDH1 and hMLH1 in nasopharyngeal carcinoma (NPC) patients.


METHODS
Genomic DNA was extracted from 19 fresh frozen NPC biopsies, which were then subjected to bisulfite conversion and methylation-specific PCR for analysis of promoter hypermethylation for the five respective genes. Three cell lines, SNU1, RKO and LS174T, were used as controls.


RESULTS
The incidences of promoter methylation were as follows: RUNX3 0/19 (0%), p16 6/19 (32%), RASSF1A 13/19 (68%), CDH1 9/19 (47%) and hMLH1 4/19 (21%). Ninety-five percent of the tumor specimens displayed aberrant methylation in at least one of these genes. No significant correlation between methylation status of these genes and clinical parameters was found.


CONCLUSIONS
Methylation of multiple genes is involved in critical pathways for cancer development in NPC. Promoter hypermethylation for RUNX3 was, however, not present.
Tan
Sing-Huang
SH
Department of Hematology-Oncology, National University Hospital, 5 Lower Kent Ridge Road, 119074, Singapore.
Ida
Hiroshi
H
Goh
Boon-Cher
BC
Hsieh
Wenson
W
Loh
Marie
M
Ito
Yoshiaki
Y
D001483:Base Sequence; D050677:Core Binding Factor Alpha 3 Subunit / Q000235:genetics*; D017931:DNA Primers; D016147:Genes, Tumor Suppressor; D006801:Humans; D008297:Male; D009303:Nasopharyngeal Neoplasms / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic
D050677:Core Binding Factor Alpha 3 Subunit; D017931:DNA Primers; C493729:Runx3 protein, human