High frequency of promoter hypermethylation of RASSF1A in tumorous and non-tumourous tissue of breast cancer.
OBJECTIVE
To determine the presence of RASSF1A promoter methylation in tumorous and non-tumorous tissues of breast cancer.


METHODS
Methylation-specific PCR was used to detect RASSF1A methylation in DNA extracted from tumorous and paired non-tumorous tissues of 40 breast cancer patients. The associations of RASSF1A hypermethylation with clinicopathological characteristics in tumorous and non-tumorous breast tissues were analysed.


RESULTS
RASSF1A promoter hypermethylation was detected in 38 of the 40 breast cancer tissues (95%) and 37 of the paired non-tumorous tissues (92.5%). When compared with the non-tumorous tissues, aberrant methylation was detected to be higher in 24 of the tumorous tissues (60%). The latter was found to be associated with lower histological grade tumours (p=0.048).


CONCLUSIONS
RASSF1A promoter hypermethylation occurred at a high frequency in breast cancer tumorous and non-tumorous tissues; the majority of tumours have a higher level of methylation status when compared with non-tumorous tissues. This supports the notion that RASSF1A methylation is an early and premalignant alteration.
Yeo
Winnie
W
Department of Clinical Oncology, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong. winnieyeo@cuhk.edu.hk
Wong
Wai-Lap
WL
Wong
Nathalie
N
Law
Bonita K
BK
Tse
Gary M
GM
Zhong
Sheng
S
D000230:Adenocarcinoma / Q000235:genetics* / Q000378:metabolism / Q000556:secondary; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism; D001940:Breast / Q000378:metabolism / Q000473:pathology*; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008593:Menopause; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000378:metabolism
D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; C411762:RASSF1 protein, human; D025521:Tumor Suppressor Proteins