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Breast Cancer Research

Open Access

Low frequency of p16 INK4a promoter methylation in mammary carcinomas as revealed by positive display of methylated sites

  • R Lilischkis1,
  • H Kneitz1 and
  • H Kreipe1
Breast Cancer Research20002(Suppl 1):P5.02

Published: 12 March 2000


Silence GeneFull TextPromoter MethylationMammary TissueMammary Carcinoma

Full text

Promoter methylation represents an important mechanism for silencing gene expression in higher eukaryotes. In order to study methylation of the promoter of the tumour suppressor p16 INK4a, we developed a fast and simple method that in contrast to previous studies relies on the positive display of methylated sites (PDM). The method is based on bisulphite treatment of DNA, PCR-amplification of the modified DNA, and restriction digest of de novo created restriction sites to positively display DNA methylation in a background of unmethylated DNA. Since methylated as well as unmethylated DNA is amplified, information on the proportion of both is provided.

Using this approach, we analysed 33 ductal invasive mammary carcinomas, 4 normal mammary tissues and 4 cell lines for methylation. p16INK4a methylation was detected in 1/33 carcinomas (3%) and in 0/4 normal tissue samples. We conclude that PDM provides a useful tool for determining the degree and pattern of promoter methylation and is suitable for screening large series of tissue samples.

Authors’ Affiliations

Institute of Pathology, Hannover Medical School, Hannover, Germany


© Current Science Ltd 2000