Epigenetic inactivation of selected genes for growth, invasivity and metastasis regulation in breast cancers diagnosis

The aim of the project was to investigate the relationship between DNA methylation levels in several cancer-associated genes and breast cancer progression using QM-MSP. In 92 breast tumours we found that stable relatively high RASSF1A methylation could be utilised as universal tumour marker and the less frequent but highly methylated CDH1 promoter can serve for identification of potentially metastasising tumours. In further 151 breast cancer patients we analysed DNA methylation of RASSF1A, ESR1, CDH1, TIMP3 and SYK genes in tumours, plasma and blood cells. Simultaneous methylation in tumours and plasma were shown in 33 patients; however, different cumulative methylation spectra were found in these two types of DNA. The positive correlation between RASSF1A methylation levels and % of breast cancer cells with ER and PR expression could aid the prognosis of hormonal therapy response. The clinical utility of plasma for analysis of cancer-associated DNA methylation is inappropriate for low detection sensitivity.