الفهرس 
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Abstract
Breast carcinogenesis involves genetic and epigenetic alterations that cause aberrant gene function. Recent progress in the knowledge of epigenomics has had a profound impact on the understanding of mechanisms leading to breast cancer, and consequently the development of new strategies for diagnosis and management of breast cancer.
In breast cancer, methylation of various genes was reported, however, only a limited number of epigenetic markers were applied in extracellular DNA studies
The present study aimed to detect the methylation status of RASSF1A and DAPK1 promoters and their relationship with various clinicopathological parameters in pretherapeutic sera of breast cancer patients, in order to evaluate the potential use of such epigenetic markers in diagnosis of breast cancer.
This study included 26 breast cancer patients and 16 patients with benign breast diseases treated at the Gynecology Department, Tübingen University Hospital , with age range from 35 to 73 years. Additional 12 age-matched healthy volunteers were included as a control group.
All subjects were subjected to the following:
1- History & general examination
2- Local examination of the breast.
3- Mammography.
4- Histological classification of tumor type according to the World Health Organization criteria (Ellis et al., 2003).
5- Histological grading of tumor according to the Nottingham modification of the Scarff-Bloom-Richardson criteria (Genestie et al., 1998).
6- TNM staging according to American Joint committee on cancer (Greene et al., 2002).
7- Detection of methylation status of RASSF1A (Yeo et al., 2005) & DAPK1 promoters (Sanchez-Cespedes et al., 2000) in serum free DNA.
This study revealed the following:
RASSF1A methylated promoter was detected in only one case (8.3%) of the healthy controls, 12.5% of benign breast diseases cases and 69.2% of breast cancer patients .
Moreover, all healthy subjects were unmethylated regarding the DAPK1. While, it was found to be methylated in 31.2% benign breast diseases patients and 88.5% of the breast cancer patients .
Using a panel of both genes revealed that at least one gene was methylated in 8.3% of control cases, 43.7% of benign diseases patients and 96.2% of cancer patients.
Furthermore, the methylation levels of RASSF1A, DAPK1 & RASSF1A/ DAPK1 panel in breast cancer group were significantly elevated as compared to the methylation levels in control groups and benign breast diseases.
In light of the data from breast cancer group, association study showed that RASSF1A methylation was associated with the higher tumor grades i.e poorly differentiated tumors. Moreover, the higher degrees of DAPK1 methylation were frequently associated with post-menopausal tumors and increased methylation of RASSF1A/DAPK1 panel was associated with the ductal tumor type.
Meanwhile, there was a non significant association between RASSF1A and/or DAPK1 and age. Furthermore, the present study revealed that RASSF1A and/or DAPK1 methylation did neither associate with family history, tumor size, tumor stage nor with presence of lymph node / remote organ metastases.
In addition, our study detected non significant association between RASSF1A and/or DAPK1 methylation and the presence of hormone (estrogen / progesterone) receptors. Moreover, there was a non-significant positive correlation between RASSF1A and DAPK1methylation, in the breast cancer group.