Proliferative breast disease include benign dysplasia and breast cancer. Today there are known models for evaluating the risk of breast cancer in women including the most popular models Gail and Claus, as well as less known model BRCAPRO, BOADICEA and Guzick–Tyrer’s. These models mainly based on analysis of family history of the disease and is not suitable for assessing recurrence or other complications of breast benign dysplasia.
The purpose of this study was to develop an algorithm for diagnosis and prognosis of benign proliferative breast disease.
Methods. The study was conducted at the Odessa Clinical Hospital (Odesa). The control group (30 healthy women aged 28–45 years) were observed according to the clinical examination programs. The first clinical group included 50 women with histologically verified breast fibroadenoma; the second group — 50 women formed from histologically verified 1 stage breast adenocarcinoma. The follow-up term was 2 years. Average age — (51.5±0.8) year in patients with breast cancer and (35.3±1.5) — the group of patients with fibrocystic mastopathy. The average age of the patients in the control group was (38.2±0.8) years.
All women were performed clinical, laboratory and instrumental (ultrasound, magnetic resonance imaging, mammography), postmortem, molecular-genetic (polymerase chain reaction (PCR), pyrosequencing) examinations.
Key gene methylation DKK4 studied using a set of EZ DNA Methylation Kit (Zymo Research, Orange, CA, USA) by PCR and further Pyrosequencing. Analysis of gene methylation GSR was held by semiquantitative COBRA. DNA was isolated from tissue samples according to protocol QIAmp DNA Mini Kit (Qiagen, USA). Isolated from tissue samples were subjected to DNA bisulfite treatment according to the protocol EpiTest Bisulfite Kits (Qiagen). The primers were designed using Methyl Primer Express v1.0 (Appled Biosystems).
The risk of breast cancer was evaluated using the model Gail. For statistical processing the software STATISTICA 10.0 (StatSoft Inc., USA) was used.
Results. According to Gail model calculations the risk of breast cancer in women with benign breast diseases did not exceed 1.9% (mean (1.6±0.1)%). Methylation of DKK4 gene was higher in breast cancer cases than control values 4.7–5.2 times as much, and the index value as compared to benign tumors — almost twice. Even greater differences are characteristic for gene methylation activity GSR — correspondently (51.6±2.5), (1.5±0.2) and (4.9±1.1)% (p<0.05).
It is shown that in women with local forms of proliferative benign lesions of breast is advisable to determine the content of methylated DNA of genes DKK4, GSR. With the value of methylated DNA gene content GSR less than 17.8% and gene DKK4 less than 33.7%, risk of breast cancer is low. With identified high risk for breast cancer the patient must be examined every six months using ultrasound and once a year mammographic studies. Researching genes DKK4, GSR methylation intensity is recommended in all cases of breast cancer under genetic susceptibility and other risk factors for women over 40.