BRCA mutations REAL-TIME PCR Genotyping

According to the latest statistics, 1 in 8 women of the general population (12%) will suffer from breast cancer during their lifetime, whereas ovarian cancer affects a smaller proportion of women, with a percentage of 1.6%. The cancer treatment effectiveness is greater when the disorder is detected during its early stages, thus reducing mortality rates.

In a significant number of cases, the disorder is hereditary, and it is associated with mutations in certain genes inherited from one parent to the offspring. Approximately, 50-70% of hereditary cases of breast and/or ovarian cancer have been correlated with mutations in the BRCA1 and BRCA2 (commonly BRCA1) genes that exhibit high penetrability.

BRCA1 and BRCA2 genes are tumour suppressor genes, meaning that when they function normally, they do not permit breast, ovarian and other cancerous cell types to proliferate uncontrollably and develop into cancer. These genes encode for nuclear proteins involved in the repair of DNA damages caused either randomly during cell division process or by the influence external factors (radiation, chemicals). When these genes carry mutations, they fail to effectively repair DNA damages, resulting in the accumulation of these damages and within a period of time promote the onset of cancer. The presence of BRCA1/ BRCA2 mutations alone, it is not capable to induce cancer development, but if an individual has inherited a pathological mutation in the BRCA genes, either form the mother or the father, the person is at a genetic predisposition (in other words has an increased risk) to develop hereditary breast and ovarian cancer. This information is significant for both the evaluation of the course of the disease and the early screening and prevention of the disease by identifying the carriers of mutations, especially in families with extensive medical history of cases who developed the disease before menopause or at a very young age (

The only way to know for certain if you carry a BRCA1 and BRCA2 gene mutation is by detecting them with the special genetic test provided by A. EVANGELOU LAB using a blood sample. This test is manufactured by the distinguished company DNA-Technology and it detects the mutations/ polymorphisms 185delAG, 4153delA, 5382insC, 3819delGTAAA, 3875delGTCT, 300T>G (Cys61Gly), 2080delA in the BRCA1 gene, and the 6174del mutation in BRCA2 gene, via the REAL-TIME PCR method.

This method is based on the quantification of fluorescence signal in each amplification cycle. The method utilises the Taqmanprobe, which when hybridised to the target sequence, it is hydrolysed by the Taq-polymerase, enabling the fluorescent detector and quencher to dislocate and separate, emitting a fluorescent signal directly proportional to the target sequence, namely BRCA1 and BRCA 2 genes amplification. Each individual carries a pair of BRCA1 gene and a pair of BRCA2 gene. The pair of each gene is inherited form each parent, one allele from the mother and one allele from the father. The FAM fluorophore detects the wild-type (normal) allele of BRCA1 and BRCA2 genes, while the HEX fluorophore detects the mutant allele. Cy5 fluorescent label it is used to detect the internal control. The Internal Process Control (IPC), is detected in the same reaction though Cy5 fluorophore and permits the quantification of isolated DNA from the biological sample during the process of DNA extraction, therefore dismissing false negative results due to insufficient amount of genetic material or improper sample transport. The advantage of this type of PCR is that by using three different fluorescent dyes, in a single reaction it simultaneously detects the two alleles of the genes, but also quantifies the genetic material of the biological specimen. The results are analysed by the qualified and experienced staff at A. Evangelou Lab, thus increasing the reliability of the results given to the candidates under examination.

It is important to clarify that the result given to the candidate under examination is an estimate of the likelihood of developing this disease as other genes have been found to contribute to the onset of the disease. The family history, diet, physical condition, clinical picture of the individual and the outcome of the test are counterbalanced by a specialist doctor in order to estimate the definitive probability for the development of the disease, consequently contributing to prevention and early diagnosis.