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Home  > Clinical services  >  BRCA Gene Testing For Ovarian Cancer  > Introduction

Background

1. Ovarian cancer epidemiology

The incidence of ovarian cancer is the third one of female reproductive system tumors;

Mortality rate of ovarian cancer is the highest;

In China, the incidence of ovarian cancer is 4.1 / 100,000, and the mortality rate is 1.7 / 100,000;

Overall 5-year survival rate of ovarian cancer is less than 30%;

                                                                               --Journal Of the National Tumor Institute, 2011,103 (17)

                                                                                                         --Globlcan 2012

2. Status of ovarian cancer treatment

Malignant tumor chemotherapy is the most important means of adjuvant therapy;

Most advanced patients have recurrent tumors or drug resistance after treatment;

Targeted therapy is an effective manner to conquer non-specific conventional chemotherapy;


Therefore, early diagnosis and treatment is extremely important in improving the survival rate of patients with ovarian tumor; and advanced ovarian cancer patients also need drugs with more significant effect and more precise targeting.


3. BRCA mutations are associated with ovarian cancer risk

The ovarian cancer risk of the general female population in lifetime is 1.3%, and the risk of breast tumor is about 12.3%;

However, for female with BRCA1 or BRCA2 mutations, risks of the above two tumors are increased significantly.

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4. Recommended guidelines for BRCA1 / 2 genetic detection of ovarian cancer patients

The study found that 23% of ovarian cancer was related to inherited genetic mutations, and 65-85% of hereditary ovarian cancers were BRCA1/2 genetic mutations. For early diagnosis of ovarian tumor, guidelines recommend that patients with ovarian cancer and their relatives should take BRCA1 / 2 genetic detection.

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Detection Significance

Ovarian cancer patients who carry BRCA1 and BRCA2 mutations are different from non-carriers in the treatment, and the mutations are correlated to chemotherapy prolongs survival time. Because of the sensitivity to chemotherapy, ovarian cancer patients who carry BRCA mutations have more drugs for chemotherapy. BRCA1/2 genetic detection has the following clinical value:


1. Assess prevalence risk

It can identify female with high-risk of ovarian tumor, and help these people and their families to develop prevention strategies in advance;


Currently, various international guidelines recommend that all patients with ovarian tumor should take BRCA1/2 genetic detection.


2. Prepare treatment plan

It can identify patients who are sensitive to platinum-based chemotherapy or who are suitable to receive targeted therapy (eg, PARP inhibitors).


Use gene sequencing technology to detect single nucleotide polymorphism (SNP) and small fragment insertion / deletion (InDel) of BRCA1/2 gene coding regions (with a total of 16 000 basic groups);


Detection Content

Use multiplex ligation-dependent probe amplification (MLPA) technique to detect large fragment rearrangement of BRCA1/2 genes (LGRs).


5-10% of hereditary BRCA1/2 mutations belong to LGRs, which can lead to protein structure and function abnormalities, therefore, LGRs are pathogenic usually; as a complement gene sequencing technology, MLPA technology can effectively improve the detection rate.

--A. Kwong et al. Tumor Genetics, 2015



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