Test Code: 2633

Hereditary Breast and Ovarian Cancer Syndrome: BRCA1/BRCA2 Deletion/Duplication Panel
Test Code: 2633
Turnaround time: 2 weeks

CONDITION DESCRIPTION

Mutations in the genes BRCA1 and BRCA2 cause hereditary breast and ovarian cancer syndrome (HBOC), an autosomal dominant cancer predisposition syndrome. Mutations in these genes are rare and account for only a small percentage of cancers; about 5-10% of all breast cancers and 10-15% of ovarian cancers are due to mutations in the BRCA1 or BRCA2 genes. Individuals with mutations in these genes, however, are at a significantly increased risk for developing breast, ovarian, and other cancers than those in the general population.

In families with HBOC syndrome, there is typically a pattern of early onset breast cancer (before the age of 50 or premenopausal). Additionally, the family history may show more than one primary breast cancer in an individual, breast cancer in two or more generations, breast cancer in a male relative, and ovarian cancer, with or without a breast cancer diagnosis. Females with a BRCA1 mutation have a 50-85% risk of developing breast cancer and up to a 44% risk of developing ovarian cancer. Females with a BRCA2 mutation have a 40-70% risk of developing breast cancer and up to a 27% risk of developing ovarian cancer. Males with a BRCA1 or BRCA2 mutation can have up to a 5-10% lifetime risk for male breast cancer and an elevated risk of prostate cancer. Additionally, both males and females with BRCA1 or BRCA2 mutations may be at elevated risks for other cancers. Individuals with a mutation in the BRCA1 or BRCA2 gene have a 50% risk of passing on the mutation to their children.

According to the National Comprehensive Cancer Network (NCCN) recommendations, BRCA1 and BRCA2 testing is suggested for individuals with a personal or family history of any of the following:

  • Early-onset breast cancer (<50 years of age), bilateral breast cancer or triple negative (PR/ER/HER2 negative) breast cancer (<60 years of age)
  • Two primary breast cancers or a diagnosis of both breast and ovarian cancer in one individual
  • Personal or family history of male breast cancer
  • Ovarian cancer at any age
  • Ethnicity with a higher mutation frequency (eg. Ashkenazi Jewish)

CEN4GEN offers the following for BRCA1 and BRCA2 testing:

  • BRCA1/BRCA2 Full Gene Sequencing and Deletion/Duplication Panel
  • BRCA1/BRCA2 Full Gene Sequencing Panel
  • BRCA1/BRCA2 Deletion/Duplication Panel

This test is for the BRCA1/BRCA2 Deletion/Duplication Panel.

References:

  • Ford et al. (1998), Am J Hum Genet, 62:676-689.
  • Shannon and Chittenden (2012), The Cancer Journal, 18(4):310-319.

GENES
BRCA1,BRCA2

INDICATIONS
This test is indicated for:

  • Confirmation of a clinical diagnosis of HBOC.
  • Carrier testing in adults with a family history of HBOC.

METHODOLOGY

DNA isolated from peripheral blood is hybridized to a CGH array to detect deletions and duplications. The targeted CGH array has overlapping probes which cover the entire genomic region.

Please note that a “backbone” of probes across the entire genome are included on the array for analytical and quality control purposes. Rarely, off- target copy number variants causative of disease may be identified that may or may not be related to the patient’s phenotype. Only known pathogenic off-target copy number variants will be reported. Off-target copy number variants of unknown clinical significance will not be reported.

DETECTION

Detection is limited to duplications and deletions. The CGH array will not detect point or intronic mutations. Results of molecular analysis must be interpreted in the context of the patient’s clinical and/or biochemical phenotype.

SPECIMEN REQUIREMENTS

Submit only 1 of the following specimen types
* Preferred specimen type: Whole Blood

Type: Whole Blood
Specimen Requirements:
In EDTA (purple top) or ACD (yellow top) tube: Infants (2 years): 3-5 ml
Older Children & Adults: 5-10 ml

Specimen Collection and Shipping: Refrigerate until time of shipment. Ship sample within 5 days of collection at room temperature with overnight delivery.

Type: Saliva
Specimen Requirements:
OrageneTM Saliva Collection kit (available through CEN4GEN) used according to manufacturer instructions.

Specimen Collection and Shipping: Store sample at room temperature. Ship sample within 5 days of collection at room temperature with overnight delivery.

SPECIAL INSTRUCTIONS
Sequence analysis is required before deletion/duplication analysis by targeted CGH array. If sequencing is performed by another third party provider, please submit a copy of the sequencing report with the test requisition.

RELATED TESTS

  • BRCA1/BRCA2 Full Gene Sequencing and Deletion/Duplication Panel
  • BRCA1/BRCA2 Sequencing Panel
  • Sequencing and deletion/duplication analysis is also available for other breast/ovarian cancer syndromes, including: TP53, PTEN, STK11, MLH1, PMS2, MSH6, and MSH2.
  • Custom diagnostic mutation analysis (test code: 6875) is available to family members if mutations are identified by targeted mutation testing or sequencing analysis.