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Bilateral Breast Cancer (BBC)

Breast cancer is a complex and heterogeneous disease with various subtypes and presentations. Among the different forms of breast cancer, bilateral breast cancer (BBC) represents a unique challenge due to its occurrence in both breasts simultaneously. Our company is committed to advancing the field of bilateral breast cancer therapy through our comprehensive diagnostics and therapy development services.

Overview of Bilateral Breast Cancer (BBC)

Bilateral breast cancer (BBC) refers to the development of cancerous tumors in both breasts simultaneously. This occurrence is relatively rare, accounting for approximately 1-3% of all breast cancer cases. BBC can be further classified into synchronous bilateral breast cancer (both tumors detected within one year) or metachronous bilateral breast cancer (tumors detected more than one year apart).

Pathogenesis of Bilateral Breast Cancer (BBC)

  • Genetic Factors
    A significant proportion of bilateral breast cancer cases are associated with hereditary factors. Mutations in genes such as BRCA1 and BRCA2 significantly increase the risk of developing bilateral breast cancer. Women with these mutations often have a higher likelihood of bilateral disease and may benefit from genetic testing and counseling.
  • Hormonal and Environmental Factors
    Hormonal factors also play a role in the development of bilateral breast cancer. Estrogen exposure, either endogenous or exogenous, has been implicated in the pathogenesis of breast cancer. Environmental factors, such as radiation exposure or certain chemical agents, may also contribute to the development of bilateral breast cancer.
The functional domains of the BRCA1 gene in bilateral breast cancer have been the subject of extensive study.Fig. 1 BRCA1 functional domains and gene location of BRCA1 PVs in bilateral breast cancer. (Fanale, Daniele, et al., 2020)

Targets of Bilateral Breast Cancer (BBC) Therapy

Human epidermal growth factor receptor 2 (HER2/neu) is overexpressed in approximately 20% of breast cancers, including bilateral cases. In addition to hormone receptors and HER2/neu, other molecular targets such as the PI3K/AKT/mTOR pathway, CDK4/6, and PARP inhibitors are being explored as potential therapeutic targets in bilateral breast cancer. Comprehensive molecular profiling and genetic testing can aid in identifying specific targets in individual cases.

Table 1 Variant of uncertain significance detected in bilateral breast cancers. (Fanale, Daniele, et al., 2020)

Gene Variant Type HGVS Nomenclature Protein Change Variant Interpretation No. Cases
BRCA1 M c.4054G > A p.Glu1352Lys VUS 1 (3.70%)
BRCA2 M c.9581C > A p.Pro3194Gln CIP 1 (3.70%)
TP53 M c.446C > T p.Ser149Phe VUS 1 (3.70%)
ATM M c.1229T > C p.Val410Ala CIP 1 (3.70%)
EPCAM M c.334G > A p.Gly112Ser VUS 1 (3.70%)
MUTYH M c.1378 C > T p.Arg460Cys VUS 1 (3.70%)
NBN M c.283G > A p.Asp95Asn CIP 1 (3.70%)
CHEK2 M c.1388G > A p.Cys463Tyr VUS 2 (7.4%)
MSH2 M c.1111G > C p.Glu371Gln VUS 1 (3.70%)
BARD1 M c.1793C > T p.Thr598Ile VUS 1 (3.70%)
MSH6 M c.663A > C p.Glu221Asp CIP 2 (7.4%)
ATM M c.6293T > C p.Leu2098Pro VUS 1 (3.70%)
RAD50 M c.1277A > G p.Gln426Arg CIP 1 (3.70%)
APC M c.5338C > T p.Pro1780Ser VUS 1 (3.70%)
RAD50 M c.1094G > A p.Arg365Gln CIP 1 (3.70%)

Systemic Therapy of Bilateral Breast Cancer (BBC)

Systemic therapy, including chemotherapy, hormone therapy, and targeted therapy, is an essential component of bilateral breast cancer treatment. Chemotherapy is administered to reduce the risk of distant metastasis, while hormone therapy targets hormone receptor-positive tumors. Targeted therapies, such as HER2-targeted agents, have significantly improved outcomes in HER2-positive bilateral breast cancer cases.

Our Services

Our experienced team of researchers and scientists is dedicated to developing innovative therapies for bilateral breast cancer. Our therapy development services encompass drug discovery, drug repurposing, and preclinical testing to ensure the efficacy and safety of potential therapeutic candidates.

Therapy Development Platforms

Animal Models of Bilateral Breast Cancer

Genetic Engineering Model Development
Every BBC case is unique, with different genetic alterations driving the disease. Our genetic engineering model development services enable researchers to customize animal models to study specific genetic alterations relevant to individual cases. For example, by introducing specific mutations in genes such as BRCA1 or BRCA2, we can create animal models that closely mimic the genetic predisposition observed in hereditary forms of BBC.
Optional Modifier Genes BRCA1, BRCA2, Others
Xenograft Model Development
Xenograft models involve the transplantation of human breast cancer cells into immunodeficient mice. These models allow researchers to study tumor growth, metastasis, and response to therapies in a more clinically relevant setting. Our company has extensive experience in xenograft model development, utilizing various human breast cancer cell lines or even primary tumor samples.
Optional Species Mouse, Rat, Dog, Cat, Pig, Tree Shrew, Caenorhabditis Elegans, Drosophila, Zebrafish, Others

In addition, we also provide other customized animal models to meet diverse needs. If you are interested in our services, please feel free to contact us for more details and quotation information of related services.


  • Fanale, Daniele, et al. "Detection of germline mutations in a cohort of 139 patients with bilateral breast cancer by multi-gene panel testing: impact of pathogenic variants in other genes beyond BRCA1/2." Cancers 12.9 (2020): 2415.

All of our services and products are intended for preclinical research use only and cannot be used to diagnose, treat or manage patients.

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