Linking contralateral breast cancer with genetics

Risk of asynchronous contralateral breast cancer in noncarriers of BRCA1 and BRCA2 mutations with a family history of breast cancer: a report from the Women's Environmental Cancer and Radiation Epidemiology Study

PURPOSE

To fully characterize the risk of contralateral breast cancer (CBC) in patients with breast cancer with a family history who test negative for BRCA1 and BRCA2 mutations.

PATIENTS AND METHODS

From our population-based case-control study comparing women with CBC to women with unilateral breast cancer (UBC), we selected women who tested negative for BRCA1 and BRCA2 mutations (594 patients with CBC/1,119 control patients with UBC). Rate ratios (RRs) and 95% CIs were estimated to examine the association between family history of breast cancer and risk of asynchronous CBC. Age- and family history-specific 10-year cumulative absolute risks of CBC were estimated.

RESULTS

Family history of breast cancer was associated with increased CBC risk; risk was highest among young women (< 45 years) with first-degree relatives affected at young ages (< 45 years; RR, 2.5; 95% CI, 1.1 to 5.3) or women with first-degree relatives with bilateral disease (RR, 3.6; 95% CI, 2.0 to 6.4). Women diagnosed with UBC before age 55 years with a first-degree family history of CBC had a 10-year risk of CBC of 15.6%.

CONCLUSION

Young women with breast cancer who have a family history of breast cancer and who test negative for deleterious mutations in BRCA1 and BRCA2 are at significantly greater risk of CBC than other breast cancer survivors. This risk varies with diagnosis age, family history of CBC, and degree of relationship to an affected relative. Women with a first-degree family history of bilateral disease have risks of CBC similar to mutation carriers. This has important implications for the clinical management of patients with breast cancer with family history of the disease.

Novel clinico-genome network modeling for revolutionizing genotype-phenotype-based personalized cancer care

Although cancer heterogeneity, even within individual tumors with different treatment responses of subcloncal cells populations, suggests the need for personalized medicine, most funding and efforts go to conventional single gene-based research and comparative-effectiveness research. Cancer arises from changes in the DNA sequence in the genomes of cancer cells. These accelerating somatic mutations dysregulate signaling pathways, including EGFR, Wnt/Notch, Hedgehog and others, with a central role in cell growth, proliferation, survival, angiogenesis and metastasis. All of these genetic alterations can now be discovered using next-generation DNA sequencing technology. This high-throughput technology can achieve two major goals: first, to complete the catalogue of driver mutations, including point mutations, rearrangements and copy-number changes, by full and targeted sequencing; and second, to explore the functional role of cancer genes and their interactions by genome-wide RNA, serial analysis of gene expression, microRNAs, protein-DNA interactions, and comprehensive analyses of transcriptomes and interactomes. This review article discusses the challenges, including costs, in completing the catalogue of driver mutations for each cancer type and understanding how cancer genomes operate as whole biological systems. Now high-quality clinical treatment and outcomes (death or survival) data from biobanks, and extensive genetics and genomics data for some common tumors, including breast, colorectal and pancreatic cancer, are available. In this article, we will describe how all these clinical and genetics data could be integrated into reverse engineering-based network modeling to approach the extremely complex genotype-phenotype map. This clinico-genome systems model, published for the first time, opens the way for the discovery of new molecular innovations, both predictive markers and therapies, towards personalized treatment of cancer. Instead of the comparative-effectiveness research or personalized medicine debate, harmonization of both can revolutionize cancer management.

Genetics and personal genomics for personalized breast cancer surgery: progress and challenges in research and clinical practice

BACKGROUND

The age of personal genomics is here. A flood of translational research discoveries may influence also surgeon oncologist. Breast-conserving surgery (BCS) is standard care in early breast cancer. Classic clinicopathologic factors are suboptimal to predict risk of ipsilateral breast cancer (IBC) recurrence and/or contralateral breast cancer (CBC). Human genetic variation may be involved in local failures.

OBJECTIVE

To describe the potential clinical utility of genetics, personal genomics, and epigenetics to identify IBC/CBC high-risk patients who might benefit from aggressive surgery (bilateral mastectomy).

DATA SOURCES AND SYNTHESIS

PubMed (MEDLINE) was searched (January 1990 to November 2008).

RESULTS

Even following current guidelines, IBC/CBC as isolated first event in a long-term aspect after treatment suggests a serious problem. Preclinical and clinical data reveal that at highest risk of IBC/CBC are patients with inherited BRCA1/2 mutations who benefited from bilateral mastectomy. Local failure risk prediction is currently unfeasible among familial non-BRCA1/2 (BRCA-test negative) and sporadic (no family history) breast cancer. Genome-wide association studies have already identified novel risk alleles with a series of tumor-initiating single-nucleotide polymorphisms (SNPs). Some of these variants and other novel SNPs and copy-number variants (CNVs) may also be relevant for local failures (IBC/CBC).

CONCLUSIONS

Beyond established risk factors, genetic testing allows identification of high-risk patients (BRCA mutation carriers) who may benefit from bilateral mastectomy rather than BCS. Human genetic variation (SNPs/CNVs) and DNA methylation may be relevant for local failures assessment. Technological revolution has opened a new avenue but multiple challenges should be overcome to integrate SNPs/CNVs as markers for IBC/CBC risk-stratification-based personalized surgery.

Genetics and genome-wide association studies: surgery-guided algorithm and promise for future breast cancer personalized surgery

Although personalized medicine and oncology in clinical practice is still a dream, some isolated first steps have been taken. Effective preventive and therapeutic interventions are now tailored in some individual breast cancer patients on the basis of BRCA, estrogen receptor and HER2 status. Personal genome-wide tests hold rational promise toward a true personalized management. The recent dramatic increase of more aggressive surgery by 150% in the USA is effective for preventing local recurrence and contralateral breast cancer but represents a surgical overtreatment that may harm patients and health systems. This article is based on three subpopulations: familial BRCA-positive patients and BRCA-negative patients, and sporadic breast cancer patients. Combining established classic and new risk factors, including familial BRCA susceptibility to breast cancer, an integrated surgery-guided algorithm for clinical validity is proposed. Future genome-wide association studies larger than those currently available using newer genotyping platforms with more than 1 million single-nucleotide polymorphisms and copy number variants will complete the genetic map. Due to the small effects of all these risk variants, further functional studies to explore the intracellular interactions of these variants and signaling pathways networks will be required. Ultimately, large, prospective, population-based studies recording family and medical history and genetic and environmental risk factors will lead to true personalized breast cancer local control.