New research methodology uncovers gene variations associated with breast cancer

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  • Variations in genes associated with breast cancer risk have been identified using a novel method. Such variants may be used for determining the risk of breast cancer and in the future could improve cancer screening.
  • Research team estimates that the remaining >1,000 variations in genes associated with breast cancer can be identified through next-generation sequencing.
  • This new method can be extended to other cancers and diseases.

Over the past 15 years, scientists around the world have attempted to identify new gene variations associated with breast cancer. Singapore researchers have now successfully developed a unique approach to do so. The research team believes this novel method utilising next-generation sequencing can also be applied to identify variations in genes in other cancers, and eventually lead to better cancer screening and prevention.

Published online in the prestigious journal Cancer Research on 3rd August 2017, the study was led by the National Cancer Centre Singapore (NCCS), and in collaboration with the KK Women’s and Children’s Hospital.

The team, comprising doctors and scientists, began by studying 283 genes in 240 women with early-onset breast cancer or a family history of breast and/or ovarian cancer. It was found that certain variants are surprisingly high in occurrence among these genes. 24 variants of the highest occurrence were selected through careful computational analysis for further genotyping, by comparing the DNA sequences between 1,516 breast cancer cases and 1,189 non-cancer cases. They discovered three variants that are significantly associated with breast cancer risk.

These variants are also known as single-nucleotide polymorphisms (SNPs), which are a type of mutation that happens when one of the four building blocks (A, C, G and T) in the DNA sequence, or genetic code, differs between individuals. Figure 1 shows an example of a SNP, where at a specific position in the genetic code, one person has a “G”, while another person has an “A”.

“To give an analogy, you can picture a person’s genetic code as a personal book with a unique spelling of words. Next-generation sequencing has allowed us to identify the differences in spelling among individuals. Through the standard research method (genome-wide association studies), scientists had managed to identify around 100 breast cancer-associated SNPs to date. With the success of this new approach, we speculate that more disease-associated SNPs can be discovered,” explained Professor Ann Lee, Principal Investigator of the study. Prof Lee is also a Principal Investigator at the Division of Medical Sciences at NCCS and Adjunct Associate Professor at the Duke-NUS Medical School and at the National University of Singapore.

This study proves the feasibility in identifying variants using next-generation sequencing, and maybe a powerful method that could potentially be used to find SNPs for the estimation of the risk of other cancers and diseases such as Alzheimer’s, cardiovascular risk, arthritis and Parkinson’s. With sufficient funding, the team hopes to move on to study other cancers as well as breast cancer in other populations.

Incase you wish to contribute towards research on improving breast cancer screening, kindly visit www.giving.sg/ncc-research-fund/breastcancerscreeningstudy or contact 6352 0772.