Germline mutations to the RECQL gene were identified in 0.5% of patients with familial breast cancer in a Chinese population, according to research presented at the 10th European Breast Cancer Conference.1
Carriers of BRCA1 and BRCA2 gene mutations are at high risk of developing breast cancer, but these mutations are involved in only 10% to 15% of inherited breast cancers. Many other candidate genes responsible for hereditary, or familial, cancers have yet to be identified.
In this study, genetic tests were performed on samples from 1114 patients in the Hong Kong Hereditary Breast Cancer Family Registry. Although their family history indicated a high risk for breast cancer, tests results for all the patients were negative for the 4 best-known breast cancer-causing mutations: BRCA1, BRCA2, TP53, and PTEN.
“We decided to test for the RECQL mutation, recently identified as being associated with an increased risk of the disease,” said Ava Kwong, MD, assistant dean and clinical associate professor at the University of Hong Kong and director of the Hong Kong Hereditary and High Risk Breast and Ovarian Cancer Programme. “We found that RECQL was present in 0.54% of the women in our group (Southern Chinese), and we also know that a similar group of Northern Chinese women, from Beijing, had a RECQL incidence of 2%.”
This 2% incidence means that mutated RECQL may be important enough to be included in genetic screening for people of Chinese origin with a family history of breast cancer.
“We need to do further work in order to be able to understand whether we are looking at founder mutations, which occur in the DNA of 1 or more individuals who were founders of a distinct population, since even within the 2 Chinese groups 2 RECQL mutation loci, or specific positions on a chromosome, were seen more than once in different families,” Kwong reported.
Kwong explained that the founders of a colony can strongly affect the genetic makeup of the population far into the future. For example, there are known to be 3 founder BRCA mutations among Ashkenazi Jews.
“The scale of the Chinese diaspora means that the RECQL mutation is most likely to be fairly prevalent in countries outside Asia,” said Kwong. Nearly 3.5 million people of Chinese origin live in the United States, and more than 400 000 live in the United Kingdom.
The RECQL mutation is also associated with a poor prognosis for patients with liver, pancreatic, or head and neck cancers across all populations, and it was commonly associated with cardiovascular disorders in the study patients’ families.
1. Kwong A, Chen J, Cheuk IW, et al. RECQL as a novel breast cancer susceptibility gene in Chinese breast cancer patients. Poster presented at: 10th European Breast Cancer Conference; March 9-11, 2016; Amsterdam, The Netherlands. Abstract 153.