Scientists from the A*STAR's GIS have identified two new EBV viral variants associated with cancers, including nasopharyngeal carcinoma (NPC) (the most common head and neck cancer in Singapore), gastric cancer, and several kinds of lymphomas.
The discovery of these EBV viral variants paves the way for the implementation of effective intervention programmes that may reduce the disease’s incidences in Asia. The study was published in Nature Genetics on 17 June 2019.
EBV infected individuals from the Cantonese dialect group are known to have a 20-time higher risk (20 to 40 cases per 100,000 individuals per year) of developing NPC than people from other regions or populations. Hence, NPC is also known as the Cantonese Cancer.
The Epstein-Barr virus (EBV) was discovered in 1964 and is the first human virus to be associated with cancers.
In the current study, scientists from the GIS, Sun Yat-sen University Cancer Center, Institute of Zoology of Chinese Academy of Sciences, as well as several other collaborating research institutes, sequenced a large batch of viral genomes from NPC patients and healthy controls (individuals with EBV infection but did not contract NPC) from both NPC-endemic and non-endemic regions. They discovered a unique EBV strain that is associated with increased risk of developing NPC.
Individuals infected by this unique EBV strain have 11 times higher risk for developing NPC than the non-carriers. Currently, over 40% of individuals in southern China are infected by this high-risk EBV strain and about 80% of the NPC cases in the Cantonese dialect group are driven by this high-risk EBV strain. This unique strain seems to have originated in Asia, followed by expansion in NPC-endemic regions.
Dr Liu Jian Jun, Deputy Executive Director at GIS and lead author of the study said, “The importance of the EBV viral variants in the development of NPC and its striking epidemic among Cantonese dialect group have been poorly explored in the past. This study provided novel insights into the NPC endemic, and potentially provides the basis for implementing effective intervention programmes to reduce its incidences.”
Professor Ng Huck Hui, Executive Director at GIS said, “The discovery of these high-risk EBV viral variants has important implications for public health efforts to reduce the burden of NPC, particularly among Cantonese speakers. Testing for these variants enables the identification of high-risk individuals for routine clinical monitoring to detect NPC early. Primary prevention through the development of vaccines against high-NPC-risk EBV strains is expected to greatly reduce the incidence rate of Cantonese Cancer.”