SINGAPORE: Scientists in Singapore have discovered two new variants of the Epstein-Barr Virus (EBV) associated with cancers, in a study that can make it easier to identify individuals at high risk of developing Cantonese cancer, hence allowing for early intervention.
Cantonese cancer refers to nasopharyngeal carcinoma (NPC), the most common head and neck cancer in Singapore.
It is named so because EBV-infected individuals from the Cantonese dialect group are 20 times more at risk of developing NPC than those from other regions or populations.
The study, published in the journal Nature Genetics on Monday (Jun 17), involved scientists from the Agency for Science, Technology and Research’s (A*STAR) Genome Institute of Singapore (GIS), Sun Yat-sen University Cancer Center, Institute of Zoology of Chinese Academy of Sciences, as well as several other collaborating research institutes.
They sequenced a large batch of viral genomes from NPC patients and healthy controls (EBV-infected individuals that did not contract NPC) from both NPC-endemic and non-endemic regions, and discovered a unique EBV strain that is associated with increased risk of developing NPC.
Individuals infected by the EBV strain, which carries the two variants, have 11 times higher risk of developing NPC than non-carriers.
Currently, more than 40 per cent of individuals in southern China are infected by the high-risk EBV strain and about 80 per cent of the NPC cases in the Cantonese dialect group are driven by this strain.
“This unique strain seems to have originated in Asia, followed by expansion in NPC-endemic regions,” said A* STAR.
EARLY DETECTION OF NPC
Lead author of the study, Dr Liu Jian Jun, 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."
Dr Liu, who is also deputy executive director at GIS, added that the 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 that 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,” said Prof Ng.