Do you know about the genetic issues of nasopharyngeal carcinoma?

Is nasopharyngeal carcinoma hereditary? The incidence of nasopharyngeal carcinoma is higher in southern China, such as Guangdong, Guangxi, Hunan and other provinces, especially in Zhaoqing, Foshan and Guangzhou in the central and western parts of Guangdong. It is reported that the incidence rate of men living in the central part of Guangdong Province and speaking the Cantonese local language is 30/100,000 to 50/100,000. As far as the whole country is concerned, the incidence rate of nasopharyngeal carcinoma gradually decreases from south to north. For example, the incidence rate in the northernmost part is no more than 2/100,000 to 3/100,000. Epidemiological surveys suggest that the cause of nasopharyngeal carcinoma may be related to factors such as Epstein-Barr virus infection, environment, diet and genetics. The site of nasopharyngeal carcinoma is hidden, and it is adjacent to organs such as the eyes, ears, nose, throat, skull base and cranial nerves. Therefore, unilateral tinnitus may occur when the tumor compresses the Eustachian tube. When invading the abducens nerve of the sixth cranial nerve, it often causes double shadows when looking outward. When invading the trochlear nerve, it often causes more vision.

Is NPC hereditary? Although HLA loci are associated with an increased risk of NPC, candidate genes that are genetic risk components have not yet been found. Therefore, a pedigree survey is needed to identify loci that determine NPC susceptibility. We conducted a genome-wide linkage analysis on 32 Cantonese-speaking NPC families living in the Pearl River Basin of Guangdong Province, which has the highest incidence of NPC in the world. Parametric and nonparametric tests showed that NPC is associated with a locus on chromosome 4. This finding was later confirmed by precision mapping.

Is nasopharyngeal carcinoma hereditary? In addition to genetic factors, Epstein-Barr virus is also closely related to nasopharyngeal carcinoma. LMP-1 may be the most important oncogenic Epstein-Barr virus-encoded protein, and most nasopharyngeal carcinoma tissues express LMP-1. The results showed that LMP-1 was detectable in about 50% of the specimens. Among the LMP-1-positive specimens, the main one was LMP-1del-LMP1 with a 30bp deletion. The frequency of Del-LMP1 was very low. The Del-LMP1 coding region had a high homology with the isolates from Shanghai, Hong Kong and Taiwan. The LMP-1 sequence of Epstein-Barr virus isolated from nasopharyngeal carcinoma patients was the same as the LMP-1 sequence of Epstein-Barr virus isolated from non-nasopharyngeal carcinoma patients. These results oppose the hypothesis that Epstein-Barr virus oncogenic strains with special LMP-1 sequences are the cause of the increased incidence of nasopharyngeal carcinoma in southern China. In addition, we also examined disease-associated polymorphisms of several other Epstein-Barr virus-encoded genes.