NBN and hepatocellular carcinoma: Common NBS1 single nucleotide polymorphisms (SNPs) in tumor cases were identified at similar frequencies as that in control cases of cirrhosis or chronic hepatitis B, except for SNP D399D, which was significantly more frequent in tumor cases [18] .Two rare SNPs (N716D and E564K) and three splicing variants (IVS12–15 A→C, IVS 6+57 T→A and IVS 5+115 A→G) in NBS1 gene were identified in five HCC cases respectively.