It has been demonstrated that patients carrying FAS-670 AG+GG genotypes or FASLG-844 CT+TT genotypes were significantly associated with mounting risk of SPMs compared with the wild-type homozygous genotypes, which makes FAS and FASLG polymorphisms a potential marker for HNSCC patients at high SPM risk (64). This evidence concerns the gene FASLG and secondary progressive multiple sclerosis.