Although TNF-α contributes to MM pathology by generating malignant plasma cells, TNF-α promoter polymorphism, especially TNF-α -238 GA + AA genotype, is associated with significant improvement in PFS and OS in MM, whereas TNF-α -308 GA and GA + AA genotypes are associated with reduced risk of MM, indicating a role of TNF-α promoter polymorphism in MM pathology. Here, TNF is linked to Miyoshi myopathy.