Doublet mutations are associated with mutation showers in mouse. The advent of massively parallel sequencing can facilitate the analysis of sufficient numbers of samples to define any doublets and then determine whether these doublets are associated with mutation showers in cancer. The non-random clustering mutations in mutation showers should provide more definitive data for the occurrence of chronocoordinate mutations in human cancers. The contribution of mutation showers to cancer remains to be determined. Much knowledge has been gained on the capacity of Schizandrin-B muscle derived stem/progenitor cells in muscle repair. However, autologous muscle-derived cells in muscular dystrophy patients can be scarce as a therapeutic cell source. Ectopic, non-muscle derived stem/progenitor cells may act as adjunctive or alternative cell sources for muscle regeneration. Bone marrow-derived stem/ progenitor cells fuse with degenerated muscle fibers in mdx mice, and participate in muscle regeneration. MyoD positive, adiposederived stem cells merge with native myoblasts in mdx mice in vitro, and restore dystrophin expression in vivo. Human fetal blood cells differentiate into myogenic cells, and upon continuous exposure to galectin-1, engraft into toxin-induced or mdx muscles. Pericytes isolated from blood vessels of human skeletal muscle engraft in mdx mice and express human dystrophin. Intramuscular or intraarterial injections of dental pulp cells into muscular dystrophy dogs lead to sparse engraftment and faint dystrophin expression, despite the infusion of a large number of cells. However, most ectopic stem cells previously used for muscle healing have been heterogeneous. Non-myogenic cells of the heterogeneous population conceptually may compromise the efficacy of muscle repair. The suboptimal efficacy of heterogeneous stem cells in muscle regeneration has prompted recent interest in exploring single cell clones. A single muscle stem cell depleted of endogenous satellite cells Acipimox infused into the tibialis anterior muscles of mice is capable of substantial self-renewal and differentiation in vivo.