Although the molecular function of M-LPH has not been clarified, a number of our findings obtained so far strongly suggest that M-LPH is involved in the maintenance of mtDNA, therefore protecting cells from mitochondrial dysfunction: (i) overexpression of M-LPH in MCF-7 breast cancer cells reduces the generation of intracellular ROS and loss of mitochondrial membrane potential (ΔΨm) caused by an inhibitor of the respiratory chain [19]. The gene discussed is MLPH; the disease is breast cancer.