MRPS27 (mitochondrial ribosomal protein S27) is an RNA-binding component of the mitochondrial small ribosomal subunit that plays a critical role in mitochondrial protein synthesis 1. The protein contains pentatricopeptide repeat domains and binds specifically to mitochondrial 12S rRNA and tRNA(Glu), though it does not affect their abundance 1. MRPS27 is essential for mitochondrial protein translation, particularly of electron transport chain components, as its knockdown results in decreased respiratory complex abundance and reduced cytochrome c oxidase activity 1. Beyond its mitochondrial functions, MRPS27 has emerged as a significant factor in cancer biology, being highly expressed in triple-negative breast cancer where it correlates with tumor stage and lymph node involvement 2. The protein promotes cancer cell stemness properties and malignant phenotypes, making it a potential therapeutic target 2. MRPS27 also appears relevant to neurological conditions, as it has been identified as a core gene in ischemic stroke through bioinformatics analyses 34. A homozygous nonsense mutation in MRPS27 was identified in a consanguineous family with autosomal recessive hereditary ataxia, suggesting it may represent a novel disease gene 5. These findings highlight MRPS27's dual role in essential mitochondrial function and pathological processes.