TOMM40L is a mitochondrial outer membrane translocase implicated in protein import into mitochondria 1. As a channel-forming protein, it likely facilitates the translocation of protein precursors across the mitochondrial outer membrane, similar to its homolog TOMM40. The gene's functional significance extends beyond basic mitochondrial biology into neurodegeneration and cancer pathology. In neurodegenerative disease, TOMM40L shows disease-relevant associations. The APOEɛ4-TOMM40L poly-T length variant (L allele) haplotype significantly increases the risk of mild cognitive impairment conversion to Alzheimer's disease (OR=5.83), with shorter conversion times, possibly mediated by cerebrospinal fluid biomarkers and mitochondrial dysfunction 2. Additionally, increased TOMM40L abundance in preserved cognitive states suggests it reflects mitochondrial oxidative phosphorylation capacity associated with better cognition across Alzheimer's disease, dementia with Lewy bodies, and Parkinson's disease dementia 1. Clinically, TOMM40L has emerged as a prognostic biomarker in hepatocellular carcinoma and endometrial cancer. It serves as a core component of mitochondria-related gene signatures predictive of adverse prognosis, poor immunotherapy response, and differential drug sensitivity 345. Notably, TOMM40L shares sequence homology with tobacco mosaic virus coat protein, raising questions about molecular mimicry mechanisms in disease 6. These findings position TOMM40L as both a functional mitochondrial protein and a clinically relevant biomarker for cognitive decline and cancer outcomes.