Ercc8, also known as Cockayne syndrome type A (CSA), plays a critical role in the nucleotide excision repair (NER) complex [2,3,5]. The NER pathway is essential for repairing DNA damage, ensuring the restoration of basic DNA functions and cellular life activities. This makes Ercc8 biologically important in maintaining genomic stability. Genetic models, such as gene knockout (KO) or conditional knockout (CKO) mouse models, can be valuable for studying its functions.

In esophageal cancer, ERCC8 was identified as a novel cisplatin-resistant gene. It may contribute to cisplatin resistance through binding to damaged DNA for nucleotide excision repair. However, it has little effect on the proliferation and migration of esophageal cancer cells in vitro [1].

In a consanguineous Pakistani family, a novel homozygous missense mutation in ERCC8 co-segregated with cerebellar ataxia. The mutation affected protein structure, stability, and likely impaired complex formation [2]. A frameshift mutation in ERCC8 was associated with keratoconus and congenital cataracts, as it led to degradation of mutant proteins, reduced DNA damage repair ability, decreased cell viability, and abnormal cell responses [3].

Novel ERCC8 variants were found in Vietnamese siblings with Cockayne syndrome without UV-sensitivity, and a compound heterozygous mutation of ERCC8 was responsible for Cockayne syndrome in a Chinese family, expanding the genetic spectrum of the disease [4,5].

In gastric cancer, individual and joint expressions of ERCC6 and ERCC8 were associated with clinicopathological parameters and prognosis, and they were mainly involved in the NER pathway and regulation of the PI3K/AKT/mTOR pathway [6]. ERCC8 was also identified as one of the pleiotropic genes shared between amyotrophic lateral sclerosis and Parkinson's disease, enriched in the negative regulation of neuron projection development [7].

In conclusion, Ercc8 is crucial for DNA repair through its role in the NER pathway. Studies using various genetic models have revealed its implications in multiple diseases, including esophageal cancer, cerebellar ataxia, keratoconus with congenital cataracts, Cockayne syndrome, gastric cancer, and comorbidities between amyotrophic lateral sclerosis and Parkinson's disease. Understanding Ercc8's functions provides insights into disease mechanisms and potential therapeutic targets.