Tap1, also known as transporter associated with antigen processing 1, is a member of the ATP-binding cassette (ABC) family. It is crucial for transporting antigen peptides from the cytoplasm to the lumen of the endoplasmic reticulum and then loading them onto major histocompatibility complex (MHC) class I molecules, thus playing a significant role in the immune response, especially in antigen presentation to regulate adaptive immunity [6,9]. It is also involved in interferon-stimulated gene (ISG)-related pathways as it has been shown to promote interferon-β production [9].

Tap1 has been studied in various disease contexts. In ankylosing spondylitis, certain polymorphisms in Tap1 (Tap1-333Val, Tap1-637Gly) were associated with the disease, especially when compared with HLA-B27-negative controls [1]. In uveal melanoma, upregulated Tap1 was linked to shorter survival, higher metastasis likelihood, and higher mortality. In vitro silencing of Tap1 in C918 cells inhibited cell proliferation and metastasis, suggesting its potential as an oncogene and prognostic marker [2]. In gastric cancer, Tap1 was identified as a T-cell related therapeutic target, and oxaliplatin could enhance immunotherapy by promoting Tap1 expression [3]. In pancreatic cancer, Tap1 promoted resistance to MEK inhibitors by enhancing drug transport out of cells, and its suppression could sensitize cells to the inhibitor [4]. In colorectal cancer, down-regulation of Tap1 was associated with immune escape and poor prognosis, and methylation of the Tap1 gene may be a mechanism for this down-regulation [5]. In gastric carcinoma, Tap1 was associated with an inflamed tumor microenvironment and could be a biomarker for immunotherapeutic response [6]. In pan-cancer analysis, Tap1 was a tumor prognostic biomarker and a predictor of immunotherapeutic responses [7]. In locally advanced gastric cancer, high Tap1 expression was associated with better overall survival [8]. Also, Tap1 has broadly antiviral activities through activating the TBK1-IRF3-mediated type I interferon production [9].

In conclusion, Tap1 is essential for antigen presentation and immune-related processes. Studies in various disease models have revealed its diverse roles in disease development, prognosis, and response to therapy. These findings highlight the importance of Tap1 in understanding disease mechanisms and developing potential therapeutic strategies for diseases such as ankylosing spondylitis, different types of cancers, and viral infections.