PASD1, or Per ARNT Sim domain containing 1, is a cancer-testis antigen. It has been shown to interact with the CLOCK:BMAL1 complex to repress transcriptional activation, thus suppressing circadian rhythms in cells [5]. PASD1 also promotes the activity of the transcription factor STAT3, which is involved in cell proliferation, survival, and differentiation, and aberrant STAT3 activation is related to tumorigenesis [3].

In multiple types of cancers, PASD1 shows potential as an immunotherapeutic target. In colorectal cancer, PASD1 mRNA and protein are expressed in a certain proportion of samples, and specific PASD1 peptides can trigger immunogenic responses, with CD8+ T cells against these peptides able to lyze HLA-A*24:02+ PASD1+ cells [1]. Similar immunogenicity and cytotoxicity effects are seen in CRC and polyps, with different peptides being most immunogenic in each [2]. In diffuse large B-cell lymphoma and multiple myeloma, PASD1-related peptides can induce CD4-positive T-helper cell and cytotoxic T-lymphocyte responses, suggesting its potential for immunotherapy [6,7,8]. In glioma, high PASD1 expression is associated with poor prognosis, and knocking down PASD1 inhibits glioma cell proliferation by promoting apoptosis [4].

In conclusion, PASD1 is a cancer-testis antigen with functions in suppressing circadian rhythms and promoting STAT3-mediated tumorigenesis. Its expression in various cancers and the immunogenic responses it elicits suggest its potential as an immunotherapeutic target, and studies on its knockdown in glioma further demonstrate its role in cancer development. The study of PASD1 provides valuable insights into cancer immunotherapy and the understanding of tumorigenesis mechanisms.