ATP6AP1 as a potential prognostic biomarker in CRC by comprehensive analysis and verification

The role of ATP6AP1 in colorectal cancer (CRC) remains elusive despite its observed upregulation in pan-cancer. Therefore, the current study aimed to assess the clinical significance of ATP6AP1 and its relationship with the immune infiltration in CRC. Transcriptome data of CRC were obtained from The Cancer Genome Atlas (TCGA) database and analyzed using the combination of R packages and tumor-related databases, including TIMER2, TISIDB, cBioPortal, and MethSurv. The tissue arrays and immunohistochemical staining were performed to verify the expression and clinical characteristics of ATP6AP1. The results revealed that ATP6AP1 expression was significantly elevated in CRC and associated with poor clinicopathological characteristics and prognosis. Furthermore, the analysis demonstrated ATP6AP1 expression was correlated with the infiltration of immune cells and cancer-associated fibroblasts in the microenvironment of CRC. Moreover, ATP6AP1 was found to be linked to various immune checkpoints and chemokines, with enrichment of cytoplasmic vesicle lumen, endopeptidase regulator activity, and endopeptidase inhibitor activity observed in the high ATP6AP1 expressional group. In conclusion, the findings of this study suggest that ATP6AP1 upregulation may serve as a biomarker for poor diagnosis in CRC and offer a potential target for immunotherapy in CRC.