Malignant tumors are a leading cause of death worldwide, second only to cardiovascular disease. They occur in every population and have a high risk of mortality. The etiopathogenesis of malignant tumors is diverse and there are still many unknowns, leading to huge diagnostic and therapeutic challenges. Therefore, the search for ideal diagnostic and therapeutic agents is ongoing. One of the promising factors affecting cancer is the nucleus accumbens associated protein 1 (NACC1). It is a transcriptional coregulator. Moreover, it plays a multifaceted role in promoting tumorigenesis. NACC1 expression analyses were performed using The Cancer Genome Atlas (TCGA) data accessed from the University of Alabama at Birmingham Cancer (UALCAN) database, and the expression data were interconnected with clinicopathological parameters. All statistical analyses were conducted using GraphPad Prism and Statistica. The results revealed that NACC1 was expressed in almost all of the analyzed cancers, and its expression level correlates with different clinicopathological parameters. This study demonstrates that NACC1 is potentially involved in the pathogenesis, invasion, and immune response associated with many cancers. However, NACC1 is not a suitable candidate as a diagnostic biomarker as it is not specific for any type of malignancy and there are discrepancies in its expression in relation to many clinicopathological parameters. The implementation of NACC1 as a therapeutic target may improve the effectiveness of cancer treatments.