Ppp2r5e, encoding the PP2A regulatory subunit B56ε, belongs to the phosphatase 2A regulatory subunit B family. Protein phosphatase 2A (PP2A) is crucial for cellular signalling, playing a pivotal role in brain function and development [3].

In cancer research, miR-19b directly negatively regulates Ppp2r5e in colorectal cancer (CRC), and Ppp2r5e downregulation mediates miR-19b-induced oncogenic effects, increasing cell viability, colonosphere formation, and migration of CRC cells. Also, miR-19b mediates 5-FU sensitivity of CRC cells through negative Ppp2r5e regulation [1]. In gastric cancer, miR-23a downregulates Ppp2r5e, suppressing apoptosis and facilitating cell growth [2]. In acute myeloid leukemia, downregulation of Ppp2r5e is common and affects the oncogenic potential of leukemic cells [4]. In lung cancer, the rs1255722AA variant genotype of Ppp2r5e confers an increased risk, and tissues with this genotype have a lower mRNA level of Ppp2r5e [6]. Additionally, apolipoprotein E (ApoE) transcriptionally represses Ppp2r5e, reducing protein expression and PP2A activity, which may be related to Alzheimer's disease [5].

In conclusion, Ppp2r5e is an important regulatory subunit gene related to PP2A function. Its dysregulation is involved in multiple diseases, especially various cancers. Studies on Ppp2r5e contribute to understanding disease mechanisms in cancer and Alzheimer's disease, potentially providing new directions for treatment.