SET Oncoprotein in Gastric Cancer: A Master Regulator of PP2A Suppression and Tumor Progression
Rohit Das, Shikha Yadav, Sudeshna Das, Priyanshu Pathak, Shatrudhan PrajapatiIntroduction:
Gastric Cancer (GC) remains a major cause of cancer-related mortality worldwide, largely owing to late diagnosis, aggressive tumor behavior, and therapeutic resistance. The SET oncoprotein (I2PP2A), a potent endogenous inhibitor of Protein Phosphatase 2A (PP2A), has emerged as an important regulator of oncogenic signaling and tumor progression in GC.
Methods:
A comprehensive review of the published literature was conducted to examine the structural characteristics, biological functions, and molecular mechanisms of SET in GC. Relevant studies investigating SET-associated signaling pathways, experimental models, biological effects, and therapeutic targeting strategies were critically analyzed.
Results:
SET overexpression is associated with poor prognosis and increased tumor aggressiveness in GC. Mechanistically, SET-mediated inhibition of PP2A sustains the activation of several oncogenic signaling pathways, including MAPK/ERK and PI3K/AKT/mTOR, and influences p53-associated signaling. Functionally, SET promotes cell-cycle progression, suppresses apoptosis, contributes to impaired DNA damage responses, and enhances cellular migration, invasion, and metastatic potential. Experimental evidence indicates that SET depletion can reduce tumor growth. In contrast, pharmacological targeting of SET using agents such as OP449, FTY720, and COG112 can restore PP2A activity and inhibit tumor-promoting phenotypes in preclinical models.
Discussion:
The SET-PP2A axis represents an important regulatory hub that integrates multiple oncogenic signaling networks involved in GC progression. Nevertheless, substantial challenges, including tumor heterogeneity, the absence of validated predictive biomarkers, limited clinical evidence, and potential therapeutic limitations, currently hinder the translation of SET-targeted strategies into clinical practice.
Conclusion:
SET is a promising oncogenic regulator and potential therapeutic target in GC. Therapeutic modulation of the SET-PP2A axis may provide a novel strategy for suppressing tumor progression and improving treatment outcomes. Further mechanistic studies and welldesigned clinical investigations are required to establish the therapeutic relevance of SET targeting and facilitate its integration into precision oncology.