A Pan-Cancer Analysis Reveals the Multifaceted Role of PABPC1L in Immune Regulation and Therapy Response

Although Poly(A)-binding protein cytoplasmic 1 like (PABPC1L) has been studied in specific cancer types, its broader potential as a prognostic biomarker remains uninvestigated, and the systematic pan-cancer analysis is currently lacking. We performed an integrated pan-cancer analysis of PABPC1L expression and function in 33 human malignant tumors. Associations between PABPC1L expression and tumor mutational burden (TMB), microsatellite instability (MSI), tumor microenvironment composition, drug sensitivity, and response to immune checkpoint blockade (ICB) were also evaluated. A gastric cancer (GC) single-cell RNA sequencing dataset was analyzed to examine the correlation between PABPC1L expression and intercellular communication networks. The relationship between PABPC1L and PD-L1 expression was investigated in human colorectal cancer (CRC) tissue. Functional validation experiments were performed in CRC and GC cell lines. PABPC1L expression was consistently upregulated in multiple cancer types and significantly associated with poor patient prognosis. Notably, PABPC1L was identified as an immunomodulatory factor. It influenced the expression of multiple immune-related genes, regulates immune cell infiltration, and correlates with the outcomes following ICB therapy. Single-cell RNA sequencing analysis of GC further indicated that PABPC1L was involved in intercellular communication networks, including immune cells. In CRC, elevated PABPC1L expression was observed in tumor tissues and positively correlated with PD-L1 levels. Functional experiments confirmed that PABPC1L promoted cell proliferation, regulated cell cycle, and impaired the sensitivity of gastric and colorectal cells to 5-FU. In conclusion, PABPC1L is identified as exhibiting oncogenic properties and is proposed to function as a key regulator of tumorigenesis and immunotherapy resistance.