Background: Prostate cancer lacks reliable biomarkers to distinguish between indolent and aggressive forms, posing diagnostic and prognostic challenges. Sall4, primarily found in embryonic stem cells, is reactivated in various cancers, but its role in prostate cancer remains unclear.

Objectives: This study aims to evaluate Sall4 protein and mRNA levels in malignant and normal prostate tissues and explore their association with clinical data. 

Materials and methods: This study was conducted from December 2022 to April 2024 at Al-Hussein Teaching Hospital, Thi-Qar, Iraq. Sall4 protein and mRNA expression levels were assessed in 40 normal tissues and 194 malignant prostate tissues using immunohistochemistry and RNAscope methods. The data were analyzed using unpaired t-tests. 

Results: The study identified a significant increase in nuclear Sall4 protein expression, assessed by immunohistochemistry, in prostate cancer tissues compared to normal tissues (P 0.001). Similarly, Sall4 mRNA levels, measured using RNAscope, were significantly higher in malignant tissues (P < 0.001). Increased Sall4 expression at both protein and mRNA levels was significantly associated with higher Gleason scores (protein: P = 0.003; mRNA: P 0.009), lymph node involvement (protein: P 0.002; mRNA: P 0.006), and metastasis (protein: P 0.001; mRNA: P 0.017). However, no significant correlation was found between Sall4 expression and tumor size. 

Conclusion: Elevated Sall4 expression may be associated with prostate tumorigenesis and aggressiveness. Further studies are needed to clarify its role and evaluate its potential as a prognostic biomarker for prostate cancer.