Objective: To investigate the expressions of phosphatidylinositol proteoglycan 5 (GPC5) and tetrahydroxynonene (4-HNE) in the PCa tissue and their impact on tumor progression.
Methods: Using immunohistochemistry, we determined the expression rates of GPC5 and 4-HNE in 50 PCa and 50 BPH tissue samples, followed by comparative analysis of the correlation between their expressions and Gleason grading.
Results: The positive expression rate of GPC5 was 94.0% in the BPH tissue, remarkably higher than 86.7%, 66.7%, 75.0%, 55.6% and 33.3% in the PCa tissues of Gleason grades 1, 2, 3, 4 and 5 (P = 0.001), with a negative correlation between the positive expression rate of GPC5 and the Gleason grade of tumors (P = 0.021). In contrast, the positive expression rate of 4-HNE was 4.0% in the BPH tissue, dramatically lower than 55.6%, 66.7%, 75.0%, 77.8% and 88.9% in the PCa tissues of Gleason grades 1, 2, 3, 4 and 5 (P = 0.001), with a positive correlation between the expression rate of GPC5 and the Gleason grade of tumors (P = 0.001). After a follow-up of 10－30 months, the expression rates of GPC5 and 4-HNE in the tissues converted to castration-resistant PCa (CRPC) showed a statistically significant difference from those remaining unconverted (P = 0.001, P = 0.048). There was a negative correlation between the positive expression rate of 4-HNE and that of GPC5 in the PCa tissue (R = －0.983, P = 0.003).
Conclusion: The low expression of GPC5 and high expression of 4-HNE are closely related to the pathological grade of PCa and its conversion to CRP, which may serve as new biological markers in assessing the malignancy and prognosis of tumors.
Keywords: prostate tumor; phosphatidylinositol proteoglycan 5; tetrahydroxynonene; immunohistochemistry.