Purpose: The aim of this study was to compare the biomolecular profile of high-grade (HG) with low-grade (LG) prostate cancers matched by preoperative serum prostate-specific antigen (PSA) levels.
Methods: From 2,560 patients undergoing radical prostatectomy for localised disease, 24 men with HG cancer (Gleason score > or =9) were eligible. Their clinical data were compared with those of 24 LG tumours (Gleason score < or =6), matched by PSA values. The expression of Ki-67, p53, Bcl-2, chromogranin A, alpha-catenin, and PSA were analysed and compared between both groups.
Results: The expression of Ki-67 (P=0.031), p53 (P=0.008), Bcl-2 (P=0.002), and chromogranin A (P=0.042) were expressed significantly higher, and alpha-catenin (P=0.020) and PSA (P<0.001) significantly lower in HG tumours. Cancer volumes of HG and LG differed significantly (10.6 cm3 vs 5.3 cm3; P=0.006). Overall, cancer volume correlated with increased expression of p53 (r=0.52; P<0.001) and chromogranin A (r=0.46; P<0.001), and with decreased expression of PSA (r=0.41; P<0.004).
Conclusions: According to our data, tumour grade is clearly associated with a change in the biomolecular profile, even between patients with similar serum PSA levels. As the prognosis of HG prostate cancer is poor, these tumours should be analysed by immunohistochemical staining to identify specific tumour features for an appropriate selection of adjuvant therapy.