Sialyl-Lewis-X, Gleason grade and stage in non-metastatic human prostate cancer

Early stage prostate cancers are now commonly encountered because of widespread use of screening tools. Increased cancer cell proliferation, and expression of sialyl Lewis could be important as predictors of clinical behaviour and survival in addition to histologic grade. In this study, the expression of sialyl-LewisX (sLeX) was determined by immunohistochemical methods in 38 routinely processed prostate biopsies and transurethral resections preceding radical prostatectomies for organ confined prostate cancers. Histologic grades were determined from pathologic reports and divided into two (2) groups; low grade (Gleason score 2-4) and medium grade (Gleason score 5-7). Tumour stages were based on radical prostatectomy reports and 29 were T2 and 9 were T3. SLeX was positive in 10 of 14 (71.4%) low grade and 14 of 24 (62.5%) medium grade cancers; 22/29 (75.9%) T2 and 8/9 (88.9%) T3 were sLeX positive; 1 of 15 (7.2%) low grade and 5 of 24 (20.8%) medium grade were strongly positive (3+) or overexpressing sLeX. Overexpression of sLeX was a feature of medium grade cancer, suggesting that localized prostate cancers with increased potential for progression and metastasis exist in the clinically non-metastatic group.