Expression of Ki-67 (MIB-1) and GLUT-1 proteins in non-advanced prostatic cancer

Abstract

The expression of Ki-67 (MIB-1) and glucose transporter-1 (GLUT-1) were evaluated in patients with clinically localized prostate cancer (PC) who had undergone radical prostatectomy with curative intent. 140 low advanced PC specimens were studied. Protein expression was assessed immunohistochemically on tumour sections and expressed as a labelling index, i.e. the percentage of positively stained cells. In the case of Ki-67 nuclear staining and in the case of GLUT-1 membrane and cytoplasmic staining was considered as positive. The patients' mean age was 62.9 ±6.2 years. There were 13 (9.3%) at pTNM stage 1, 78 (55.7%) at stage 2, 40 (28.6%) at stage 3 and 9 (6.4%) at stage 4, respectively. 75 (53.6%) tumours were well differentiated (Gleason score ≤ 6), 52 (37.1%) moderately differentiated (Gleason score of 7) and 13 (9.3%) poorly differentiated (Gleason score 8-10). The mean pre-operative serum PSA was 9.9 ± SE 0.5 ng/ml, and the mean LI was equal to 8.1 ±0.6% and 29.7 ±2.0%, for MIB-1 and GLUT-1, respectively. Increase of pathological tumor volume and tumor grade was associated with statistically significant growth of PSA (p < 0.011) and MIB-1LI (p < 0.003), however, for GLUT-1 LI the relation was not significant. Ki-67 expression was correlated with PSA levels (p = 0.013) and GLUT-1 scores (p = 0.04). In PC, an increase in the proliferation rate (higher MIB-1LI) in higher pTNM stages and tumour grades may point to Ki-67 as a good marker of biological aggressiveness useful in selecting patients for more aggressive treatment. A correlation between proliferation and GLUT-1 score may be the evidence of active glycolytic metabolism in hypoxic regions.