Prognostic value of Ki-67 for prostate cancer death in a conservatively managed cohort.

BACKGROUND: Standard clinical parameters cannot accurately differentiate indolent from aggressive prostate cancer. Our previous work showed that immunohistochemical (IHC) Ki-67 improved prediction of prostate cancer death in a cohort of conservatively treated clinically localised prostate cancers diagnosed by transurethral resection of the prostate (TURP). Here, we present results in a more clinically relevant needle biopsy cohort. METHODS: Biopsy specimens were microarrayed. The percentage of Ki-67 positively stained malignant cells per core was measured and the maximum score per individual used in analysis of time to death from prostate cancer using a Cox proportional hazards model. RESULTS: In univariate analysis (n=293), the hazard ratio (HR) (95% confidence intervals) for dichotomous Ki-67 (≤ 10%, >10%) was 3.42 (1.76, 6.62) χ(2) (1 df)=9.8, P=0.002. In multivariate analysis, Ki-67 added significant predictive information to that provided by Gleason score and prostate-specific antigen (HR=2.78 (1.42, 5.46), χ(2) (1 df)=7.0, P=0.008). CONCLUSION: The IHC Ki-67 scoring on prostate needle biopsies is practicable and yielded significant prognostic information. It was less informative than in the previous TURP cohort where tumour samples were larger and more comprehensive, but in more contemporary cohorts with larger numbers of biopsies per patient, Ki-67 may prove a more powerful biomarker.

Fibroblast growth factor 2 regulates endothelial cell sensitivity to sunitinib.

The vascular endothelial growth factor (VEGF) receptor tyrosine kinase inhibitor sunitinib has been approved for first-line treatment of patients with metastatic renal cancer and is currently being trialled in other cancers. However, the effectiveness of this anti-angiogenic agent is limited by the presence of innate and acquired drug resistance. By screening a panel of candidate growth factors we identified fibroblast growth factor 2 (FGF2) as a potent regulator of endothelial cell sensitivity to sunitinib. We show that FGF2 supports endothelial proliferation and de novo tubule formation in the presence of sunitinib and that FGF2 can suppress sunitinib-induced retraction of tubules. Importantly, these effects of FGF2 were ablated by PD173074, a small molecule inhibitor of FGF receptor signalling. We also show that FGF2 can stimulate pro-angiogenic signalling pathways in endothelial cells despite the presence of sunitinib. Finally, analysis of clinical renal-cancer samples demonstrates that a large proportion of renal cancers strongly express FGF2. We suggest that therapeutic strategies designed to simultaneously target both VEGF and FGF2 signalling may prove more efficacious than sunitinib in renal cancer patients whose tumours express FGF2.

The identification of chromosomal translocation, t(4;6)(q22;q15), in prostate cancer.

Our previous work identified a chromosomal translocation t(4;6) in prostate cancer cell lines and primary tumors. Using probes located on 4q22 and 6q15, the breakpoints identified in LNCaP cells, we performed fluorescence in situ hybridization analysis to detect this translocation in a large series of clinical localized prostate cancer samples treated conservatively. We found that t(4;6)(q22;q15) occurred in 78 of 667 cases (11.7%). The t(4;6)(q22;q15) was not independently associated with patient outcome. However, it occurs more frequently in high clinical T stage, high tumor volume specimens and in those with high baseline PSA (P=0.001, 0.001 and 0.01, respectively). The t(4;6)(q22;q15) occurred more frequently in samples with two or more TMPRSS2:ERG fusion genes caused by internal deletion than in samples without these genomic alterations, but this correlation is not statistically significant (P=0.0628). The potential role of this translocation in the development of human prostate cancer is discussed.

Ki-67 and outcome in clinically localised prostate cancer: analysis of conservatively treated prostate cancer patients from the Trans-Atlantic Prostate Group study.

Treatment decisions after diagnosis of clinically localised prostate cancer are difficult due to variability in tumour behaviour. We therefore examined one of the most promising biomarkers in prostate cancer, Ki-67, in a cohort of 808 patients diagnosed with prostate cancer between 1990 and 1996 and treated conservatively. Ki-67 expression was assessed immunohistochemically, in two laboratories, by two different scoring methods and the results compared with cancer-specific and overall survival. The power of the biomarker was compared with Gleason score and initial serum prostate-specific antigen (PSA). Both methods showed that Ki-67 provided additional prognostic information beyond that available from Gleason score and PSA: for the semi-quantitative method, Deltachi(2) (1 d.f.)=24.6 (P<0.0001), overall survival chi(2)=20.5 (P<0.0001), and for the quantitative method, Deltachi(2) (1 d.f.)=15.1 (P=0.0001), overall survival chi(2)=10.85 (P=0.001). Ki-67 is a powerful biomarker in localised prostate cancer and adds to a model predicting the need for radical or conservative therapy. As it is already in widespread use in routine pathology, it is confirmed as the most promising biomarker to be applied into routine practice.