Hypoxia, angiogenesis and apoptosis markers in locally advanced rectal cancer.

BACKGROUND AND AIMS: Hypoxia-inducible factor 1alpha (HIF-1alpha) is a critical regulatory protein of cellular response to hypoxia. HIF-1alpha triggers the angiogenic process through activation of the vascular endothelial factor (VEGF) gene. The bcl-2 anti-apoptotic and the death promoting p53 genes, regulate the apoptotic cell death. We investigated the relationship between hypoxia, angiogenesis and apoptosis and their prognostic impact in patients with advanced rectal cancer. PATIENTS AND METHODS: The immunohistochemical expression of HIF-1alpha, VEGF, p53 and bcl-2 and the determination of microvessel density (MVD), apoptotic index (AI) were carried out in tumour tissue samples obtained from 92 patients with locally advanced rectal cancer (LARC) (T3,4/N+/-). RESULTS: HIF-1alpha high reactivity and VEGF overexpression were noted in 47.8 and 44.6% of the examined cases, respectively. They significantly correlated with lymph node metastasis (P<0.001) and low rectal location (P=0.016). HIF-1alpha expression was directly correlated with VEGF up-regulation (P<0.001) and MVD (P<0.001). VEGF expression was closely interrelated with MVD (P<0.001). In univariate analysis advanced grade, infiltrative pattern of tumour growth, vascular invasion, positive lymph node status, HIF-1alpha expression and VEGF upregulation were related to decreased disease-free and overall survival. In multivariate analysis, only high HIF-1alpha reactivity and positive lymph node status emerged as independent variables of adverse prognostic significance. CONCLUSION: HIF-1alpha and VEGF may play an important predictive and prognostic role in patients with LARC.

Evaluation of hypoxia-inducible factor 1alpha overexpression as a predictor of tumour recurrence and progression in superficial urothelial bladder carcinoma.

OBJECTIVES: To investigate the possible role of hypoxia-inducible factor 1alpha (HIF-1alpha, a transcription factor important in regulating O(2) homeostasis and physiological responses to oxygen deprivation) in the recurrence and progression of superficial urothelial bladder cancer, and to examine its expression in relation to proliferation status, apoptotic activity and intratumoral angiogenesis. PATIENTS AND METHODS: Paraffin wax-embedded tissue from 140 patients with superficial primary urothelial bladder carcinoma was immunostained for HIF-1alpha, Ki-67, single-stranded DNA antibody for apoptotic cells, p53, bcl-2, vascular endothelial growth factor and CD31 antigen. We calculated the proliferative rate, the apoptotic index and the microvessel density (MVD). The mean (sem) follow-up was 46 (3.5) months, within which 86 patients relapsed while 18 progressed to a higher tumour stage and/or grade. RESULTS: HIF-1alpha expression was more common in high-grade superficial urothelial carcinomas. The positivity was related to increased proliferative activity (P = 0.012), apoptotic rate (P = 0.006) and MVD (P < 0.001). HIF-1alpha overexpression had a marginal adverse influence on progression-free survival (P = 0.058; univariate analysis), but when combined with p53 overexpression, the unfavourable impact was statistically important (P = 0.028). In multivariate analysis, only grade and the high Ki-67 labelling index were significant predictors of recurrence-free survival, while T-stage and the HIF-1alpha+/p53+ phenotype emerged as the only independent variables of adverse prognostic significance for time to progression. CONCLUSIONS: HIF-1alpha overexpression combined with aberrant mutant p53 nuclear protein accumulation seem to indicate an aggressive phenotype, suggesting a potential biological model predictive of future risk of disease progression in patients with superficial urothelial bladder carcinoma. These indicators may be helpful in clinical practice to discriminate superficial bladder cancer worth a more intensive follow-up, or more aggressive treatment.

Hypoxia-inducible factor 1 alpha expression correlates with angiogenesis and unfavorable prognosis in bladder cancer.

INTRODUCTION AND OBJECTIVES: Hypoxia-inducible factor 1 alpha (HIF-1 alpha) is a critical regulatory protein of cellular response to hypoxia and is closely related to the triggering of the angiogenic process. We examined the relationship between hypoxia and angiogenesis, as well as their prognostic impact in patients with urothelial bladder cancer. METHODS: The immunohistochemical expression of HIF-1 alpha was evaluated in 93 formalin-fixed paraffin-embedded primary transitional cell carcinoma tissue samples. HIF-1 alpha was recognized through nuclear staining of positive cells. The angiogenic profile was individually assessed immunohistochemically using a monoclonal antibody to vascular endothelial growth factor (VEGF) and microvessel density (MVD) was calculated with immunohistochemical staining of the adhesion molecule CD31 of the endothelial cells. RESULTS: A significant positive association between HIF-1 alpha immunoreactivity and histological grade (p=0.009) was found. VEGF and MVD were closely related to tumor grade (p=0.06 and p<0.001) and clinical stage (p=0.04 and p<0.01, respectively). HIF-1 alpha was significantly correlated with VEGF expression (p=0.01) and MVD (p<0.001). Patients characterized by HIF-1 alpha overexpression had significantly worse overall (p=0.009) and disease-free survival (p=0.03). When HIF-1 alpha, histologic grade and stage were included in multivariate Cox regression analysis, HIF-1 alpha emerged as an independent prognostic factor (p=0.02) along with grade and stage, but lost its independent prognostic value after the inclusion of angiogenic factors in the multivariate model. In the subgroup of patients with T1 disease, HIF-1 alpha emerged as a significant negative predictor of the time to first recurrence. CONCLUSIONS: HIF-1 alpha and angiogenesis markers may play an important predictive and prognostic role in patients with bladder cancer. HIF-1 alpha may be of biologic and clinical value as its overexpression is related to up-regulation of VEGF, the stimulation of angiogenesis and worse prognosis.