HIF-1α mRNA gene expression levels in improved diagnosis of early stages of prostate cancer

Abstract

Objectives: Several clinical studies have indicated that the rates of invasive growth and metastatic disease in cancer depend on the degree of hypoxia, which is mediated by hypoxia-inducible factor 1 α (HIF-1α). To determine its potential role as a marker for prostate cancer (CaP) diagnosis, HIF-1α mRNA levels were measured in blood samples of patients diagnosed with different stages of prostatic disease. Methods: HIF-1α mRNA levels were measured by quantitative reverse transcriptase–polymerase chain reaction (qRT-PCR) and correlated with accurate clinicopathological data. Quantitative data were compared with serum prostate-specific antigen (PSA) measurements to determine variations in the accuracy of the CaP diagnosis. Results: HIF-1α mRNA levels were significantly upregulated in patients with localized CaP (LocCaP; n=63; p<0.0001), compared with patients with no evidence of malignancy (NEOM) and benign prostatic hyperplasia (BPH) (n=35 for both patient groups combined). Receiver operator characteristic (ROC) curve analysis demonstrated that HIF-1α specificity for the NEOM/BPH diagnosis was 88.6%. Sensitivity for LocCaP was 74.6% with an overall diagnostic efficiency of 79.6%. Specificity of the NEOM diagnosis at PSA levels of 4.0 ng ml–1 was 28.6% and sensitivity of the LocCap diagnosis was 65.1%, demonstrating a reduced overall diagnostic efficiency, compared with that given by HIF-1α measurements, of 52.0%. Levels of HIF-1α in patients with metastatic CaP (MetCaP; n=27)) were similar to those in the NEOM/BPH group. Conclusions: HIF-1α is upregulated early in CaP development with subsequent downregulation at later metastatic stages. This study demonstrates increased accuracy of early-stage disease diagnosis using HIF-1α qRT-PCR compared with serum PSA measurements. HIF-1α may therefore be a useful adjunct, together with other diagnostic markers used in relative qRT-PCR and current diagnostic techniques (including serum PSA and PSA velocity) to minimize unnecessary biopsies indicated by elevated serum PSA levels alone.