Purpose: Other cDNA microarray studies have shown that hepsin is one of the highly over expressed genes in prostate cancer tissue compared with nonmalignant and benign prostatic hyperplasia tissue. We quantitatively analyzed hepsin gene expression with real-time polymerase chain reaction and calculated its relationships with clinicopathological parameters in a large cohort of samples.Materials and Methods: Matched prostate tissue samples from the cancerous and noncancerous parts of the same prostates were obtained from 90 patients with prostate cancer who underwent radical prostatectomy. Quantitative reverse transcriptase-polymerase chain reaction was performed using LightCycler Fast Start DNA Master SYBR Green I on a LightCycler (Roche Diagnostics GmbH, Mannheim, Germany) system. The ratio of hepsin-to-␤-actin (a housekeeping gene) was used to normalize data.Results: Hepsin over expression in cancerous compared with noncancerous tissue was found in 81 of the 90 patient samples (90%, p Ͻ0.001). In 48 patients (53%) hepsin over expression was more than 10-fold in cancerous tissue. The ratio of cancerous-to-noncancerous hepsin expression was significantly higher in the 39 patients with grade 3 tumors compared with the 51 with grade 2 tumors (median 15.5 vs 9.6, p ϭ 0.031). For the prognosis a cutoff at the 75th percentile provided a significant difference between patients at lower risk (pT2, G2 and Gleason score less than 7) and higher risk (pT3/4, G3 and Gleason score 7 or greater) for relapse.Conclusions: This report of the quantitative analysis of hepsin expression, which is the first to our knowledge, shows strong and significant over expression in prostate cancer tissue. Hepsin expression may be a new prognostic marker that could be used for assessing prostate cancer aggressiveness.

Neuropsin is a novel serine protease, the expression of which is highly localized in the limbic areas of the mouse brain and which is suggested to be involved in kindling epileptogenesis and hippocampal plasticity. The 2.1-Å resolution crystal structure of neuropsin provides the first three-dimensional view of one of the serine proteases highly expressed in the nervous system, and reveals a serine protease fold that exhibits chimeric features between trypsin and nerve growth factor-␥ (NGF␥), a member of the kallikrein family. Neuropsin possesses an N-glycosylated "kallikrein loop" but forms six disulfide bonds corresponding to those of trypsin. The ordered kallikrein loop projects proline toward the active site to restrict smaller residues or proline at the P2 position of substrates. Loop F, which participates in forming the S3/S4 sites, is similar to trypsin rather than NGF␥. The unique conformations of loops G and H form an S1 pocket specific for both arginine and lysine. These characteristic loop structures forming the substratebinding site suggest the novel substrate specificity of neuropsin and give a clue to the design of its specific inhibitors.Proteases have been shown to play essential roles in the nervous system, including those of neurite outgrowth (1), neural degeneration (2), and synaptic plasticity (3). These actions are thought to be mediated by the proteolytic cleavage of zymogen precursors, the activation of specific cell surface receptors, or the degradation of extracellular matrix proteins (4). Neuropsin was cloned from a mouse hippocampal cDNA library using sequences for key regions of the serine protease domain of nerve growth factor (NGF)-␥ 1 (5). In the brain, no NGF␥ has been identified so far, though NGF␤ is present. Neuropsin is one of the serine proteases highly expressed in the nervous system (6 -8). The expression of neuropsin is localized at highest concentration in the hippocampus and the amygdala, which are important for acquisition of memory and emotional memory, respectively. This localization is in contrast to that of tissue plasminogen activator (tPA), which is well documented to play a crucial role in the nervous system by mediating plasticity but is distributed more uniformly across the other brain regions and throughout other organs (9). Activity-dependent changes in expression of neuropsin have been observed upon direct hippocampal stimulation and induction of kindling, which is a model for epilepsy and neuronal plasticity characterized by the progressive development of electrographic and behavioral seizures (5, 10). A single intraventricular injection of monoclonal antibodies specific to neuropsin reduces or eliminates the epileptic pattern (11). Moreover, oxidative stress is shown to effect the expression of neuropsin in the limbic areas, which might be related to the disturbance in shockavoidance learning of mice (12). These activity-dependent changes and the specific localization of neuropsin indicate the involvement of this protease in hippocampal plasticity and its p...