Correlation between Beta1 integrin expression and prognosis in clinically localized prostate cancer

Integrins are transmembrane glycoprotein receptors that regulate cell-matrix interactions, thus functioning as sensors from the environment. They also act as cell adhesion molecules that are responsible for the maintenance of the normal epithelial phenotype. Some studies have reported a correlation between carcinogenesis and changes in integrin expression, especially β1 integrin, however its role in prostate cancer (PC) is unclear. The aim of our study was to evaluate the expression of β1 integrin in localized PC and to correlate the pattern of expression with recurrence after surgical treatment. Methods For this case-control study, we retrospectively selected surgical specimens from 111 patients with localized PC who underwent radical prostatectomy. Recurrence was defined as a PSA level exceeding 0.2ng/mL after surgery, and the median follow-up was 123 months. Integrin expression was evaluated by immunohistochemistry in a tissue microarray containing two samples from each tumor. We employed a semiquantitative analysis and considered a case as positive when the expression was strong and diffusely present. Results: There was a loss of 11 cases during the tissue micro array assembling. β1 expression was positive in 79 of the 100 evaluated cases (79%). The univariate and multivariate analyses showed that the negative expression of β1 integrin was associated with biochemical recurrence (p = 0.047) and time to recurrence after radical prostatectomy (p = 0.023). When β1 was negative, the odds ratio for recurrence was 2.78 times higher than that observed in the positive cases [OR = 2.78, p = 0.047, IC 95% (1.01-7.66)]. Conclusions: The loss of β1 integrin immune expression was correlated with biochemical recurrence in patients treated with radical prostatectomy for localized PC.

Tgf-β1 expression as a biomarker of poor prognosis in prostate cancer

OBJECTIVE: To evaluate the correlation between transforming growth factor beta (TGF-β1) expression and prognosis in prostate cancer. PATIENTS AND METHODS: TGF-β1 expression levels were analyzed using the quantitative real-time polymerase chain reaction to amplify RNA that had been isolated from fresh-frozen malignant and benign tissue specimens collected from 89 patients who had clinically localized prostate cancer and had been treated with radical prostatectomy. The control group consisted of li patients with benign prostate hyperplasia. The expression levels of TGF-β1 were compared between the groups in terms of Gleason scores, pathological staging, and prostate-specific antigen serum levels. RESULTS: In the majority of the tumor samples, TGF-β1 was underexpressed 67.0 percent of PCa patients. The same expression pattern was identified in benign tissues of patients with prostate cancer. Although most cases exhibited underexpression of TGF-β1, a higher expression level was found in patients with Gleason scores >7 when compared to patients with Gleason scores <7(p = 0.002). Among the 26 cases of TGF-β1 overexpression, 92.3 percent had poor prognostic features. CONCLUSIONS: TGF-β1 was underexpressed in prostate cancers; however, higher expression was observed in tumors with higher Gleason scores, which suggests that TGF-β1 expression may be a useful prognostic marker for prostate cancer. Further studies of clinical specimens are needed to clarify the role of TGF-β1 in prostate carcinogenesis.

Tumor banks: the cornerstone of basic research in urology

PURPOSE: Tumor banks have the primary responsibility for collecting, cataloging, storing and disseminating samples of tissues, cells and fluids, which are used by researchers to identify diagnostic molecular markers, prognostic indicators and therapeutic targets. The objective of this review was to describe a simple, reliable and reproducible protocol for obtaining and storing samples of urological tumors. MATERIALS AND METHODS: Urogenital tumor tissues were collected by the surgeons from the Urology Division of University of Sao Paulo Medical School. The obtained surgical specimens were immediately placed in liquid nitrogen, dry ice or in a tube containing RNAlater ®, and then stored by cryopreservation (-80°C). A mirror fragment was fixed in 10 percent formalin processed routinely and embedded in Paraplast®. RESULTS: We developed a protocol for the collection, cataloging, storage, conservation and use of tumor samples. During a period of one year the Urological Tumor Bank of the Urology Division stored 274 samples of prostate, bladder, kidney, penis and testicle tumors of different histological types, 74 urine and 271 serum samples. CONCLUSIONS: Having biological materials characterized and available along with the clinical patient information provides an integrated portrait of the patients and their diseases facilitating advances in molecular biology. It also promotes the development of translational research improving methods of diagnosis and cancer treatment.