Previous studies in hereditary and sporadic prostate cancer have indicated the existence of a tumor suppressor gene in chromosomal region 19p13. The BRG1 gene in this region is one of the possible candidates, based on both the frequency of inactivating mutations in human cancer cell lines, including the prostate cancer cell line DU145, and its functional properties. To our knowledge, no studies have been done to evaluate possible involvement of the BRG1 gene in clinical prostate cancer. To accomplish this, we carried out a complete mutation analysis of all 35 BRG1 exons in tumor and constitutional DNA samples from 21 prostate cancer patients. We report the absence of somatic mutations in the panel of samples employed, but the existence of five germline single nucleotide polymorphisms (SNPs) in CpG islands of the BRG1 gene, among them, three novel ones. In conclusion, the study excludes the presence of common BRG1 mutations in prostate cancer.
Prostate cancer remains the most commonly diagnosed life-threatening malignancy and the second leading cause of death from cancer in men. However, little is known about molecular mechanisms that underline its initiation and progression. The aim of this thesis is to characterize the involvement of three different genes and their protein products in human prostate cancer in the panel of clinical samples and established cell lines, in order to gain additional information about the development and progression of the disease. Additionally, a cytological characterization of prostatic intraepithelial neoplasia (PIN), a well established precursor of prostate cancer, has been done. Paired tumor and constitutional DNA from prostate cancer patients has been used to perform mutational analysis of the BRG1 gene. In total, by combining SSCP and sequence analyses, DNA from twenty one patients has been screened. The analysis of all 35 BRG1 coding exons revealed the absence of somatic mutations, but presence of five SNPs, three of which were novel (Paper I). In order to evaluate Pim-1 expression in human prostate cancer and prostatic intraepithelial neoplasia, immunohistochemical analysis has been done on an extended series of clinical samples. By previous studies, Pim-1 was shown to be involved in cell cycle regulation, and overexpression of Pim-1 protein was detected in prostate cancer. The results show a relative Pim-1 overexpression in HGPIN as compared to cancer. Upregulation of Pim-1 at premalignant stages suggests its involvement in the development of prostate cancer, possibly playing a role in the transition from precancerous lesions to invasive cancer. Additionally, Pim-1 expression may be a useful tool for distinguishing HGPIN from benign prostatic epithelium (Paper II). A combination of immunohistochemistry and FISH analyses has been used to study protein expression and gene copy number of ezrin, a gene which is actively involved in the regulation of growth and metastatic capacity of cancer cells. The results show that ezrin has higher protein expression in HGPIN and prostate cancer as compared to normal prostate epithelium. However, FISH results did not reveal any copy number changes of this gene, indicating that ezrin protein overexpression cannot be explained by gene amplification. The data suggest that higher protein expression of ezrin in prostate cancer precursor lesions may indicate its involvement in the pathogenesis of the disease in its initial steps (Paper III). Paper IV assessed ezrin immunostaining patterns in benign and malignant prostatic tissue in order to investigate possible correlations between its expression and histopathological and prognostic data. The results show the correlation of ezrin immunoreactivity with adverse prognostic factors, thus strengthening the hypothesis of the role of ezrin in prostate tumorigenesis. A sampling method for simulating fine-needle aspiration cytology (FNAC) was used to characterize cytological features of PIN. This is believed to be the first attempt to describe PIN cytologically and distinguish it from invasive cancer. For this study, cancer-free specimens containing PIN were selected. Smears with invasive prostate cancer were used for comparison. Cancer smears showed high cellularity and dissociation of atypical cells, while PIN smears only contained a few clusters of atypical cells. Furthermore, pronounced nuclear atypia, prominent and multiple nucleoli and mucin were more common in the cancer. These results indicate that PIN should not be diagnosed by FNAC alone. However, a highly cellular smear with dissociated, distinctly atypical cells seems to preclude PIN (Paper V). Collectively, the results of this study further characterize the process of transition from premalignancy to invasive prostate cancer and suggest possible early oncogenic events in the prostate.
Abstract Microbeam irradiation is spatially fractionated radiation on a micrometer scale. Microbeam irradiation with therapeutic intent has become known as microbeam radiation therapy (MRT). The basic concept of MRT was developed in the 1980s, but it has not yet been tested in any human clinical trial, even though there is now a large number of animal studies demonstrating its marked therapeutic potential with an exceptional normal tissue sparing effect. Furthermore, MRT is conceptually similar to macroscopic grid based radiation therapy which has been used in clinical practice for decades. In this review, the potential clinical applications of MRT are analysed for both malignant and non-malignant diseases.
Background: Grid therapy has in the past normally been performed with single field photon-beam grids. In this work, we evaluated a method to deliver grid therapy based on interlacing and crossfiring grids of mm-wide proton beamlets over a target volume, by Monte Carlo simulations. Material and methods: Dose profiles for single mm-wide proton beamlets (1, 2 and 3 mm FWHM) in water were simulated with the Monte Carlo code TOPAS. Thereafter, grids of proton beamlets were directed toward a cubic target volume, located at the center of a water tank. The aim was to deliver a nearly homogeneous dose to the target, while creating high dose heterogeneity in the normal tissue, i.e., high gradients between valley and peak doses in the grids, down to the close vicinity of the target. Results: The relative increase of the beam width with depth was largest for the smallest beams (+6.9 mm for 1 mm wide and 150 MeV proton beamlets). Satisfying dose coverage of the cubic target volume (σConclusions: A nearly homogeneous dose distribution can be obtained in a target volume by crossfiring grids of mm-wide proton-beamlets, while maintaining the grid pattern of the dose distribution at large depths in the normal tissue, close to the target volume. We expect that the use of this method will increase the tumor control probability and improve the normal tissue sparing in grid therapy.
Biochemical functions of certain amino acids and their role in improving fodder protein are described. Different aspects of biological significance of proteins and methods of its increase are discussed. It is indicated that concentrates prepared from green plants and starch- and cellulose-containing materials proteinized under the action of microorganisms can be used as an additional source of fodder protein. It is demonstrated that lysine and tryptophane concentrates can be effectively applied to raise the nutrient properties of fodder protein. The data are presented concerning the relations between protein and vitamin nutrition, as well as vitamin absorption and transport depending on the acceptor and receptor proteins of blood and tissues.
