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Abstract Background Epidemiological studies suggested the chemopreventive role of higher calcium intake in colorectal carcinogenesis. We examined genetic polymorphisms that might influence calcium metabolism: lactase (LCT) gene 13910 C/T polymorphism causing lactose intolerance and calcium-sensing receptor (CaSR) gene A986S polymorphism as a responsible factor for the altered cellular calcium sensation. Methods 538 Hungarian subjects were studied: 278 patients with colorectal cancer and 260 healthy controls. Median follow-up was 17 months. After genotyping, the relationship between LCT 13910 C/T and CaSR A986S polymorphisms as well as tumor incidence/progression was investigated. Results in patient with colorectal cancer, a significantly higher LCT CC frequency was associated with increased distant disease recurrence (OR = 4.04; 95% CI = 1.71–9.58; p = 0.006). The disease free survival calculated from distant recurrence was reduced for those with LCT CC genotype (log rank test p = 0.008). In case of CaSR A986S polymorphism, the homozygous SS genotype was more frequent in patients than in controls (OR = 4.01; 95% CI = 1.33–12.07; p = 0.014). The number of LCT C and CaSR S risk alleles were correlated with tumor incidence (p = 0.035). The CCSS genotype combination was found only in patients with CRC (p = 0.033). Conclusion LCT 13910 C/T and CaSR A986S polymorphisms may have an impact on the progression and/or incidence of CRC.

The main autocrine/paracrine role of the active metabolite of vitamin D(3), 1alpha,25-dihydroxyvitamin D(3) (1,25-D(3)), is inhibition of cell growth and induction of cell differentiation and/or apoptosis. Synthesis and degradation of the secosteroid occurs not only in the kidney but also in normal tissue or malignant extrarenal tissues such as the colon. Because 25-hydroxyvitamin D(3) 24-hydroxylase (CYP24A1) is considered to be the main enzyme determining the biological half-life of 1,25-D(3), we have examined expression of the CYP24A1 mRNA (by real-time RT-PCR) and protein (by immunohistochemistry) in normal human colon mucosa, colorectal adenomas, and adenocarcinomas in 111 patients. Although 76% of the normal and benign colonic tissue was either completely devoid of or expressed very low levels of CYP24A1, in the majority of the adenocarcinomas (69%), the enzyme was present at high concentrations. A parallel increased expression of the proliferation marker Ki-67 in the same samples suggests that overexpression of CYP24A1 reduced local 1,25-D(3) availability, decreasing its antiproliferative effect.

Properties of bone graft can determine the effectiveness, short and long term success of bone substitution procedure. In this paper, a brief report about advantages and disadvantages of modern bone substitution processes is presented and authors have explicated the opportunity of the usage of gypsum as bone graft. Recently, calcium sulfate dihydrate has been demonstrated as safe biodegradable osteoconductive bone void filler. However, its exact mechanism of action on bone cells and the molecular process of bone substitution is yet unknown. Authors have investigated the effect of gypsum on bone cells using molecular biology methods. Gypsum proved to be an ideal culture surface for proliferation of mice preosteoblastic cells, while polymethilmetacrylate bone cement - generally used in clinical practice as bone substitution material - inhibited cell growth. Gene expression profile of cells has significantly changed on gypsum surface - genes involved in new bone formation have expressed with an increased ratio - and an increased alkaline phosphatase activity has been measured from these cultures. Our results support the use of gypsum as synthetic bone graft and new properties of calcium sulfate dihydrate have been demonstrated due to molecular biological approach.

Dehydroepiandrosterone and dehydroepiandrosterone-sulfate are precursors of androgens and estrogens, support the gonadal sexual steroid production. The levels of dehydroepiandrosterone and dehydroepiandrosterone-sulfate are maximal between the ages of 20 and 30 years, then start a decline of 2% per year, leaving a residual of 10-20% of the peak production by the eight decade of life. The age-associated decrease may lead to osteoporosis, deterioration of lipid-metabolism, cardiovascular diseases and second type of diabetes mellitus. Decreased levels were found in autoimmune diseases and in sexual dysfunction, too. Intracrinology describes the formation of active hormones which exert their action in the same cells where synthesis took place without release into the pericellular compartment. The high local androgen and estrogen concentration may be important in the pathomechanism of hirsutism, acne, seborrhea, breast and prostate cancer. Administration of dehydroepiandrosterone resulted in a reduction of postmenopausal osteoporosis, also the decreased symptoms in systemic lupus erythematosis, psychiatric diseases and sexual disfunction. The authors summarize the metabolism of dehydroepiandrosterone and dehydroepiandrosterone-sulfate and their role in different diseases.