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1.
Human prostate specimens commonly contain a spectrum of epithelial changes, including normal acinar and ductal structures, hyperplasia, intraepithelial neoplasia (dysplasia), and carcinoma. Since vascular endothelial growth factor (VEGF) expression is dependent on cell type and tissue microenvironment, meaningful quantitation of the levels of this mRNA in pathological specimens requires analysis at the microscopic level. Phosphorimage analysis of the binding of radiolabeled cRNA probes to tissue sections allows quantitation of mRNA levels, but the resolution is limited. Alternatively, emulsion autoradiography allows visualization of mRNA levels at cellular resolution, but quantitation is difficult. We have developed a method of quantitating steady state mRNA levels in tissue sections at the microscopic level, using autoradiography and quantitative image analysis. In this study, we describe the method and apply it to quantitation of VEGF mRNA in human prostate specimens. The VEGF mRNA level was low in nonepithelial stromal tissue (0.8 dpm/mm2), high in normal and benign hyperplastic epithelium (17-18 dpm/mm2), and significantly decreased in intraepithelial neoplasia (6.4 dpm/mm2) and in microacinar carcinoma that had invaded the stroma (3.5 dpm/mm2). Immunohistochemical staining detected VEGF protein in epithelial and stromal cells, with highest levels on the luminal surface of normal epithelium and in stromal cells, and lower levels in benign hyperplasia, intraepithelial neoplasia, and carcinoma. No correlation between VEGF expression in epithelium and nearby vessel density was observed. The results indicate a decrease in the steady state level of VEGF mRNA when prostate epithelial cells become transformed, escape the confines of glandular structure and invade the stroma, and suggest that the progression of prostatic carcinoma through the stages examined in this study is not associated with increased VEGF expression, in contrast to the elevated VEGF expression associated with progression of several other tumor types.  相似文献   

2.
PURPOSE: We tried to clarify the role of fibroblast growth factors (FGFs) and those receptors (FGF-Rs) in cell proliferation of human prostate cancer. METHODS: The mRNA expression of FGF1, FGF2, FGF7, FGF-R1, FGF-R2 (IIIb), and FGF-R2 (IIIc) was investigated by RT-PCR in androgen sensitive cells (LNCaP), androgen-independent cells (PC3) and primary cultured stromal (PS) and epithelial cells (PE) from benign prostatic hyperplasia (BPH). Expression of the mRNA of FGF-R1, FGF-R2 (IIIb) and FGF-R2 (IIIc) in human prostate cancer tissue was similarly analyzed. Furthermore, the level of FGF-R1 expression in human prostate cancer was measured by semi-quantitative RT-PCR. RESULTS: FGF-R1 mRNA was detected in LNCaP, PC3 and the primary cultured stromal cells of BPH. FGF-R2 (IIIb) was seen in LNCaP cells and the primary cultured epithelial cells of BPH, while FGF-R2 (IIIc) was only observed in PC3. FGF1 mRNA was expressed in LNCaP and PC3, while FGF2 mRNA was in PC3 alone. The expression of FGF7 mRNA was detected only in the primary cultured stromal cells. Of 17 patients with human prostate cancer, FGF-R2 (IIIb) was detected in 2 and FGF-R2 (IIIc) in 15. Histological type of two cases having FGF-R2 (IIIb) were well differentiated adenocarcinoma. The mRNA levels of FGF-R1 in poorly and moderately differentiated types were significantly higher than those in well differentiated ones (p < 0.05). CONCLUSION: These findings suggest that several changes of expression in FGFs and FGF-Rs may correlate with malignant progression of human prostate cancer.  相似文献   

3.
4.
Benign prostatic hyperplasia (BPH) is the most common benign proliferative disorder of unknown etiology found in men. Because insulin-like growth factors (IGFs) with their binding proteins (IGFBPs) are involved in the control of cellular proliferation, differentiation, and metabolism, we compared their secretion by prostatic epithelial and stromal cells in primary culture from the four different zones of normal prostate and from hyperplastic tissue to assess their contributions to the hyperplastic development. IGF-I could not be detected in the conditioned medium from either epithelial or stromal cells from normal and BPH tissues. IGF-II concentrations were the same in the conditioned medium from the epithelial cells of the different zones of the normal prostate and that of BPH cells. IGF-II concentrations secreted in stromal cell culture medium, however, were higher in the periurethral zone than in the peripheral and central zones. Moreover, in the periurethral zone, stromal cells secreted higher concentrations of IGF-II than did epithelial cells. Also, BPH stromal cells secreted more IGF-II than did BPH epithelial cells. IGFBP-3, IGFBP-2, and IGFBP-4 were all secreted by both epithelial and stromal cells. In contrast, IGFBP-5 was only produced by stromal cells of the periurethral zone of the normal prostate and BPH tissue. IGFBP-3 was predominantly secreted by normal stromal cells of the transitional zone. We observed that BPH stromal cells presented the same pattern of IGF-II and IGFBP production as normal stromal cells of the periurethral zone. These data support the hypothesis that the periurethral zone is the main region of the prostate implicated in the development of BPH. They also suggest that the variability in both IGF-II secretion and the secreted forms of IGFBPs, depending on anatomical location within the organ, may be important for the autocrine regulation of normal and hyperplastic prostate growth.  相似文献   

5.
A systematic, comparative study of the accessory sex glands of the adult male rat after androgen withdrawal was carried out. The changes were investigated by using scanning electron microscopy at different intervals after surgical castration. The main common signs of epithelial cell involution were flattening of the cell surface, reduction of the size and number of microvilli, some blurring of the cell borders, cessation of secretory activity and diminution of the luminal volume of the glands. Overall, confident signs of atrophy were evident after one week, and complete epithelial involution was reached by the third week. The epithelial cell atrophy was accompanied by a relative stromal hyperplasia. The new observation seems to be that the process of stroma consolidation is progressing for a considerable time subsequent to the completion of the epithelial involution. This phenomenon is particularly evident in the dorsal prostate, the seminal vesicle and the coagulating gland.  相似文献   

6.
BACKGROUND: Nitric oxide (NO) is synthesized by inducible nitric oxide synthase (iNOS) and plays an important role in tumor growth and angiogenesis. NO generation by iNOS also influences the cytotoxicity of macrophages and tumor-induced immunosuppression. Before now, the expression of iNOS in prostate carcinoma tissue had not been determined. METHODS: In this study, tissue sections from 16 patients with prostate carcinoma were studied immunohistochemically and compared with tissue specimens from 10 patients with benign hyperplasia. RESULTS: Positive iNOS immunostaining was detected in all sections from patients with prostate carcinoma. The malignant epithelial cells were highly positive. The antibody against iNOS also marked round cells, which had the same cell shape as that observed for macrophages. These cells were located in stroma and epithelium adjacent to tumor islets. However, round cells in benign tissue stained negative for iNOS. None of the benign hyperplasia specimens stained positive for iNOS immunohistochemically. CONCLUSIONS: Prostate carcinoma tissue had a high iNOS content, whereas benign tissue did not. The authors suggest that epithelial iNOS expression can be used as a specific immunohistochemical marker for prostate carcinoma. NO generation by iNOS may play multiple roles in the development of this disease.  相似文献   

7.
In order to well understand the expression of mRNA for insulin-like growth factor I and II in normal and hyperplastic prostate, in situ hybridization were used to detect them in a total of 35 cases of prostate. Both the normal and the hyperplastic prostate expressed the mRNA for IGF-I/II. The mRNA for IGF-I was mainly expressed by the epithelial cells and the IGF-II was mainly expressed by the stromal cells. The hyperplastic tissues expressed higher levels of the mRNA for IGF-I and IGF-II. The results suggested that the IGF might play an important role in the regulation of prostate growth and the pathogenesis of benign prostatic hyperplasia.  相似文献   

8.
Vascular endothelial growth factor (VEGF) is a key regulator of endothelial growth and permeability. However, VEGF may also target nonendothelial cells, as VEGF receptors and responsiveness have been detected for example in monocytes, and high concentrations of VEGF have been reported in human semen. In this work we present evidence that overexpression of VEGF in the testis and epididymis of transgenic mice under the mouse mammary tumor virus (MMTV) LTR promoter causes infertility. The testes of the transgenic mice exhibited spermatogenic arrest and increased capillary density. The ductus epididymidis was dilated, containing areas of epithelial hyperplasia. The number of subepithelial capillaries in the epididymis was also increased and these vessels were highly permeable as judged by the detection of extravasated fibrinogen products. Intriguingly, the expression of VEGF receptor-1 (VEGFR-1) was detected in certain spermatogenic cells in addition to vascular endothelium, and both VEGFR-1 and VEGFR-2 were also found in the Leydig cells of the testis. The infertility of the MMTV-VEGF male mice could thus result from VEGF acting on both endothelial and nonendothelial cells of the male genital tract. Taken together, these findings suggest that the VEGF transgene has nonendothelial target cells in the testis and that VEGF may regulate male fertility.  相似文献   

9.
10.
Angiogenesis is an essential component of endometrial regeneration after menses in preparation for implantation. Vascular endothelial growth factor (VEGF) is a secreted angiogenic peptide with mitogenic activity specific for endothelial and trophoblast cells. VEGF-immunoreactivity was detected in glandular epithelium throughout the menstrual cycle by immunohistochemistry, but, showed cyclic variation in the stroma and the blood vessels. During the early proliferative phase, strong staining was seen in the glandular epithelial cells while staining in the stroma was confined to a subpopulation of stromal cells and endometrial blood vessels appeared negative. In contrast, very intense staining of the endometrial stromal cells was seen in the mid proliferative endometrium possibly due to increased synthesis of VEGF by oestrogen. In the late proliferative endometrium, staining was seen in the endothelial cells and the perivascular stromal cells around the endometrial blood vessels. The greatest degree of immunostaining of stromal cells was observed in the mid to late proliferative endometrium. Throughout the secretory phase no staining was seen around the endometrial blood vessels and staining of endometrial stromal cells was confined to early secretory endometrium. In the late secretory endometrium only the glands were positive to VEGF antibody. The observed increase in the immunostaining of stroma suggests increased production of VEGF from early to mid and late proliferative endometrium which parallels the increase in the oestradiol levels in the proliferative phase of the menstrual cycle. It is proposed that VEGF may serve as a paracrine mediator of the effects of ovarian steroids on endometrial vascular development.  相似文献   

11.
BACKGROUND: Regional variations in stromal-epithelial interactions, mediated through soluble growth factors, may be responsible for differences in epithelial growth and death observed between regions of the rat prostatic ductal system. Since transforming growth factor-beta 1 (TGF-beta 1) can induce prostatic epithelial cell death in vitro and in vivo, we examined the localization and production of TGF-beta 1 with respect to the functional regions of the rat prostatic ductal system. METHODS: The distribution of TGF-beta 1 in the rat ventral prostate was examined by immunohistochemistry. Cell type-specific expression of TGF-beta 1 was determined using RT-PCR analysis of prostate epithelial and stromal cell fractions separated by Percoll gradient centrifugation. RESULTS: Immunohistochemical staining of normal prostate revealed regional variations in stromal TGF-beta 1 protein, which was most abundant in the stroma surrounding the degenerative proximal ducts. TGF-beta 1 staining was also tightly associated with the prostatic smooth muscle. Results of RT-PCR experiments confirmed the major source of TGF-beta 1 mRNA in normal rat prostate to be the stroma, with lesser expression by the epithelium. CONCLUSIONS: Stromal TGF-beta 1 was associated with cell death in the adjacent epithelial cell compartment in the prostatic ductal system, and alpha-smooth muscle actin-positive stromal cells may play a negative growth-regulatory role in the rat ventral prostate through production of TGF-beta 1.  相似文献   

12.
Growth of the prostate is controlled by androgen. However, there is information indicating that androgen may not act directly, but may act indirectly through polypeptide growth factors, to control prostate growth. This review will focus on the involvement of members of the fibroblast growth factor (FGF) family in this process. The properties of FGFs and FGF-receptors are described that implicate these molecules in growth control. Information is provided that prostate stromal cells synthesize FGF2 and FGF7. FGF2 is a potent mitogen for stromal cells; whereas, FGF7 is exclusively a mitogen for epithelial cells. Transforming growth factor beta (TGF beta), also produced by prostate cells, inhibit cell growth. This suggests that prostate growth is controlled by autocrine and paracrine mechanisms. Evidence is presented that altered FGF expression accompanies benign prostatic hyperplasia and prostate cancer. A model is proposed whereby androgen regulates TGF beta, influencing FGF2 and FGF7 expression, and in turn regulating growth of the prostatic stroma and epithelium. An imbalance in the influence of these growth factors may contribute to prostate disease.  相似文献   

13.
Although intraepithelial pigment in the prostate gland has been termed melanosis, the nature of the pigment is not entirely clear, and many pathologists are not aware of its existence. We examined 863 hematoxylin and eosin (H + E) stained slides from 150 surgical specimens of prostate (69 needle biopsies, 66 transurethral resections, 14 radical prostatectomies, and 1 suprapubic prostatectomy) from 149 patients (age range, 47 to 90 years; mean 70 years) in an effort to characterize this pigment. The 1-3 microns in diameter, predominantly subnuclear, yellow-brown to gray-brown granules with a dark blue rim (by H + E) stained positively with Fontana-Masson, periodic acid-Schiff with diastase, Congo red, luxol fast blue, and oil-red-O and exhibited yellow autofluorescence consistent with lipofuscin. H + E stained slides revealed pigment in the benign epithelium in 86 of 150 cases (57%), within stromal macrophages in eight cases, and in atypical epithelium in two cases of high-grade prostatic intraepithelial neoplasia. Ten cases of invasive adenocarcinoma without recognizable pigment in H + E stained sections were stained by the Fontana-Masson technique, and pigment was identified in malignant epithelium in three of these cases. Ultrastructural examination of intraepithelial pigment in KII-fixed tissue from three radical prostatectomy specimens demonstrated the typical appearance of lipofuscin. Although intraepithelial pigment in prostatic biopsy or resection specimens is usually considered characteristic of seminal vesicle epithelium, our study demonstrates that lipofuscin is commonly present in epithelial cells of benign prostatic hyperplasia and less frequently in those of prostatic intraepithelial neoplasia and adenocarcinoma. The recognition of this pigment is important in preventing diagnostic confusion with seminal vesicle epithelium and with melanocytic lesions.  相似文献   

14.
Blood samples were collected from 52 incident cases of histologically confirmed prostate cancer, an equal number of cases of benign prostatic hyperplasia (BPH) and an equal number of apparently healthy control subjects. The three groups were matched for age and town of residence in the greater Athens area. Steroid hormones, sex hormone-binding globulin, and insulin-like growth factor 1 (IGF-1) were measured in duplicate by radioimmunoassay in a specialized US centre. Statistical analyses were performed using multiple logistical regression. The results for IGF-1 in relation to prostate cancer and BPH were adjusted for demographic and anthropometric factors, as well as for the other measured hormones. There was no relation between IGF-1 and BPH, but increased values of this hormone were associated with increased risk of prostate cancer; an increment of 60 ng ml(-1) corresponded to an odds ratio of 1.91 with a 95% confidence interval of 1.00-3.73. There was also some evidence for an interaction between high levels of testosterone and IGF-1 in relation to prostate cancer. This finding suggests that, in addition to testosterone, IGF-1 may increase the risk of prostate cancer in humans.  相似文献   

15.
The hypoxia-inducible endothelial cell-specific mitogen vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) is expressed in low amounts in adult human brain, but is highly upregulated in the perinecrotic palisading cells of glioblastomas. We observed high VEGF expression in cerebellar hemangioblastomas, which are highly vascular, nonnecrotic and presumably nonhypoxic tumors, and hypothesized that a mechanism other than hypoxia leads to VEGF upregulation. Because hemangioblastomas develop in patients with von Hippel-Lindau disease, and mutations of the von Hippel-Lindau tumor suppressor (VHL) gene have also been reported in sporadic hemangioblastomas, we investigated VHL expression in normal cerebellum and in hemangioblastomas and tested the hypothesis that mutations in the VHL gene lead to upregulation of VEGE We observed constitutive expression of VHL mRNA, but downregulation of VEGF mRNA in the postnatal cerebellum. In the adult cerebellum, VHL is predominantly expressed in neuronal cells. In hemangioblastomas, VHL expression appears to be restricted to stromal cells, suggesting that the neoplastic component is the stromal cell. VHL-deficient renal cell carcinoma cells (786-0) produced significantly higher levels of VEGF mRNA and protein compared with 786-0/ wt10 cells, which were stably transfected with the wild-type VHL gene. Our observations suggest that VHL mutations affect stromal cells in hemangioblastomas and that VEGF is upregulated in stromal cells as a consequence of mutations in the VHL gene.  相似文献   

16.
Human benign prostatic epithelial cells contain functional melatonin receptors that can suppress cell growth and viability. The development of benign prostatic hyperplasia in men is assumed to result from androgen-estrogen imbalance. The impact of sex steroids on melatonin receptors in human benign prostate epithelial cells was investigated. The suppression by melatonin of [3H]thymidine incorporation and cGMP, and the enhancement of cAMP levels in the cells were used as markers of melatonin responses. Dihydrotestosterone (DHT) and 17 beta-estradiol (E2) separately increased [3H]thymidine incorporation into the cells, but suppressed it when combined. In cells grown with DHT, melatonin responses were extenuated. E2 greatly reduced the apparent affinity of [125I]melatonin binding in these cells without affecting binding site density. In parallel, the ability of melatonin to suppress [3H]thymidine incorporation into the cells was ablated within 1 h after the addition of E2. The melatonin-mediated increase in cAMP and decrease in cGMP concentrations were also ablated by E2. Preincubation of the cells with bis-indolylmaleimide (GF 102903X), a specific inhibitor of protein kinase C, prevented the E2-mediated inactivation of melatonin binding and the inhibitory action on [3H]thymidine incorporation. Prolonged (18-h) incubation of the cells with phorbol 12-myristate 13-acetate to down regulate protein kinase activity, partially restored [125I]melatonin binding and responsiveness in the E2-treated cells. These data indicate that 1) DHT and E2 enhance prostate epithelial cells growth, but reduce cell growth when combined; 2) DHT extenuates the inhibitory effects of melatonin on epithelial cell growth; and 3) E2 acts to inactivate melatonin receptors and consequently responses in human epithelial benign prostatic hyperplasia cells. This process is probably mediated by protein kinase C. Together, these results show an interplay between melatonin and sex steroids in the regulation of benign prostatic epithelial cell growth.  相似文献   

17.
Androgen has an important role in development of the prostate, and the actions of androgen are mediated, in part, by locally produced growth factors. These growth factors are postulated to mediate stromal-epithelial interaction in the prostate to maintain normal tissue physiology. Transforming growth factor-alpha (TGF-alpha) is one of the growth factors that can stimulate prostatic growth. The expression of TGF-alpha is thought to be regulated by androgen. The expression of epidermal growth factor receptor (EGFR), which is the receptor of TGF-alpha and EGF, also may be regulated by androgen. The hormonal and developmental regulation of TGF-alpha and EGFR messenger RNA (mRNA) levels in isolated epithelial and stromal cells from rat ventral prostate was investigated. The expression of mRNA for TGF-alpha and EGFR was analyzed by a quantitative RT-PCR (QRT-PCR) procedure developed. Observations from this assay demonstrated that both epithelial and stromal cells expressed the mRNA for TGF-alpha and EGFR. TGF-alpha mRNA expression was constant during postnatal, pubertal, and adult development of the prostate. EGFR mRNA expression was elevated at the midpubertal period and decreased with age. After castration of 60-day-old adult rats, both TGF-alpha and EGFR mRNA were significantly enhanced. TGF-alpha mRNA expression was stimulated by EGF in stromal cells (4.5-fold increase) but was not changed by any treatment in epithelial cells. EGFR mRNA levels were stimulated by EGF and keratinocyte growth factor treatment and inhibited by testosterone treatment in epithelial cells. Stromal cell EGFR mRNA levels were not affected by any treatment. Both testosterone and EGF stimulated incorporation of 3H-thymidine into prostatic stromal and epithelial cells. Anti-TGF-alpha antibody significantly inhibited testosterone-stimulated 3H-thymidine incorporation into stromal cells and epithelial cells. Immunocytochemical localization of TGF-alpha and EGFR demonstrated expression on the luminal surface of epithelial cells within prostatic ducts, and minimal expression was observed in stromal cells. Results indicate that testosterone does not directly regulate TGF-alpha mRNA levels but does inhibit EGFR mRNA levels. Interestingly, anti TGF-alpha antibody suppressed the effect of testosterone on 3H-thymidine incorporation into prostatic stromal and epithelial cells. This finding suggests that testosterone may act indirectly on prostatic cells to influence TGF-alpha actions. TGF-alpha mRNA levels were influenced by EGF in stromal cells only, and EGFR mRNA levels were influenced by testosterone, EGF, and keratinocyte growth factor in epithelial cells. These observations suggest that regulation of TGF-alpha and EGFR is distinct between the cell types. In conclusion, a network of hormonally controlled growth factor-mediated stromal-epithelial interactions is needed to maintain prostate development and function.  相似文献   

18.
OBJECTIVE: To define the distribution of neuroendocrine (NE) cells in the different compartments of the verumontanum (utricle, ejaculatory ducts, main prostatic ducts) in relation to other areas of the prostate. MATERIALS AND METHODS: A retrospective study was conducted of 30 radical prostatectomy specimens processed in toto as whole-mount sections. Among these cases, 15 patients had received a preoperative short course of total androgen blockade. The distribution and number of NE cells in the prostatic utricle and in normal areas of the prostate were analysed using chromogranin A (CgA) and serotonin immunohistochemistry; prostate-specific antigen (PSA) immunostaining was performed systematically on a consecutive section. Six cases of endometrioid carcinomas were also investigated using these methods. The vascularization of the verumontanum was assessed by factor VIII immunohistochemistry and examined in relation to vascular endothelial growth factor (VEGF) immunohistochemistry. RESULTS: There were significantly more NE cells in the prostatic utricle than in the main prostatic ducts of the verumontanum and the peripheral prostatic acini. In the ejaculatory ducts. there were NE cells only in the extreme distal portion. Cells immunoreactive for PSA were present at the level of the utricle and the extreme distal portion of the ejaculatory ducts. The distribution, number and shape of NE cells were unaltered by hormonal treatment. NE cells of the verumontanum were positive for VEGF expression. Factor VIII detected more vessels around the utricle and ejaculatory ducts. NE cells (positive for CgA and serotonin) were observed in three cases of endometrioid carcinoma. CONCLUSION: The high concentration of NE cells found in the prostatic utricle suggests a possible role for these cells in human fertility. Moreover, neuroendocrine differentiation in endometrioid (large duct) carcinoma, documented for the first time, supports the concept that this cancer type is a variant of a conventional adenocarcinoma.  相似文献   

19.
Intercellular adhesion molecule (ICAM-1), vascular cell adhesion molecule (VCAM-1), and the lymphocyte function-associated antigen (LFA-1) are cell adhesion molecules thought to play an important role in the complex process of airway inflammation and tumor cell growth. The aim of this study was to examine the distribution of ICAM-1, VCAM-1, and LFA-1 in adenocarcinoma of lung and in major cellular compartments of non-neoplastic lung tissue. We examined cellular compartments in tissue from five bronchoalveolar carcinomas, three acinar adenocarcinomas, and one colon cancer metastatic to the lung. The compartments in neoplasms included the tumor cells proper, endothelial cells within the tumor vasculature, tumor stromal cells, and tumor-infiltrating lymphocytes. The compartments in non-neoplastic lung tissue included lung endothelial cells, pulmonary lymphocytes, interstitial fibroblasts, Type II alveolar pneumocytes, and bronchial epithelial cells. ICAM-1 was expressed in tumor cells from all of the nine adenocarcinomas. In contrast, VCAM-1 expression was not identified in tumor cells from any of the nine adenocarcinomas. ICAM-1 was expressed in all cellular compartments of the non-neoplastic lung tissue, whereas VCAM-1 was expressed only in pulmonary lymphocytes and interstitial fibroblastic cells. LFA-1 was uniformly expressed in tumor-infiltrating lymphocytes from each of the nine tumors and all of the lymphocytes in non-neoplastic lung tissue. This study showed major differences in the expression of ICAM-1 and VCAM-1 in tumor cells from pulmonary adenocarcinoma and also provided evidence for a wider distribution of ICAM-1, compared with VCAM-1, in non-neoplastic cellular compartments of the lung. ICAM-1 expression was particularly noticeable in bronchial and alveolar epithelial cells. Upregulation of ICAM-1 in pulmonary adenocarcinoma might foster binding by LFA-1-bearing lymphocytes, with a possible impact on the vulnerability of tumor cells to host defense mechanisms.  相似文献   

20.
Transforming growth factor-beta proteins are key regulators of cellular growth and differentiation. To understand the role of TGF-beta in colonic tumour progression, 47 paraffin embedded samples from colonic tumours (13 adenomas, and 34 adenocarcinomas) were studied. Gene mutations in the region coding for the active protein were studied by PCR SSCP analysis of exons 5, 6, and 7. TGF-beta1 mRNA expression and localization were studied by NISH using cDNA probes generated by RT-PCR. Protein distribution was investigated by immunohistochemistry using antibodies against both intracellular and extracellular forms. Three mutations were found: one in exon 5 (Dukes C) and two in exon 7 (Dukes C and A). TGF-beta1 mRNA was observed in 9 (69%) of 13 adenomas and in 30 (88%) of 34 adenocarcinomas. Levels of TGF-beta1 mRNA and proteins were higher in colorectal carcinomas than in colorectal adenomas. Tubular adenomas associated with dysplasia showed greater expression of TGF-beta1 than adenomas without dysplasia and than non-neoplastic colonic mucosa. In dysplasia and cancer, epithelial neoplastic cells and stromal cells were positive for TGF-beta1. In normal tissue endothelial cells and granulocytes sporadically showed immunoreactivity for TGF-beta1, whereas epithelial cells were all negative. The three mutations in TGF-beta1 exons 5, 6 and 7 found in colorectal adenocarcinomas suggest that TGF-beta1 mutation may play a role in colorectal carcinogenesis and that the presence of the mutant form contributes to the transformed state. Our two other findings, the loss of staining gradient in normal colonic mucosa and the higher levels of TGF-beta1 mRNA and proteins in colorectal carcinomas than in colorectal adenomas, indicate that the de-regulation of TGF-beta1 expression may occur as an early event in colorectal carcinogenesis. Although TGF-beta1 expression is generally a reflection of cellular differentiation, tumour grade is not associated with TGF-beta1 mRNA expression. Beside being present in the epithelial cells of the colonic tumours, TGF-beta1 mRNA also occurred in the stroma: its localization in the macrophages adjacent to tumour strongly suggests that TGF-beta1 could be secreted by macrophages. This hypothesis should lead to new therapeutic strategies for colorectal carcinoma.  相似文献   

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