Papel de la activación adicional del gen RA en el desarrollo del fenotipo resistente a la castración en el cáncer de próstata / Additional activation of the AR gene may be involved in the development of the castration resistance phenotype in prostate cancer

Introducción Diversos estudios han demostrado que los cambios en el gen RA pueden estar asociados a un fenotipo de enfermedad más agresivo e incluso al cáncer de próstata resistente a la castración. Por este motivo, hemos investigado las alteraciones citogénicas y moleculares asociadas al RA.Materiales y métodos Para evaluar la metilación del RA, realizamos un análisis citogenético-molecular mediante hibridación fluorescente in situ que utiliza sondas específicas para el gen del RA (Xq11.12) y el centrómero del cromosoma X. Respecto a la actividad del RA, realizamos un análisis cualitativo de la actividad del receptor de andrógenos humano. Para analizar la expresión del RA en las líneas celulares PC3 y LNCaP, utilizamos ensayos de qPCR.ResultadosEn el ensayo qPCR, encontramos una regulación a la baja del RA en la línea celular PC3 en comparación con la LNCaP. Hallamos la presencia de polisomía del cromosoma X en las líneas celulares PC-3 y LNCaP mediante el ensayo FISH. En el ensayo HUMARA-Q encontramos la presencia de dos cromosomas X/célula y actividad en ambos RA de la línea celular PC-3. En las células LNCaP hallamos la presencia de dos cromosomas X/célula y la metilación de solo un RA.Conclusión El fenotipo del cáncer de próstata resistente a la castración representa un gran desafio en el tratamiento urológico. Estos cromosomas X y las alteraciones ligadas al RA pueden contribuir a una mejor comprensión de la enfermedad; sin embargo, deben realizarse más estudios para arrojar más luz sobre el papel del RA en el fenotipo del cáncer de próstata resistente a la castración (AU)

Introduction Several studies have already shown that changes in the AR gene may be associated with a more aggressive disease phenotype and even castration-resistant prostate cancer. Thus, we investigated cytogenetic and molecular alterations linked to AR.Materials and methods To evaluate AR methylation, we performed a cytogenetic-molecular analysis using fluorescence in situ hybridization that uses specific probes for the AR gene (Xq11.12) and the X chromosome centromere. For AR activity, we performed a qualitative analysis of human androgen receptor activity. To analyze the expression of AR in PC3 and LNCaP cell lines, we used qPCR assays.ResultsIn the qPCR assay, we found downregulation of AR in the PC3 cell line compared with the LNCaP. We found the presence of X chromosome polysomy in PC-3 and LNCaP cell lines by FISH assay. In the HUMARA-Q assay, we found two X chromosomes/cell and the activity of both AR in the PC-3 cell line. In LNCaP cells, we found two X chromosomes/cell and methylation of only one AR.Conclusion Castration-resistant prostate cancer phenotype represents a significant challenge in the setting of urological management. The X chromosomes and AR-linked alterations may contribute to a better understanding of the disease. However, further studies should be performed in an attempt to elucidate as much as possible the role of AR in the castration-resistant prostate cancer phenotype (AU)

Additional activation of the AR gene may be involved in the development of the castration resistance phenotype in prostate cancer.

INTRODUCTION: Several studies have already shown that changes in the AR gene may be associated with a more aggressive disease phenotype and even castration-resistant prostate cancer. Thus, we investigated cytogenetic and molecular alterations linked to AR. MATERIALS AND METHODS: To evaluate AR methylation, we performed a cytogenetic-molecular analysis using fluorescence in situ hybridization that uses specific probes for the AR gene (Xq11.12) and the X chromosome centromere. For AR activity, we performed a qualitative analysis of human androgen receptor activity. To analyze the expression of AR in PC3 and LNCaP cell lines, we used qPCR assays. RESULTS: In the qPCR assay, we found downregulation of AR in the PC3 cell line compared with the LNCaP. We found the presence of X chromosome polysomy in PC-3 and LNCaP cell lines by FISH assay. In the HUMARA-Q assay, we found two X chromosomes/cell and the activity of both AR in the PC-3 cell line. In LNCaP cells, we found two X chromosomes/cell and methylation of only one AR. CONCLUSION: Castration-resistant prostate cancer phenotype represents a significant challenge in the setting of urological management. The X chromosomes and AR-linked alterations may contribute to a better understanding of the disease. However, further studies should be performed in an attempt to elucidate as much as possible the role of AR in the castration-resistant prostate cancer phenotype.

Intratumoral heterogeneity of ADAM23 promotes tumor growth and metastasis through LGI4 and nitric oxide signals.

Intratumoral heterogeneity (ITH) represents an obstacle for cancer diagnosis and treatment, but little is known about its functional role in cancer progression. The A Desintegrin And Metalloproteinase 23 (ADAM23) gene is epigenetically silenced in different types of tumors, and silencing is often associated with advanced disease and metastasis. Here, we show that invasive breast tumors exhibit significant ADAM23-ITH and that this heterogeneity is critical for tumor growth and metastasis. We demonstrate that while loss of ADAM23 expression enhances invasion, it causes a severe proliferative deficiency and is not itself sufficient to trigger metastasis. Rather, we observed that, in ADAM23-heterotypic environments, ADAM23-negative cells promote tumor growth and metastasis by enhancing the proliferation and invasion of adjacent A23-positive cells through the production of LGI4 (Leucine-rich Glioma Inactivated 4) and nitric oxide (NO). Ablation of LGI4 and NO in A23-negative cells significantly attenuates A23-positive cell proliferation and invasion. Our work denotes a driving role of ADAM23-ITH during disease progression, shifting the malignant phenotype from the cellular to the tissue level. Our findings also provide insights for therapeutic intervention, enforcing the need to ascertain ITH to improve cancer diagnosis and therapy.

Influence of a hypercholesterolemic diet on the collagen composition of the bladder wall extracellular matrix in rats.

PURPOSE: To investigate the effects of hypercholesterolemic diet on the collagen composition of urinary bladder wall. MATERIALS AND METHODS: Forty-five female 4-week-old Wistar rats were divided into three groups: 1) control group fed a normal diet (ND); 2) model of bladder outlet obstruction (BOO) group fed a ND; and 3) group fed a HCD (1.25% cholesterol). Total serum cholesterol, LDL cholesterol and body weight were assessed at baseline. Four weeks later, group 2 underwent a surgical procedure resulting in a partial BOO, while groups 1 and 3 underwent a sham similar surgical procedure. Six weeks later, all animals had their bladders removed; serum cholesterol and LDL cholesterol levels and body weights were measured. Morphological and morphometric analysis was performed by Picrosirius staining and collagen types I and III were identified by immunofluorescence. Statistical analysis was completed and significance was considered when p<0.05. RESULTS: Rats fed an HCD exhibited a significant increase in LDL cholesterol levels (p<0.001) and body weight (p=0.017), when compared to the groups fed a ND during the ten-week study period. Moreover, the HCD induced morphological alterations of the bladder wall collagen, regarding thin collagen fibers and the amounts of type III collagen when compared to the control group (p=0.002 and p=0.016, respectively), resembling the process promoted in the BOO model. CONCLUSIONS: A hyper-cholesterolemic diet in Wistar rats promoted morphological changes of the bladder types of collagen, as well as increases in body weight and LDL cholesterol.

Structural variations among monocot emergent and amphibious species from lakes of the semi-arid region of Bahia, Brazil.

Temporary lakes are common in the semi-arid region of the State of Bahia and form water mirrors in the rainy season. In this period, various vegetal species appear having different life forms adapted to the seasonality conditions of the rainfall regime. This work surveyed the adaptive anatomical structures of some emergent and amphibious monocot species occurring in these lakes. We studied the anatomy of roots, rhizomes, leaves and scapes of Cyperus odoratus, Oxycaryum cubense, Pycreus macrostachyos (Cyperaceae) - amphibious species; and of Echinodorus grandiflorus (Alismataceae), Eichhornia paniculata (Pontederiaceae) and Habenaria repens (Orchidaceae) - emergent species. The anatomical features of the dermal, fundamental and vascular systems confirming the tendency of the adaptive convergence of these plants to temporary lacustrine the environment include: single layered epidermal cells with a thin cuticle layer in the aerial organs; the presence of air canals in all the organs; few or no supporting tissues; and less numerous conducting elements and thinner cell walls in the xylem. The reduction of the supporting tissues, the number of stomata, which can even be absent, and the number of conducting elements and the degree of cell wall lignification in the xylem of the emergent species is more accentuated than that of the amphibious species. The pattern of distribution of aerenchyma in the roots of the studied species was considered important to distinguish between amphibious and emergent life forms.

Comparative analysis of the leaf anatomy in two Parodiolyra species (Poaceae: Olyreae) occurring on forests in Eastern Brazil.

Parodiolyra is a member of Olyreae, a tribe of herbaceous bamboo species within the Poaceae. The genus has five species, four of which were previously regarded as belonging to Olyra L. Parodiolyra has a Neotropical distribution and only two species occur on forests in Eastern Brazil: P. micrantha (Kunth) Zuloaga & Davidse and P. ramosissima (Trin.) Soderstr. & Zuloaga, the first widely distributed in the Neotropics while the second is endemic to the state of Bahia. Leaf anatomy of the two species was analysed with the aid of an optical microscope. The objective was to describe the microscopic characters and evaluate if they can be useful for the taxonomy of the genus. The observed anatomical structures did not differ from other genera of herbaceous bamboos, however some characters, both from the mesophyll and the epidermis, were useful to delimit the two species.

Development of a rabbit's urethral sphincter deficiency animal model for anatomical-functional evaluation

OBJECTIVE: The aim of the study was to develop a new durable animal model (using rabbits) for anatomical-functional evaluation of urethral sphincter deficiency. MATERIALS AND METHODS: A total of 40 New Zealand male rabbits, weighting 2.500 kg to 3.100 kg, were evaluated to develop an incontinent animal model. Thirty-two animals underwent urethrolysis and 8 animals received sham operation. Before and at 2, 4, 8 and 12 weeks after urethrolysis or sham operation, it was performed cystometry and leak point pressure (LPP) evaluation with different bladder distension volumes (10, 20, 30 mL). In each time point, 10 animals (8 from the study group and 2 from the sham group) were sacrificed to harvest the bladder and urethra. The samples were evaluated by H&E and Masson's Trichrome to determine urethral morphology and collagen/smooth muscle density. RESULTS: Twelve weeks after urethrolysis, it was observed a significant decrease in LPP regardless the bladder volume (from 33.7 ± 6.6 to 12.8 ± 2.2 cmH2O). The histological analysis evidenced a decrease of 22% in smooth muscle density with a proportional increase in the collagen, vessels and elastin density (p < 0.01). CONCLUSIONS: Transabdominal urethrolysis develops urethral sphincter insufficiency in rabbits, with significant decrease in LPP associated with decrease of smooth muscle fibers and increase of collagen density. This animal model can be used to test autologous cell therapy for stress urinary incontinence treatment.

Anatomia dos órgãos vegetativos de Hymenaea martiana Hayne (Caesalpinioideae-Fabaceae): espécie de uso medicinal em Caetité-BA / Anatomy of vegetative organs of Hymenaea martiana Hayne (Fabaceae-Caesalpinioideae): a species of medicinal use in Caetité-Bahia State, Brazil

Hymenaea martiana Hayne (Fabaceae-Caesalpinioideae) apresenta grande valor na medicina popular em Caetité. A casca, entrecasca do caule e a resina, são utilizadas no tratamento de diversos males. Neste estudo são apresentadas a caracterização anatômica e histoquímica dos órgãos vegetativos. Amostras foram coletadas e processadas segundo técnicas usuais em anatomia vegetal e histoquímica. Todos os órgãos apresentam, em visão transversal, epiderme unisseriada e cavidades secretoras. Cutícula espessa ocorre em todos os órgãos aéreos. A raiz é tetrarca. Colênquima lacunar foi encontrado no caule. Bainha de fibras esclerenquimáticas envolve os feixes vasculares dos órgãos aéreos. Células pétreas ocorrem no pecíolo. Tricomas tectores ocorrem em ambas as faces da folha. A folha é hipoestomática com estômatos paracíticos e o mesofilo é dorsiventral. Cristais de oxalato de cálcio ocorrem no caule, pecíolo e lâmina foliar. Compostos fenólicos ocorrem na raiz, pecíolo e nervura central da folha. Grãos de amido ocorrem na raiz, caule e pecíolo. Lipídios ocorrem em todos os órgãos. Acredita-se que compostos fenólicos e cavidades secretoras de resina podem justificar a utilidade medicinal da espécie pela população de Caetité.

Hymenaea martiana Hayne (Fabaceae-Caesalpinioideae) shows a great value in folk medicine in Caetité. Its bark, stem-bark and resin are used to treat various ailments. In this study, the anatomical and histochemical characterization of vegetative organs is reported. Samples were collected and processed according to usual techniques of plant anatomy and histochemistry. All organs have, by cross-sectional view, uniseriate epidermis and secretory cavities. Thick cuticle occurs in all aerial organs. The root is tetrarch. Lacunar collenchyma was found in the stem. Sclerenchymatic sheath of fibers surrounds the vascular bundles of the aerial organs. Stone cells occur in the petiole. Trichomes occur on both sides of the leaves. The leaf is hypostomatic with paracytic stomata and the mesophyll is dorsiventral. Calcium oxalate crystals occur in the stem, petiole and leaf blade. Phenolic compounds occur in the root, petiole and midrib of the leaf. Starch grains occur in the root, stem and petiole. Lipids occur in all organs. It is believed that phenolic compounds and resin secretory cavities may justify the use of medicinal species by the population of Caetité.

Expression of TERT in precancerous gastric lesions compared to gastric cancer

The objective of this study was to determine the levels of TERT mRNA and TERT protein expression in stomach precancerous lesions such as intestinal metaplasia (IM) and gastric ulcer (GU) and compare them to gastric cancer (GC). Real-time PCR was performed to detect TERT mRNA expression levels in 35 biopsies of IM, 30 of GU, and 22 of GC and their respective normal mucosas. TERT protein was detected by immunohistochemistry in 68 samples, 34 of IM, 23 of GU, and 11 of GC. Increased TERT mRNA expression levels were observed in a significant number of cases, i.e., 46 percent of IM, 50 percent of GU, and 79 percent of GC. The relative mean level of TERT mRNA after normalization with the β-actin reference gene and comparison with the respective adjacent normal mucosa was slightly increased in the IM and GU groups, 2.008 ± 2.605 and 2.730 ± 4.120, respectively, but high TERT mRNA expression was observed in the GC group (17.271 ± 33.852). However, there were no statistically significant differences between the three groups. TERT protein-positive immunostaining was observed in 38 percent of IM, 39 percent of GU, and 55 percent of GC. No association of TERT mRNA and protein expression with Helicobacter pylori infection or other clinicopathological variables was demonstrable, except for the incomplete type vs the complete type of IM. This study confirms previous data of the high expression of both TERT mRNA and protein in gastric cancer and also demonstrates this type of changed expression in IM and GU, thus suggesting that TERT expression may be deregulated in precursor lesions that participate in the early stages of gastric carcinogenesis.

Expression of TERT in precancerous gastric lesions compared to gastric cancer.

The objective of this study was to determine the levels of TERT mRNA and TERT protein expression in stomach precancerous lesions such as intestinal metaplasia (IM) and gastric ulcer (GU) and compare them to gastric cancer (GC). Real-time PCR was performed to detect TERT mRNA expression levels in 35 biopsies of IM, 30 of GU, and 22 of GC and their respective normal mucosas. TERT protein was detected by immunohistochemistry in 68 samples, 34 of IM, 23 of GU, and 11 of GC. Increased TERT mRNA expression levels were observed in a significant number of cases, i.e., 46% of IM, 50% of GU, and 79% of GC. The relative mean level of TERT mRNA after normalization with the ß-actin reference gene and comparison with the respective adjacent normal mucosa was slightly increased in the IM and GU groups, 2.008 ± 2.605 and 2.730 ± 4.120, respectively, but high TERT mRNA expression was observed in the GC group (17.271 ± 33.852). However, there were no statistically significant differences between the three groups. TERT protein-positive immunostaining was observed in 38% of IM, 39% of GU, and 55% of GC. No association of TERT mRNA and protein expression with Helicobacter pylori infection or other clinicopathological variables was demonstrable, except for the incomplete type vs the complete type of IM. This study confirms previous data of the high expression of both TERT mRNA and protein in gastric cancer and also demonstrates this type of changed expression in IM and GU, thus suggesting that TERT expression may be deregulated in precursor lesions that participate in the early stages of gastric carcinogenesis.

Antimutagenicity protection of Ginkgo biloba extract (Egb 761) against mitomycin C and cyclophosphamide in mouse bone marrow.

Ginkgo biloba (Egb 761) extract, the most prescribed phytomedicine in Europe for the treatment of cerebral insufficiency and vascular diseases, was tested for its possible protective effects against mitomycin C (MMC)- and cyclophosphamide (CP)-induced mutagenicity using the micronucleus test in mouse bone marrow. The extract was co-administered to mice at doses of 50, 100 and 200 mg/kg (po) with 4 mg/kg (ip) MMC or 24 mg/kg (ip) CP. All doses of Egb 761 were significantly (P < 0.05) effective in reducing the frequency of micronucleated polychromatic erythrocytes, when compared with MMC or CP alone. Based on these results, we suggest that Egb 761 possesses both direct and indirect antimutagenic potential.

Abnormal expression of MDM2 in prostate carcinoma.

Mutation of p53 is rare in localized prostate carcinoma. The oncoprotein MDM2, whose gene has a response element for p53, promotes the degradation of p53 protein and inhibits its transcriptional activation of genes related to cell cycle arrest and apoptosis, constituting a negative feedback control. We studied p53 and MDM2 expression by immunohistochemistry and looked for mutations in p53 exons 5 to 8 by polymerase chain reaction-single strand conformational polymorphism in 118 patients submitted to radical prostatectomy for localized prostate cancer. In 28 cases, we studied cell proliferation by immunohistochemistry, using antibody for Ki-67, and apoptosis by the deoxynucleotidyl transferase mediated dUTP biotin nick end labeling technique. Although no p53 mutations were found, p53 protein was detected in 31.4% of the cases, and these cases had higher Gleason scores (P = .03) and more advanced tumor stages (P = .02). MDM2 was overexpressed in 40.7% of the cases, and these cases had greater tumor volumes (P = .001). Tumors that were positive for both p53 and MDM2 were larger (P = .003) and of more advanced stage (P = .03). Within the 28-case subset, the proliferative index was higher among MDM2-positive tumors (P = .046), and the apoptotic index was lower among p53-positive tumors (P = .01). We conclude that, although p53 mutation is a rare event in prostate carcinogenesis, the detection of p53 protein by immunohistochemistry is common and is associated with decreased apoptosis and increased histologic grade and tumor stage. We also conclude that the overexpression of MDM2 has a role in prostate carcinogenesis, being frequently detected and associated with increased cell proliferation and tumor volume. Finally, we propose that the MDM2-positive/p53-positive phenotype identifies prostate cancers with aggressive behavior.

Urinary continence and pathological outcome after bladder neck preservation during radical retropubic prostatectomy: a randomized prospective trial.

PURPOSE: Bladder neck preservation during radical prostatectomy has been advocated for improving urinary continence. We compared bladder neck preservation and resection in a randomized trial, looking at continence rates and surgical cancer control. MATERIALS AND METHODS: Patients with stage T1c-T2c prostate cancer underwent radical retropubic prostatectomy with maximal preservation of the external urinary sphincter. Bladder neck preservation or resection was chosen by chance during surgery. Urinary continence (1 or no protective pad daily) was assessed by interview 2 days after catheter removal, and 2 and 6 months after surgery. The surgeon, pathologist and interviewer were the same throughout. Neither patient nor interviewer knew which procedure was done. Planned enrollment was 120. RESULTS: Enrollment was stopped after 70 patients because surgical margins were positive only at the bladder neck in 10% of the preservation group but in none of the resection group (p = 0.08). Each group was assigned 35 patients but the bladder neck could not be preserved in 4 and 1 died, leaving 31 in the preservation group and 38 in the resection group. There were no statistically significant differences between groups in early or late urinary continence rates. Two days after catheter removal, and 2 and 6 months after surgery the respective rates were 79%, 87% and 95% with resection, and 67%, 87% and 97% with preservation. CONCLUSIONS: In our opinion bladder neck preservation during radical retropubic prostatectomy does not improve urinary continence and might compromise cancer control. The external sphincter appears more important for continence after radical prostatectomy.

Effect of platelet-activating factor antagonists (BN-52021, WEB-2170, and BB-882) on bacterial translocation in acute pancreatitis.

Bacterial translocation is an important source of pancreas infection in acute pancreatitis. The effect of platelet-activating factor (PAF) in the pathogenesis of acute pancreatitis has been proved in various studies. The aim of this study was to determine whether potent PAF antagonists influence bacterial translocation in acute pancreatitis. Acute pancreatitis was induced in 62 Wistar rats by injection of 2.5% sodium taurocholate into the biliopancreatic duct. The rats treated with PAF factor antagonists received intravenous injection of WEB-2170 (10 mg/kg), lexipafant (5 mg/kg), and BN-52021 (5 mg/kg) 30 minutes before induction of acute pancreatitis. Six hours after induction of acute pancreatitis, bacteriologic cultures and histologic scoring of tissues were performed. There was a statistically significant reduction in bacterial translocation to the mesenteric lymph nodes and liver but not to the pancreas of the rats treated with PAF antagonists. No significant increase in the intestinal bacterial population of any group was found. There were no statistical differences between the pancreatic histologic scores of the groups. PAF antagonists reduced bacterial translocation to distant sites other than the pancreas, preventing the bacterial dissemination that occurs in the early phase of acute pancreatitis and may have beneficial effects on the evolution of this disease.

Monoclonality of asynchronous bilateral lymphoma of the testis.

OBJECTIVES: Lymphoma is the most frequent testicular malignancy in men over 60 years of age. Even though patients present initially with localized disease, the high incidence of bilateral involvement, synchronous or not, and early systemic dissemination are characteristic of these neoplasms. Sometimes the interval between tumor involvement of both testes is long. The question is raised whether either the patient has a predisposition to present new clones of transformed lymphocytes, or the same disease using the same pathway from a systemic reservoir infiltrates the contralateral testis. METHOD: Polymerase chain reaction and DNA sequencing were used to detect immunoglobulin heavy chain (IgH) rearrangement in paraffin-embedded specimens from asynchronous tumors affecting the right and left testis of a 85-year-old man with an interval period of 13 months. RESULTS: Both tumors showed the same IgH rearrangement. CONCLUSIONS: The lymphoma affecting the left and right testis derived from the same clone. It makes a strong case that lymphoma of the testis is the first manifestation of a systemic disease and should be treated aggressively early at the beginning of the disease.

Immunohistochemical Mdm2 expression in minor salivary gland tumours and its relationship to p53 gene status.

Mdm2 protein is a cellular regulator of p53 protein activity. Minor salivary gland tumours were investigated for immunohistochemical expression of Mdm2 protein and for p53 gene status. Formalin-fixed sections were submitted to monoclonal antibody anti-Mdm2 through use of the streptavidin-biotin method. Nuclear immunoreactivity was scored 1 (0-25% nuclei positive), 2 (26-50%), 3 (51-75%) and 4 (> 75%). The scores found were: PLGA = 1-4; ACC = 3 and 4; ACA = 2 and 4; PA = 3. Genomic DNA of p53 gene exons 5-8 was examined by polymerase chain reaction and no alterations were detected. The strong immunohistochemical Mdm2 expression may represent an alternative mechanism to the development of salivary gland tumours.

No relationship between proliferative activity and the MACIS prognostic scoring system in papillary thyroid carcinoma.

BACKGROUND: The MACIS score uses metastasis, age, completeness of resection, local invasion, and tumor size to stratify patients with papillary thyroid carcinoma (PTC) into four groups with different survival. METHODS: Immunostaining for proliferating cell nuclear antigen (PCNA) was done in 43 cases of PTC. Relationships between proliferative index (percentage of cells that were PCNA positive) and the MACIS parameters were examined. Double staining for PCNA and for silver-stained nucleolar organizer regions (AgNORs, indicating proliferation) was performed in 10 cases. RESULTS: PCNA was detected only in tumor cells. The proliferative index was low (mean, 14.2%; median, 13.0%), did not differ between MACIS groups (p = 0.56), and showed no association with individual MACIS parameters. PCNA immunostaining correlated with AgNOR staining. The mean AgNOR count was 2.28 in PCNA-positive cells and 1.85 in PCNA-negative cells (p

Detection of codon 12 mutation in the K-ras oncogene in pancreatic tumors.

Mutations at codons 12, 13, or 61 of the H-ras, K-ras, and N-ras have been detected in human neoplasias by a variety of techniques. Some of these techniques are very sensitive and can detect K-ras mutation in 90% of the cases of pancreatic adenocarcinomas. We analyzed 11 samples of pancreatic adenocarcinoma, three samples of pancreatic mucinous cystadenoma, and two samples without tumors in formalin-fixed paraffin embedded tissue sections. K-ras mutations at codon 12 were detected by a two-step PCR-enriched technique in all the samples of pancreatic adenocarcinoma, but not in cystadenoma or control samples. This technique may be useful for early detection of pancreatic cancer.

Analysis of p53 expression and proliferative assessment using PCNA in localized prostate carcinoma.

The surgical specimens from 51 men submitted to radical prostatectomy for localized prostate cancer were examined by immunohistochemistry using proliferation cell nuclear antigen (PCNA) monoclonal antibody to evaluate the proliferative index (PI). The relationship between PI, biological variables and p53 protein expression was evaluated by immunohistochemistry. PI was low in invasive localized prostate carcinoma (mean, 12.4%) and the incidence of PCNA-positive cells was significantly higher in tumors with p53 expression (P = 0.0226). There was no statistical difference in PCNA values when biological parameters such as Gleason score, tumor volume, extraprostatic involvement, seminal vesicle infiltration or lymph node metastasis were considered. We conclude that proliferative activity is usually low in prostate carcinoma but is correlated with p53 immune staining, indicating that p53 is important in cell cycle control in this neoplasm.