Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0001430 (adenoma)
 21,222 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although almost all pituitary tumors are benign adenomas, a surprisingly large number of these tumors invade tissues outside of the pituitary gland. Such invasion, by itself, is not diagnostic of pituitary carcinomas, which are exceedingly rare (0.13% of 2,342 pituitary tumors in one series). Several different criteria are available to determine whether a tumor is invasive. Intraoperative biopsies demonstrate an 85% incidence of microscopic invasion of the dura. Evidence of gross invasion at surgery and radiologic evidence of invasion on magnetic resonance imaging (MRI) and computed tomographic (CT) scans occur at a much lower incidence but may be more predictive of surgical cure. Invasive adenomas also have higher proliferation rates than do noninvasive adenomas, as shown by immunohistochemical detection of proliferating cell nuclear antigen (PCNA), Ki-67, and MIB-1. The expression of p53, increased epidermal growth factor receptors, and protein kinase C activity also correlate with invasion and aggressive behavior. Clinically significant invasion is more frequent with macroadenomas. Macroadenomas of all pituitary tumor subtypes except gonadotroph macroadenomas have a greater than 50% incidence of gross invasion. Currently, there is no accepted means of predicting an adenoma's clinically significant invasiveness and long-term aggressiveness.
 ...
PMID:Aggressive pituitary tumors. 977 77

Colorectal cancer arises from a series of precursor stages, the so called adenoma-carcinoma sequence. Increased rectal mucosal proliferation may be an early step in this sequence. Because dietary factors are implicated in the etiology of colorectal cancer, one might predict that diet would also be associated with proliferation. We conducted this study to examine the association of diet with rectal mucosal proliferation. Rectal mucosal proliferation was measured in endoscopic biopsy specimens by proliferating cell nuclear antigen (PCNA) immunohistochemistry and whole crypt mitotic counts (WCMCs). Diet was evaluated using a validated quantitative food frequency questionnaire. The correlation between PCNA labeling index (LI) and WCMCs was determined using Kendall's tau, a nonparametric measure of correlation. Logistic regression was used to examine the effect of proliferation on adenoma status, controlling for confounders. The relationship between proliferation and dietary and demographic factors was examined using linear regression. There were 308 patients who had one or both measures of proliferation. There was no significant correlation between PCNA LI and WCMCs (Kendall's tau = 0.04; P = 0.35). Neither measure of proliferation was predictive of adenoma status, even after adjusting for potential confounders. Body mass index and calories per day were significant predictors of WCMC (P = 0.01 and P = 0.03, respectively). PCNA labeling index was not associated with any dietary variables, although its association with dietary fat nearly reached statistical significance (P = 0.09). The association between proliferation and diet were generally inconsistent. There appears to be no simple relationship between colorectal cancer risk factors, colorectal adenomas, and these two measures of rectal mucosal proliferation. We need simpler, more reliable intermediate markers for use in etiological and intervention studies.
 ...
PMID:Rectal mucosal proliferation, dietary factors, and the risk of colorectal adenomas. 982 7

The purpose of this study was to correlate proliferating cell nuclear antigen (PCNA) immunostaining with clinicopathological findings in 60 follicular thyroid tumors. Mean proliferative index (PI) was significantly higher for carcinoma (73%) than microfollicular adenoma (19.6%) (p<0.0001). For atypical and oncocytic adenomas, intermediate PI values (64% and 50%) correlated with size and cytological atypia but not with sex and age. PCNA immunostaining is of limited value for differential diagnosis of malignant and atypical tumors but could be useful for identification of actively growing atypical follicular thyroid nodules on fine needle aspiration biopsies.
 ...
PMID:Expression of proliferating cell nuclear antigen in follicular thyroid tumors: correlation with clinicopathological findings. 1002 5

Alveolar adenoma of lung is a rare benign neoplasm of uncertain histogenesis. Its rarity hampers characterization of its epithelial and mesenchymal elements. Clinical and histopathologic features of 17 alveolar adenomas were reviewed. Histochemistry was performed on 10 cases, ultrastructural analysis on two, and immunohistochemistry on six cases for pneumocyte markers, thyroid transcription factor (TTF-1), surfactant protein markers pro-SP-B and pro-SP-C, and the Clara cell marker, CC10. Immunohistochemistry was performed in nine cases for desmin, smooth muscle actin, muscle-specific actin, cytokeratin, proliferating cell nuclear antigen (PCNA), factor VIII, and carcinoembryonic antigen. The mean age was 53 years. Seven cases occurred in men, and nine occurred in women. The age and sex were not known for one patient. The tumors were coin lesions on chest radiographs in asymptomatic patients except for one (cough). The mean size was 2.2 cm. The tumors were well demarcated with multiple cystic spaces containing granular material. Mostly type 2 pneumocytes lined the cystic spaces with fewer type 1 cells and no Clara cells. This was confirmed by staining for TTF-1, pro-SP-B, and pro-SP-C and by ultrastructure. CC10 was negative in all cases. The stroma varied from prominent spindle cells with a myxoid matrix to thin alveolar septa. The interstitial spindle cells resembled fibroblasts by immunohistochemistry and ultrastructure. Follow-up data available in five cases showed no recurrence at 2, 2, 5, 8, and 13 years. In summary, alveolar adenoma is a benign neoplasm consisting of an intimate admixture of alveolar epithelial and septal mesenchymal tissue. Most of the epithelial cells are type 2 pneumocytes, and the interstitial stromal cells are fibroblasts or fibroblast-like cells. Recognition of its characteristic morphological appearance allows for its distinction from other benign lesions of the lung.
 ...
PMID:Alveolar adenoma: a histochemical, immunohistochemical, and ultrastructural analysis of 17 cases. 1002 43

Most toxic thyroid nodules (TTN) result from clonal expansion of a single cell caused by a somatic mutation in the thyrotropin (TSH) receptor, the Gsalpha protein, or yet unknown proteins. Expanding a single cell into a TTN with thousands of cells suggests a prolonged increase in proliferation compared to nonaffected surrounding cells. To test this hypothesis, we evaluated cell proliferation in TTN. Tissue from 20 TTN and their surrounding normal thyroid tissue was studied for the occurrence of the proliferating cell nuclear antigen (PCNA) and Ki-67 epitope as markers for cell proliferation. The labeling index (number of labeled cells versus total cell number) for nodular and surrounding tissue was calculated. Nineteen samples were evaluated for PCNA immunohistochemistry. In 16 TTN, a significant (p< or =0.05%) up to 3-fold increase in the labeling index for PCNA was detectable. In only 3 toxic nodules (2 without a detectable TSH receptor or Gsalpha protein mutation), we found no significant difference in the labeling index compared to the surrounding tissue. Because labeling for KI-67 was much lower, only 16 toxic thyroid nodules were quantified. Twelve of these showed significantly (p< or =0.05%) increased labeling indices. The increase of the labeling index for both markers was similar for histologically defined adenoma versus adenomatous nodule or nodules with or without TSH receptor mutation or clonal versus polyclonal origin of toxic nodules studied. These findings are evidence that an increased thyroid epithelial cell proliferation is a uniform feature common to most TTNs, independent of their histopathological or molecular characteristics. Although increased proliferation in many TTNs is very likely the result of TSH receptor mutations, the cause of increased proliferation in TTN without a mutation is unknown.
 ...
PMID:Increased thyroid epithelial cell proliferation in toxic thyroid nodules. 1021 99

Our previous studies have demonstrated the significant enzymatic activity of glycogen phosphorylase (GP) in the gastric carcinoma and proliferating cells of particular intestinal metaplasia (IM). This paper reviewed the identification of the GP isoform in the gastrointestinal carcinoma, and the investigation on the role of this molecule in the gastrointestinal carcinogenesis. The only isoform expressed in gastric cancer was brain-type GP (BGP) using polymerase chain reaction (PCR) analysis. The expression of BGP, oncogene products and proliferating cell nuclear antigen in the gastric and colorectal carcinomas, their premalignant lesions, and the normal mucosa were examined using 136 gastric and 96 colorectal surgically resected specimens, and 55 endoscopically resected colorectal adenomas. The BGP visualized by immunohistochemistry was commonly present in intestinal-type gastric (80.6%) and colorectal (83.3%) carcinomas, whereas no BGP expression was seen in the normal human gastric and large intestinal mucosa except in the BGP foci described below. IMs with BGP had close correlation with intestinal-type gastric carcinoma, and some of them coexpressed accumulated p53 protein. The expression of BGP during 'adenoma carcinoma sequence' (ACS) showed excellent correlation with the increased dysplasia and was found prior to p53 expression. Positive staining in overtly normal looking colonic mucosa (BGP foci) was observed mainly around carcinomas without any adenoma component, and frequent p53 mutation (41.2%) was detected in the BGP foci using PCR-single strand conformation polymorphism analysis. It is suggested that BGP is a novel biomarker for carcinogenesis in the intestinal-type gastric carcinoma and in both of the pathways of ACS and the 'de novo' colorectal carcinoma.
 ...
PMID:Carcinogenesis of intestinal-type gastric cancer and colorectal cancer is commonly accompanied by expression of brain (fetal)-type glycogen phosphorylase. 1037 90

We report a case of vesical tubulovillous adenoma that occurred in a background of protracted chronic cystitis with intestinal-type glandular metaplasia and extensive cellular atypia (dysplasia) in the flat mucosa. Flow cytometry analysis showed DNA aneuploidy in the adenoma. Increased expression of the tumor suppresser gene, p53, and also of cellular proliferation markers (proliferating cell nuclear antigen and MIB-1) were detected in the villous adenoma and in the dysplastic regions of the flat metaplastic mucosa. These findings provide insight into the biology of intestinal metaplasia and also lend support to the theory of the chronic irritation-metaplasia-dysplasia-carcinoma sequence.
 ...
PMID:Tubulovillous adenoma of the urinary bladder. 1043 Feb 79

Few studies have been conducted focusing on a potential role of reactive oxygen species in tumor cell metabolism. Here we studied human colorectal adenocarcinomas and adenomas to determine whether oxidative stress is imposed on cancer cells in vivo and used specific antibodies against 8-hydroxy-2'-deoxyguanosine (8-OHdG), 4-hydroxy-2-nonenal (HNE)-modified proteins, and 3-nitro-L-tyrosine (3-NT) to determine whether there is an association between oxidative stress and cellular proliferation. Higher levels of oxidative modifications in DNA and proteins were observed in carcinoma cells, but not in adenoma cells, than in the corresponding nontumorous epithelial cells by immunohistochemistry as well as high-performance liquid chromatography (HPLC)-based 8-OHdG determination. The fraction of proliferating cell nuclear antigen-positive cells was proportionally associated in adenocarcinomas with the staining intensities of 8-OHdG and 3-NT. Furthermore, Western blot analysis of the proteins extracted from carcinoma cells revealed several specific proteins modified by HNE or peroxynitrite. Thus we concluded that colorectal carcinoma, but not adenoma cells, are exposed to more oxidative stress than their corresponding nontumorous epithelial cells, regardless of clinical stage and histology, and further that the oxidative stress in carcinoma cells might stimulate cellular proliferation.
 ...
PMID:Persistent oxidative stress in human colorectal carcinoma, but not in adenoma. 1046 15

To elucidate the contribution of growth factors to the development, growth and behavior of human pituitary adenomas, the authors used competitive reverse transcription-polymerase chain reactions to quantify expression of mRNAs for growth factors extracted from pituitary adenomas. As previously diagnosed by endocrinologic evaluation, the pituitary adenomas in this study consisted of six prolactin-producing, six growth hormone (GH)-producing, four follicle-stimulating hormone producing and six nonfunctioning adenomas. The mRNAs examined included those for platelet-derived growth factor (PDGF) B-chain, transforming growth factor (TGF)-beta1, epidermal growth factor (EGF), basic fibroblast growth factor (bFGF) and insulin-like growth factor (IGF)-I and -II; proliferating cell nuclear antigen (PCNA) as an indicator of cell proliferation; and pituitary-specific transcription factor-1 (Pit-1) which is a nuclear transcription factor expressed in the anterior pituitary. All factors except the last were expressed in all adenomas, and expression of PDGF B-chain, TGF-beta1, EGF, bFGF and IGF-II did not differ between the four adenoma varieties. Pit-1 was expressed only in GH- and prolactin-producing adenomas. PCNA expression also showed no differences. However, IGF-I mRNA in GH-producing adenomas was significantly lower than in prolactin-producing and nonfunctioning adenomas despite high serum IGF-I levels (1121+/-253 ng/ml). The analysis on IGF-I receptor mRNA was significantly lowered in GH-producing adenoma compared with the other types of adenoma. These findings suggest that the attenuation of negative feedback through the pituitary GH-IGF-I axis may be involved in development of GH-producing adenoma.
 ...
PMID:Quantitative analysis of growth-related factors in human pituitary adenomas. Lowered insulin-like growth factor-I and its receptor mRNA in growth hormone-producing adenomas. 1049 42

In previous exposure-response studies, we have documented non-linearities for some of the early effects in rat liver of diethylnitrosamine (DEN) and a near no-effect levels for initiation of promotable liver neoplasms at the lowest cumulative exposure of 0. 5 mmol/kg body weight; this in spite of formation of DNA adducts and induction of hepatocellular altered foci (HAF). To extend these investigations, in an initiation segment, young male F344 rats were administered four exposures of DEN ranging from a cumulative total of 0.25 mmol, which is half of the previously used low exposure, up to 2 mmol per kg body weight, an effective initiating exposure. These exposures were achieved by once weekly intragastric instillations of one-tenth the total exposures for up to 10 weeks. The initiation segment was followed by a 4 week recovery segment, to allow for remission of acute and subchronic effects of DEN, after which the groups were maintained on 0.06% phenobarbital in the diet for 24 weeks to promote liver tumor development in order to assess initiation. During and after initiation and at the end of recovery, selected groups were studied for several crucial effects involved in hepatocarcinogenicity. The low exposure produced a low-level of DNA ethylation at both 5 and 10 weeks of exposure, measured as O(4)-ethylthymidine, the most persistent promutagenic ethylation product. At the 5 week interval, the adduct values of the higher exposures were less than proportional to the increment of exposure, suggestive of nonlinearity. Assessment of cellular proliferation by staining for proliferating cell nuclear antigen revealed that the lowest exposure did not increase the replicating fraction of hepatocytes during the initiation (10 weeks) or recovery (4 weeks) segments, whereas in the three higher exposure groups, proliferation was increased in relation to dose and time. Preneoplastic HAF expressing glutathione S-transferase-placental-type were present at low multiplicity in control livers and their multiplicity was increased in all exposure groups by the end of exposure, at which time the increase in the high exposure group was disproportionately greater than the increment of exposure. After phenobarbital administration in the promotion segment, all exposure groups exhibited further HAF increases at 39 weeks. At the end of the promotion segment, no hepatocellular neoplasm was found in 80 controls or in 40 rats in the low exposure group. In the mid-low exposure group, which was the previously studied low exposure, only one adenoma was found, yielding a 3% incidence, while in the two higher exposure groups, 32 and 80% of rats exhibited liver neoplasms, which were increased disproportionately greater than the increments of exposure. Thus, the findings document non-linearities of early DEN effects and at the lowest cumulative dose, a no-effect level (NEL) or threshold for initiation of promotable liver neoplasms. These findings provide a conceptual basis for understanding why low-level exposures to DNA-reactive carcinogens may convey no cancer risk.
 ...
PMID:Diethylnitrosamine exposure-responses for DNA ethylation, hepatocellular proliferation, and initiation of carcinogenesis in rat liver display non-linearities and thresholds. 1055 Apr 82


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>