Primary Adenoma Research Articles

Correlation between PCNA expression and AgNOR dots in pituitary adenomas.

Nucleolar organizer regions are segments of DNA associated with argyrophilic proteins (AgNORs). Our previous findings showed that the number, the area, and the intranuclear localization of AgNOR dots differ according to tumor aggressiveness and to the hormone-immunopositivity of pituitary adenomas. Proliferating cell nuclear antigen (PCNA) is a nuclear protein, whose expression is correlated with cell proliferation. The aim of the present paper was to examine PCNA-labeling indexes in pituitary adenomas and to correlate them with AgNOR dots in various immunohistochemical types of the tumors. Histological slides from 32 pituitary tumors and one normal pituitary were silver-stained and analyzed with a computerized system for microscopic image analysis. We found that the percentage of PCNA-positive cells did not differ significantly among examined groups of monohormonal adenomas. However, tumors immunopositive for alpha-subunit (alpha-SU) showed a significantly higher (p < 0.05) PCNA index than adenomas immunonegative for that unit. PCNA index in recurrent tumors was significantly higher than in primary adenomas. There was a moderate positive correlation between the PCNA index and the mean area of AgNOR dots and a similar correlation between the PCNA index and the area of the biggest dot in the nucleus. The obtained results reveal that the PCNA indexes and estimated parameters of AgNOR dots differ according to tumor aggressiveness.

Silver-Staining Nucleolar Organizer Region Quantification in Pituitary Adenomas.

Nucleolar organizer regions (NORs) are segments of DNA, encoding for ribosomal RNA. They are associated with argyrophilic proteins and, thus, they can be localized through silver staining. A correlation has been shown between the number, the size, or the intranuclear localization of AgNORs, and the proliferative activity of cells. The aim of this study was to examine numerous features of AgNORs in pituitary adenomas and to relate them to immunohistochemical typing of tumor. Histologic slides from 32 pituitary tumors and one normal pituitary were silver-stained and analyzed with a computerized system for microscopic image analysis, supported by an AgNORmeter95 program. All the tumors were also immunocytochemically characterized. We have found that gonadotropinomas, when compared with pleurihormonal adenomas, revealed a lower proportion of nuclei with a single AgNOR and a higher percentage of marginal dots. Recurrent adenomas, when compared with primary adenomas, showed a higher proportion of nuclei with three AgNOR dots, a larger total area of dots in the nuclei, and a higher standard deviation of the AgNOR dot area in the nucleus. Adenomas immunopositive for prolactin, when compared with immunonegative ones, showed a larger mean area of the AgNOR dot, a larger area of the biggest dot in the nucleus, and a higher proportion of nuclei within a single dot. These results suggest that the estimated parameters of AgNOR dots differ according to tumor aggressiveness and to the hormone immunopositivity of pituitary adenomas.

Viability of Deformed Cells

Most of the researchers in the field of cryobiology believe that the mechanism of damage during freezing with low cooling rates is chemical and related to the hypertonicity of the extracellular solution. However, there is some evidence to indicate that cells may be destroyed during freezing also by compression between ice crystals. We have developed an experimental procedure to study the effect of cell compression on viability. Using human prostate primary adenoma cancer cells we show that cell viability decreases steeply when cells are compressed to 30% of their original diameter. If uniform expansion of cell membrane is assumed, this corresponds to a 50% increase in the cell membrane surface area. A simple mathematical model shows that the temperature at which the compression effect may cause cell damage is related to the spacing between ice crystals. When the ice crystals are spaced at distances comparable to the cell diameter the model combined with our experimental data predicts compression damage at about −1.8°C. This is consistent with experimental observation on frozen cell destruction in the presence of antifreeze proteins.

Expression of PRAD1/cyclin D1, retinoblastoma gene products, and Ki67 in parathyroid hyperplasia caused by chronic renal failure versus primary adenoma

In primary hyperparathyroidism, certain genetic abnormalities responsible for parathyroid tumorigenesis are proposed, and it has been reported that the overexpression of PRAD1/cyclin D1 induced by a DNA rearrangement of the parathyroid hormone (PTH) gene is one of the genetic disorders in a number of primary parathyroid adenomas. However, in secondary hyperparathyroidism caused by uremia, the mechanism of monoclonal proliferation in nodular parathyroid hyperplasia is not well understood. To elucidate the mechanism, we examined the expression of PRAD1/cyclin D1, retinoblastoma gene products, and Ki67 in primary adenoma and secondary hyperplasia. In adenomas (N = 15) and associated glands (N = 7) with normal histology obtained from patients with primary hyperparathyroidism and in diffuse (N = 14), multinodular (N = 58), and single nodular (N = 28) glands from patients who underwent parathyroidectomy for renal hyperparathyroidism, the expression of these cell cycle regulators was evaluated by immunohistochemical technique. A labeling index was used to define the proportion of cells with positive nuclear staining by each antibody. In 6 out of 15 (40%) primary adenomas, PRAD1/cyclin D1 was overexpressed (a labeling index of more than 500), possibly because of the PTH gene rearrangement, but not in secondary hyperplasia, including single nodular glands. Compared with diffuse hyperplasia, nodular hyperplasia showed a significantly higher expression of PRAD1/cyclin D1 (P < 0.05), retinoblastoma gene products (P < 0.05), and Ki67 (P < 0.05). However, no statistically significant correlation between the expression of PRAD1/cyclin D1 and that of Ki67 was observed in both primary adenoma and secondary hyperplasia. These results suggest that in secondary hyperplasia caused by uremia, at least remarkable overexpression of PRAD1/cyclin D1 induced by PTH gene rearrangement may be not the major genetic abnormality responsible for tumorigenesis. Heterogenous genetic changes seem to contribute to monoclonal proliferation of parathyroid cells induced by the expression of PRAD1/cyclin D1 or by some other mechanism independent of the amplification of the proto-oncogene.

Evaluation of retinoblastoma and Ki-67 immunostaining as diagnostic markers of benign and malignant parathyroid disease.

Assessment of the malignant potential of parathyroid tumors in the absence of metastases can be difficult using morphologic criteria alone. In this study we have examined a total of 58 parathyroid tumors (31 benign, 15 malignant, and 12 equivocal) from 54 patients using immunohistochemistry with monoclonal antibodies directed against the retinoblastoma (RB) protein and the cell cycle-associated antigen Ki-67 to evaluate their role as diagnostic markers. RB protein immunoreactivity was not useful for distinguishing between benign and malignant parathyroid tumors. Analysis of the proliferation marker Ki-67 showed that there was a trend toward more intense staining in the malignant cases. The Ki-67 labeling index was highest in the parathyroid cancers (median 33) and lowest in the sporadic primary adenomas (median 2). An observation that might have clinical implications is that tumors from patients with familial hyperparathyroidism linked to chromosome 1q showed a high Ki-67 index, indicating strong proliferative activity (median 25). This correlates well with the clinical observation of tumors with malignant potential in this syndrome. Because of the considerable overlap between groups of tumors, Ki-67 is not suitable for definitive differentiation between benign and malignant tumors. However, Ki-67 may give valuable information about which patients should be followed more closely.;1999>

Expression of the alpha- and beta-subunits of human chorionic gonadotropin by subsets of parathyroid cells in states of hyperparathyroidism.

The alpha-subunit of human chorionic gonadotropin (hCG-alpha) has previously been found to be expressed in hyperplasias and tumours of numerous endocrine tissues including all those involved in MEN-I syndrome except the parathyroid glands. In the present immunohistochemical investigation of 86 patients with various states of hyperparathyroidism, expression of hCG-alpha by subsets of parathyroid cells was shown in 46 cases (54 per cent) including all states of hyperparathyroidism investigated: primary adenoma (n = 34, 44 per cent); uraemic secondary hyperplasia (n = 34, 53 per cent); MEN-I (n = 13, 77 per cent); MEN-II (n = 2, 100 per cent); and parathyroid carcinoma (n = 3, 100 per cent). Although the number of parathyroid cells expressing hCG-alpha was in general low, the occurrence of numerous immunoreactive cells appeared to be concentrated in primary adenoma and MEN-I (20 and 33 per cent of positive cases, respectively). No expression was found in ten normal control glands, except for very rare cells in one case. Expression of hCG-alpha was in part associated with that of hCG-beta, which appeared to be more commonly expressed than hCG-alpha in cases of secondary hyperparathyroidism. In separate experiments, Bouin fixation was found to preserve the immunoreactivity of hCG-alpha and hCG-beta better than the formalin fixation used in this study, suggesting that the figures may be underestimates. These immunohistochemical results are in agreement with a previous biochemical study showing hCG-alpha and hCG-beta in extracts of parathyroid tumours and extend to the parathyroid glands the otherwise ubiquitous finding of hCG-alpha expression in MEN-I-related neoplasms.

Identification of NFIB as recurrent translocation partner gene of HMGIC in pleomorphic adenomas.

Approximately 12% of all pleomorphic adenomas of the salivary glands are characterized by chromosome aberrations involving the chromosome segment 12q13-15. Several chromosomes have been found as translocation partners of chromosome 12, and some of these recurrently. Recently, the HMGIC gene was identified as the target gene affected by the 12q13-15 aberrations. Here, we report the identification and characterization of a new translocation partner gene of HMGIC in pleomorphic adenomas. 3'-RACE analysis of a primary adenoma with an apparently normal karyotype revealed an HMGIC fusion transcript containing ectopic sequences derived from the human NFIB gene, previously mapped to chromosome band 9p24.1. The HMGIC NFIB fusion transcript was also confirmed by RT-PCR. Since the chromosome segment 9p12-24 is repeatedly involved as translocation partner of chromosome 12q13-15 in pleomorphic adenomas, we tested whether NFIB might be a recurrent partner of HMGIC. RT-PCR analysis of a second adenoma with an ins(9;12)(p23;q12q15) as the sole anomaly, revealed that also in this tumor an HMGIC/NFIB hybrid transcript was present. The reciprocal NFIB/HMGIC fusion transcript, however, could not be detected in any of these tumors. Nucleotide sequence analysis of the fusion transcripts indicated that the genetic aberration in both tumors resulted in the replacement of a carboxy-terminal segment of HMGIC by the last five amino acids of NFIB. In conclusion, our results reveal the recurrent involvement of the NFIB gene as translocation partner gene of HMGIC in pleomorphic adenomas.

Immunocytochemical detection of a reduction in 1,25 dihyroxyvitamin D3 receptor expression in uraemic parathyroid tissue.

The vitamin D receptor is expressed in nuclei of parathyroid cells and plays an important role in the regulation of cell growth and parathyroid hormone secretion. A number of studies have shown reduced receptor expression in uraemic parathyroid glands but the relationship between receptor expression and renal function has not been identified. This study used archive parathyroid tissue from patients with primary adenomas, dialysis patients with diffuse hyperplasia secondary to uraemia and normal parathyroid tissue. An immunocytochemical assay with a vitamin D receptor antibody was used to identify parathyroid cells expressing receptor in their nuclei. In patients with a serum creatinine < or = 110 mumol/l, 81.94% +/- 6.5 of parathyroid cells expressed vitamin D receptor. This fell to a mean of 49.3% in two patients with a serum creatinine between 110 and 300 mumol/l and to 40.17% +/- 8.6 in dialysis patients. Vitamin D receptor expression in parathyroid glands is reduced in renal failure.

Somatic mutations of the ret protooncogene in sporadic medullary thyroid carcinoma are not restricted to exon 16 and are associated with tumor recurrence.

Germline point mutations in exons 10, 11, and 16 of the ret protooncogene have been identified as causative in multiple endocrine neoplasia type 2 and in familial medullary thyroid carcinoma (MTC). Somatic point mutations of the same gene, exclusively associated with codon 918 of exon 16, have also been reported in few cases of sporadic medullary thyroid carcinoma. We analyzed the blood and tumor DNA of 19 patients with sporadic MTC and 6 patients with primary parathyroid adenoma for point mutations at exons 10, 11, and 16 of the ret protooncogene by restriction analysis of the PCR-amplified product and by sequence analysis of exons 10 and 11. A Cys634-->Tyr mutation was found in both the tumoral and blood DNA of one patient, indicating that he was affected by an hereditary form of MTC, erroneously considered sporadic. In the other 18 patients with MTC, somatic point mutations of ret were found in 8 cases (44.4%). In 5 cases the mutation affected exon 16 (Met918-->Thr), and in 3 cases it affected exon 11 (Cys634-->Arg in 1 and Cys634-->Trp in 2); these 3 mutations were confirmed by sequence analysis. The remaining 10 patients had no mutation in exon 10 by either restriction analysis or sequence analysis. Clinical data showed that 75% of the patients whose tumor carried ret mutation had tumor recurrence and/or increased serum calcitonin concentrations during the postsurgical follow-up period as opposed to 10% of the patients without mutations (P < 0.02, by chi2 analysis). No ret mutation was found in the tumoral DNA from parathyroid adenomas. Our findings indicate that the somatic ret point mutation frequently found in sporadic MTC may affect not only exon 16 but also exon 11 and is associated with less favorable clinical outcome.

Ultrastructure of renal-cell tumors induced in mice by 1,2-dimethylhydrazine

Fifteen primary renal adenomas induced with 1,2-dimethylhydrazine in CBA mice and 3 passages of adenomas transplanted subcutaneously were examined by electron microscopy. A well-developed brush border was found in one primary adenoma, this being in line with histochemical data on the presence of markers of the proximal canaliculi epithelium in this tumor. In other tumors a reduced brush border (5 cases) and apical canaliculi (14 cases) were revealed, which are typical of the proximal canaliculi epithelium. The ultrastructure of the types of adenoma cells is described. Atypical tumor cells with intracellular lumina were found in transplanted adenomas

The pathogenesis of parathyroid gland hyperplasia in chronic renal failure

A 58-year-old female dialysis patient was admitted to the Nephrology Department at the Hopital Necker because of severe secondary hyperparathyroidism. She had had chronic interstitial nephritis with slowly progressive chronic renal failure for more than 10 years. Intermittent home hemodialysis treatment was started 18 years ago. Symptoms and signs of hyperparathyroidism were present before the patient developed end-stage renal failure, and the severity of osteitis fibrosa progressed despite the initiation of renal replacement therapy. Thirteen years ago, the patient first underwent a surgical neck exploration. One large parathyroid gland weighing 4500 mg was removed. One other gland was identified, which was biopsied and had a normal aspect; it was left in place. The remaining glands could not be identified. Operative and light microscopic findings were compatible with the diagnosis of primary adenoma. The plasma calcium concentration decreased markedly immediately after parathyroidectomy, and radiologic signs of osteitis fibrosa regressed. Severe aluminum intoxication, mainly due to aluminum-contaminated dialysis fluid, was diagnosed 9 years ago. An appropriate dialysis water purification system with reverse osmosis was put in place, and the patient received deferoxamine treatment for several months 8 years ago. Soon thereafter, recurrence of hyperparathyroidism became evident. Several attempts at treating the osteitis fibrosa medically were undertaken, first using calcium carbonate and thereafter small doses of oral 1-alpha cholecalciferol. Several transient hypercalcemic and hyperphosphatemic episodes finally led to cessation of the administration of vitamin D derivatives. Three years ago, the plasma calcium level ranged between 2.5 and 2.7

Immunoreactive Characteristics and Classification of Hyperparathyroidism.

Hyperparathyroidism is caused mainly by three different conditions: namely, secondary hyperplasia, primary hyperplasia, and adenoma with only a few cases due to carcinomas. Histological distinction among these diseases is still difficult. In an attempt to characterize the three conditions, 17 cases from patients with hyperparathyroidism and 12 with normal glands were investigated immunohistochemically using antibodies against PTH, PTHrP, Ki-67 (MIB-1), and chromogranin A. The normal glands showed a diffuse staining pattern for PTH, and focal staining for PTHrP and for chromogranin A. Secondary hyperplasia demonstrated either focal, diffuse, or mixed staining in one gland with the three antibodies. For the primary hyperplasias and adenomas, the cases could be divided into two groups. The first group (group I), including 1 case of primary hyperplasia and 3 cases of adenoma, showed a homogeneous staining pattern with all three antibodies. A heterogeneous staining pattern similar to secondary hyperplasia was found in the other 8 cases that formed the second group (group II). There were five types of cytologic staining patterns after immunostaining. In secondary hyperplasia and group II, several patterns appeared simultaneously. On the contrary, only one pattern was found in group I. The proliferative index (P1) from Ki-67 staining of group I was also significantly higher than in group II. A lower P1 was observed in the normal glands. The present results indicate that different immunohistochemical characteristics exist in primary hyperplasias and in adenomas.

Molecular Genetics of Turcot’s Syndrome

Genetic abnormalities in 13 of 14 families with concurrent primary brain tumors and multiple colorectal adenomas (Turcot’s syndrome) are reported from the Johns Hopkins University School of Medicine and other centers.

Magnetic resonance imaging of hepatic neoplasms

Excellent diagnostic images of the liver can now be obtained with magnetic resonance imaging (MRI) because of new imaging techniques. The flow void phenomenon allows excellent anatomic detail of the liver. Morphologic features, comparison of tumor signal to normal parenchymal signal, and tumor behavior in various pulse sequences help to define liver tumors. The MRI characteristics of primary hepatomas, cavernous hemangiomas, hepatic cysts, liver adenomas, and focal nodular hyperplasia are among the hepatic lesions described. In most instances, MRI helps in differential considerations and in some cases will provide a specific diagnosis.

Coexisting primary hyperparathyroidism and thyroid toxic adenoma

Coexisting primary hyperparathyroidism and thyroid toxic adenoma

DNA analysis and parathyroid pathology

The nuclear DNA content of 85 parathyroid glands (4 carcinomas, 39 adenomas, 21 secondary parathyroid hyperplasias, and 21 normal parathyroid glands) were determined by flow cytometric analysis. All normal parathyroid glands, 85% of the adenomas, and 83.3% of the secondary hyperplastic glands had DNA indices within values of 0.85-1.1. Paraffin-embedded fixed glands showed less DNA staining than that found with fresh or normal glands. Glands from patients with carcinoma showed DNA indices outside the normal DNA index range. When the percent of nuclei within the G0/G1 phase of the cell cycle was compared between the study groups, highly significant results were found. While patients with secondary hyperplasia showed a similar distribution to the normal glands studied, only 48% of primary adenomas showed over 80% of cells within the G0/G1 region. A clear subgroup of adenomas was defined with more rapidly cycling tetraploid cells, and showing classical adenoma pathology. This group showed negative correlation with gland weight, plasma calcium, and ionized calcium. These findings suggested that a different etiology of the disease process occurs between secondary hyperplasia and parathyroid adenoma. Such abnormal adenomas may form a group worthy of long-term follow-up.

Primary duodenal carcinoma arising in a non-vaterian tubulo-villous adenoma

Primary duodenal carcinoma and duodenal adenoma are rare tumours. Duodenal carcinoma makes up about 0.3% of all malignant tumours of the gastrointestinal tract (Alwmark et al. 1980; Spira et al. 1977). The present paper describes a duodenal carcinoma arising in a mixed tubulo-villous non-Vaterian adenoma in a 68 year old male. Immunocytochemical analysis revealed evidence of neuroendocrine differentiation in both adenoma and carcinoma. In a review of the literature a correlation between the size of adenoma and the probability of concomitant carcinoma is demonstrated. Duodenal adenoma measuring more than 4 cm in diameter should be considered potentially malignant.

The electrophysiological effects of thyrotropin-releasing hormone are similar in human TSH- and prolactin-secreting pituitary cells.

We studied the electrophysiological properties of individually characterized TSH-secreting cells cultured from pituitary fragments surgically removed from three patients, two who had primary TSH-secreting adenomas and one who had chronic TSH hypersecretion (hyperplasia) secondary to primary hypothyroidism. The TSH-secreting cells were excitable and had calcium-dependent action potentials. More than 80% of the cells cultured from the two patients with TSH-secreting adenomas were spontaneously active, whereas fewer cells (20%) cultured from the hypothyroid patient were spontaneously active. TRH (50 nmol/L) induced a complex pattern of electrical changes. The initial response was transient hyperpolarization (activation of potassium conductance), followed by increased low amplitude voltage fluctuations occasionally leading to action potentials. These TRH-induced electrophysiological changes were similar to those reported in rat and human PRL-secreting adenoma cells. These results suggest that TRH may have an identical mode of action in tumoral PRL and TSH cells. In the cells from the hypothyroid patient, the initial response to TRH cells was similar, but the second phase response was greater. The findings that the cells cultured from these patients behaved differently with regard to their electrophysiological characteristics (action potentials) and responses to TRH may reflect the different clinical conditions from which they were derived.

Invasiveness, metastasis, and transplantability of mouse liver nodules.

Data are presented which show that various mouse liver nodular lesions, such as hyperplastic nodules, hepatocellular adenomas, and hepatocellular carcinomas, differ not only morphologically but also biologically regarding their behavior in the primary and secondary hosts. The hyperplastic nodules grew slowly by expansion without affecting the integrity of the lobular structure. The primary hepatocellular adenomas also grew slowly by expansion but eliminated the histoid liver structure. Neither lesions metastasized to the regional lymph nodes and distant organs. Upon isogeneic transplantation, the adenomas required a long latent period before manifesting an expansive type of growth without invasion and metastasis. The primary hepatocellular carcinomas grew fast, destroyed surrounding parenchyma, and those showing moderately to poorly differentiated cellular morphology metastasized to regional lymph nodes and distant organs. Upon transplantation hepatocellular carcinomas grew fast, invaded locally, metastasized distantly, and killed the recipients within a few weeks. Thus hepatocellular adenomas and carcinomas represent two distinct entities both morphologically and biologically. Thus the agents should be classified according to the type of nodular liver lesions they "induce" in the mouse liver. The least innocuous agents would be those resulting in the development of hyperplastic nodules. They should not be labelled as hepatocarcinogens. On the other side of the spectrum should be the agents "inducing" the hepatocellular carcinomas and they should be classified as mouse liver carcinogens. The agents capable of affecting significantly the hepatocellular adenomas but not the hepatocellular carcinomas should be considered as tumorigens, since they are causally related only with the benign liver lesions. Combining both benign and malignant liver tumors for statistical purposes is not justified unless each type of tumor has been affected in a statistically significant incidence. If this were not the case, classification of the agent should be in accordance with the type of lesions induced significantly. In order to use the induction of hepatocellular carcinomas in rodents as an indication of carcinogenic risk in humans appropriately, one has to verify within the limits of feasibility that the identical carcinogenic effects and the subsequent events occur both in rodents and humans.(ABSTRACT TRUNCATED AT 400 WORDS)

Carcinogenicity of sodium dichromate and chromium (VI/III)oxide aerosols inhaled by male wistar rats

In inhalation chambers, male Wistar rats of the strain TNO-W74 were continously exposed to submicron aerosols of sodium dichromate and to a pyrolyzed Cr(VI)/Cr(III) (3:2) oxide mixture. The sodium dichromate (Na 2Cr 2O 7) aerosol had the chromium concentrations of 25, 50 and 100 μg/m 3, the chromium oxide mixture (Cr 5O 12) had the chromium concentration of 100 μg/m 3. After 18 months of inhalation the rats were held under conventional conditions for a further year. The experimental groups consisted of 20 rats and the control group of 40 rats. More than 90% of the rats in each group reached 2 years. At the end of the study the mortality rates amounted to 35%, 45% and 25% in the 3 sodium dichromate aerosol groups, respectively, and 50% in the chromium oxide mixture aerosol group, which was not significantly different from that of the controls (42.5%), living under the same conditions in filtered fresh air. In all sodium dichromate exposed groups significant effects were neither found clinically nor from hematology and clinical chemistry compared to the controls. In the chromium oxide mixture group, however, there was a number of significant findings. Elevated white and red blood cell counts and serum cholesterol as well as decreased serum total immunoglobulin levels at different stages of the study were observed together with few local lung effects determined histophathologically in this group. We assume that these effects are mainly due to the increased chromium lung burden of the rats. At the end of the study the lung chromium retention was about 10 times higher for the rats exposed to chromium oxide versus sodium dichromate at an aerosol Cr-concentration of 100 μg/m 3, while the kidney chromium retention was measured to be nearly equal in both groups. Three primary lung tumors (2 adenomas and 1 adenocarcinoma) and 1 malign tumor of the pharynx were found at the highest Cr-concentration (100 μg/m 3) of the sodium dichromate aerosol, 1 primary adenoma of the lung was in the chromium oxide mixture group exposed also to a Cr-concentration of 100 μg/m 3. No primary lung tumors were observed in the other experimental and control groups. These results indicate a weak carcinogenicity at 100 μg/m 3 for the rats continuously exposed to submicron Na 2Cr 2O 7 and Cr 5O 12 aerosols. Thus, there may be a small carcinogenic risk from occupational relevant chromium air levels. However, results have to be confirmed with larger animal populations.