Differential loss of heterozygosity at 7q31.2 in follicular and papillary thyroid tumors.

We analysed 42 differentiated thyroid tumors including 15 follicular adenomas (FA), 13 papillary thyroid cancers (PTC) and 14 follicular thyroid carcinomas (FTC) with 13 microsatellite markers specific for the long arm of human chromosome 7 within 7q31; this region is deleted frequently in several other tumor types. Overall, 20 of the 42 samples analysed (48%) displayed LOH with one or more of the markers tested. LOH was detected most frequently (78%) in FTC, the most malignant of the thyroid tumors. A smallest common deleted region (SCDR) was defined in this tumor type flanked by markers D7S480 and D7S490. This SCDR is distinct from D7S522, the most commonly deleted locus in many other tumors, which was deleted in only one FTC. D7S522 did show LOH in two of six informative PTCs. None of the PTC and only two of the FAs showed LOH in the FTC SCDR. Since FA is considered a premalignant stage of FTC, our results suggest that inactivation of a putative tumor suppressor at 7q31.2 may be acquired during adenoma to carcinoma progression. The absence of LOH at this locus amongst PTC suggests that inactivation of this tumor suppressor is specific for FTC. In conclusion, LOH at 7q31 is a frequent event in differentiated thyroid cancer, and we have defined a 2 cM SCDR specific for FTC.

Fine-needle aspiration. Usefulness for diagnosis and management of metastatic carcinoma to the thyroid.

The usefulness of fine-needle aspiration (FNA) for the diagnosis and management of metastatic carcinoma to the thyroid was determined by reviewing the records of 19 patients identified during a six-year period. Fine-needle aspiration was able to document metastatic cancer to the thyroid in 14 patients with, and five patients without a history of prior nonthyroidal cancer. Breast, kidney, and lung were the most frequent carcinomas metastatic to the thyroid. Age range and time from diagnosis of the primary carcinoma to documentation of metastasis were similar to those in prior surgical series from this institution. The finding of metastatic disease on FNA was totally unexpected in four patients. The possibility of metastasis was not mentioned before FNA in six patients with a known history of nonthyroidal cancer. Only six patients underwent a thyroid operation after FNA. Fine-needle aspiration was able to direct appropriate surgical or conservative management without adversely affecting survival among patients.

Management of thyroid nodules in pregnancy.

BACKGROUND: Disorders of the thyroid are common in pregnancy. In particular, a thyroid nodule is frequently discovered before or during pregnancy. OBJECTIVE: To develop guidelines for the management of thyroid nodules during pregnancy. METHODS: We reviewed the cases of 40 pregnant patients with thyroid nodules evaluated during a 10-year period Cytological findings were compared with available histological findings, and concordance rates were determined. The rank sum test was used for statistical analysis. RESULTS: Fine-needle aspirations of thyroid nodules in 62% of patients were benign cytologically (25 patients). Of 8 patients with negative cytological results who had thyroidectomy, all had benign disease histologically (100% concordance rate). Cytological findings of papillary cancer (3 patients) strongly correlated with final histological diagnosis (100% concordance rate), whereas papillary cancer was confirmed histologically in only 2 of 4 patients with cytological findings suspicious for this disease (50% concordance rate). All 3 nodules with cytological findings suspicious for follicular neoplasm were benign adenomas histologically. Of 2 nodules suspicious for Hürthle cell neoplasm, l was Hürthle cell adenoma and the other was Hürthle cell carcinoma (100% concordance rate). Thyroidectomy during the second trimester of pregnancy or the early postpartum period was successful. CONCLUSIONS: The approach to thyroid nodules in pregnancy should be similar to that for nonpregnant patients. Thyroidectomy should be performed (1) during the second trimester for malignant lesions and cytological findings suspicious for papillary cancer and (2) in the postpartum period for cytological findings suspicious for follicular neoplasm.

In vitro and in vivo detection of somatostatin receptors in pheochromocytomas and paragangliomas.

Fifty-one adrenal pheochromocytomas and 14 paragangliomas were evaluated for somatostatin (SRIH) receptor content with in vitro autoradiography on tissue sections from surgically removed tumors, using iodinated 125I[Tyr]3 octreotide as radioligand. Thirty-seven of 51 pheochromocytomas were SRIH receptor positive (73%), as well as 13 of 14 paragangliomas (93%). These SRIH receptors were of high affinity, pharmacologically specific for SRIH and localized on the tumor tissue. Using in vivo imaging techniques with radiolabeled SRIH analogs, paragangliomas could be visualized in five patients, as well as pheochromocytomas in two of three patients. All tumors tested subsequently in vitro (n = 7) were shown to contain SRIH receptors. A majority of pheochromocytomas were also shown to have a high tumoral SRIH content as measured by immunohistochemical techniques. Detection of SRIH messenger RNA in pheochromocytomas by in situ hybridization indicated that the SRIH was produced in the tumors. A weak inverse correlation was observed between SRIH receptor status and tumoral SRIH content, suggesting that SRIH receptors may be down-regulated by high levels of endogenous SRIH in some tumors. There was no correlation between the SRIH receptor status and sex, age, tumor size, benign vs. malignant tumor, or urinary metanephrine excretion. These tumors were also analyzed for allelic losses on various chromosomes and showed significant loss of heterozygosity (LOH) on chromosomes 1p, 3p, 17p, and 22q. All eight tumors with LOH on chromosome 1p were SRIH receptor positive (100%), whereas only 6 of 11 tumors without LOH on 1p (55%) were SRIH receptor positive, suggesting a correlation between LOH on 1p and SRIH receptor positive status. SRIH receptors thus represent a consistent pathobiochemical marker for most of these adrenal and extra-adrenal tumors. In addition, these receptors may be of potential interest for the in vivo localization of these tumors.

Immunohistochemical analysis of sodium iodide symporter expression in metastatic differentiated thyroid cancer: correlation with radioiodine uptake.

The ability of thyroid cancers to concentrate radioiodine (RAI) is dependent, in part, upon the expression and functional integrity of the sodium iodide symporter (NIS). However, some differentiated thyroid carcinomas (DTCs) and most undifferentiated thyroid carcinomas lack the ability to concentrate iodide and are thereby insensitive to 131I therapy. Variation of NIS protein expression may be an important factor in this behavior. We wished to determine whether NIS protein expression in primary DTC tumors correlated with the subsequent RAI uptake by metastatic lesions in the same patients. We obtained paraffin-embedded tissue specimens from 60 patients with metastatic thyroid cancer who had undergone total or near-total thyroidectomy at the Mayo Clinic for DTC and had known presence or absence of RAI uptake in their tumor deposits determined by total body scanning after thyroid hormone withdrawal. Tissue sections from the primary intrathyroidal tumors were subjected to immunostaining (IS) using a monoclonal antibody against human NIS. Slides were subsequently examined for specific IS by two independent reviewers. For each patient, whole body scan (WBS) uptake was recorded, and correlation between results of IS and WBS was analyzed. Of 43 patients with a positive WBS, 37 also had positive IS of their tumors. In six patients with negative IS, a positive WBS was documented, and in three of these cases TSH at the time of surgery was less than 0.3 mIU/liter. Of the 17 patients with negative WBS, 10 were also negative on IS. Positive IS accurately predicted a positive scan in our study in 84% of cases; the ability of the IS to detect all cases with a positive scan was 86%, and it increased to 90% when patients who were receiving thyroid hormone therapy at the time of surgery were excluded from the analysis. Overall, the results of our retrospective study suggest that NIS IS of the thyroidal primary tumor in patients with papillary and follicular thyroid cancers has substantial ability to predict the behavior of subsequent deposits of metastatic and recurrent cancer with respect to iodine trapping and concentration. Our findings require confirmation in prospective studies to more accurately determine the predictive ability of the test and its role in the postoperative management of patients with DTC. If confirmed, NIS IS of DTC primary lesions may prove useful in the management of patients with known or suspected metastatic thyroid cancer.

Immunohistochemical detection and localization of a 72-kilodalton heat shock protein in autoimmune thyroid disease.

Recently described immunological functions for heat shock proteins (HSPs) and our previous demonstration of site-selective HSP-72 expression in cultured fibroblasts derived from extrathyroidal manifestations of Graves' disease (GD) prompted us to determine whether expression of the inducible 72-kilodalton HSP can be detected in human thyroid tissues. Immunohistochemistry was performed on formalin-fixed paraffin-embedded thyroid tissue specimens from patients with GD, Hashimoto's thyroiditis (HD), and multinodular goiter (MNG) as well as on normal thyroid tissue. A mouse monoclonal anti-HSP-72 antibody and an ultrasensitive avidin-biotin-peroxidase complex detection system were used for these studies. Striking differences in HSP-72 immunoreactivity were detected both between tissues from GD and HD compared with MNG and normal thyroid and between GD thyroid glands treated preoperatively with antithyroid medication and untreated GD glands. Strong HSP-72 reactivity in GD and HD tissues was detected in thyroid follicles as well lymphocytic infiltrates. No HSP-72 reactivity was detected in MNG or normal thyroid tissue. HSP-72 immunoreactivity was markedly reduced in GD glands that received preoperative antithyroid drug treatment. In conclusion, high levels of HSP-72 expression in autoimmune thyroid disease may reflect a state of chronic cellular stress, but could also represent an immunomodulatory factor of relevance in the autoimmune process in GD.

Tissue eosinophilia and eosinophil degranulation in Riedel's invasive fibrous thyroiditis.

The etiology of Riedel's invasive fibrous thyroiditis (IFT) has remained obscure. This rare disorder has been confused in the past with the more common fibrous variant of Hashimoto's disease. The typical histological features of IFT, in particular the presence of an invasive fibrosclerotic process in conjunction with a prominent chronic inflammatory infiltrate, suggest that the release of fibrogenic cytokines and other factors from these cellular infiltrates may play an important role in the pathogenesis of this condition. Our observations in routinely processed tissue sections obtained from patients with documented IFT of striking tissue eosinophilia led us to hypothesize that eosinophils and their products may play a role in the evolution of this disease. Immunofluorescence staining with affinity-purified polyclonal rabbit antibody directed against human eosinophil granule major basic protein revealed marked tissue eosinophilia and abundant extracellular deposition of major basic protein in all specimens from 16 patients with IFT. By contrast, only occasional eosinophils and no extracellular major basic protein were detected in control thyroid tissues obtained from patients with multinodular goiter, Graves' disease, Hashimoto's disease, and normal thyroid tissue. The presence of marked eosinophil infiltration and extracellular major basic protein deposition in IFT and other associated fibrosclerotic conditions suggests a role for eosinophils and their products in propagating the fibrogenesis seen in IFT.

Analysis of human sodium iodide symporter immunoreactivity in human exocrine glands.

The human sodium iodide symporter (hNIS) is an intrinsic transmembrane protein that mediates the active transport of iodide across the basolateral membrane of thyroid follicular cells. In addition to normally functioning thyroid tissue, various extrathyroidal tissues, including salivary gland, lacrimal gland, gastric mucosa, choroid plexus, and lactating mammary gland, have been demonstrated to accumulate iodide. After cloning and molecular characterization of the sodium iodide symporter, expression of hNIS messenger ribonucleic acid has been detected in a broad range of extrathyroidal tissues using Northern blot analysis and RT-PCR. In this study we used both monoclonal and polyclonal antibodies directed against different portions of hNIS protein together with a highly sensitive immunostaining technique to assess hNIS protein expression in tissue sections derived from normal human salivary and lacrimal glands, pancreas, as well as gastric and colonic mucosa. Immunohistochemical analysis of normal human salivary and lacrimal glands revealed marked hNIS immunoreactivity in ductal cells and less intense staining of acinar cells. Further, immunostaining of gastric and colonic mucosa showed marked hNIS immunoreactivity confined to chief and parietal cells in gastric mucosa and to epithelial cells lining mucosal crypts in colonic mucosa. In normal human pancreas, hNIS immunoreactivity was located in ductal cells, exocrine parenchymal cells, and Langerhans islet cells. In conclusion, our study demonstrates the expression of hNIS protein by several human exocrine glands, suggesting that iodide transport in these glands is a specific property conferred by the expression of hNIS protein, which may serve important functions by concentrating iodine in glandular secretions.

Distant metastases in papillary thyroid carcinoma: 100 cases observed at one institution during 5 decades.

The present study was designed to define the factors that predict survival in patients with distant metastases (DM) from papillary thyroid carcinoma. We performed a retrospective review of the records of 100 consecutive patients (45 females and 55 males; age range, 8-91 yr) who developed DM after primary treatment at our institution from, 1940-1989. Median follow-up for the 20 survivors was 21 yr (range, 3-38). Cause-specific survival rates at 5, 10, and 15 yr were 40%, 27%, and 24%, respectively, and were not significantly different between the eras 1940-1954, 1955-1969, and 1970-1989 (P = 0.74). By univariate analysis, age at diagnosis of DM was the most important predictor of survival (P < 0.0001), with improved survival occurring in younger patients. Tumor-related factors associated with improved survival included complete resection of the primary tumor (P < 0.005), histological grade 1 (P = 0.006), diploid nuclear DNA (P = 0.03), and lung as first site of DM (P = 0.018). By univariate analysis, use of radioiodine therapy was associated with improved survival (vs. other forms of therapy, P < 0.001). However, by multivariate analysis only age, site of DM, and degree of extrathyroidal invasion of the primary tumor were identified as significant predictors of survival. None of the four treatment variables (external radiation, surgery, chemotherapy, or radioiodine) was a significant predictor of survival in the Cox model. Our retrospective data indicate that 1) outcome has changed little over 5 decades for patients with DM from papillary thyroid carcinoma; and 2) current forms of therapy do not appear to impact on survival.

Development of monoclonal antibodies against the human sodium iodide symporter: immunohistochemical characterization of this protein in thyroid cells.

The thyroid sodium-iodide symporter (NIS) is responsible for iodide concentrating ability within thyroid follicular cells. We sought to develop monoclonal antibodies against human NIS (hNIS) for use as reagents in structure-function studies of the protein, as well as potential tools in the assessment of NIS expression in benign and malignant thyroid tissues. Synthetic peptides corresponding to the second ExMD and to the carboxy-terminal ExMD of hNIS were produced and utilized as antigens to develop monoclonal antibodies, which were tested by Western blotting using membranes prepared from COS-7 cells transiently transfected with a pcDNA3 plasmid containing the gene for the full-length hNIS, or a control vector. Western blotting showed a major band with molecular weight (MW) of approximately 97 kDa and several minor bands with MW of approximately 160 kDa, 68 kDa, 30 kDa, and 15 kDa, all specific for hNIS-transfected cells. Immunohistochemistry was performed in various types of thyroid tissues and nonthyroidal tissues, using the monoclonal antibodies. Strong immunostaining was observed in Graves' tissue, intermediate staining in papillary and follicular thyroid cancer, and no staining in Hürthle cell cancer or in nonthyroidal tissue. The staining was specific for the follicular epithelium in each of the tissues and was most intense in the basolateral portion of the cell membrane. Overall, our observations indicate that the monoclonal antibodies are specific for hNIS and will be invaluable reagents for investigating the role of NIS in thyroid disease.

Frequent loss of heterozygosity on chromosomes 3p and 17p without VHL or p53 mutations suggests involvement of unidentified tumor suppressor genes in follicular thyroid carcinoma.

Follicular thyroid carcinoma (FTC) exhibits frequent loss of heterozygosity (LOH) on chromosomes 10q and 3p, suggesting involvement of tumor suppressor genes. We screened 14 FTC (10 Hurthle cell carcinomas and 4 nonoxyphilic FTC), 14 papillary thyroid carcinomas, and 7 follicular adenomas for LOH on chromosome arms 1p, 3p, 3q, 10p, 10q, 11p, 11q, 13q, 17p, and 17q. LOH was more frequent in FTC than in follicular adenoma or papillary thyroid carcinoma. In FTC, rates of LOH on 3p (86%), 17p (72%), and 10q (57%) were higher than the average rate of LOH (33%; P < 0.05). Most frequently involved were 3p21-25 and 17p13.1-13.3, the sites for the VHL (3p25-26) and p53 (17p13.1) tumor suppressors. We, therefore, characterized these genes by dideoxy fingerprinting and DNA sequencing. Two FTC had mutations in p53, but only 1 of these exhibited LOH at 17p. No VHL gene mutations were found. Thus, neither p53 nor VHL genes play a significant role in the pathogenesis of differentiated thyroid cancer. LOH on 17p, but not on 3p or 10q, was correlated with mortality. Accordingly, 3p and 10q LOH may represent early, and 17p LOH late, events in FTC development. The data suggest the presence of novel tumor suppressor genes on chromosomes 3p and 17p that may be important in the pathogenesis of FTC.

Fine-needle aspiration biopsy of thyroid nodules. Impact on thyroid practice and cost of care.

We studied the impact of fine-needle aspiration biopsy on the management of patients with solitary thyroid nodules. Sixty-four patients were examined before the introduction of fine-needle aspiration biopsy, and 147 patients were examined after its introduction. The percentage of patients who underwent thyroid operation decreased from 67 percent to 43 percent, while the yield of carcinoma increased from 14 percent to 29 percent. Cost of medical care per patient declined by 25 percent. The results suggest that fine-needle aspiration biopsy provides valuable information to assist in the selection for surgery of patients with solitary nodules. Fine-needle aspiration appears to be safe, reliable, and cost-effective. The merits of the technique commend it for routine use in the evaluation of thyroid nodules.

Hyalinizing trabecular adenoma of the thyroid gland.

The hyalinizing trabecular adenoma, a distinctive lesion, is important because it may mimic medullary and papillary carcinoma microscopically. We describe 11 such tumors obtained from women ages 27-72 years (mean, 46 years). The initial pathologic diagnoses were carcinoma (five cases), adenoma (two cases), paraganglioma (one case), and "indeterminate" (three cases). None of the tumors recurred or metastasized (mean follow-up, 10 years). Grossly, the neoplasms measured 0.3-4 cm in diameter, and were yellow-tan and circumscribed. Microscopically, they were encapsulated or circumscribed and solid, or vaguely lobulated. The polygonal, oval, and elongated tumor cells were arranged in trabeculae, clusters, or both, and were often inserted vertically into capillaries. The sharply outlined cells had finely granular cytoplasm that was either acidophilic, amphophilic, or clear. Typical features included oval and elongated nuclei, perinucleolar vacuoles, acidophilic nuclear inclusions, fine nuclear grooving, and infrequent mitotic figures. Perivascular hyaline fibrosis and cell degeneration mimicked amyloid, but these tumors were Congo red-negative. Occasional trabeculae featured round or irregularly shaped follicles, sometimes with papillary infoldings, that were either empty or contained colloid-like material and psammoma bodies. Immunostaining of tumor cells was positive for thyroglobulin and negative for calcitonin. Among six tumors analyzed by flow cytometry, five displayed a diploid pattern and one showed an aneuploid peak.

Leiomyoblastomas and their relationship to other smooth-muscle tumors of the gastrointestinal tract. An electron-microscopic study.

Twelve cases of gastrointestinal leiomyoblastoma were studied by electron microscopy, and the findings were compared with those in 12 cases of leiomyoma and nine cases of leiomyosarcoma of the gastrointestinal tract. All of the "classic" ultrastructural features of smooth-muscle tumors, including subplasmalemmal dense patches, pinocytotic vesicles, cytoplasmic microfilaments and dense bodies, and focal basement membrane formation, were present in the leiomyoblastomas ; however, extensive sampling was commonly necessary to demonstrate such findings. In contrast, these features were more prominent in leiomyomas and leiomyosarcomas.

Hyalinizing trabecular adenoma of the thyroid gland: recognition and characterization of its cytoplasmic yellow body.

Many round, pale yellow, cytoplasmic inclusion bodies were found in hematoxylin and eosin-stained sections of a hyalinizing trabecular adenoma of the thyroid. The bodies were refractile and frequently had a microvacuolated or granular substructure. They were usually located close to the nucleus, often indented it, and rarely occurred within it. Histochemically, they showed a glycosaminoglycan, proteoglycan, and lipid content, displayed autofluorescence on exposure to ultraviolet light, and were unreactive with a variety of immunostains. Ultrastructurally, the inclusions were consistent with giant lysosomes, showing parallel whorled and arrayed membranes ("fingerprint" bodies) as a component of their substructure. Review of sections of 75 hyalinizing trabecular adenomas in our files revealed that the cytoplasmic bodies were present in all cases (100%), indicating that these inclusions most likely are a universal feature of the neoplasm.

Pathology of the thyroid in amiodarone-associated thyrotoxicosis.

Among 83 consecutive patients operated on for thyrotoxicosis at the Mayo Clinic between January 1, 1980 and May 1, 1986, four had a combination of pathologic findings that were similar and unexpected: involutional changes; degenerative and destructive follicular lesions; and zones of fibrosis. These four, but none of the remaining 79, were being treated with amiodarone for cardiac tachyarrhythmias; this drug is known to be taken up by the thyroid gland. Characteristically, small groups of involuted follicles exhibited varying degrees of damage ranging from degenerative changes in a few lining cells to total follicular destruction. Damaged follicular cells were swollen and featured granular or vacuolated cytoplasm. This type of cytoplasmic alteration has been reported to occur in pneumocytes and hepatocytes damaged by amiodarone. Therefore, the drug probably is the cause of the thyroid cell damage, and follicular disruption (with consequent release of iodothyronines into the circulation) is likely to be an important contributor to the associated thyrotoxicosis.

Analysis of Hurthle cell neoplasms of the thyroid by interphase fluorescence in situ hybridization.

Recent studies have indicated that numerical chromosomal abnormalities including changes in p53 and cyclin D1 may be involved in Hurthle cell tumorigenesis. We analyzed a series of Hurthle cell neoplasms of the thyroid to evaluate the diagnostic and prognostic utility of numerical anomalies by DNA fluorescent probes for cyclin D1 and p53 gene loci and chromosomes 5, 7, 11, 12, 17, and 22. Interphase fluorescence in situ hybridization (FISH) analysis was performed on paraffin-embedded tissue sections from 10 Hurthle cell adenomas, 19 Hurthle cell carcinomas, and 7 normal thyroid tissues used as controls. Directly labeled fluorescent DNA probes for the centromere region of chromosomes 7, 11, 12, and 17 and locus-specific probes for chromosomes 5 and 22, cyclin D1, and p53 were utilized for dual-probe hybridizations. Sixty percent (6 of 10) Hurthle cell adenomas and 63% (12 of 19) Hurthle cell carcinomas showed chromosome gains. Twenty percent (2 of 10) Hurthle cell adenomas and 26% (5 of 19) Hurthle cell carcinomas showed chromosome losses. Normal thyroid tissues used as controls showed no chromosomal abnormalities. Among Hurthle cell tumors with chromosomal abnormalities, adenomas averaged 2.7 gains and 0.3 losses per case, and carcinomas averaged 3.3 gains and 0.6 losses per case. The two adenomas with chromosome losses each showed loss of one chromosome, whereas the five carcinomas with losses averaged 1.8 losses per case. Chromosome 22 was the most common loss identified, occurring in three of the 11 patients who died of disease. These results indicate that chromosomal imbalances as gains are common in both benign and malignant Hurthle cell neoplasms, but Hurthle cell carcinomas tend to have more chromosome losses than adenomas. Among Hurthle cell carcinomas in this study, chromosome losses were identified only from patients who died of disease. The loss of chromosome 22 may have prognostic value in Hurthle cell carcinoma of the thyroid.

Evaluation of nodular thyroid disease.

There is no doubt that FNA biopsy is the best initial diagnostic step for the evaluation of a nodular thyroid. The successful use of FNA biopsy depends greatly on the experience of the clinician performing the aspiration and the expertise of the cytopathologist. The procedure is safe, expedient, and cost-effective. Complications are extremely rare. The accuracy of the technique in experienced hands is better than 95 per cent.

Monoclonal antibodies against the human sodium iodide symporter: utility for immunocytochemistry of thyroid cancer.

The recent cloning of the thyroidal protein that is responsible for iodide transport, the sodium iodide symporter (hNIS), has made possible studies designed to characterize its structure, function and expression in thyroidal tissues. Using a mannose binding protein (MBP)-hNIS fusion protein as antigen, we have developed mouse monoclonal antibodies against hNIS to utilize as tools in such studies. Twenty-four clones were initially recovered which recognized the MBP-hNIS fusion protein, but only two of them were specific for hNIS while the others recognized MBP alone. Both antibodies were found to be immunoglobulin G (IgG) 1kappa (kappa). The specificity of antibodies was tested by Western blotting using membranes prepared from COS-7 cells transiently transfected with the pcDNA3 plasmid containing the full-length hNIS cDNA, or cells transfected with the pcDNA3 vector. A major band with a molecular weight (MW) of approximately 97 kDa, and several minor bands with MW of approximately 160 kDa, approximately 68 kDa, approximately 30 kDa and approximately 15 kDa, were detected specifically in the hNIS-transfected cells. After enzymatic deglycosylation, the major band was present at 68 kDa, as expected based upon the amino acid sequence of hNIS. Immunohistochemistry was performed with several different types of thyroid tissue and non-thyroidal tissues, using the monoclonal antibodies. Strong immunostaining was observed in Graves' tissue, with intermediate staining in papillary and follicular thyroid cancers and an absence of staining in Hürthle cell cancer. The staining was specific for the follicular epithelium and was concentrated in the basolateral portion of the cell membrane. These monoclonal hNIS antibodies should prove useful in the characterization of NIS expression in benign and malignant thyroid tissue and in studies characterizing its structure and function.

Abdominal fluid cytology in patients with gastrointestinal malignant lesions.

In a group of 76 patients with various gastrointestinal malignant lesions, we found that peritoneal washings contained tumor cells in 43% of patients with gastric cancer, 22% of those with pancreatic cancer, and 3% of those with colonic cancer. Aside from tumor site, we were unable to identify any criteria that would help to predict the presence of malignant cells in peritoneal fluid specimens. We found no malignant cells on cytology in patients with early localized cancer. The ease of obtaining such data, coupled with the fact that the test is inexpensive, makes cytologic assessment attractive. Furthermore, the results of cytology have been shown to bear a direct relationship to prognosis in some cancers and may serve as an indication for more intensive therapy. The results of sequential cytology tend to support the theory that tumor manipulation may be a source of intraperitoneal spread in certain tumors.