Immunostaining of galectin-3 and CD44v6 using fine-needle aspiration for distinguishing follicular carcinoma from adenoma

Beyond immunohistochemistry and immunocytochemistry: a current perspective on galectin-3 and thyroid cancer

Introduction: Thyroid nodules are very common in the general population, most are benign, and do not require any intervention. However, often a challenge exists in discriminating benign thyroid nodules from cancer, without performing a biopsy or operation. Galectin-3 is a beta-galactoside binding protein that is involved in diverse biological processes and has been found to have increased expression in many human cancer types including thyroid cancer. As a result, recent studies have investigated its utility as a serum biomarker for thyroid cancer, as well as a novel target for in vivo molecular imaging of cancer. Additionally, given its role in tumorigenesis and cancer progression, galectin-3 targeting is currently under investigation for its potential utility as treatment for thyroid cancer.Areas covered: Recent studies of galectin-3 as a serum marker for thyroid cancer diagnosis, and in the preclinical setting as a target for cancer imaging and therapy.Expert opinion: Even though current studies evaluating galectin-3 as a serum marker and target for cancer imaging and therapy are promising, further research is required before it can be adopted into routine clinical use.

Diagnostic Utility of Molecular and Imaging Biomarkers in Cytological Indeterminate Thyroid Nodules

Indeterminate thyroid cytology (Bethesda III and IV) corresponds to follicular-patterned benign and malignant lesions, which are particularly difficult to differentiate on cytology alone. As ~25% of these nodules harbor malignancy, diagnostic hemithyroidectomy is still custom. However, advanced preoperative diagnostics are rapidly evolving.This review provides an overview of additional molecular and imaging diagnostics for indeterminate thyroid nodules in a preoperative clinical setting, including considerations regarding cost-effectiveness, availability, and feasibility of combining techniques. Addressed diagnostics include gene mutation analysis, microRNA, immunocytochemistry, ultrasonography, elastosonography, computed tomography, sestamibi scintigraphy, [18F]-2-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET), and diffusion-weighted magnetic resonance imaging.The best rule-out tests for malignancy were the Afirma® gene expression classifier and FDG-PET. The most accurate rule-in test was sole BRAF mutation analysis. No diagnostic had both near-perfect sensitivity and specificity, and estimated cost-effectiveness. Molecular techniques are rapidly advancing. However, given the currently available techniques, a multimodality stepwise approach likely offers the most accurate diagnosis, sequentially applying one sensitive rule-out test and one specific rule-in test. Geographical variations in cytology (e.g., Hürthle cell neoplasms) and tumor genetics strongly influence local test performance and clinical utility. Multidisciplinary collaboration and implementation studies can aid the local decision for one or more eligible diagnostics.

Molecular Signature of Indeterminate Thyroid Lesions: Current Methods to Improve Fine Needle Aspiration Cytology (FNAC) Diagnosis

Fine needle aspiration cytology (FNAC) represents the gold standard for determining the nature of thyroid nodules. It is a reliable method with good sensitivity and specificity. However, indeterminate lesions remain a diagnostic challenge and researchers have contributed molecular markers to search for in cytological material to refine FNAC diagnosis and avoid unnecessary surgeries. Nowadays, several "home-made" methods as well as commercial tests are available to investigate the molecular signature of an aspirate. Moreover, other markers (i.e., microRNA, and circulating tumor cells) have been proposed to discriminate benign from malignant thyroid lesions. Here, we review the literature and provide data from our laboratory on mutational analysis of FNAC material and circulating microRNA expression obtained in the last 6 years.

[Clinical importance of thyroid gland cytology]

The cytological evaluation of fine needle biopsies (FNB) of the thyroid gland crucially depends on a close cooperation between clinicians and cytopathologists. Scintigraphy, sonography as well as clinical data and patient history are necessary for a correct interpretation of the indications for FNB; moreover, these data are of outstanding importance for cytopathologists for the correct interpretation of the cytomorphological findings. This overview describes the present standards in the acquisition, technical workup and cytopathological interpretation of thyroid gland tissue obtained by FNB, particularly focusing on the rapidly growing relevance of additional molecular pathological investigations to increase the diagnostic accuracy of thyroid FNB.

A Pilot Study of Galectin-3, HBME-1, and p27 Triple Immunostaining Pattern for Diagnosis of Indeterminate Thyroid Nodules in Cytology With Correlation to Histology

Supplemental Digital Content is available in the text.

Indeterminate thyroid nodules form a heterogenous group of lesions that constitute 5% to 30% of thyroid cytology diagnoses. We introduce a triple immunostaining protocol for subtyping. Galectin-3, HBME-1, and p27 triple immunostaining, performed on destained cytology slides and formalin-fixed paraffin-embedded tissue, was developed and applied to 51 patients retrospectively with preoperative cytologic diagnoses of follicular lesion of undetermined significance (n=40), atypia of undetermined significance (n=6), and suspicious for follicular neoplasm (n=5). The malignant rate in this series was 43.1% (22/51). A hierarchal evaluation algorithm was generated based on digital image quantitation of triple-stained histologic sections, and applied to both cytology and histology specimens. Fifty of 51 cytology cases have triple staining validated by internal controls. In cytology specimens, the individual sensitivities and specificities of p27, Galectin3, and HBME1 for cancer with 95% confidence interval are: 86.2% (0.674, 0.955)/66.7% (0.431, 0.845); 77.3% (0.542, 0.913)/72.4% (0.525, 0.866); and 72.7% (0.496, 0.884)/93.1% (0.758, 0.988), respectively. Sensitivity is increased to 95.5% (0.751, 0.998), but specificity is decreased to 69.0% (0.490, 0.840), if Galectin3 and HBME1 are both used in combination as markers for malignancy. However, the level of specificity is increased to 86.2% (0.674, 0.955) and sensitivity remains high 100% (0.808, 1) if in addition, using the Galectin3/HBME1:p27 ratio (ratio ≥2 indicating malignancy) for 2 or 3 markers positive cases. Thus, the triple staining method on cytology slides and histology sections shows a similar sensitivity/specificity/positive predictive value/negative predictive value of 100.0%/86.2%/84.0%/100.0% and 95.5%/86.2%/84.0%/96.2%, respectively (P=0.92). Overall, p27 is the most frequent single positive marker (19/50, 38% in cytology), consistent with benign nature of most indeterminate thyroid nodules. Galectin-3 and HBME-1 colocalization (positive in the same cell) was demonstrated in thyroid cancer in 45.5% (10/22) of histology sections, but in none of the normal thyroid tissues and benign thyroid lesions. This supports the notion that synchronous activation of Galectin-3 and HBME-1 occurs in thyroid malignancy and is highly specific for malignancy. We have demonstrated the performance and pattern of triple immunostaining for subtyping indeterminate thyroid nodules. Further studies and validation in different larger populations are warranted.

Sensitivity and Specificity of Galectin-3 and Glypican-3 in Follicular-Patterned and Other Thyroid Neoplasms

INTRODUCTION

Diagnosing follicular-patterned thyroid neoplasm can be quiet challenging in some cases, where an immunohistochemical profiling becomes mandatory. Galectin-3 may be a helpful tool for classical PTC diagnosis, but it cannot be considered as a diagnostic marker of malignancy. Glypican-3, in contrast, is not thoroughly studied in thyroid neoplasms.

AIM

Determine the sensitivity and specificity of galectin-3 and glypican-3 in diagnosing thyroid carcinoma and follicular-patterned thyroid carcinoma.

MATERIALS AND METHODS

A retrospective study was conducted on archival blocks diagnosed from pathology department between 2010 and 2012 including 17 cases of follicular adenoma, 16 cases of Classic Papillary Thyroid Carcinoma (PTC), 6 cases of Follicular Variant of Papillary Thyroid Carcinoma (FVPTC), 3 cases of follicular carcinoma, 5 cases of medullary carcinoma and 1 case of Hürthle cell carcinoma. The nearby non neoplastic (normal) thyroid follicles present in both adenoma and carcinoma cases were also evaluated.

STUDY DESIGN

Evaluation of both galectin-3 and glypican-3 expression using standard immunohistochemical techniques.

STATISTICAL ANALYSIS USED

Descriptive analysis of the variables and statistical significances were calculated by non-parametric chi-square test using the Statistical Package for the Social Sciences version 12.0 (SPSS).

RESULTS

Five (30%) and 4 (24%) out of the 17 studied follicular adenoma cases, were positively stained by galectin-3 and glypican-3 respectively, while 30 (97%) and 25 (81%) cases out of the studied 31 carcinoma cases were positively stained by galectin-3 and glypican-3 respectively. The sensitivity, specificity and diagnostic accuracy of galectin-3 vs. glypican-3 in discrimination between thyroid carcinoma and adenoma was 96.8%, 70.6%, and 87.5%vs. 81% 76.5% and 79% respectively. As for the discrimination between follicular-patterned thyroid carcinoma and follicular adenoma it was 90%, 71% and 78% vs. 90% 76.5% and 82%.

CONCLUSION

Glypican-3 is more specific while galectin-3 is more sensitive in diagnosing thyroid carcinoma while glypican-3 is more specific than galectin-3 in discriminating follicular-patterned neoplasm.

Application of Immunohistochemistry in Thyroid Pathology

Context

Accurate classification of follicular-patterned thyroid lesions is not always an easy task on routine surgical hematoxylin-eosin–stained or cytologic fine-needle aspiration specimens. The diagnostic challenges are partially due to differential diagnostic criteria that are often subtle and subjective. In the past decades, tremendous advances have been made in molecular gene profiling of tumors and diagnostic immunohistochemistry, aiding in diagnostic accuracy and proper patient management.

Objective

To evaluate the diagnostic utility of the most commonly studied immunomarkers in the field of thyroid pathology by review of the literature, using the database of indexed articles in PubMed (US National Library of Medicine) from 1976–2013.

Data Sources

Literature review, authors' research data, and personal practice experience.

Conclusions

The appropriate use of immunohistochemistry by applying a panel of immunomarkers and using a standardized technical and interpretational method may complement the morphologic assessment and aid in the accurate classification of difficult thyroid lesions.

Immunohistochemical levels of matrix metalloproteinase-2 and CD44 variant 6 protein in the diagnosis and lateral cervical lymph node metastasis of papillary thyroid carcinoma

OBJECTIVES

To investigate the ability of matrix metalloproteinase (MMP)-2 and CD44 variant 6 (CD44v6) protein levels to diagnose papillary thyroid cancer (PTC), compared with routine diagnostic methods using tissue sections; to explore the relationship between MMP-2 and CD44v6 protein levels and lymph node metastases (LNM) in PTC.

METHODS

Archival PTC specimens from patients with PTC, with or without lateral cervical LNM, were included in this retrospective immunohistochemical study. MMP-2 and CD44v6 protein levels were analysed immunohistochemically using routinely prepared tissue sections.

RESULTS

Specimens from 66 patients with PTC were reviewed retrospectively (35 patients with lateral cervical LNM; 31 patients without LNM). The percentages of samples with cells that demonstrated positive protein staining differed significantly between PTC specimens, benign thyroid nodules and adjacent normal follicular epithelium (MMP-2: 86.4%, 60.0%, and 25.7%, respectively; CD44v6: 80.3%, 37.1% and 22.9%, respectively). The level of CD44v6 protein staining was found to be significantly and positively correlated with the level of MMP-2 protein staining in PTC specimens.

CONCLUSIONS

Both MMP-2 and CD44v6 might be useful tumour markers for predicting risk of lateral cervical LNM in patients with PTC.

Expression of CK-19, galectin-3 and HBME-1 in the differentiation of thyroid lesions: systematic review and diagnostic meta-analysis

Background

To distinguish between malignant and benign lesions of the thyroid gland histological demonstration is often required since the fine-needle aspiration biopsy method applied pre-operatively has some limitations. In an attempt to improve diagnostic accuracy, markers using immunocytochemistry and immunohistochemistry techniques have been studied, mainly cytokeratin-19 (CK-19), galectin-3 (Gal-3) and Hector Battifora mesothelial-1 (HBME-1). However, current results remain controversial. The aim of the present article was to establish the diagnostic accuracy of CK-19, Gal-3 and HBME-1 markers, as well as their associations, in the differentiation of malignant and benign thyroid lesions.

Methods

A systematic review of published articles on MEDLINE and The Cochrane Library was performed. After establishing inclusion and exclusion criteria, 66 articles were selected. The technique of meta-analysis of diagnostic accuracy was employed and global values of sensitivity, specificity, area under the summary ROC curve, and diagnostic odds ratio (dOR) were calculated.

Results

For the immunohistochemistry technique, the positivity of CK-19 for the diagnosis of malignant thyroid lesions demonstrated global sensitivity of 81% and specificity of 73%; for Gal-3, sensitivity of 82% and specificity of 81%; and for HBME-1, sensitivity of 77% and specificity of 83%. The association of the three markers determined sensitivity of 85%, specificity of 97%, and diagnostic odds ratio of 95.1. Similar results were also found for the immunocytochemistry assay.

Conclusion

This meta-analysis demonstrated that the three immunomarkers studied are accurate in pre- and postoperative diagnosis of benign and malignant thyroid lesions. Nevertheless, the search for other molecular markers must continue in order to enhance this diagnostic accuracy since the results found still show a persistency of false-negative and false-positive tests.

Virtual slides

Http://www.diagnosticpathology.diagnomx.eu/vs/3436263067345159

Update on the molecular signature of differentiated thyroid cancer: clinical implications and potential opportunities

With the development and maturation of new technologies, there has been a steady incorporation of powerful new tools into the evaluation and management of thyroid nodules and thyroid cancer. An increasing number of reports on oncogene testing and molecular screening in fine-needle aspiration biopsy samples have been published. However, there remains a paucity of data and consensus on combining both conventional and molecular technologies to determine the diagnosis and/or prognosis of disease. All patients with differentiated thyroid cancer stand to benefit from the identification and incorporation of reliable molecular markers into clinical practice. Identification of reliable markers would allow for stratification of treatment, affording the medical and surgical teams an ability to individually tailor evaluation and treatment, applying aggressive therapy and monitoring only when clinically warranted. For the majority of patients with thyroid cancer, the incorporation of a validated, multifaceted molecular profiling system may not improve survival; however, there is great opportunity for these efforts to decrease the morbidity associated with our current approach.

Diagnostic utility of galectin-3 in thyroid cancer

Galectin-3 (Gal-3), which has received significant recent attention for its utility as a diagnostic marker for thyroid cancer, represents the most well-studied molecular candidate for thyroid cancer diagnosis. Gal-3 is a protein that binds to beta-galactosidase residues on cell surface glycoproteins and has also been identified in the cytoplasmic and nuclear compartment. This marker has been implicated in regulation of normal cellular proliferation and apoptosis, as well as malignant transformation and the metastasis of cancer cells. We here present a mechanistic review of Gal-3 and its role in cancer development and progression. Gal-3 expression studies in thyroid tissue and cytologic tumor specimens and their methodological considerations are also discussed in this article. Despite great variance in their methodology, the majority of immunohistochemical studies found that Gal-3 was differentially expressed in thyroid carcinoma compared with benign and normal thyroid specimens, suggesting that Gal-3 is a good diagnostic marker for thyroid cancer. Recent studies have also demonstrated improved methodological reliability. On the other hand, Gal-3 genomic expression studies have shown inconsistent results for diagnostic utility and are not recommended. Overall, the development of Gal-3 as a diagnostic marker for thyroid cancer represents a promising avenue for future study, and its clinical application could significantly reduce the number of diagnostic thyroid operations performed for cases of indeterminant fine needle aspiration biopsy cytology, and thus positively impact the current management of thyroid nodular disease.

CD44v6 expression in intraductal papillary mucinous neoplasms of the pancreas

OBJECTIVES

The purpose of this study was to examine CD44v6 expression in intraductal papillary mucinous neoplasms (IPMNs) and clarify the role of CD44v6 in progression, invasion, metastasis, and morphogenesis of IPMNs.

METHODS

One hundred fifty-one samples of IPMNs and 30 normal controls were subjected to immunohistochemical analysis for CD44v6. The IPMNs were divided into 4 groups according to the grade of atypia (adenoma, borderline IPMN, noninvasive carcinoma, and invasive carcinoma) and 5 subtypes according to histological phenotype (gastric, intestinal, pancreatobiliary, oncocytic, and unclassified). Correlations were investigated between CD44v6 expression and clinicopathological characteristics including grade of atypia, subtype, lymph node metastasis, and invasion pattern.

RESULTS

Whereas normal ductal epithelium did not express CD44v6, CD44v6 expression was observed from the early stage of IPMNs and up-regulated in the progression of IPMNs to invasive carcinoma. CD44v6 expression in intestinal-type IPMNs was significantly lower compared with that in other subtypes. Whereas no correlation was observed between lymph node metastasis and CD44v6 expression in invasive IPM carcinomas, the invasion pattern was significantly correlated to CD44v6 expression.

CONCLUSIONS

The present data indicate that CD44v6 expression determines the morphology and aggressiveness of IPMNs and is involved in development and invasion of IPMNs.

One in four patients with follicular thyroid cytology (THY3) has a thyroid carcinoma

BACKGROUND

Fine-needle aspiration (FNA) biopsy is the cornerstone of assessment of thyroid nodules. Cytological criteria for benign (THY2) and malignant (THY5) aspirates are well established and reliable. When cytology suggests a follicular neoplasm (THY3), only formal histological assessment can differentiate between benign and malignant lesions. The objective of this study was to determine the factors predictive of malignancy in thyroid nodules when cytological assessment is restricted to euthyroid patients living in an area without endemic goiter who undergo routine diagnostic lobectomy once the FNA raises the suspicion of a follicular neoplasm.

METHOD

Retrospective review of histological and clinical data in a cohort of patients with a palpable thyroid nodule and THY3 cytology.

RESULTS

Between January 2000 and December 2007, 1981 patients (346 males and 1635 females) underwent 2809 thyroid FNAs. There were 201 THY3 reports (9%). Histology demonstrated thyroid carcinomas in 57 patients (31 follicular carcinomas, 11 Hurthle cell carcinomas, 11 papillary carcinomas, 1 medullary thyroid carcinoma, 1 poorly differentiated thyroid cancer, 1 lymphoma, and 1 metastatic renal carcinoma). Benign tumors were found in 144 patients with follicular adenomas (n = 76), Hurthle cell adenomas (n = 33), multinodular goiter (n = 13), adenomatoid nodules (n = 15), colloid nodules (n = 4), and thyroiditis (n = 3). THY3 cytology was more predictive of malignancy in men (13/34 male symbol vs. 44/167 female symbol, p < 0.001, chi(2) test). The risk for malignancy was 1:4 for the entire group and 1:3 for patients under 30 years and over 60 years. About 17/46 nodules over 40 mm in diameter were carcinomas, compared with only 35/140 in nodules under 40 mm (p < 0.01, chi2 test).

CONCLUSION

One in four patients with cytological features of a follicular neoplasm has a thyroid carcinoma. A large nodule (>4 cm) with THY3 cytology has a high likelihood of being a cancer, and arguably such patients could be offered total thyroidectomy rather than diagnostic lobectomy.

Serum galectin-1 and galectin-3 levels in benign and malignant nodular thyroid disease

BACKGROUND

Since the histological expression of galectins is increased in thyroid carcinoma, determination of their serum levels may provide useful preoperative information. The goal of this study was to determine if a difference in galectin serum levels could be detected between benign and malignant nodular thyroid diseases.

DESIGN

Using validated ELISAs, the concentrations of several galectins were prospectively measured in serum samples from 30 healthy individuals and preoperatively in 90 patients with thyroid disease. Seventy-one patients had multiple thyroid nodules (MTN), 13 patients had a single thyroid nodule (STN), and 6 patients had Graves' disease. Nine of 71 patients with MTN had fine-needle aspiration biopsy (FNAB) of their nodules and in 7 patients a "benign" diagnosis was made, in 0 patient a "malignant" diagnosis was made, and in 2 patients a "suspicious" diagnosis was made. Six of 13 patients with STN had FNAB of their nodules and in 2 patients a "benign" diagnosis was made, in 3 patients a "malignant" diagnosis was made, and in 1 patient a "suspicious" diagnosis was made.

RESULTS

Thyroid disease was associated with higher levels of galectins-1 and -3 compared to normal subjects. Using a threshold value of 3.2 ng/mL as a cut-off point, the measurement of serum galectin-3 separated micro- and macropapillary thyroid carcinoma (PAP_CA) from patients with nonmalignant thyroid disease with 74% specificity, 73% sensitivity, 57% positive predictive value, and 85% negative predictive value. Elevated serum galectin-3 concentrations (>3.2 ng/mL) detected 87% of macropapillary thyroid carcinomas and 67% of micropapillary thyroid carcinomas.

CONCLUSIONS

Serum levels of galectins-1 and -3 are relatively high in patients with thyroid malignancy but there is considerable overlap in serum galectin-3 concentrations between those with benign and malignant nodular thyroid disease and, to a lesser extent, between those with and without nodular thyroid disease.

Application of immunohistochemistry to thyroid neoplasms

CONTEXT

Thyroid lesions with nodular architecture and follicular pattern of growth often pose difficulties in accurate diagnosis during the assessment of cytologic and histologic specimens. The diagnosis of follicular neoplasm on cytology or of follicular tumor of uncertain malignant potential on histology is likely to cause confusion among clinicians and delay effective management of these lesions. Occasionally, thyroid tumors represent unusual or metastatic lesions and their accurate diagnosis requires immunohistochemical confirmation.

OBJECTIVE

To review the literature on the applications of immunohistochemistry in the differential diagnosis of thyroid tumors.

DATA SOURCES

Relevant articles indexed in PubMed (National Library of Medicine) between 1976 and 2006.

CONCLUSIONS

Our review supports the use of ancillary techniques involving a panel of antibodies suitable for immunohistochemistry and molecular analysis in the assessment of thyroid nodules. These tools can improve diagnostic accuracy when combined with standard morphologic criteria.

Is galectin-3 a good method for the detection of malignancy in patients with thyroid nodules and a cytologic diagnosis of “follicular neoplasm”? A critical appraisal of the evidence

BACKGROUND

Thyroid nodules are the most common surgical disease of the thyroid. Fine-needle aspiration biopsy (FNAB) is the most commonly employed tool for establishing a diagnosis. However, 15% to 25% of FNAB reports yield inconclusive results. Immunostaining of cytological smears from FNAB with galectin-3 has been proposed as a tool for differentiating between benign and malignant nodules. We performed a systematic review to evaluate the utility of galectin-3.

METHODS

Prospective studies of nodules with FNAB reports of "follicular neoplasm" and with a definitive diagnosis confirmed by histopathology were selected. Calculations of individual sensitivity, specificity, and positive and negative likelihood ratios were made.

RESULTS

The articles selected were those with the best methodological quality.

CONCLUSION

Galectin-3 could be a good tool to guide therapeutic decision in patients with thyroid nodules and FNAB results of follicular neoplasm, but available information has methodological flaws that precludes a definitive answer about galectin-3 utility in the clinical setting.

Percutaneous large-needle aspiration biopsy histology of palpable thyroid nodules: technical and diagnostic performance

AIM

To report original and review existing data on safety and performance of large-needle aspiration biopsy (LNAB) histology in the preoperative selection of palpable thyroid nodule.

METHODS AND RESULTS

The English literature and original data were reviewed or analysed. The literature on LNAB of thyroid nodules did not report any complications. A study on needle dimensions has explained why LNAB obtains more tissue than fine-needle aspiration (FNA) and is safe. LNAB histology has higher specificity than FNA cytology and markedly reduces the number of inadequate and indeterminate FNA findings. A comparison of 150 FNA-derived cell blocks with 200 LNAB-derived histological blocks after galectin-3 determination in a large nationwide (Italian) study has shown that one to two sections in 10% of the FNA cell blocks and at least five sections in 90% of the LNAB blocks were available for further determinations of thyroid tumour markers.

CONCLUSION

LNAB merits further consideration for the preoperative selection of thyroid nodules.

Intraoperative pathologic examination: cost effectiveness and clinical value in patients with cytologic diagnosis of cellular follicular thyroid lesion

OBJECTIVE

Routine use of intraoperative pathologic examination (IOPE), including frozen section (FS) and scrape preparation cytology (SPC), during diagnostic thyroid lobectomy continues to be a source of controversy. We sought to better delineate the usefulness and cost-benefit ratio of IOPE in the context of cytologically diagnosed cellular follicular lesion (CFL) or follicular neoplasm (FN).

DESIGN

Records of 205 patients who underwent thyroidectomy for cytologically diagnosed FN or CFL between 1997 and 2005 were retrospectively reviewed. IOPE results, patient demographics, and tumor characteristics were correlated to final histopathologic diagnoses. Sensitivity, specificity, predictive values, accuracy, and costs of IOPE were calculated.

MAIN OUTCOME

IOPE correctly identified 3 of 16 follicular carcinomas and 9 of 36 papillary carcinomas. Sensitivity, specificity, and accuracy were 23%, 99%, and 78%, respectively. On univariate analysis, malignancy risk among follicular nodules did not correlate with age, gender, or nodule size. On multivariate analysis, nodule size was predictive of malignancy (p < 0.05). Over the entire patient series, routine IOPE resulted in a net cost savings of $74,304.33.

CONCLUSIONS

IOPE reduced costs and limited the number of completion thyroidectomies necessary. IOPE is specific, cost effective, and of minimal additional risk when performed routinely for patients with CFL or FN.

Immuno-PET of undifferentiated thyroid carcinoma with radioiodine-labelled antibody cMAb U36: application to antibody tumour uptake studies

PURPOSE

We tested the suitability of the chimeric monoclonal anti-human CD44 splice version 6 antibody (cMAb U36) for targeting and visualising human anaplastic thyroid carcinoma with PET. We also performed experiments aimed at elucidating the relation between tumour interstitial fluid pressure (TIFP) and the tumour uptake of antibodies.

METHODS

The affinity and specificity of the cMAb U36 for KAT-4 cells were evaluated in vitro, as was the Na+/I- symporter (NIS) expression. Biodistribution studies were performed on KAT-4 carcinoma-bearing mice injected with 124I-cMAb U36 or free iodine. Biodistribution studies were also performed in animals treated with the specific TGF-beta1 and -beta3 inhibitor Fc:TbetaRII, which lowers TIFP. Treated and non-treated animals were scanned by microPET.

RESULTS

Cultured human undifferentiated/anaplastic thyroid carcinoma KAT-4 cells expressed low levels of NIS and uptake of free iodine was insignificant. The cMAb U36 expressed an affinity (KD) of 11+/-2 nM. Tumour radioactivity uptake reached maximum values 48 h after injection of 124I-cMAb U36 (approximately 22%IA/g). KAT-4 carcinomas were readily identified in all 124I-immuno-PET images. Radioactivity tumour uptake in Fc:TbetaRII-treated animals was significantly lower at 24 and 48 h after injection, and five times higher thyroid uptake was also noted.

CONCLUSION

We successfully used 124I-cMAb U36 to visualise CD44v6-expressing human anaplastic thyroid carcinoma. Given the lack of NIS expression in KAT-4, tumour visualisation is not due to free iodine uptake. Lowering the TIFP in KAT-4 carcinomas did not increase the uptake of mAbs into tumour tissue.

Molecular diagnostic methods in the diagnosis and follow-up of well-differentiated thyroid carcinoma

Thyroid cancers are the most common endocrine malignancies and are being diagnosed with increased frequency in modern clinical practice. Among other diagnostic modalities, fine-needle aspiration (FNA) biopsy of clinically suspicious thyroid nodules is becoming increasingly popular. Preliminary investigations have suggested that molecular diagnostic assays using tumor-specific markers may improve the sensitivity and accuracy of FNA and so may be expected to reduce the frequency of open surgical procedures by identifying those patients with demonstrably benign lesions who do not require definitive surgical excision of their lesions for diagnosis. At the same time, thyroid-specific mRNA assays (especially thyroglobulin mRNA testing) have been used by investigators in the postoperative follow-up of patients with thyroid cancer as a potential means of detecting tumor recurrence in the peripheral blood. Although these studies have not all reported unqualified successes--indeed, some problems based on both technical and biologic limitations have been identified-these assays still hold out the possibility that potentially important new advances in the management of patients with well-differentiated thyroid cancer may be offered by these and other molecular diagnostic methods.

Progress in the preoperative diagnosis of thyroid nodules: managing uncertainties and the ultimate role for molecular investigation

The preoperative evaluation of thyroid nodules currently relies on a clinical assessment of risk factors and an algorithm based on imprecise tests. With serum TSH, thyroid ultrasound and fine-needle aspiration (FNA) with or without ultrasound guide, accounting for the routine initial evaluation, indeterminate aspirates remain the major obstacle for confidently advising patients whether to have surgery or not. Recent clinical guidelines have attempted to settle various controversies but many inherent errors of clinical testing result in delayed diagnosis and unnecessary surgery. A better solution may ultimately involve the use of molecular markers of thyroid carcinogenesis but further research is still needed regarding the basic biology of thyroid cancer.