The value of histomorphometric nuclear parameters in the diagnosis of well differentiated follicular carcinomas and follicular adenomas of the thyroid gland

Immunohistochemical Biomarkers in Thyroid Pathology

The application of immunohistochemistry to the diagnosis of thyroid lesions has increased as new biomarkers have emerged. In this review, we discuss the biomarkers that are critical for accurate diagnosis, prognosis, and management. Immunohistochemical markers are used to confirm that an unusual tumor in the thyroid is indeed of thyroid origin, either of follicular epithelial or C-cell differentiation; the various mimics include nonthyroidal lesions such as parathyroid tumors, paragangliomas, thymic neoplasms, and metastatic malignancies. Tumors of thyroid follicular epithelial cells can be further subclassified using a number of immunohistochemical biomarkers that can distinguish follicular-derived from C-cell lesions and others that support malignancy in borderline cases. The use of mutation-specific antibodies can distinguish papillary carcinomas harboring a BRAF^V600E mutation from RAS-like neoplasms. Immunostains have been developed to further identify molecular alterations underlying tumor development, including some rearrangements. Altered expression of several biomarkers that are known to be epigenetically modified in thyroid cancer can be used to assist in predicting more aggressive behavior such as a propensity to develop locoregional lymphatic spread. Immunohistochemistry can assist in identifying lymphatic and vascular invasion. Biomarkers can be applied to determine dedifferentiation and to further classify poorly differentiated and anaplastic carcinomas. The rare tumors associated with genetic predisposition to endocrine neoplasia can also be identified using some immunohistochemical stains. The application of these ancillary tools allows more accurate diagnosis and better understanding of pathogenesis while improving prediction and prognosis for patients with thyroid neoplasms.

Programmed death-ligand 1 expression by digital image analysis advances thyroid cancer diagnosis among encapsulated follicular lesions

Recognition of noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTP) that distinguishes them from invasive malignant encapsulated follicular variant of papillary thyroid carcinoma (EFVPTC) can prevent overtreatment of NIFTP patients. We and others have previously reported that programmed death-ligand 1 (PD-L1) is a useful biomarker in thyroid tumors; however, all reports to date have relied on manual scoring that is time consuming as well as subject to individual bias. Consequently, we developed a digital image analysis (DIA) protocol for cytoplasmic and membranous stain quantitation (ThyApp) and evaluated three tumor sampling methods [Systemic Uniform Random Sampling, hotspot nucleus, and hotspot nucleus/3,3'-Diaminobenzidine (DAB)]. A patient cohort of 153 cases consisting of 48 NIFTP, 44 EFVPTC, 26 benign nodules and 35 encapsulated follicular lesions/neoplasms with lymphocytic thyroiditis (LT) was studied. ThyApp quantitation of PD-L1 expression revealed a significant difference between invasive EFVPTC and NIFTP; but none between NIFTP and benign nodules. ThyApp integrated with hotspot nucleus tumor sampling method demonstrated to be most clinically relevant, consumed least processing time, and eliminated interobserver variance. In conclusion, the fully automatic DIA algorithm developed using a histomorphological approach objectively quantitated PD-L1 expression in encapsulated thyroid neoplasms and outperformed manual scoring in reproducibility and higher efficiency.

MicroRNA signature in thyroid fine needle aspiration cytology applied to "atypia of undetermined significance" cases

BACKGROUND

MicroRNA (miR) expression signatures are proposed to be able to differentiate thyroid cancer from benign thyroid lesions. We selected eight miRs (miR-146b, -221, -187, -197, -346, -30d, -138, and -302c) to examine the potential use of miRs to supplement diagnostic cytology in cases designated as "atypia of undetermined significance."

METHODS

miR expression was measured in thyroid fine needle aspiration (FNA) specimens by quantitative polymerase chain reaction. Gene expression analyses and linear discriminant analysis (LDA) were performed in a training sample set (n=60) to obtain a classification rule to predict FNA cases as benign or malignant. The predictions were cross-validated by comparing with the corresponding histological diagnoses. A validation sample set (n=68) was further tested with the established four-miR LDA classification rule.

RESULTS

A set of four miRs (miR-146b, -221, -187, and -30d) was identified that could differentiate malignant from benign lesions. A four-miR LDA classification rule was obtained and used to predict FNA cases as benign or malignant. For the training sample set, we obtained a diagnostic accuracy of 93.3%, sensitivity of 93.2%, specificity of 93.8%, positive predictive value (PPV) of 0.98, and negative predictive value (NPV) of 0.83. For the validation sample set, we obtained a diagnostic accuracy of 85.3%, sensitivity of 88.9%, specificity of 78.3%, PPV of 0.89, and NPV of 0.78. For the 30 atypia cases in the validation sample set, we obtained a diagnostic accuracy of 73.3%, sensitivity of 63.6%, specificity of 78.9%, PPV of 0.64, and NPV of 0.79. Based on the miR predictions, we classified the atypia cases predicted as "malignant" into "high risk" and those predicted as "benign" into "low risk" categories. While thyroid carcinomas, particularly papillary thyroid carcinomas (PTCs), were relatively enriched in the high-risk category, this particular miR panel is subject to inaccurate results in follicular neoplasias in atypia cases.

CONCLUSIONS

We demonstrate that miR amplification from FNA samples is feasible and that the particular four miR profile in this study can identify PTCs. However, further refinement is required for application to FNA cytology of "atypia of undetermined significance" cases due to low accuracy in classifying follicular neoplasias.

Nuclear morphometry in cytopathology: a prognostic indicator for canine cutaneous mast cell tumors

Twenty-nine canine cutaneous mast cell tumors (MCTs) were morphometrically analyzed with regard to mean nuclear area (MNA) using cytopathology smears. The results showed a correlation between MNA and survival. When graded into 2 morphometrically different groups, there were statistically significant differences among high- and low-grade MCTs, regarding both Romanowsky-type stain and hematoxylin and eosin. Cytomorphometry could also separate histologic grade II tumors with better prognosis from the more aggressive MCTs. The results indicated that nuclear morphometry on cytopathology preparations can predict the biological behavior of cutaneous MCTs in dogs in an independent manner, yielding a rapid and reproducible diagnosis, which renders the method useful for veterinary oncology.

The extracellular matrix protein 1: its molecular interaction and implication in tumor progression

The extracellular matrix protein 1 (ECM1) is expressed around blood vessels, which suggest a role for ECM1 in angiogenesis. Recombinant ECM1 stimulates proliferation of cultured endothelial cells and promotes blood vessel formation in the chorioallantoic membrane of chicken embryos. These observations make ECM1 a possible trigger for angiogenesis, tumor progression and malignancies. Interaction of ECM1 with perlecan, MMP-9 and fibulin-1C/D contributes to this hypothesis. However, the importance of ECM1 in cancer biology has been neglected so far. Nevertheless, a survey of ECM1 expression in different tumors indicated that ECM1, although not tumor specific, is significantly elevated in many malignant epithelial tumors that give rise to metastases, emphasizing its relevance in the cancer process.

Diagnostic and extent of disease multigene assay for malignant thyroid neoplasms

BACKGROUND

Approximately 30% of fine-needle aspiration (FNA) biopsies of thyroid nodules are indeterminate, nondiagnostic, or suspicious. The purpose of the current study was to determine the accuracy of novel candidate diagnostic markers to distinguish benign from malignant thyroid neoplasms, and to predict the extent of disease.

METHODS

A real-time quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) assay of 6 novel candidate diagnostic and extent of disease marker genes (extracellular matrix protein 1 [ECM1]; transmembrane protease, serine 4 [TMPRSS4]; angiopoietin 2 [ANGPT2]; TIMP metallopeptidase inhibitor 1 [TIMP1]; ephrin-B2 [EFNB2], and epidermal growth factor receptor [EGFR]) was used in 126 thyroid tissues. To evaluate the performance of the scoring model for the diagnostic markers in combination, the area under the receiver operating characteristic (ROC) curve (AUC) was determined.

RESULTS

The levels of ECM1, TMPRSS4, ANGPT2, and TIMP1 mRNA expression were found to be independent diagnostic markers of malignant thyroid neoplasms. The AUC for the 4 diagnostic genes in combination was 0.993 with a sensitivity of 100%, a specificity of 94.6%, a positive predictive value of 96.5%, and a negative predictive value of 100%. In 31 thyroid nodule FNA biopsy samples, the scoring model had a sensitivity of 91.0%, a specificity of 95.0%, a positive predictive value of 92.9%, and a negative predictive value of 92.3%. The multigene assay correctly classified 93% of tumors into the correct risk group (low-risk vs. high-risk) with a sensitivity of 78.9% (true positive in high-risk tumors), specificity of 92% (true negative in low-risk tumors), positive predictive value of 87.5%, and negative predictive value of 92%. In 11 malignant thyroid nodule FNA samples, the extent of disease scoring model correctly identified 3 of 4 high-risk differentiated thyroid cancers and 7 of 7 low-risk differentiated thyroid cancers.

CONCLUSIONS

This novel multigene assay is an excellent diagnostic and extent of disease marker for differentiated thyroid cancer and would be a helpful adjunct to FNA biopsy of thyroid nodules.

ECM1 and TMPRSS4 Are Diagnostic Markers of Malignant Thyroid Neoplasms and Improve the Accuracy of Fine Needle Aspiration Biopsy

OBJECTIVE

The objective of this study was to determine whether genes that regulate cellular invasion and metastasis are differentially expressed and could serve as diagnostic markers of malignant thyroid nodules.

SUMMARY AND BACKGROUND DATA

Patients whose thyroid nodules have indeterminate or suspicious cytologic features on fine needle aspiration (FNA) biopsy require thyroidectomy because of a 20% to 30% risk of thyroid cancer. Cell invasion and metastasis is a hallmark of malignant phenotype; therefore, genes that regulate these processes might be differentially expressed and could serve as diagnostic markers of malignancy.

METHODS

Differentially expressed genes (2-fold higher or lower) in malignant versus benign thyroid neoplasms were identified by extracellular matrix and adhesion molecule cDNA array analysis and confirmed by real-time quantitative polymerase chain reaction (PCR). The area under the receiver operating characteristic (AUC) curve was calculated to determine diagnostic accuracy of gene expression level cutoffs established by logistic regression analysis.

RESULTS

By cDNA array analysis, ADAMTS8, ECM1, MMP8, PLAU, SELP, and TMPRSS4 were upregulated, and by quantitative PCR, ECM1, SELP, and TMPRSS4 mRNA expression was higher in malignant (n = 57) than in benign (n = 38) thyroid neoplasms (P< 0.002). ECM1 and TMPRSS4 mRNA expression levels were independent predictors of a malignant thyroid neoplasm (P < 0.003). The AUC was 0.956 for ECM1 and 0.926 for TMPRSS4. Combining both markers improved their diagnostic use (AUC 0.985; sensitivity, 91.7%; specificity, 89.8%; positive predictive value, 85.7%; negative predictive value, 82.8%). ECM1 and TMPRSS4 expression analysis improved the diagnostic accuracy of FNA biopsy in 35 of 38 indeterminate or suspicious results. The level of ECM1 mRNA expression was higher in TNM stage I differentiated thyroid cancers than in stage II and III tumors (P < or = 0.031).

CONCLUSIONS

ECM1 and TMPRSS4 are excellent diagnostic markers of malignant thyroid nodules and may be used to improve the diagnostic accuracy of FNA biopsy. ECM1 is also a marker of the extent of disease in differentiated thyroid cancers.

Fractal dynamics in the differential diagnosis of thyroideal follicular neoplasms

In this study, we investigated the sensitivity, specificity, and predictive values of morphometric parameters of thyroideal follicular neoplasms based on concepts of fractal geometry. Thirty-seven follicular adenomas and 36 well-differentiated follicular carcinomas were assessed morphometrically. The nuclear area, nuclear area fraction, nuclear regularity factor, nuclear elongation factor, and slope setting (representing the ratio between the nuclear perimeter and nuclear regularity factor) were subjected to fractal dimensions analysis. By univariate analysis, the nuclear area, nuclear area fraction, nuclear regularity factor and slope values discriminate between adenomas and carcinomas. By multivariate analysis, the nuclear area, nuclear area fraction and slope values possess significant discriminatory powers in distinguishing between adenomas and carcinomas. Incorporating the nuclear area, nuclear area fraction, and slope values leads to a discriminatory power with 92% specificity and 83% sensitivity. The reciprocal relationships between the nuclear area, nuclear perimeter, and nuclear regularity factor of the cells of thyroideal adenomas and carcinomas may be expressed by fractal dimensions. Analysis limited to one parameter provides incomplete data. Expressing variations of the nuclear perimeter as a function of the nuclear regularity factor, the slope values constitute an independent attribute that significantly differentiates thyroideal adenomas from carcinomas.

Hyperinnervation and mast cell activation may be used as histopathologic diagnostic criteria for vulvar vestibulitis

OBJECTIVE

Vestibulitis is currently diagnosed based only on clinical criteria. To achieve histopathological diagnostic criteria, we carried out a computerized image analysis method.

METHODS

Vestibular tissues removed from 40 women with severe vestibulitis were immunostained for mast cell count and degranulation by C-kit and mast cell tryptase, respectively. Vestibular nerve cells total area was evaluated after S-100 stain. Controls were 7 women aged 18-48. The images were converted to a digital signal, and analyzed using Image Proplus V4 software.

RESULTS

We found a significant increase in inflammatory infiltrate, number of mast cells and degranulated mast cells in vestibulitis compared to normal controls. The inflammatory cells were localized around the superficial minor vestibular glands. The total nerve fiber area was ten times higher in vestibulitis patients than in controls. A significant positive correlation was found between the total nerve fiber area and the number of mast cells in the vestibulitis group of patients.

CONCLUSION

We documented two diagnostic histopathological criteria for vestibulitis: (1) the presence of eight or more mast cells per 10 x 10 microscopic field, and (2) the total calculated area of the nerve fibers is ten times higher than expected. These findings re-establish the inflammatory nature of the vestibulitis. It is speculated that the trigger for the local outburst of nerve fibers could be related to the activation of the mast cells by a topical agent.

Morphometry of canine cutaneous mast cell tumors

Twenty-four canine cutaneous nodules, diagnosed as mast cell tumors by fine-needle aspiration biopsy and confirmed by histopathologic analysis by staining with hematoxylin and eosin (HE) and toluidine blue, were analyzed by computerized nuclear morphometry on panoptic- and HE-stained cytopathology slides. Two hundred nuclei per lesion were examined. The morphometric parameters investigated were nuclear area, mean diameter, perimeter, regularity factor, and ellipticity factor. Lesions were graded as I (well differentiated), II (intermediate differentiation), or III (poorly differentiated) according to the following morphologic features: invasiveness, cellularity and cellular morphology, mitotic index, and stromal reaction. Nuclear morphometric results were then compared with histopathologic grades. Values of nuclear area, mean diameter, and perimeter increased with increase in histopathologic grade, but statistical analysis revealed significant differences only between grades II and III and between grades I and III when HE was used (P < 0.01) and between grades I and III with panoptic stain (P < 0.05). The ellipticity factor and regularity factor did not reveal significant differences between histopathologic grades. The results indicate that nuclear morphometric analysis, in combination with the rapid and inexpensive cytopathology technique, can help in mast cell tumor grading, thus contributing to the establishment of a more precise prognosis and treatment.