CD15 (LeuM1) immunoreactivity: prognostic factor for sporadic and hereditary medullary thyroid cancer? Study Group on Multiple Endocrine Neoplasia of Austria

MicroRNA-21 and long non-coding RNA MALAT1 are overexpressed markers in medullary thyroid carcinoma

BACKGROUND

Non-coding RNAs, including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), are well-recognized post-transcriptional regulators of gene expression. This study examines the expression of microRNA-21 (miR-21) and lncRNA MALAT1 in medullary thyroid carcinomas (MTCs) and their effects on tumor behavior.

METHODS

Tissue microarrays (TMAs) were constructed using normal thyroid (n=39), primary tumors (N=39) and metastatic MTCs (N=18) from a total of 42 MTC cases diagnosed between 1987 and 2016. In situ hybridization with probes for miR-21 and MALAT1 was performed. PCR quantification of expression was performed in a subset of normal thyroid (N=10) and primary MTCs (N=32). An MTC-derived cell line (MZ-CRC-1) was transfected with small interfering RNAs (siRNAs) targeting miR-21 and MALAT1 to determine the effects on cell proliferation and invasion.

RESULTS

In situ hybridization (ISH) showed strong (2+ to 3+) expression of miR-21 in 17 (44%) primary MTCs and strong MALAT1 expression in 37 (95%) primary MTCs. Real-time PCR expression of miR-21 (P<0.001) and MALAT1 (P=0.038) in primary MTCs were significantly higher than in normal thyroid, supporting the ISH findings. Experiments with siRNAs showed inhibition of miR-21 and MALAT1 expression in the MTC-derived cell line, leading to significant decreases in cell proliferation (P<0.05) and invasion (P<0.05).

CONCLUSION

There is increased expression of miR-21 and MALAT1 in MTCs. This study also showed an in vitro pro-oncogenic effect of MALAT1 and miR-21 in MTCs. The results suggest that overexpression of miR-21 and MALAT1 may regulate MTC progression.

Stage-Specific Embryonic Antigen-1 (SSEA-1) Expression in Thyroid Tissues

Stage-specific embryonic antigen-1 (SSEA-1), also known as CD15, is a member of a cluster of differentiation antigens that have been identified in various normal tissues and in different types of cancers including papillary and medullary thyroid carcinoma. SSEA-1 may be expressed in normal stem cells and cancer stem-like cells. To evaluate the potential diagnostic and prognostic utility of SSEA-1 in thyroid tumors, we analyzed the expression of SSEA-1 in normal and neoplastic thyroid tissues by immunohistochemistry (IHC) using a tissue microarray with 158 different tissue cores. To evaluate the potential utility of SSEA-1 as a surface marker, we also assessed the expression of SSEA-1 in thyroid cell lines by flow cytometric analysis. SSEA-1 immunoreactivity was identified in malignant thyroid follicular epithelial cancers but not in the benign thyroid tissues. Anaplastic thyroid (ATC) (80 %) and conventional papillary thyroid carcinoma (PTC) (60.7 %) showed significantly higher percentage of cases that were SSEA-1 immunoreactive than follicular variant of papillary thyroid carcinoma (FVPTC) (20.6 %) and follicular carcinoma (FCA) (32.1 %). Flow cytometric analysis of cultured thyroid cell lines showed that a small subpopulation of ATC and PTC thyroid tumor cells had SSEA-1 immunoreactivity which may represent thyroid cancer stem-like cells. The ATC cells expressed more SSEA-1 immunoreactive cells than the PTC cell lines. Our findings suggest that expression of SSEA-1 immunoreactivity in thyroid neoplasms was associated with more aggressive thyroid carcinomas. SSEA-1 is a marker that detects malignant thyroid neoplasms in formalin-fixed paraffin-embedded thyroid tissue sections and may be a useful marker for thyroid cancer stem-like cells.

Early diagnosis and curative therapy of medullary thyroid carcinoma by routine measurement of serum calcitonin in patients with thyroid disorders

To identify patients with medullary thyroid carcinoma (MTC) at a potentially curable stage of the disease, serum concentrations of calcitonin (hCT) were determined in 14,000 patients (including 10,158 patients with thyroid nodules) referred to a thyroid outpatient clinic. Excluding patients in whom elevated basal hCT concentrations had already been known at the time of their referral, 507 patients with thyroid nodules presented basal concentrations of hCT of more than 10 pg/ml. Following stimulation by IV pentagastrin (0.5 microg/kg BW), hCT concentrations of more than 100 pg/ml were seen in 103 patients. This group included 32 new cases of MTC (29 patients with sporadic MTC and 3 new index cases of the familial form) and 43 patients with C cell hyperplasia (CCH). Among the 3,843 patients without thyroid nodules, 2 were found to harbor sporadic MTC while 4 had CCH. As compared to 1.1 cases of MTC per 1,000 patients with nodular thyroid diseases diagnosed in our institution before hCT screening was begun, 3.2 cases of MTC per 1,000 patients were identified when hCT was determined in all patients with thyroid nodules. The determination of hCT in all patients with thyroid nodular disease facilitates the timely diagnosis of MTC, thus providing the chance of curative surgery.

Expression of cdc25B and cdc25A in medullary thyroid carcinoma: cdc25B expression level predicts a poor prognosis

Cdc25B and cdc25A phosphatases are prominent stimulators of cell cycle progression and have been suggested to play oncogenic roles. In this study, we immunohistochemically investigated the expression of these phosphatases in medullary thyroid carcinoma. Cdc25B was positive in 35.8% of cases examined. Its positivity was linked only to patient age. However, patients with cdc25B-positive tumors showed a significantly worse disease-free survival rate (P=0.0210) than those with cdc25B-negative tumors. Cdc25A was positive in only 17.2% of cases and was not related to clinicopathological parameters or prognosis. These findings suggest that cdc25B can be regarded as having prognostic significance and as a novel marker of biologically aggressive characteristics in this carcinoma.

Clinicopathologic and Prognostic Significance of the Expression of Mucins, Simple Mucin Antigens and Histo-Blood Group Antigens in Papillary Thyroid Carcinoma

We have previously analyzed the expression of MUC1, underglycosylated MUC1, MUC2, MUC5AC, Tn, sialyl Tn, Lewis(a), sialyl Lewis(a), Lewis(x), and sialyl Lewis(x) in papillary thyroid carcinoma (PTC). The present study of 26 thoroughly scrutinized cases of PTC with "good" or "bad outcome" and a minimum of 10 yr of follow-up (or until death of the patients) was undertaken in an attempt to find if there is any relationship between the expression of the aforementioned antigens and the clinicopathologic and morphologic features of the cases and to evaluate the prognostic significance of the immunohistochemical pattern of PTC. We observed a significant or suggestive association between the expression of MUC1, underglycosylated MUC1, MUC2, Lewis(a), and Lewis(x) and the older age of the patients, and a suggestive association between Lewis(x) expression and lymph node metastasis and venous invasion. There was also a strong correlation between extrathyroid invasion, lymph node metastasis, intrathyroid dissemination, and venous invasion and patients outcome thus demonstrating, once more, the prominence of the classic clinicopathologic and morphologic features in the prognostic evaluation of PTC. The immunohistochemical study of mucins, simple mucin antigens, and histo-blood group antigens did not provide additional prognostic information, but for the significant association of Lewis(x) immunoreactivity to the group of "bad outcome."

Thyroid carcinoma

During the past years advances have been made in the understanding of the molecular mechanisms involved in the initiation and progression of thyroid carcinoma. Mutations in tumor suppressor genes such as p53 and oncogenes such as N-ras may be important for progression of well-differentiated thyroid carcinomas. Activation of the ret protooncogene located on chromosomal region 10q11.2 has been identified as a key factor in the initiation of papillary and medullary carcinoma. Integration of these discoveries into a prognostic classification scheme may allow us to better predict the biologic behavior of tumors in individual patients. Despite the recent advances in our understanding of the molecular events occurring during thyroid carcinogenesis, major questions persist regarding aspects of patient management. New diagnostic modalities may enable us to noninvasively discriminate between benign and malignant thyroid nodules, and to detect recurrent disease earlier. Although the optimal surgical procedure for well-encapsulated tumors is still debated, recent clinical studies have shown that for those patients with tumors > 1.5 cm, the routine use of RAI and hormone suppression can improve local control and survival rates. Findings in two recent reviews suggest that patients with widely invasive thyroid masses benefit from the surgical removal of all gross tumor. Further investigation is required to define the role of adjuvant radiotherapy and the most appropriate management of unresectable disease. Incorporation of prognostic markers into clinical staging systems should allow surgeons to better tailor their treatment plans for each patient. Translation of recent basic science advances into the clinical arena may also aid in the development of novel treatment strategies for patients with aggressive tumors.

Differential reactivity of HBME-1 and CD15 antibodies in benign and malignant thyroid tumours. Preferential reactivity with malignant tumours

We studied a wide range thyroid tumours and non-neoplastic conditions (total 463 cases) immunohistochemically to evaluate the possible diagnostic potential of HBME-1 and CD15 antibodies. HBME-1 monoclonal antibody recognizes a biochemically unknown epitope present in mesothelioma and variably present in some adenocarcinomas. CD15 antibodies recognize a sugar epitope also included in Lewis X blood group antigen. All papillary (145/145) and follicular carcinomas (27/27) were HBME-1 positive, usually in the the majority of tumour cells. In contrast, cases of nodular goitre and papillary hyperplasia either showed no reactivity or were focally positive (in a third of cases). The patterns of CD15 reactivity were generally similar, although smaller numbers of tumour cells were positive in papillary carcinomas, and only 50% of follicular carcinomas were positive. Because fetal thyroid also showed CD15 reactivity, this antigen appears to behave as an oncofetal antigen in relation to thyroid tissue. Anaplastic carcinomas were negative with both antibodies, indicating the loss of these epitopes upon high grade malignant transformation. We conclude that HBME-1 and CD15 immunohistochemistry may be helpful in the histological differential diagnosis between benign lesions and differentiated thyroid carcinomas, especially papillary tumours. Although the biochemical basis of HBME-1 reactivity is unknown, increased CD15 reactivity in malignant thyroid tumours probably reflects changes in thyroid follicular epithelial glycoconjugates related to malignant transformation.

Multivariate analysis of patients with medullary thyroid carcinoma. Prognostic significance and impact on treatment of clinical and pathologic variables

BACKGROUND

The prognostic significance of the histologic and clinical features of medullary thyroid cancer (MTC) and their impact on therapy and outcome have been evaluated infrequently in the same series.

METHODS

Fifty-tree patients with MTC (32 females, 21 males; 44 sporadic, 9 familial MTC [4 families]; mean age: 46.11 +/- 14.04 years) who were operated on consecutively between 1970 and 1992 were studied. All pathology slides were reviewed. Patients were followed with clinical examination, serum calcitonin (CT), and carcinoembryonic antigen (CEA) assay, and imaging procedures (median follow-up: 4 years; mean: 5.66 +/- 4.85 years; range: 0-19 years). Impact on survival was evaluated with Kaplan-Meier survival curves compared with the log rank test for these variables: familiarity, sex, age, pT, N, M, stage, histotype, necrosis, calcitonin, gene-related peptide (CGRP), CT, CEA, thyroglobulin, chromogranin A, chromogranin A PHE5, neuron-specific enolase, amyloid, argyrophilia, synaptophysin Y38, external radiotherapy, chemotherapy, 131I therapy, postsurgical serum CT, and postsurgical serum CEA, Multivariate analysis was performed using Cox's proportional hazards model for statistically significant factors (P < 0.05).

RESULTS

Ten- and 15-year cause-specific survival were 71% and 54%. Nineteen patients (35.8%) appeared to be cured and 8 (15.1%) were alive with high serum CT levels but no proven metastases. Eight recurrences as distant sites and four at the cervical region were diagnosed. Stage M, N, necrosis, and postsurgical CT and CGRP were significant prognostic factors for survival by univariate analysis, but only the stage was significant by multivariate analysis.

CONCLUSIONS

Stage and postsurgical serum CT level are the most powerful and the most useful prognostic factors for MTC, while survival did not correlated significantly with the majority of available immunohistochemical markers.