THE ROLE OF IMMUNOHISTOCHEMICAL MARKERS IN PREDICTING RECURRENCE OR DEATH IN PATIENTS WITH MEDULAR THYROID CANCER

Introduction. Medullary thyroid cancer (MTC) belongs to a class of rare neuroendocrine aggressive tumors and arises from parafollicular cells (C-cells). An important modern problem is the development of ways to predict the recurrence of this disease. The aim of the study is to determine the role of immunohistochemical tumor markers of medullary thyroid cancer in predicting recurrence or death. Materials and methods. The analysis of the prospective study included 22 patients with MTC, 5 of whom have developed a recurrence and 4 have died at the end of the 10-year (120 months) follow-up period. Immunohistochemical examinations were performed using monoclonal antibodies of tumor markers calcitonin, chromogranin A, vimentin and Ki-67. Results. The discrepancy between the data of histological and immunohistochemical examinations in MTC is 12.0%, which indicates the hyperdiagnosis of this nosology and argues the importance of performing immunohistochemical examinations to verify the diagnosis. Patients who had a recurrence of MTC had significantly (p <0.05) lower levels of calcitonin expression (5.00 [5.00; 5.00] points) compared with patients who did not relapse, where this figure was 6.00 [6.00; 7.00] points. In patients with MTC, an increase in calcitonin expression was significantly associated with an increase in chromogranin A expression (r = + 0.49, p = 0.02); a similar relationship was found for the proportions of immunopositive cells of these tumor markers: r = + 0.68, p = 0.001. At the same time, it was found that the increase in the level of calcitonin expression was apparently combined with the decrease in the level of Ki-67 expression (r = -0.52, p = 0.02). It was also found that the increase in the level of vimentin expression is combined with an increase in the expression (r = + 0.64, p = 0.001) and the proportion of immunopositive cells of chromogranin A (r = + 0.45, p = 0.038). Conclusions. Low levels of calcitonin expression are prognostically unfavorable markers for the recurrence of MTC. Specific tumor markers are important in the treatment process and for the dynamic monitoring of patients with MTC.

THE ROLE OF CALCITONIN IN THE PREOPERATIVE STAGE AS THE PREDICTOR OF MEDULLARY THYROID CANCER METASTASES

the aim of the stydy was to analyze the detectability of medullary thyroid metastases in patients at treatment and diagnostic stages, to investigate the applicability of serum calcitonin level as predictor of possible presence of medullary thyroid metastases. The study included data from 148 patients who underwent surgical treatment for the initial diagnosis of medullary thyroid cancer. The age of patients ranged from 12 to 83 years, the mean age was 48,2±1,9 years; the distribution by gender was as follows: men – 34 (23%), women – 114 (77%). Patients were divided into two groups depending on the pathomorphological report: 1 group (100 (67,6%) – patients without metastases), 2 group (48 (32,4%) – patients with locoregional metastases). Among 148 studied patients with medullary thyroid cancer, as a result of the histopathological conclusion, in 48 (32,4%) metastases were detected in regional lymph nodes, among which 10 (6,7%) patients had metastases only in the central collector and 38 (25, 7%) –both in the central and lateral collectors. At the preoperative stage, the level of undiagnosed metastases by ultrasound was 64,58% (31 patients). Subsequently, at the intraoperative stage, during the rapid histological biopsy, the number of undiagnosed metastases decreased to 37,5% (18 patients), and in the postoperative period, according to the results of histopathological examination, the remaining patients were diagnosed with the medullary thyroid cancer metastases. Ultrasound helped to detect metastases in 17 patients, which was 35,42% of all detected metastases. At the stage of intraoperative study, the detection of metastases increased and amounted to 30 (62,5%), and in the postoperative period as a result of histopathological examination metastases were confirmed in 48 patients (100%). Quantitative indicators of both detected and undiagnosed metastases at all stages of treatment and diagnostic search are statistically significant (p<0,01). The detection of metastases in the central lymphatic collector (N1a) at the preoperative stage was 2,08%, this index has doubled (to 4,16%) after intraoperative rapid histological conclusion, and after histopathological conclusion the index has increased more than 10 times (20,84 %). This tendency to grow of metastaseses detection was followed also on lateral collectors: N1b and psilateral were observed at 15 (31,2%) patients at the preoperative stage, their number increased to 23 (47,9%) intraoperatively and to 31 (64,6%) postoperatively; N1b contralateral was observed in 1 (2,1%), 5 (10,4%) and 7 (14,6%), respectively. Such a low percentage of metastases detection at the preoperative stage by ultrasound prompted to CT level study as the predictor of possible metastases. We investigated the preoperative basal blood CT value as a marker of the medullary thyroid cancer metastases presence probability. Due to the small number of the group (n=10) with N1a, the association of CT (cut-off level 137 pg/ml) with the possible presence of metastases was not significant (AUC = 0.594), while in the group with N1b there was a more significant difference. Thus, CT cut-off levels of 358 pg/ml for N1b ipsilateral, and 498 pg/ml for N1b contralateral detection of possible metastases in collectors, with AUC: 0.877 and 0.832, respectively, which justifies the importance of the lateral neck dissection in addition to the mandatory central dissection in order to remov possible medullary thyroid cancer metastases. Thus, ultrasound is insufficiently reliable method of metastases verifying in medullary thyroid cancer (DE = 35.4% at d mts <0.6 cm). In the absence of ultrasound data (or fine needle aspiration (FNA) biopsy results) on the presence of metastases to raise awareness of the disease prevalence, to clarify the prognosis of its development it’s important to use the additional criterion – the calcitonin level. Basal calcitonin level is the reliable predictor of the medullary thyroid cancer metastases. Its cut-off level of 137 pg/ml indicates the possible presence of metastases in the central group (N1a) (AUC=0,594). The CT cut-off level – 358 pg/ml (AUC=0,793) suggests the presence of the medullary thyroid cancer metastases (N1a+N1b). CT cut-off levels – 358 pg/ml for N1b ipsilateral, and 498 pg / ml for N1b contralateral (AUC: 0,877 and 0,832), respectively. The calculated values of the countersensitivity test to detect metastases for different levels of basal CT in the preoperative stage in the clinical setting will help the practitioner in deciding on treatment tactics to determine the extent of surgery in patients diagnosed (or suspected) with the medullary thyroid cancer metastases.

Calcitonin level in the postoperative period as a risk factor for persistence of medular thyroid cancer

Aim — to evaluate the possibility of using basal calcitonin levels in the postoperative period to assess the effectiveness of surgical treatment of medullary thyroid cancer and the likelihood of its persistence (recurrence). Materials and methods. A single-site retrospective study was conducted to assess results of surgical treatment of 194 patients (74.2 % women and 25.8 % men), from them148 (76.3 %) patients had primary forms of the disease (group 1) and 46 (23.8 %) the recurrent form (group 2). Primary surgery included thyroidectomy, supplemented with thecentral and lateral dissection of the neck. Patients in group 1 were divided into two subgroups depending on the postoperative calcitoninlevels: group 1A with normal calcitonin levels (≤ 18 pg/ml)and group 1B with hypercalcitoninemia (> 18 pg/ml). The quantitative­determination of blood serum calcitonin levels was performed using automatic immunochemiluminescent analyzer «MAGLUMI» («Snibe Diagnostic», China) in 1 week and 1 year after surgery. Accumulation and primary data processing were performed in MS Excel 2013, statistical processing was performed using StatPlus programs with descriptive statistics, parametric and nonparametric methods for testing statistical hypotheses (Student’s criteria, Mann-Whitney, Fisher angular transformation), analysis of conjugation tables, ROC-analysis. The results were considered statistically significantat p < 0.05. Results. The average duration of follow-up was 67.5 months. The results of surgery were analyzed in terms of absence or presence of clinical recurrence, calcitoninlevels in the early postoperative period (5 days) were used as a predictor. After 2 years of follow-up,normocalcitoninemiawas accompanied by recurrence in almost 2 % of cases, while hyper­calcitoninemia — in 61 % to 74 %, depending on the stage and frequency of the disease. The correlationsbetween postoperative calcitonin levels and presence of recurrence (persistence) of medullary thyroid cancer has been established: AUC = 0.928 (0.867; 0.989, Juden index (J) = 0.429, threshold (cut-off point) ≥ 28.1 pg/ml, sensitivity = 0.938 (0.854; 1,000), specificity = 0.855 (0.789; 0.920), predictive value of positive result(PPV) = 0.699, predictive value of negative resultPNV = 0.991. Moreover, countersensitivity scores and incidence of negative test results in patients with relapse depending on the level of postoperative calcitonin were calculated. Conclusions. Postoperative calcitonin levels in 5 days after surgery can be used for assessment of efficacy of the surgical treatment (AUC — 0,928 (0,867; 0,989), Juden index — 0,429)). The prognosis of recurrence-free disease does not depend on the disease stage. At calcitonin levels < 18 pg/ml, clinical signs of the disease persistence (recurrence) were detected in 1.5 % of cases (PNV = 0.991). The reliability of predicting the disease recurrence depended on the stage and frequency of surgery: PRV = 0.612 in primary forms without metasta­­ses, PRV = 0.825 in recurrent forms. Calcitonin values < 28.1 pg/ml can be considered a relatively «safe» level.

Prognostic Performance of Alternative Lymph Node Classification Systems for Patients with Medullary Thyroid Cancer: A Single Center Cohort Study

Background Lymph node ratio (LNR) and the log odds of positive lymph nodes (LODDS) have been proposed as alternative lymph node (LN) classification schemes. Various cut-off values have been defined for each system, with the question of the most appropriate for patients with medullary thyroid cancer (MTC) still remaining open. We aimed to retrospectively compare the predictive impact of different LN classification systems and to define the most appropriate set of cut-off values regarding accurate evaluation of overall survival (OS) in patients with MTC. Methods 182 patients with MTC who were operated on between 1985 and 2018 were extracted from our medical database. Cox proportional hazards regression models and C-statistics were performed to assess the discriminative power of 28 LNR and 28 LODDS classifications and compare them with the N category according to the 8th edition of the AJCC/UICC TNM classification in terms of discriminative power. Regression models were adjusted for age, sex, T category, focality, and genetic predisposition. Results High LNR and LODDS are associated with advanced T categories, distant metastasis, sporadic disease, and male gender. In addition, among 56 alternative LN classifications, only one LNR and one LODDS classification were independently associated with OS, regardless of the presence of metastatic disease. The C-statistic demonstrated comparable results for all classification systems showing no clear superiority over the N category. Conclusion Two distinct alternative LN classification systems demonstrated a better prognostic performance in MTC patients than the N category. However, larger scale studies are needed to further verify our findings.

Tumor-Related Molecular Regulatory Mechanisms of Long Non-Coding RNA RMST: Recent Evidence

Background: Long non-coding RNA rhabdomyosarcoma 2-associated transcript (LncRNA RMST) will affect every aspect of tumor progression, such as proliferation, translocation and apoptosis. As a result, RMST can be used as an attractive biomarker for early diagnosis and clinical therapies of different disease states. This article aims to review pathophysiological functions, molecular mechanisms as well as promising biotherapies of RMST in multiple tumors. Methods: Through the systematic induction and summary of 46 papers published in PubMed concerning this study, the molecular mechanisms of RMST in all kinds of tumors have been reviewed. Results: LncRNA RMST is a tumor-related regulatory mediator, aberrantly expressed in diverse tumors, regarding medullary thyroid cancer, hepatocellular carcinoma, endometrial carcinoma, colon cancer, pancreatic cancer, glioma, Wilm’s tumor and breast cancer. Furthermore, as a mechanism-based player, RMST probably guides the translation and post-translation modification, containing DNA methylation and SUMOylation. It is capable of regulating distinct tumor cells and stem cells of biological behaviors via various molecular pathways. Conclusion: LncRNA RMST, potentially as an original therapeutic target, is valuable in the occurrence, development and apoptosis of different tumors.

Reduced MHC class II expression in medullary thyroid cancer identifies patients with poor prognosis

Increasing body of recent studies determining the expression of tumor-specific major histocompatibility complex (MHC) class II protein support its potential role in several malignancies but little is known in human medullary thyroid cancer (MTC). Here we report the expression of MHC-II and its clinicopathologic and prognostic relevance in MTC patients. Immunohistochemistry staining revealed a significant reduction in tumor cell specific MHC-II expression in a higher AJCC stage and its poor prognostic correlation with human MTC development. Further statistical analysis identified the low MHC-II expression as a significant and independent risk factor for MTC recurrence and patient survival. Moreover, in vitro studies showed that the MHC-II expression was remarkably increased by RET inhibitors, which were prescribed to treat advanced MTC. Similarly, inhibitors blocking the MAPK/ERK and AKT/mTOR pathways also augmented MHC-II expression, suggesting their implications in RET-MHC-II signaling axis. Importantly, in vitro assays manifested enhanced peripheral blood leukocytes-mediated cytotoxicity in MTC cells treated with RET inhibitors, which were partially alleviated by HLA knock-down. Together, our study demonstrates that low MHC-II expression levels may serve as a prognostic biomarker for aggressive diseases in MTC patients and indicates that RET activation may promote MTC immune escape through down-regulating MHC-II expression.