| BackgroundThyroid cancer is the most common malignant tumor of the endocrine system,accounting for about 1% of all malignant tumors.In recent years,the number of thyroid cancer patients has been increasing with the continuous updating of the means of examination and the increasing awareness of patients' health.The common pathological types of thyroid cancer are mainly divided into four categories: Papillary thyroid carcinoma(PTC),Follicular thyroid carcinoma(FTC),Medullary thyroid carcinoma(MTC)and anaplastic thyroid carcinoma(ATC).Among them,papillary thyroid cancer and follicular thyroid cancer(DTC)together account for about 95%,medullary thyroid cancer for about 3%,undifferentiated thyroid cancer for less than 1%.Compared with differentiated thyroid cancer,medullary cancer is more aggressive.About 55% of patients diagnosed with medullary thyroid cancer are accompanied by lymph node metastasis and extraglandular invasion.The overall survival rate of these patients is about 5 years,which is one of the main causes of death of thyroid cancer patients.At present,the preoperative diagnosis of medullary thyroid cancer mainly depends on color Doppler ultrasound,fine needle aspiration biopsy and calcitonin.For the treatment of medullary thyroid cancer,surgery is still the first choice.Total thyroidectomy and regional lymph node dissection are generally selected.Specific surgical scope is generally based on preoperative examination and family history.For cases with suspected lymph node metastasis indicated by color Doppler ultrasound and serum calcitonin greater than 200 pg/mL before operation,total thyroidectomy plus neck lymph node dissection on the affected side and prophylactic lymph node dissection on the contralateral side can be selected.However,there is still controversy about the specific extent of lymph node dissection in cases where preoperative color Doppler ultrasound does not indicate lymph node metastasis.In addition,some patients who have undergone surgical treatment will have recurrence,or even multiple recurrences,which will reduce the quality of life and worsen the prognosis of patients.For some patients with medullary thyroid cancer who have already had distant metastasis,multiple recurrences or refractory treatment,there is still no obvious effective treatment.As a research hotspot in the field of cancer molecular biology,microRNAs have been proved to be involved in many pathophysiological processes.A large number of literatures have shown that microRNAs can regulate the expression of target genes in different ways,thus affecting the occurrence and development of diseases.Even some microRNAs have been proved as diagnostic markers for assistant diagnosis.They can also be used as drug targets to intervene in the treatment of cancer and improve the prognosis of disease.Similarly,a large number of aberrant microRNAs have been found in thyroid cancer.According to the literature,hsa-microRNA-30 a plays a regulatory role in the formation and development of many cancers,including head and neck squamous cell carcinoma,liver cancer and breast cancer.However,the expression in medullary thyroid carcinoma has not been reported in the literature.At present,genomics and transcriptome research is gradually deepening,a large number of chip sequencing results are stored in different databases.In this study,microarray data from a public database were used to predict differentially expressed microRNAs in medullary thyroid cancer cells,and then RT-PCR was used to detect the expression of target microRNAs in clinically collected thyroid cancer samples.The relationship between the expression of target microRNAs and the clinicopathological characteristics of medullary thyroid cancer was analyzed.Objectives1.To study the expression of hsa-mir-30 a in medullary thyroid carcinoma.2.To investigate the correlation between the expression disorder of hsa-mir-30 a and the clinicopathological features of medullary thyroid carcinoma.3.To investigate the diagnostic value of the expression disorder of hsa-mir-30 a in medullary thyroid carcinoma with or without lymph node metastasis.Materials and Methods1.The expression profiles and clinical information of microRNAs numbered GSE97070 and GSE72728 were retrieved from GEO database.The data were processed by limma package to analyze the differential expression of microRNAs in medullary thyroid carcinoma.2.Forty patients with medullary thyroid cancer were randomly selected to collect thyroid cancer tissues and normal thyroid tissues adjacent to the cancer.Target microRNAs in the samples were detected by qRT-PCR.The clinical information of the 40 patients was also counted.The relationship between target microRNAs and clinicopathological features of medullary thyroid carcinoma was analyzed,and the relationship between target microRNAs and clinicopathological features of medullary thyroid carcinoma in GSE72728 was also analyzed.The two results were mutually validated.3.Predict the target gene of microRNAs,speculate the mechanism of microRNAs in the formation and development of medullary thyroid cancer,and provide direction for future research.4.Rex64 3.5.2 software was used to run limma software package for screening differential microRNAs.The screening conditions were |logFold Change(FC)|>1,adj.P < 0.01,and visual volcanic maps were made.SPSS 19.0 software and GraphPad Prism 8 software were used to study the correlation between microRNAs and clinical features.T test and chi-square test were selected according to the distribution type.If P < 0.05,the correlation was significant.ResultsThe expression of hsa-microNA-30 a in medullary thyroid cancer was lower than that in normal samples.It was negatively correlated with the size of medullary thyroid cancer,lymph node metastasis,TNM stage and other clinicopathological features,but not with age,sex,thyroid cancer typing,extraglandular invasion and multiple lesions.Medullary thyroid carcinoma with lymph node metastasis has good diagnostic value.Conclusions1.The expression of hsa-microRNA-30 a in medullary thyroid carcinoma is lower than that in normal thyroid tissue.It is inferred that hsa-microNA-30 a can inhibit the development of thyroid medullary carcinoma;2.The low expression of hsa-miRNA-30 a was significantly correlated with the size of medullary thyroid carcinoma,lymph node metastasis,TNM stage and other clinicopathological features,but not with the age,sex,thyroid cancer typing,extraglandular invasion,multi-focus and other clinicopathological features;3.The imbalance of has-microRNA-30 a expression has a good diagnostic value for the preoperative diagnosis of medullary thyroid carcinoma with lymph node metastasis. |
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