Abstract: Objective A variety of bioinformatics analysis tools and immunohistochemical staining were used to investigate the expression and clinical diagnostic significance of sequence similarity 20 family members A(FAM20A)in thyroid cancer(TC). Methods The data related to thyroid cancer were obtained from the Cancer Genome Atlas(TCGA)database,the expressed difference of FAM20A between TC tissues and normal tissues was analyzed,and the ROC curve was drawn to calculate the AUC value and evaluate the diagnostic efficacy of FAM20A in TC.The GSE205733 thyroid cancer dataset was downloaded from the GEO database to analyze the level of FAM20A gene in TC tissues,and perform the gene set enrichment analysis(GSEA).The protein interaction network of FAM20A was analyzed using the online database STRING.At the same time,the pathological tissue samples of 29 patients who underwent thyroid nodule surgery in the department of Thyroid Surgery,Beijing Luhe Hospital affiliated to Capital Medical University from March 2022 to February 2023 were collected,and the pathological tissue paraffin sections and immunohistochemical staining was performed to verify and compare the expression of FAM20A in TC and benign thyroid nodule samples. Results The results of the TCGA database showed that compared with normal thyroid tissues,the expression of FAM20A was significantly increased in TC tissues(P＜0.001).The expression of FAM20A was associated with clinical TNM staging and pathological classification of TC(P＜0.05).FAM20A showed significant diagnostic efficacy for thyroid carcinoma(AUC=0.828).The analysis of GSE205733 data showed that compared with normal tissues,FAM20A expression significantly increased in TC tissues(P＜0.001).The GSEA enrichment analysis results showed that FAM20A was mainly related to signaling pathways such as P53 and interleukin.The STRING database showed that the proteins that interact with FAM20A mainly include PEAK,FAM20C and ENAM.The immunohistochemical staining results showed that the expression of FAM20A was significantly increased in TC tissues(P＜0.05). Conclusion The FAM20A gene is highly expressed in TC tissues,and is associated with clinical TNM staging and pathological classification of patients.It can serve as a potential molecular marker for diagnosis of TC and is associated with signaling pathways such as P53 and interleukin,providing a theoretical basis for studying the molecular mechanism of TC progression and the development of targeted drugs.

Key words: Bioinformatics, Family with sequence similarity 20 member A, Thyroid cancer