Expression Significance of Paired Alkaline Amino Acid Lyase 4 in Thyroid Nodules

ZHANG Liang; SHAN Wei; MA Yunsheng

Abstract：Objective To compare the expression distribution of paired amino acids converting enzyme 4(PACE4)subtypes PACE4-FL and PACE4-CT in benign and malignant thyroid nodules,providing reference data for the identification of benign and malignant thyroid nodules.Methods Thyroid tissue chunks from patients who underwent thyroidectomy in Anshan Cancer Hospital from 2017 to 2020 was found.According to pathological types,the malignant nodules were selected as papillary carcinoma,follicular carcinoma and medullary carcinoma.Benign nodules,proliferative,glial,adenomatous nodules,follicular adenoma and thyroiditis types were selected.The corresponding tissue sections were immunostained with antibodies to PACE4-FL,the full-length PACE4 protein subtype of PACE4,and its replacement subtype PACE4-CT.The lesion area of the tumor was compared with the surrounding normal tissue,and the staining was evaluated by an experienced pathologist.Results There was no or low expression of PACE4-FL in non-diseased thyroid tissues(P＜0.01).The expression rate of PACE4-FL in malignant nodules was significantly higher than that in benign nodules(P＜0.01),and the immunostaining specificity of PACE4-FL was 95.8％.In malignant lesions,PACE4-FL was most clearly expressed in typical papillary carcinomas.On the contrary,the expression was low in follicular papillary carcinoma.In follicular carcinoma,60％showed high expression of immunostaining.In benign nodules,the expression of PACE4-CT was similar in pathological and non-pathological(normal)tissues(P＞0.05).In malignant nodules,the expression of PACE4-CT in the lesion area was significantly lower than that in the adjacent non-lesion area.Conclusion The differential expression of PACE4-FL and PACE4-CT in thyroid cancer is high and low,especially the differential expression of PACE4-FL is expected to be a potential biomarker for the detection or screening of thyroid cancer.