Expression Of RETmRNA In Malignant Breast And Thyroid Tissues Of Patients With Multiple Primary Carcinomas In Breast And Thyroid And The Clinical Significance

Objective Breast cancer is one of the most common malignancy among women. During the therapy of breast caicinoma we fond that:a part of patients with breast cancer were diagnosed with thyroid disease, while the pathologic diagnosis of the these patients were almost papillary thyroid carcinoma after the operation. On this study we investigate the expression of RET (rearranged during transfection)gene in malignant breast tissues of 33 patients who get thyroid cancer after malignant breast disease surgery and to investigate the clinicopathologic correlation.Methods The expression of RET tyrosine kinase domain (RET-TK)of thirty-three specimens of malignant breast and thyroid tissues from patients with multiple primary carcinomas in breast and thyroid were analyzed by RT-PCR, additionally thyroid tissues were detected RET/PTC1 and RET/PTC3. Thirty specimens of malignant breast tissues and twenty specimens of benign breast tissues were also included as control cases for breast cancer. Besides thirty specimens of papillary thyroid carcinoma (PTC) and twenty specimens of benign thyroid tissues were for thyroid cancer as control cases.Results (1)57.6% of breast carcinoma tissues of patients with multiple primary carcinomas in breast and thyroid (19/33) expressed RET tyrosine kinase domain (RET-TK).30% of patients with breast cancer (9/30) expressed RET-TK.10% of patients with benign breast disease(2/20) expressed RET-TK. The positive rates of three groups were different significantly between any two groups respectively (P＜0.05).(2)Statistic analysis showed evident correlation between the expression of RET-TK and estrogen receptor (ER)(P<0.05), no significant difference was found regarding the age of the patients, tumor size, metastasis of lymph node and the expression of Her-2 state(P＞0.05). (3) 60.6% of thyroid carcinoma tissues of patients with multiple primary carcinomas in breast and thyroid (20/33) expressed RET tyrosine kinase domain (RET-TK). 46.7% of patients with PTC (14/30) expressed RET-TK.5% of patients with benign thyroid disease (1/20) expressed RET-TK. The positive rates of three groups were different significantly between any two groups respectively (P< 0.05).(4)21.2% of patients with multiple primary carcinomas in breast and thyroid(7/33) expressed RET/PTC1,3, including two cases expressing RET/PTC 1(6.1%) and five cases expressing RET/PTC3(15.1%).20.0% of PTCs(6/30) expressed RET/PTC1,3, including two cases expressing RET/PTC 1(6.7%) and four cases expressing RET/PTC3(13.3%). None of the twenty patients with benign thyroid diseases expressed RET/PTC1,3.(5)Statistic analysis did not show any correlation between the expression of RET-TK or RET/PTC and clinicopathologic parameters. (6)16 patients expressed RET-TK both in breast carcinoma tissues and in thyroid carcinoma tissues,3 patients expressed RET-TK only in breast carcinoma tissues,4 patients expressed RET-TK only in thyroid carcinoma tissues.Conclusions The activation of the RET gene is closely associated with the pathogenesis of multiple primary carcinomas in breast and thyroid. RET/PTC1,3 does not account for occurrence of the multiple primary carcinomas in breast and thyroid in Qingdao,China.