| Chapter 1 The expression of lection-related molecules correlateswith the qualitative diagnosis of thyroid carcinomasBackground: Up to now, no special method has been established to identify the group of malignant tumors in a presurgical phase because of different histological and behavior patterns. FNAC (fine-needle aspiration cytology) boasts excellent diagnostic accuracy for anaplastic and medullary carcinomas, but the main limitation is the lack of sensitivity in the evaluation of follicular lesions. Galectin-3 and CD44v6 are two groups of lectin-related molecules, the expression of which is altered during cell proliferation, malignant transformation and tumor progression. At present, the study of galectin-3 expression in thyroid carcinomas has not been found in native literatures, moreover, we have not found foreignreports about the significance of galectin-3 and CD44v6 expression in qualitative diagnosis together with prognostic assessment of thyroid tumors. Therefore, in this study we examined their expression hi a spectrum of surgically excised benign and malignant thyroid lesions and analyzed the relationship between their abnormal expression and differential diagnosis as well as prognostic assessment of thyroid carcinomas in order to explore the clinical significance of the specific tumor marker.Methods: 60 tissue samples were examined in this study. They were taken from patients who had undergone thyroidectomy, including 37 thyroid carcinomas (20 papillary carcinomas, 14 follicular carcinomas, 2 anaplastic carcinomas and 1 medullary carcinoma), 23 benign thyroid lesions (15 adenomas and 8 nodular goiters) and 10 normal thyroid tissues obtained from histologically normal areas adjacent to the lesions or the other lobe. All the specimens were fixed in 10% neutral formalin, embedded in paraffin, and cut into sections. Immunostaining was performed on these sections using monoclonal antibodies against PCNA (proliferaing cell nuclear antigen), galectin-3 and CD44v6, and the results were analyzed qualitatively and half-quantitatively. The levels of PCNA expression were evaluated by PI (Proliferation Index), namely a percentage of positive cells in a total of 1000 counted cells.Results:1. The PI of differentiated thyroid carcinomas was 38 + 15, while that of undifferentiated carcinomas was 78 ?0. Undifferentiated carcinomas showed significantly higher PI than undifferentiated carcinomas (P<0.05), although the PI of malignant lesions was not predominantly different from benign lesions.2. The incidence of galectin-3 positive expression in thyroid carcinomas(86.49%, 32/37) was significantly higher than that in benign lesions (4.3f %, 1/23) (P<0.005). The normal thyroids were negative for galectin-3. An intense and diffuse cytoplasmic staining was observed in all 20 papillary carcinomas and 6 of 14 follicular carcinomas. Galectin-3 immunostaining in follicular carcinomas showed great variability. The two cases of anaplastic carcinoma were all positive staining and 1 medullary carcinoma was negative. The diagnostic accuracy of galectin-3 evaluation was 97.67% in papillary carcinomas and 86.49% in follicular carcinomas respectively, compared to its expression in benign lesions.3. The incidence of CD44v6 positive expression in thyroid carcinomas (89.19%, 33/37) was significantly higher than that in benign lesions (21.74%, 5/23) (P< 0.005). The normal thyroids were also negative for CD44v6. The pattern of staining for CD44v6 was mainly membranous but cytoplasmic, as well. The frequency of CD44v6 positive expression in NI lesions (96.43%, 27/28) was higher than that in NO lesions (66.67%, 6/9), thus it could be seen that the levels of CD44v6 expression was different in different pathologic stages of thyroid rumors.Conclusion:1. The proliferating activity of tumor cells is associated with the differentiation degree. The higher the proliferating activity is, the lower the differentiation degree is.2. Galectin-3 expression in thyroid carcinomas is higher than tha... |
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