| Tumor development and progression was a multi-stage complicated process. Tumor invasion and metastasis was the major reason of the death of tumor patient. The research on the molecular mechanism of tumor biology showed that invasion and metastasis process was regulated by a lot of specific genes and correlation factors. They were activated, inhibited, inter-synergism or antagonism to influence tumor biological characteristic finally. These regulatory mechanism included over activation of oncogene, inactivation of anti-oncogene, regulation of tumor cell proliferation cycle and apoptosis et al.Thyroid cancer was one of the frequent malignant tumor. It took about 1% among the malignant tumor and made serious threaten to human health. Thyroid cancer was a kind of disease that caused by disbalance regulation of oncogene and anti-oncogene. Because of its hiding pathogenesis, slowing progression, it was hard to distinguish the benign and malignant thyroid tumor. This made huge difficulty to clinical diagnosis and therapy. Thus, to identify the molecular markers of the benign and malignant thyroid tumor would make contribution to clinical diagnosis and therapy. At present, a lot of oncogene and tumor markers have found on the basis of research progress of tumor on molecular and protein level. A lot of makers showed close relationship to thyroid tumor development, progression, and turnover. This brought the promising prospect of diagnosis and therapy of thyroid tumor. For the past few years, researchers demonstrated that KAI1/CD82 and Survivin participated tumor progression. They could be the tumor makers. Survivin was a kind of oncogene. It was a new inhibitor of apoptosis protein. It was also the most powerful inhibitor of apoptosis that found so far. KAI1/CD82 was a tumor-metastasis suppressor gene and encoded a protein of CD/82. It belonged to a structurally distinct superfamily of membrane glycoproteins TM4SF (transmembrane 4 superfamily or tetraspan superfamily). TM4SF proteins had four highly conserved hydrophobic regions, presumed to be transmembrane domains, and a extracellular hydrophilic domains. There were three potential N-glycosylated domains, which located on the surface of the leukocyte and other cells. The membrane location of TM4SF and extensive glycosylation suggested that they function in cell-cell interactions and cell-extracellular matrix interactions, both of which were important in tumor invasion and metastasis.This study detected the expression of Survivin and KAI1/CD82 in different histological types of thyroid cancers through immunohistochemistry assay and RT-PCR assay. We then analyzed the relationship and associativity between the expression of Survivin and KAI1/CD82 and the malignant degree of thyroid cancer.The results were as follows:1. Expression of Survivin in thyroid cancerImmunohistochemistry assay showed that positive Survivin expression located in the cell plasma. It showed negative expression of Survivin in normal thyroid. But in the thyroid cancer, it was significant higher than in the normal tissue. It increased with the histological malignant degree of the thyroid cancer. The positive expression ratio in thyroid papillary carcinoma, follicular carcinoma and medullary carcinoma were 60%, 69.2%, and 91.6%. In the medullary carcinoma, Survivin showed strong positive expression. RT-PCR assay showed that the relative expression value of Suvivin in thyroid papillary carcinoma, follicular carcinoma and medullary carcinoma were59.154±10.086,67.25±8.478,86.898±6.944. It was 32.148±9.513 in the normal thyroid tissue. The expression of Survivin in different histological types of thyroid cancer were significant higher than in normal thyroid tissue(P<0.05).2. Expression of KAI1/CD82 in thyroid cancerImmunohistochemistry assay showed that KAI1/CD82 expressed in normal thyroid tissue. It mainly located in the cell membrane, some located in the cell plasm. The positive expression ratio in thyroid papillary carcinoma, follicular carcinoma and medullary carcinoma were 80%, 53.8%, and 16.7%. Statistic analysis showed that there was no significant difference of KAI1/CD82 expression between normal thyroid tissue and papillary carcinoma. But it decreased significantly in follicular carcinoma and medullary carcinoma. RT-PCR assay showed that the relative expression value of KAI1/CD82 in thyroid papillary carcinoma, follicular carcinoma and medullary carcinoma were85.406±12.992,70.1±10.880,30.682±13.270. It was 91.124±12.292 in the normal thyroid tissue. The relative expression value decreased significantly in follicular carcinoma and medullary carcinoma compared with normal thyroid tissue. The expression the KAI1/CD82 decreased when the histological malignant degree of thyroid cancer increased. In summary, expression of Survivin and KAI1/CD82 had a close relationship with malignant degree of thyroid cancer. Expression of Survivin had a positive correlation with the malignant degree of thyroid cancer while the expression KAI1/CD82 had a negative correlation. They could play important roles in thyroid cancer development and progression. Combining detection of the expression of Survivin and KAI1/CD82 in thyroid cancer and even other tumors would make contribution to the tumor diagnosis and therapy. |
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