Tg MRNA Test In Peripheral Blood And Its Potential Use In The Diagnosis And Follow-up Of Thyroid Cancer

As a most frequent malignant tumor, thyroid cancer has a variant growth behavior. 98% of the cancer can be classified as Differentiated Thyroid Cancer (DTC). Although with low malignancy, it is reported that from 20% to 40% of the DTC patients still suffer from the recurrence. So the early diagnosis and follow-up to patients after surgery treatment is really essential. Blood serum thyroglobulin (Tg) test is an important and routine method to monitor the thyroid remnant and relapse of thyroid cancer, though 10%-25% of the patients are Tg autologous antibody (Tg Ab) positive. As the existence of Tg Ab interferes the immunology test of Tg, this in advance influences the judgment of thyroid cancer patients'real status during follow-up. To quantitatively mesure the Tg mRNA in peripheral blood, we can eliminate the negative impact of Tg Ab and gain more precise message of patients. But whether the Tg mRNA results can be used in the follow-up of thyroid cancer patients, there is still disputation.In the first part of this study, through the investigation of how to get enough total RNA with high quality from limited human peripheral blood samples, how the preserve condition can impact total RNA isolation, we put our efferts on how to get total RNA within a clinical standard from blood samples. The results show the preservation of blood samples, including the temperature, period and sample freezing/thawing has large impact on the total RNA isolation. The standard method of isolating RNA is meaningful and our method of isolating total RNA from small volumes of blood can get enough total RNA with high quality. And the obtained RNA can be used in the down-stream application.In the second part of the study, we focus on the Tg mRNA quantitative test in peripheral blood and thyroid cancer tissues by quantitative real-time PCR technology. Together with the blood serum Tg and Tg Ab test results, we thoroughly analyze the possibility of Tg mRNA quantitative test used in the clinical follow-up of DTC patients. The quantitative real-time PCR results illustrates that Tg mRNA is the highest in the blood samples from thyroid cancer patients, which is higher than that in patients of the control group, the struma nodosa group and the hyperthyroidism group. The statistic difference p values are 0.0005,0.0002 and 0.0027 relatively. Serum Tg and Tg Ab level are also essential to the tested Tg mRNA. The coefficient of regression is 0.693 and 0.633 seperatedly. Thyroid cancer staging is with no strong relation with the expressed Tg mRNA level in peripheral blood.In general,we prove that Tg mRNA quantitative test result is valuable in the follow-up of thyroid cancer patients under surgery treatment, especially to the Tg Ab positive patients. Tg mRNA quantitative test can be a compliment factor to judge the real status of DTC patients.What we provide is the experimental results of supporting Tg mRNA quantitative test as a regular clinical method in the early diagnosis, treatment and follow-up of thyroid cancer.