Aim: Several studies suggested that there is a relationship between serum levels of IGF1 or their polymorhisms and some cancer types. The genetic polymorphism in the region of IGF promoter region which is composed of cytosineadenine repeats, affects the promoter activity. It is suggested that serum IGF1 levels are inversely associated with the length of CA repeats. There are studies reporting that the carriers of the CA 19 allele are more likely to develop some cancer types through chronically high IGF1 levels. The relationship between IGF1 and thyroid cancer derived from the experiences in acromegalic patients as thyroid cancer freguency was found to be increased in acromegaly patients. The aim of our study was to examine CA 19 allele frequency in thyroid cancer patients and healthy controls and determine the association of this polymorphism with thyroid cancer and with its prognostic factors.
Patients and methods: 161 patients with well differentiated thyroid cancer (papillary and follicular) were included in this study. The clinicopathological variables and prognostic factors were obtained from the medical records. Age and sex matched 101 volunteers were accepted as control group. The IGF1 (CA) repeats were studied with PCR by using proper primers belonging to IGFI (CA) 19 area from DNA samples in both groups.
Results: The frquency of CA 19 allele was not different in thyroid cancer patients than the control group (P=0.87). But within the thyroid cancer patients CA 19 allele was found to be associated with soft tissue and vascular invasion (P values were 0.03 and 0.05 respectively).
Conclusion: IGF1 gene polymorphism (CA 19 allele) is found not to be associated with the development of thyroid cancer but it is found to be associated with some poor prognostic factors like soft tissue and vascular invasion in well differentiated thyroid cancer patients.