Association of the Length of CA Dinucleotide Repeat in the Epidermal Growth Factor Receptor with Risk and Age of Breast Cancer Onset in Isfahan

The epidermal growth factor receptor (EGFR) also known as HER1 or ErbB1 is a prominent member of the erbB proto-oncogene family, which encodes a receptor tyrosine kinase with a pivotal role in the regulation of cell growth and differentiation. The aim of this research was to study the CA repeat polymorphism in intron I of EGFR among the patients with breast cancer and healthy controls. We have also evaluated risks for breast cancer, age of onset and grade of tumor associated with the CA repeat polymorphism.In the present work, the association of breast cancer with the polymorphic CA repeat in 108 cases of breast cancer and 108 matched controls was studied. After DNA extraction from blood, CA dinucleotide region was amplified by PCR technique and the number of CA repeats was determined by polyacrylamide gel electrophoresis and sequencing.Our findings demonstrate that women with two short CA repeat (< 19) are at a significantly higher risk of breast cancer, at an estimated odds ratio of 1.86. We have also found that women with short alleles (< 19) had much greater risk of developing cancer before the age of 55 (OR=3.36).Our results suggested that shorter CA repeat length may be associated not only with the risk of breast cancer but also with the age of developing cancer in Isfahanian population. We did not find any relation between the CA repeats length and tumor staging.