The Relationship of CAC Polymorphism in HOXA1 Gene and Breast Cancer

HOXA1 is a transcription factor. In the human mammary gland, the expression of the HOXA1 gene is very low or absent during normal growth and differentiation, but it is expensed at high levels in breast cancer lesions. To date, there has been no study on the relationship between CAC repeat (polyhistidine) in the first exon of HOXA1 gene and the cancer risk. The purpose of this study was to investigate polymorphism of CAC in in the first exon of HOXA1 gene among patients with breast cancer and healthy individuals to clear the relationship of CAC polymorphism in HOXA1 Gene and the risk of breast cancer.

Peripheral blood samples were collected from 193 women with breast cancer and 200 healthy women. After DNA extraction from peripheral blood samples by salting-out method and amplification of desired sequence by polymerase chain reaction (PCR), the number of CAC repeat was determined by polyacrylamide gel electrophoresis and direct sequencing.

Five different length of CAC repeat in the range of 3-7 and 5 allele combinations (genotypes) were observed among patients and controls. The most frequent allele in both patients and controls was the 7-CAC repeat. No significant association was observed between this allele and breast cancer risk. Statistical analyses showed significant association between homozygote 7 and estrogen and progesterone receptors.

Our findings demonstrate that there is no significant association between CAC repeat in exon 1of HOXA1 gene and breast cancer risk. However, there is a significant association between homozygote 7 genotype and estrogen and progesterone receptors.