Estrogen is believed to be pre-initiator in the risk of breast cancer. The BRCA1
is a tumor suppressor gene associated with breast and ovarian cancer risk. This report
describes functional analysis of two BRCA1 missense mutations (Asp67Glu and
Thr1051Ser) observed in the familial breast/ovarian cancer patients in Thailand. Levels of
luciferase activity of the two mutations were relatively lower than in the wild-type BRCA1.
It is indicated that mutants may fail to promote the estrogen receptor dependent functions.
It is presumed that estrogen and insulin/IGF-1 regulate c-Myc and cyclin D1 during breast
cancer cell proliferation. It is also likely to affect ubiquitination mechanism. Since three
affected cancer families carry the Asp67Glu mutation, it is believed that this type of
mutation could have some effect on breast/ovarian cancer progression.
