A medical study has found that having a gene mutation can increase the risk of developing blood clots for those women who are undergoing breast cancer treatment.

Researchers discovered that women who were taking tamoxifen for early-stage breast cancer and developed blood clots, had higher chances of carrying a gene mutation, compared to those women who were taking the same medicine and did not suffer from this problem.   

Tamoxifen is one of the most widely used medicines by women after the surgery. It is used by both pre and post menopausal women who are suffering from hormone receptor-positive breast cancer. But, one of the most widely reported side effect of this medicine is that women who consume it, tend to develop blood clots, or thromboembolic events (TEs).

It has also been established in earlier studies that the medicine, when used by healthy women can increase the risk of developing these clots by almost two times. The risks in women aged 50 years of above are considerably higher. 

The genetic mutation Factor V Leiden (FVL) is among the most commonly inherited and can also lead to an increased risk of thrombosis.

Researchers studied 412 women, who received this drug for treatment for stage I, II, or IIIA breast cancer during January 1999 and April 2005. These women had a median age of 64 and 141 patients developed thromboembolic events (TEs) while 271 did not develop these problems.