Patients with ER positive tumors who had a genetic variant at a specific location along the HDAC9 DNA sequence were found to develop breast cancer nearly five years earlier than those with the normal sequence at that same location (49.3 years versus 54.1 years). Conversely, those with ER negative disease with the same variant at that DNA location, developed breast cancer nearly six years later than ER negative patients with the normal sequence (53.7 years versus 48.0 years). Investigators note though, that the comparison for the estrogen receptor negative group was statistically limited because the number of cases in that group was small.

The team also evaluated Caucasians whose breast cancer responds to the hormone progesterone (progesterone receptor positive). Investigators looked at the relationship between a variation in the HDAC9 gene at a different DNA location and disease recurrence. Women who carried the sequence variation at this location demonstrated a strong association with recurrence, i.e. they were more than four times as likely to experience a recurrence.

"These genetic variants in the HDAC9 gene could ultimately affect signaling through the estrogen receptor, thus possibly leading to the alteration of the clinical features of breast cancer. The more specifics we have about how genetics alter age of diagnosis and natural biology of breast cancer could help us to better tailor treatment options in the future," noted Dr. Hirshfield.

Another researcher on the study includes Hongyan Liang, MD, a hematology-oncology fellow at UMDNJ-Robert Wood Johnson Medical School. The work is supported by funding from New Jersey Commission on Cancer Research and The Breast Cancer Research Foundation.

Source: CTRC-AACR San Antonio Breast Cancer Symposium