Though breast cancer is one of the more publicized and well-studied cancer types, treatment for this disease remains imperfect. Many women are overdiagnosed while some don’t receive sufficient treatment to prevent metastasis. But scientists say the guessing game over a breast cancer’s aggressiveness could soon be over. They’ve identified a molecular biomarker that can distinguish between likely non-invasive to likely aggressive breast cancer – critical information that could alter treatment and subsequent outcomes for thousands of women.
The same breast cancer diagnosis does not guarantee the same outcome. In some cases, the breast cancer is so slow-growing that it doesn’t invade and may even be considered benign. By contrast, some breast cancers are so aggressively invasive that doctors have to continually play catch up with the cancer. It’s clear that a cancer as complex as breast cancer can’t have a one-size-fits-all approach. But how can doctors tell from the onset?
By intensely pouring through the expression profiles of about 350 genes associated with breast cancer, researchers from the Whitehead Institute say they’ve found a culprit for cancer aggressiveness. "Early-stage cancers are not all the same. Some are destined to go rogue and should be treated from the outset with this understanding in mind," said Piyush Gupta, the senior study author.
The gene is known as SMARCE1, and is involved in transcriptional activation and repression of other genes. Gupta and colleagues found that SMARCE1 was abundant in early-stage cancers that are more likely to have aggressive outcomes.
"It's clear that SMARCE1 is affecting all of the key players in invasion and metastasis," said Ethan Sokol, the study’s lead author. "It's amazing when you look at the list of the things it's regulating."
"We looked at every step of the metastatic cascade, and the tumor growth at the primary site, as well as the growth at the distant metastases, are not affected by this gene," said Yu-Xiong Feng, the study’s co-author. "Only the invasion is affected by SMARCE1." In other words, SMARCE1 is involved in tumor metastasis.
When SMARCE1 levels were analyzed in tissue samples from hundreds of early stage breast cancer patients, the team found a clear trend: those with higher SMARCE1 expression were more likely to have cancer metastasis. SMARCE1 seemed to be required for breast cancer cells’ escape to secondary sites.
The results provide a clear biomarker for sorting out patients who may require the full arsenal of chemotherapy and radiation, versus those patients in whom careful monitoring may be sufficient. Of course further validation on the SMARCE1 biomarker is needed, but already the study has big implications on how treatment can be personalized to every breast cancer patient’s unique disease.
Additional source: MNT
