Gene responsible for our sense of smell could play a role in the spread of cancer

By Georgia Lambert via SWNS

A gene that is responsible for our sense of smell could play a role in the spread of breast cancer to the brain, a study reveals.

Breast cancer sufferers often die from the condition if the malignancy spreads to the brain, so stopping this from happening is of paramount importance to clinicians who are looking for new ways to prevent these disastrous outcomes for patients.

Among those concerned were researchers from Massachusetts General Hospital (MGH) and after conducting a study, they discovered that the olfactory receptor gene that plays a central role in our sense of smell, may, in fact, be an important player in the spread of breast cancer to the brain, bones, and lungs.

The team also found that inhibiting the gene, OR5B21, caused a "significant" decrease in the metastasis or the spread of breast cancer cells to these organs, which could be a target for future therapy to prevent its spread.

Senior author, Dr. Bakhos Tannous said: “The common perception is that the only role of olfactory receptors, which line the nasal cavity and relay sensory data to the brain, is to recognize odor and smell."

Dr. Tannous, who is also the director of the Experimental Therapeutics Unit in the Department of Neurology at MGH, added: “Our work suggests that the olfactory receptor 5B21 is also a novel oncogene that may figure prominently in cancer progression by driving breast cancer cells to the brain and other sites in the body.”

Breast cancer is the second most frequently diagnosed malignancy behind lung cancer, and the leading cause of cancer in women, with more than two million new cases reported each year.

Co-corresponding author, Dr. Litia Carvalho said: "The olfactory receptor family of genes is known to be overexpressed in a variety of cancers, including prostate, melanoma, lung, and liver, though its role in breast cancer has been understudied in the past."

The team learned through its research with animal models that the gene OR5B21 enhances or "primes" the breast cancer cells, ready to spread through a signaling pathway that activates a process known as the epithelial to mesenchymal transition (EMT).

This process then prompts multiple changes in the olfactory cells which include an enhanced migratory capacity to travel to distant organs, especially the brain.

Lead author, Mao Li, a graduate student researcher in the Experimental Therapeutics Unit, explained: "This activation converts a wide range of extracellular signals into intracellular messages through the signaling pathway NF-κB/STAT, resulting in cell proliferation, invasion, and metastasis (spreading).

“Our findings are novel for the field, though further research is needed to determine exactly how OR5B21 induces metastasis.”

The authors added: "Future research might also lead to a molecular inhibitor of OR5B21 in response to the team’s discovery that downregulating the olfactory receptor resulted in a significant decrease in cancer cell metastasis."

Dr. Tannous said: "Our hope is that using OR5B21 as a target for adjuvant therapy could help fill a huge unmet medical need by preventing breast cancer metastasis to the brain and other organs, and thus prolong survival of patients.”

The study was published in the iScience journal.