Chemo promotes breast cancer metastasis

JKZX.COM Thursday Jan 3, 2019 — Doctors often ask breast cancer patients to receive chemotherapy before surgery. But such chemotherapy commonly known as neoadjuvant therapy may increase the risk of metastasis although it is intended to reduce the size of the tumor to help breast conserving surgery, according to a new study published in December 2018.

The neoadjuvant therapy can put breast cancer patients whose tumors are not responsive to this chemotherapy at particularly higher risk. Chemotherapy can not only train tumor cells to become even more dangerous, but also open gateways for cancer cells to migrate to remote tissues to develop more lethal secondary cancer.

Michele De Palma and colleagues, authors of the study report, tested two commonly used chemotherapy drugs paclitaxel and doxorubicin in experimental tumor models. They found that treated with these drugs, the mammary tumors (similar to human breast cancer tumors) release small vesicles called exosomes that contain a protein called annexin-A6 which is not found in untreated tumors. In other words, chemotherapy promotes the production of this protein.

What Annexin-A6 does after exosomes migrate to remote organs like the lung where annexin-A6 stimulates the lung cells to produce another protein called CCL2, which attracts immune cells known as monocytes. This immune response can be dangerous as released monocytes can facilitate the survival and growth of cancer cells in the lung – the very first step in metastasis.

The researchers found that patients with breast cancer who have received chemotherapy drugs have higher Annexin-A6 levels. They found that neutralizing annexin-A6 or blocking monocytes during chemotherapy can prevent mammary tumors from metastasizing to the lung. This means that annexin-A6 promotes metastasis.

Professor De Palma works at the Swiss Institute for Experimental Cancer Research (ISREC) within the School of Life Sciences at EPFL.

Early studies indicate that chemotherapy can cause damage to healthy cells and help produce a protein called WNT16B, which causes cancer cells to grow, invade remote tissues, and develop drug resistance to chemotherapy drugs.

Chemotherapy drugs can also damage the immune system for a long term in breast cancer patients and reduce major immune cells for at least nine months post-treatment.

Another bad thing chemotherapy drugs can do is open gateways for breast cancer cells to spread to the blood and remote parts of the body.

An Australian study has found that chemotherapy increases the overall 5-year survival by only 2.2% while the overall 5-year survival rate is 62.2%.

Thirty percent of early stage cancer patients who receive chemotherapy and radiotherapy will develop advanced cancer, that is, they will have their cancers spread to remote tissues and turn their early stage cancer into stage 4 cancer which are no longer treatable.