Thursday, August 14, 2014

Bacteria used to shrink tumors

Video credit: © AAAS/Carla Schaffer
CANCER DIGEST – Aug. 13, 2014 – Researchers have shown that injections of a weakened version of a bacterium that thrives in a very low oxygen environment can shrink tumors in rats, pet dogs, and a human patient.

The microbe, Clostridium novyi, is commonly found in soil and lives only in oxygen-poor environments, which makes it ideal for adaption to oxygen-starved cells in tumors that are difficult to treat with chemotherapy and radiation.

After removing the toxin-producing gene, researchers at Johns Hopkins Kimmel Cancer Center tested the microbe on 16 pet dogs whose owners consented to have their cancer-stricken pets treated with the new therapy. Six of the dogs had an anti-tumor response 21 days after their first treatment. Three of the six showed complete eradication of their tumors.

The first human patient to enroll in the Phase I investigational study was a 53-year old woman with retroperitoneal leiomyosarcoma, a cancer of muscle connective tissue. Despite eight rounds of chemotherapy and radiation, the cancer had spread to her liver, lungs, abdomen, upper arm, and shoulder. 

The researchers injected Clostridium novyi into the patient's metastatic right shoulder tumor. Within days, CT scans and biopsies demonstrated that the bacteria had infiltrated the tumor and had begun destroying tumor cells. Weeks later, a follow-up MRI showed that a significant amount of tumor had been destroyed.

The researchers propose the treatment may act as a new type of "biosurgery" to eat away tumors in hard to reach places. The study was published Aug. 13, 2014, in Science Translational Medicine.

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