Gene with a death wish helping to destroy tumors

23,000 people will be told they have brain cancer this year. 13,000 will die. A gene with a death wish is now helping destroy life-threatening tumors.

Every day everyone in the Kass family heads outdoors to skate, and scoot. Always watching nearby is mom. It was right after her little girl Sloan was born, Marni started feeling strange.

"I didn't know what it was,” said Marni Kass who suffers from brain tumor.

She thought she was suffering from postpartum depression. What she had was a brain tumor. She had surgery to remove it, chemo and radiation to kill what was left, but it wasn't enough.

She was given four months to live, and now, three years later, she's still fighting.

"They actually have tentacles that spread into the brain, and that's why we have a hard time getting it all out," said Santosh Kesari, MD, PhD, a Neuro-Oncologist from UC San Diego Moores Cancer Center.

Marni is one of the first patients in the country to have a virus injected into her brain to kill the cancer.

"When we inject, the virus infects the cells around it, then makes more of itself and spreads to the next cells," said Dr. Kesari.

Neuro-Oncologist Santosh Kesari at the Moores Cancer Center says a virus called Toca 511 carries a suicide gene to cancer cells. It keeps replicating as it finds more cancer cells. After four weeks, patients are given a drug that's activated by the suicide gene.

"That gene converts it to a chemotherapy drug,” Dr. Kesari said.

It delivers a toxic dose to the cancer cells without harming healthy cells in the brain. Marni is hoping this is the procedure that wipes out her tumor for good-and allows her to focus on her family.

Doctor Kesari believes using suicide genes could someday be the norm for treating all different types of cancer.

That could mean there wouldn't be the need for open surgeries. Instead, just a biopsy to deliver cancer fighting drugs.


REPORT: MB # 3467

BACKGROUND: Glioblastoma (GBM) belongs to a family of brain tumors called "astrocytomas." These are tumors which arise from astrocytes - star-shaped cells of the brain which play a role in supporting normal brain tissue. There are four stages of astrocytoma and GBM is the fourth; it is also the most aggressive type of nervous system tumor. (SOURCE:,,
SYMPTOMS: General symptoms of GBM are essentially the same as for other brain tumors, they include, headache, weakness, seizures, clumsiness; and having difficulty walking.
Specific symptoms will depend on the size and location of the GBM. The symptoms of brain cancer are numerous and not specific to brain tumors, meaning they can be caused by many other illnesses as well. The only way to know for sure what is causing the symptoms is to undergo diagnostic testing (SOURCE:, WebMD)
TREATMENT: The standard method of treating GBM has been essentially unchanged for many decades-surgical resection of as much of the tumor as is safe, followed by radiation therapy and chemotherapy (usually designed to damage DNA or to otherwise inhibit DNA replication) (SOURCE:

KILLING BRAIN CANCER: Cancer cells are able to replicate, but there's a trade-off: They cannot ward off infection as effectively as healthy cells. So scientists have been looking for ways to create viruses that are too weak to damage healthy cells yet strong enough to invade and destroy tumor cells.

UC San Diego Moores Cancer Center researchers and surgeons are among the first in the nation to treat patients with recurrent brain cancer by directly injecting an investigational viral vector into their tumor.

The trial is investigating the use of Toca 511 for injection in combination with Toca FC, extended-release tablets. Toca 511 is a retroviral replicating vector that is designed to deliver a cytosine deaminase (CD) gene selectively to cancer cells. After allowing time for the administered Toca 511 to spread through the cancerous tumor those cancer cells expressing the CD gene can convert flucytosine into the anti-cancer drug 5-fluorouracil. In this study, patients receive cycles of oral Toca FC monthly for up to six months.


Santosh Kesari, MD, PhD
UC San Diego Moores Cancer Center
(858) 822-6346

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