Marker helps docs pick kids' bone cancer treatment

Osteosarcoma is the most common bone cancer in kids, and it's generally seen in teens, when bone growth is at its fastest. It is also seen in the over 60s. Treatment is usually chemotherapy and surgery, and while response to chemo meds often tags a better chance of survival, there are no widely-used biomarkers to identify these better responders. Researchers at University of California-Davis have spotted a marker that could pick out the patients who will respond to standard therapy, and those who will need more aggressive treatment, or simply a different regimen.

Those patients whose tumors show signs of cancer cell death (necrosis) are generally the ones that will have the best chance of survival. In a study published in Human Pathology, the researchers looked at a protein called P16, which inhibits cell growth. They took samples of the tumors of patients with osteosarcoma before and after chemotherapy and looked at the levels of P16, and found that the patients with cancer cells that expressed this protein were the most likely to respond to the chemotherapy.

"It is useful to know ahead of time if patients are likely to respond to standard therapy," said Dariusz Borys of UC Davis. "Those who have tumors that do not express P16 would be especially good candidates for more aggressive or experimental treatments to see if they might respond better."

According to the researchers, this is the first time that a biomarker has been identified that predicts treatment success for osteosarcoma, and could lead to personalized treatment for patients. The next step will be to look at samples from more patients to strengthen the argument for using the biomarker. Better understanding of why some cancer cells stop expressing P16 could also lead to better treatments for this form of cancer.

- read the press release
- see the abstract

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