Hope for more effective pain relief for cancer patients

MedWire News: German researchers have found that two substances released by tumours make nerve cells particularly sensitive, a finding that make lead to the development of novel drugs to block the severe pain often experienced by cancer patients.

“Pain is one of the most severe and debilitating symptoms associated with several forms of cancer,” explain Dr Rohini Kuner, from the University of Heidelberg, and team.

But they add: “Despite recent advances, the molecular mechanisms underlying the development and maintenance of cancer-evoked pain are not well understood.”

Dr Kuner and team therefore examined tissue from mice with cancer to determine what chemicals that might trigger pain were released by tumours.

They identified two molecules, called G-CSF and GM-CSF, which were previously known only as growth factors for blood-forming stem cells. Contact with these molecules made nerve cells in the vicinity of the cancer tissue significantly more sensitive to pressure, as the researchers demonstrated by testing nerve activity with electrodes.

“The findings are consistent with descriptions of cancer patients who say that merely touching the affected area is painful,” said Dr Kuner.

The researchers injected protein antibodies to block the contact sites on nerve cells for these signalling molecules and found the sensitivity of nerve cells was reduced.

Writing in the journal Nature Medicine, Dr Kuner and team conclude: “These results show that G-CSF and GM-CSF are important in tumour-nerve interactions and suggest that their receptors on… nerve fibres constitute potential therapeutic targets in cancer pain.”