Researchers studied how bone cancer pain develops in rats and found that a specific cellular signaling pathway called Rac1/PAK1 plays a key role. When tumors grow in bone, this pathway becomes overactive and causes changes in nerve cell structures called dendritic spines, which leads to increased pain sensitivity. By blocking this pathway with a drug called NSC23766, scientists were able to reduce pain and reverse the harmful changes to nerve cells, suggesting a new potential treatment approach for cancer patients suffering from bone pain.