The scientists found that regular, long-term antihistamine use was associated with an increased risk for developing anaplastic astrocytomas and low-grade brain tumors.
"To our knowledge, this report is the first time that anyone has looked at this particular relationship ?the potential effects of antihistamines on the development of brain tumors in adults," said Scheurer. "It's apparent that some type of inflammatory response is playing some role in the development of brain tumors. We don't know exactly what that role is or the specific mechanisms, but we're on the road to finding out.
"This again points to the fact that brain tumors are caused by a combination of several environmental, endogenous and genetic factors," he said. "They are not related to one specific cause, but rather, to several that are interplaying with one another to create tumors. We're trying to figure out what those key factors and genes are and how they interact with one another."
Scheurer said several studies have reported that people with allergies or asthma have a lower risk of developing glioblastomas. One report showed that those who take non-steroidal anti-inflammatory drugs, or NSAIDs, also have a reduced risk for developing such high-grade tumors. He and Bondy focused on antihistamines because people who have allergies typically take antihistamines.
"We knew that the different types of tumors have different etiologies and different genetic characteristics and we wanted to see if there were differences in risk," Bondy said. Scheurer and Bondy are also looking at certain different variations of genes in individuals and how they respond to inflammatory processes in the brain. "We're hopefully looking at some genes related to inflammatory cytokines and we'll see how indivi
Source:American Association for Cancer Research