July 15, 2005

Asthma gene variants may cut risk of brain cancer

By Anthony J. Brown, MD

NEW YORK (Reuters Health) - New research suggests that gene
variants, which are known to raise the risk of asthma, decrease
the risk of glioblastoma multiforme (GBM), a common type of
brain cancer that is rapidly fatal.

Variants or "polymorphisms" are minor changes in a gene
that can influence how often the associated protein is produced
in a cell and how well it functions.

Several reports have linked asthma with a reduced risk of
brain tumors, but the studies may have suffered from various
design issues, lead author Dr. Judith Schwartzbaum, from Ohio
State University in Columbus, told Reuters Health. "So, to me,
the evidence just wasn't credible."

In the present study, Schwartzbaum's team looked for an
association between asthma-related gene variants and GBM in a
study of 111 patients with this tumor and 422 comparison
subjects. An extensive literature search was conducted to
identify variants that have been consistently linked to an
increased or decreased risk of asthma.

In agreement with previous findings, self-reported asthma
was associated with a decreased risk of GBM, the researchers
note in the journal Cancer Research.

Two variants were tied to a heightened risk of GBM, whereas
another was associated with a reduced risk. As it turns out,
the two former variants are known to decrease the risk of
asthma, whereas the latter raises the risk.

"Now I'm interested in determining if these polymorphisms
just happen to have independent roles in the two diseases or
does having asthma or allergy symptoms reduce the risk of GBM,"
Schwartzbaum said.

"I'd also like to find a polymorphism that increases the
risk of both diseases," rather than raises the risk of one and
lowers the risk of the other. Such a variant could serve as a
target for new drugs, she explained.

SOURCE: Cancer Research, July 15, 2005.