NEW YORK, Dec 17 (Reuters Health) -- High blood levels of organochlorines
-- compounds once used as pesticides -- have been linked to gene mutations found
in patients with cancer of the pancreas, Spanish researchers report in the
December 18/25th issue of The Lancet.
The study is the first to link a genetic alteration commonly found in
pancreatic cancer patients and an environmental substance, according to a
statement issued by the editors of the journal.
"The results... suggest new roles for organochlorines in the development
of several cancers in human beings," according to Professor Miquel Porta from
Institut Municipal d'Investigacio Medica in Barcelona, Spain, and associates.
Organochlorine compounds, such as DDT, DDE, and PCB, have been thought to
be possible carcinogens -- cancer-causing chemicals -- but before this study,
there was no information linking them to pancreatic cancer, the authors explain.
Patients who were already diagnosed with pancreatic cancer were 5 to 10
times more likely to show increased blood levels of organochlorines than were
patients hospitalized for reasons other than cancer, the researchers report.
Furthermore, DDT and DDE concentrations were highest in those patients who
showed mutations in a gene, called K-ras, which is believed to be a critical
target for carcinogens.
"The results do not necessarily imply that organochlorines play a direct
part in activation of K-ras," the authors write. "Rather, the compounds might
enhance the effects of K-ras (mutations) or might provide a growth advantage to
the mutated cells."
"(These) results could improve our understanding of the causes of
pancreatic cancer, and might help to clarify the relation between organochlorine
compounds and risks of several other (cancers)," the team concludes.
Current blood levels of organochlorines probably reflect exposure to
pesticides in the environment over the past decade, the investigators note.
Despite the restricted use of organochlorine pesticides in Spain since the
mid-1980s, recent surveys revealed the presence of DDE in 78%-100% of meat
samples and PCB in 50% of fish samples.
