AMSTERDAM--Innovative strategies for thwarting metastasis are
now at the brink of clinical application, Lance Liotta, MD, of
the National Cancer Institute, reported at the 9th NCI-EORTC Symposium
on New Drugs in Cancer Therapy.
"Proteins that regulate invasion and metastasis and the process
of invasion provide new cellular targets for prevention and new
molecular targets for intervention," Dr. Liotta said.
The thinking behind the new approach is that current anticancer
therapy often fails because it begins too late, after metastasis
has already occurred. Instead, Dr. Liotta argued, the ideal moment
to act would be during the window of opportunity between the time
that the cells become hyperplastic and the time that they acquire
the ability to invade and metastasize.
Analyzing Precursor Lesions
NCI pathologists Drs. Buck and Zhuang have developed a new laser
capture technique for microdissecting and genetically analyzing
precursor lesions, which enables them to determine which cells
are most likely to become invasive.
Applying this method, they found that the same genetic locus was
missing in 90% of invasive prostate carcinoma samples and in 70%
of precursor PIN (prostatic intraepithelial neoplasia) lesions
from the same patients. "This implicates a new suppressor
gene to be identified at 8p21," he said.
The NCI team has also used the new microdissection technique together
with X-chromosome inactivation analysis to prove that carcinoma
in situ of the breast does develop into invasive carcinoma.