NORFOLK, VirginiaUsing an innovative technique called protein chip mass
spectrometry, researchers at Eastern Virginia Medical School in Norfolk have
identified specific serum protein profiles that may enhance the detection of
breast cancer. Lori Wilson, MD, previously research associate at Eastern
Virginia Medical School and now surgical oncology fellow at John Wayne Cancer
Institute in Santa Monica, California, reported that in early testing, the
biomarker profiles have shown a specificity and sensitivity that approaches
that of mammography.
Protein chip mass spectrometry searches for multiple differentially
expressed proteins to create unique protein profiles. For their study, the
researchers used Surface-Enhanced Laser Desorption/Ionization (SELDI)/Time of
Flight (TOF) mass spectrometry. They applied the SELDI/TOF technology to sera
collected through the division of surgical oncology from both healthy women and
women with breast cancer.
"Our samples were prospectively collected and were pretreatment as well as
from normal healthy patients," Dr. Wilson said. "We analyzed 139 female sera by
our SELDI technology, and the clinicopathologic information was recorded in our
breast study data base."
Patient samples were classified as normal/benign or cancer. The median age
was 46.5 years in the normal/benign patients and 59.3 years in the patients
with breast cancer. The overall age range was 21 to 91 years. Eighty percent of
the breast cancer patients were staged as ductal carcinoma in situ (DCIS) or
stages I or II. Only 13% were stage III and 7% were stage IV.
Serum Sample Processing
"In serum sample processing for the SELDI analysis, we initially used the
IMAC copper chip but decided to use the SAX chip to increase the number of
proteins that were resolved with the mass spectrometry. We noted that with two
chips there were peaks that were conserved but also peaks that we could isolate
on one chip or the other," Dr. Wilson said.
Those samples were similarly processed through denaturing in the presence of
urea buffer and were applied onto the chip in duplicate and randomized, she
added. The nonspecific proteins were washed away with binding buffer, and then
the data analysis and peak labeling were performed with Wizard Biomarker