CHICAGO—Researchers have identified a genetic test that when used with DNA testing would detect a higher number of genetic mutations in colorectal cancer patients, according to a study in the February 16 issue of JAMA,a theme issue on medical applications of biotechnology.

Hereditary nonpolyposis colorectal cancer (HNPCC) has historically been diagnosed based on family history, according to background information in the article. Approximately 70 percent of HNPCC cases and a proportion of cases that do not fit these criteria can be accounted for by mutations in any one of several genes involved in DNA mismatch repair (a mechanism that corrects errors made during DNA replication). Identification of a mutation may prompt genetic counseling, screening, and surveillance of relatives to reduce illness and risk of death. It has been proposed that screening of all patients with colorectal cancer for mismatch repair gene mutations may be both feasible and desirable.

"The accurate identification and interpretation of mismatch repair mutation carriers is essential for clinical management of colorectal cancer patients and for scientific studies in which the mutation status of participants is an important variable. Currently, most genetic testing is performed by genomic DNA sequence analysis, but certain classes of gene mutations are not detected using this approach,..." the authors write.

There is evidence that large genomic mutations may account for a substantial proportion of colorectal cancer cases. Recent studies have suggested that conversion analysis, in which human chromosomes are separated in hybrids prior to mutation screening, represents a more sensitive mutation detection method than conventional DNA sequencing for identifying such mutations. There have been no studies comparing the relative accuracy and specificity of conversion analysis with other mutation testing methods in a rigorous way, which is essential if the method is to be widely used clinically and in research.

Graham Casey, Ph.D., of the Cleveland Clinic Lerner College of Medicine, Cleveland, and colleagues performed a blinded comparison of conventional DNA sequencing and conversion analysis to identify certain genetic mutations in 89 colorectal cancer cases. The study included patients who participate in the Colon Cancer Family Registry. Mutation analyses were performed in participant samples determined to have a high probability of carrying certain mutations. Samples from a total of 64 hereditary nonpolyposis colorectal cancer cases, 8 hereditary nonpolyposis colorectal cancer-like cases, and 17 cases diagnosed prior to age 50 years were analyzed from June 2002 to June 2003.

The researchers found that conversion analysis identified all mutations detected by genomic DNA sequencing, plus other mutations, particularly large genomic deletions, yielding an increase of 33 percent (14 of 42) in diagnostic yield of deleterious mutations. Conversion analysis also provided additional information on the deleterious consequence of other sequence changes for an increase of 56 percent (35 of 63) in the diagnostic yield of genetic testing compared with genomic DNA sequencing alone.

NEW TEST IMPROVES DETECTION OF BLADDER CANCER

CHICAGO—Testing for a certain protein in urine was found to increase the accuracy for diagnosis of bladder cancer, according to a study in the February 16 issue of JAMA, a theme issue on medical applications of biotechnology.

Bladder cancer is the fifth most common malignancy in the United States, according to background information in the article. Early detection improves prognosis, treatment options, and quality of life. Although the 5-year survival rate is 95 percent when tumors are detected while they are confined to the mucosa (membrane), up to 25 percent of the approximately 60,000 bladder tumors predicted to be diagnosed this year will be detected after they have become invasive or metastatic, which lowers 5-year survival to approximately 48 percent and 10 percent, respectively. As a result, 13,000 Americans will die of bladder cancer this year.

A combination of methods is used for diagnosis of bladder cancer because no single procedure detects all malignancies. Urine tests are frequently part of an evaluation, but have either been nonspecific for cancer or required specialized analysis at a laboratory.

H. Barton Grossman, M.D., of M.D. Anderson Cancer Center, Houston, and colleagues investigated whether a new, point-of-care, noninvasive urine-based test for the protein NMP22 proteomic marker could improve detection of bladder cancer. The researchers compared the ability of this test to detect cancer with that of urine cytology (cells), which must be analyzed in a clinical laboratory. The study included 23 academic, private practice, and veterans' facilities in 10 states which enrolled 1,331 patients at elevated risk for bladder cancer (history of smoking and certain symptoms) from September 2001 to May 2002. Patients at risk for malignancy of the urinary tract provided a urine sample for analysis of NMP22 protein and cytology prior to cystoscopy (visual examination of the bladder using a special instrument that is passed through the urethra).

Bladder cancer was diagnosed in 79 patients. "We found that the NMP22 test is a useful adjunctive tool in the evaluation of patients at risk for bladder cancer and that it identified several malignancies missed by initial cystoscopy. Specificity of the NMP22 test was lower than for cytology (85.7 percent vs. 99.2 percent), but sensitivity was significantly greater (55.7 percent vs. 15.8 percent), with test results available during the patient visit," the authors write. "The proteomic marker detected 4 cancers that were not visualized during initial cystoscopy, including 3 that were muscle invasive and 1 carcinoma in situ."

According to the article, the average Medicare reimbursement for voided cytology is approximately $56, compared with $24 for the NMP22 point-of-care assay.

SINGLE-DONOR PANCREAS ISLET TRANSPLANTATION PROCEDURE SHOWS PROMISE FOR PATIENTS WITH TYPE 1 DIABETES

CHICAGO—Patients with type 1 diabetes who received islet transplantation from a single donor pancreas were insulin independent one year later, according to a study in the February 16 issue of JAMA, a theme issue on medical applications of biotechnology.

Type 1 diabetes remains a therapeutic challenge, according to background information in the article. The success rate of islet (cells that produce insulin to control blood sugar levels) transplants has recently been increased markedly by transplanting a higher number of islets prepared from 2 to 4 donor pancreases. However, for islet transplants to become a widespread clinical reality, additional advances are still needed. In particular, restoration of insulin independence must be achieved with a single donor, as is also the case with pancreas transplants, to reduce the risks and costs and increase the availability of islet transplantation.

Bernhard J. Hering, M.D., of the University of Minnesota, Minneapolis, and colleagues conducted a study to assess the effectiveness and safety of islet transplantation from a single pancreas. The trial was conducted from July 2001 to August 2003 and enrolled eight women with type 1 diabetes.

During the trial there were no serious, unexpected, or procedure- or immunosuppression-related adverse events. All eight recipients achieved insulin independence and freedom from hypoglycemia. Five remained insulin-independent for longer than 1 year.

"Our results mark a distinct advance in islet transplant efficacy. We not only achieved insulin independence using islets from only 1 donor pancreas [as compared with 2 to 4 in another trial], we also achieved superior glycemic control (as evidenced by normal results of oral glucose tolerance testing in 4 of 5 recipients with sustained insulin independence) using significantly fewer islets," the authors write. "These findings may have implications for the ongoing transition of islet transplantation from clinical investigation to routine clinical care."

MOST EPISODES OF TRANSIENT DETECTION OF HIV 'BLIPS' NOT CLINICALLY SIGNIFICANT IN PATIENTS RECEIVING HAART

CHICAGO—Patients with human immunodeficiency virus type 1 (HIV-1) who have been able to suppress the virus while receiving highly active antiretroviral therapy (HAART) experience intermittent episodes of detectable viremia (presence of the HIV virus in the bloodstream), which are also known as "blips." These blips may raise concerns about drug resistance, lead to costly repeat testing, and sometimes result in changes in medications. A new preliminary communication published in the February 16 issue of JAMA, a theme issue on medical applications of biotechnology, finds most blips in the study population appear to be random variations rather than clinically significant elevations in viremia.

Richard E. Nettles, M.D., from Johns Hopkins University School of Medicine, Baltimore, and colleagues investigated the nature and clinical significance of blips by assessing the HIV-1 RNA (ribonucleic acid) levels of 10 patients every 2 to 3 days over 3 to 4 months between June 19, 2003 and February 9, 2004.

RESEARCHERS FIND NEW TECHNIQUE TO IDENTIFY FETAL GENETIC MATERIAL FROM AMNIOTIC FLUID

CHICAGO—A preliminary report suggests that cell-free fetal messenger RNA (ribonucleic acid) can be extracted from amniotic fluid (fluid around the fetus), and then be analyzed to study gene expression changes that may reflect the well-being of the fetus, according to a paper in the February 16 issue of JAMA, a theme issue on medical applications of biotechnology.

In background information in the article, the authors write that fetal monitoring in the womb is now "limited to noninvasive methods such as measurement of uterine size or anatomic evaluation by fetal sonography. In addition, genetic analysis can be performed on amniotic fluid components..." They add that the "cell-free component of the amniotic fluid is discarded after these analyses and is therefore available for research and future clinical applications."

Paige B. Larrabee, M.D., from Tufts-New England Medical Center, Boston, and colleagues analyzed four samples of cell-free amniotic fluid from pregnant women between 20 and 32 weeks' gestation and who had certain conditions that required procedures to reduce an excessive amount of amniotic fluid. The control group in this study was 6 pooled amniotic fluid samples from women at 17 weeks' gestation who were undergoing amniocentesis (removal of amniotic fluid to test for hereditary diseases and congenital defects in the fetus). "After extraction from the normally discarded fraction of amniotic fluid, RNA was amplified twice, labeled, and analyzed using gene expression microarrays." The researchers were able to study the expression of developmental transcripts, such as for certain proteins.

NEW TECHNIQUE MAY HELP DETECT FETAL SINGLE GENE DISORDERS

CHICAGO—A technique called size-fractionation performed on a sample of the mother's blood allows researchers to identify fetal DNA molecules separate from maternal DNA as a way to determine which pregnancies may be at risk for genetic disorders, according to a preliminary communication in the February 16 issue of JAMA, a theme issue on medical applications of biotechnology.

Currently, prenatal diagnosis of hereditary genetic disorders relies on invasive procedures, such as amniocentesis or chorionic villous sampling [prenatal test that detects genetic abnormalities], which are associated with a small, but significant risk of fetal loss, the authors provide as background information.

Ying Li, Ph.D., from University Hospital, Basel, Switzerland, and colleagues analyzed a total of 32 blood samples collected at 10 to 12 weeks gestation between February 15, 2003 and February 25, 2004 in Bari, Italy, from women with risk for Beta-thalassemia (a group of inherited blood disorders that occur with high frequency in the Mediterranean population) in their newborns immediately prior to chorionic villous sampling. Samples in which the father and mother did not carry the same mutation were examined. Four distinct point mutations of the Beta-globin gene were examined. Presence or absence of the paternal mutant allele (gene) was correctly determined in 81 percent to 100 percent of the cases with only one false-positive test.

NON-INVASIVE ISLET CELL TRANSPLANT PROCEDURE REVERSES TYPE 1 DIABETES

VIDEO:
B-ROLL
Photo of Sherry as young child
Sherry today
Sherry with her kids in kitchen

AUDIO:
SINCE AGE FIVE, SHERRY CROCCO (crock-oh) HAS HAD TYPE ONE DIABETES. HER CONDITION INCLUDES HYPOGLYCEMIA UNAWARENESS, MEANING HER BODY CAN NO LONGER TELL WHEN HER BLOOD SUGAR LEVELS ARE TOO LOW, AND SHE CAN SUDDENLY PASS OUT.

AUDIO:
"Okay, I'm with the kids, do they know how to call 9-1-1, 4-years old, they had to be sure, okay if mommy can't wake up this is what you need to do."

VIDEO:
B-ROLL
Graphic of islet
Sherry in hospital room-nurse taking blood
IV bag labeled "Islets"
Surgeons performing cell transplant
GFX/JAMA COVER

AUDIO:
PEOPLE WITH TYPE ONE DIABETES CAN'T PRODUCE ISLETS (EYE-lets), THE CELLS THAT MAKE INSULIN TO CONTROL BLOOD SUGAR LEVELS. SO SHERRY ENROLLED IN A UNIVERSITY OF MINNESOTA STUDY... THAT TRANSPLANTED ISLET CELLS FROM A DONOR CADAVER PANCREAS INTO HER BODY. SHE WAS ONE OF EIGHT TYPE ONE DIABETICS TO RECEIVE THE TRANSPLANT. THE STUDY FINDINGS APPEAR IN A THEME ISSUE OF JAMA, THE JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION, ON MEDICAL APPLICATIONS OF BIOTECHNOLOGY.

VIDEO:
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@: 47
Super: Bernhard Hering, M.D.
University of Minnesota
Runs :15

AUDIO:
"All eight recipients became diabetes-free and insulin independent after islet transplantation and were protected from hypoglycemia episodes after transplantation."

VIDEO:
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Sherry with Dr. Hering in hospital room
Dr. Hering and colleagues at conference table

AUDIO:
THAT MEANS NO MORE INSULIN SHOTS AND NO MORE FAINTING SPELLS, AT LEAST INITIALLY. DR. BERNHARD (ber-NARD) HERING (HAIR-ing) AND HIS COLLEAGUES TRACKED THE EIGHT PATIENTS FOR A YEAR AFTER TRANSPLANT.

VIDEO:
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Bernhard Hering, M.D.
University of Minnesota
Runs :10

AUDIO:
"Five of eight recipients have remained diabetes-free and insulin independent at the end of the one-year follow-up period of the study."

VIDEO:
B-ROLL
Catheter in transplant video - islets moving through catheter
Pancreas transplant surgery
Lab techs working with fluids

AUDIO:
THE DOCTORS USED A CATHETER TO SEND THE ISLET CELLS INTO THE LIVER AND BLOOD STREAM. DOCTORS HAVE PERFORMED PANCREAS TRANSPLANTS TO GIVE DIABETICS ISLET CELLS, BUT HERE, THE CELLS FOR ALL EIGHT PATIENTS CAME FROM EIGHT CADAVER PANCREAS' - A SINGLE DONOR FOR EACH PATIENT.

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Bernhard Hering, M.D.
University of Minnesota
Runs :05

AUDIO:
"Now we really see that cell therapy can reverse diabetes."

VIDEO:
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More transplant video
Sherry in hospital room giving blood
Sherry in kitchen with her kids
Sherry with her kids walking outside

AUDIO:
THE CELL TRANSPLANT TAKES ONLY ABOUT A HALF-HOUR. BUT PATIENTS MUST KEEP TAKING STRONG DRUGS TO STOP THEIR BODIES FROM REJECTING THE DONOR CELLS. STILL, SHERRY HAS ONE WORD TO DESCRIBE LIVING ESSENTIALLY DIABETES FREE - "AWESOME."