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New hope for detecting deadly pancreatic cancer

By DR. V. UPENDER RAO
Published March 5, 2007

The American Association of Cancer Research recently held its fifth annual International Conference on Frontiers in Cancer Prevention in Boston. A new blood test for early detection of pancreatic cancer was reported.

Anna Lokshine associate professor of medicine and pathology at the University of Pittsburgh School of Medicine, said that this blinded and independently validated assay can detect pancreatic cancer in its early stages with a sensitivity of 87 percent and specificity of 98 percent. Lokshine and colleagues are developing a similar assay for early detection of prostate cancer, as well.

The currently available tumor markers have several shortcomings. They are not specific for any cancer and their detection depends on the amount secreted by the tumor.

Early tumors secrete very little or none at all, so the markers are not detected in a typical blood test as used today. When detected, the tumors are usually large and advanced; therefore, these tests are not suitable for early detection.

The new assay does not depend on markers secreted by the tumor. It detects the communicating signals between the tumor, its surrounding tissues, the immune system, the various growth and other factors responsible for tumor development and propagation.

This test is based on a protein micro array system that can detect up to 100 proteins, peptides and DNA molecules in a very small sample.

Researchers tested 100 pancreatic cancer patients and 400 healthy controls. In the process, they examined 95 tumor-related proteins and identified 10 biomarkers, which conferred the test a high level of accuracy and very few false positive results.

As opposed to the validation samples, when tested on actual patients and healthy control samples, the test emerged with 95 percent sensitivity and 98 percent specificity.

Dr. Lokshine said that the assay will be further refined to minimize the number of false positive results. She also added that this assay will be tested on samples provided by those who participated in the Prostate, Lung, Colon and Ovarian Cancer Screening Trial earlier.

The participants provided blood samples for six years in a row. Some of the participants developed pancreatic cancer. The samples they provided before cancer development will be examined by the new assay to see if early detection would have been possible.

Pancreatic cancer is one of the most lethal of all solid tumors. In 2007, there will be an estimated 37,170 new cases and 33,370 deaths from it. This grim statistic indicates that almost all patients diagnosed with pancreatic cancer will die of it.

While early detection is the only hope for cure, there are no reliable tests for early detection available at this time. When refined and validated, the new assay may make a significant contribution towards early detection and cure of pancreatic cancer.

V. Upender Rao, MD, FACP, practices at the Cancer and Blood Disease Center in Lecanto

[Last modified March 4, 2007, 20:08:41]