Blood Test for CD24 Detects Colon Neoplasms

CHICAGO — A blood test for a protein associated with colorectal cancer can detect adenomas and colorectal cancer, according to two studies of a total of 370 patients.

The test, the first of its kind, holds promise for early disease detection and surveillance, said Dr. Nadir Arber of Tel Aviv Medical Center, Israel, at the annual Digestive Disease Week.

“This is a simple blood test measuring the levels of CD24 protein [a cell surface protein and P-selectin ligand] in peripheral blood lymphocytes (PBLs), and we can successfully distinguish healthy subjects from patients with colorectal neoplasm,” Dr. Arber reported at a research forum that was sponsored by the AGA Institute.

The findings provide further substantiation that CD24 levels are significantly elevated in the majority of patients with adenomas and colorectal cancer (CRC), he said.

Previous research by Dr. Arber and his colleagues with both animal and human cancer cell lines confirmed the overexpression of CD24 in the colonic mucosa as an early event in CRC carcinogenesis, and identified the protein as a potential biomarker for early CRC detection and a target for therapy (Gastroenterology 2006;131:630-9).

The low level of public compliance with current CRC screening techniques underscores the need for a noninvasive test, Dr. Arber said.

Analyses of PBLs for expression of CD24 detected CRC in a pilot study of 203 consecutive subjects with a sensitivity and specificity of 70.5% and 83.3%, respectively. The test also distinguished patients with adenomas from normal patients with a sensitivity and specificity of 84.2% and 73.5%, respectively (confidence interval 95%).

An external third-party evaluation of 143 blood samples from this population yielded a lower specificity of 65% for normal versus CRC patients and a specificity of 76.7% for normal versus adenoma patients. Dr. Arber noted in an interview that the somewhat lower specificity could be attributed to potential degradation of the protein during storage and transportation.

Patients completed a detailed questionnaire, provided a blood sample, and underwent a colonoscopy. PBLs were isolated and analyzed with Western blot, a technique that detects levels of a protein using antibodies specific to the target protein. Sensitivity and specificity for CD24 were calculated using receiver operating characteristic curves.

In a second validation study of an independent sample of 167 subjects, the blood test yielded improved values for the detection of CRC (sensitivity 92.3%; specificity 83.8%). The values for the detection of normal versus CRC and adenoma patients were 77.1% and 86.8%, respectively.

Dr. Arber said that a goal of further research is to collect data on CD24 levels and polyp size.

When asked what additional research would be needed before the test could be widely offered for CRC detection and surveillance, Dr. Arber said he is focusing on increasing the test's negative predictive values and is exploring whether there are certain subpopulations for whom the test is not predictive.

In its current form, the test, based on Western blot analysis, can be performed in any hospital, Dr. Arber said. He added that he and his colleagues are developing an ELISA (enzyme-linked immunosorbent assay) kit designed to facilitate use of the test in any laboratory worldwide.

Dr. Arber disclosed that he is chief scientist at Micromedic Technologies Ltd., which supported this research. Dr. Arber also is on the review panel for GI View Ltd., which develops gastrointestinal diagnostic devices, and has received research support from Pfizer.

The test can be performed in any hospital, Dr. Nadir Arber said.

Source Courtesy Dr. Nadir Arber

CHICAGO — A blood test for a protein associated with colorectal cancer can detect adenomas and colorectal cancer, according to two studies of a total of 370 patients.

The test, the first of its kind, holds promise for early disease detection and surveillance, said Dr. Nadir Arber of Tel Aviv Medical Center, Israel, at the annual Digestive Disease Week.

“This is a simple blood test measuring the levels of CD24 protein [a cell surface protein and P-selectin ligand] in peripheral blood lymphocytes (PBLs), and we can successfully distinguish healthy subjects from patients with colorectal neoplasm,” Dr. Arber reported at a research forum that was sponsored by the AGA Institute.

The findings provide further substantiation that CD24 levels are significantly elevated in the majority of patients with adenomas and colorectal cancer (CRC), he said.

Previous research by Dr. Arber and his colleagues with both animal and human cancer cell lines confirmed the overexpression of CD24 in the colonic mucosa as an early event in CRC carcinogenesis, and identified the protein as a potential biomarker for early CRC detection and a target for therapy (Gastroenterology 2006;131:630-9).

The low level of public compliance with current CRC screening techniques underscores the need for a noninvasive test, Dr. Arber said.

Analyses of PBLs for expression of CD24 detected CRC in a pilot study of 203 consecutive subjects with a sensitivity and specificity of 70.5% and 83.3%, respectively. The test also distinguished patients with adenomas from normal patients with a sensitivity and specificity of 84.2% and 73.5%, respectively (confidence interval 95%).

An external third-party evaluation of 143 blood samples from this population yielded a lower specificity of 65% for normal versus CRC patients and a specificity of 76.7% for normal versus adenoma patients. Dr. Arber noted in an interview that the somewhat lower specificity could be attributed to potential degradation of the protein during storage and transportation.

Patients completed a detailed questionnaire, provided a blood sample, and underwent a colonoscopy. PBLs were isolated and analyzed with Western blot, a technique that detects levels of a protein using antibodies specific to the target protein. Sensitivity and specificity for CD24 were calculated using receiver operating characteristic curves.

In a second validation study of an independent sample of 167 subjects, the blood test yielded improved values for the detection of CRC (sensitivity 92.3%; specificity 83.8%). The values for the detection of normal versus CRC and adenoma patients were 77.1% and 86.8%, respectively.

Dr. Arber said that a goal of further research is to collect data on CD24 levels and polyp size.

When asked what additional research would be needed before the test could be widely offered for CRC detection and surveillance, Dr. Arber said he is focusing on increasing the test's negative predictive values and is exploring whether there are certain subpopulations for whom the test is not predictive.

In its current form, the test, based on Western blot analysis, can be performed in any hospital, Dr. Arber said. He added that he and his colleagues are developing an ELISA (enzyme-linked immunosorbent assay) kit designed to facilitate use of the test in any laboratory worldwide.

Dr. Arber disclosed that he is chief scientist at Micromedic Technologies Ltd., which supported this research. Dr. Arber also is on the review panel for GI View Ltd., which develops gastrointestinal diagnostic devices, and has received research support from Pfizer.

The test can be performed in any hospital, Dr. Nadir Arber said.

Source Courtesy Dr. Nadir Arber

CHICAGO — A blood test for a protein associated with colorectal cancer can detect adenomas and colorectal cancer, according to two studies of a total of 370 patients.

The test, the first of its kind, holds promise for early disease detection and surveillance, said Dr. Nadir Arber of Tel Aviv Medical Center, Israel, at the annual Digestive Disease Week.

“This is a simple blood test measuring the levels of CD24 protein [a cell surface protein and P-selectin ligand] in peripheral blood lymphocytes (PBLs), and we can successfully distinguish healthy subjects from patients with colorectal neoplasm,” Dr. Arber reported at a research forum that was sponsored by the AGA Institute.

The findings provide further substantiation that CD24 levels are significantly elevated in the majority of patients with adenomas and colorectal cancer (CRC), he said.

Previous research by Dr. Arber and his colleagues with both animal and human cancer cell lines confirmed the overexpression of CD24 in the colonic mucosa as an early event in CRC carcinogenesis, and identified the protein as a potential biomarker for early CRC detection and a target for therapy (Gastroenterology 2006;131:630-9).

The low level of public compliance with current CRC screening techniques underscores the need for a noninvasive test, Dr. Arber said.

Analyses of PBLs for expression of CD24 detected CRC in a pilot study of 203 consecutive subjects with a sensitivity and specificity of 70.5% and 83.3%, respectively. The test also distinguished patients with adenomas from normal patients with a sensitivity and specificity of 84.2% and 73.5%, respectively (confidence interval 95%).

An external third-party evaluation of 143 blood samples from this population yielded a lower specificity of 65% for normal versus CRC patients and a specificity of 76.7% for normal versus adenoma patients. Dr. Arber noted in an interview that the somewhat lower specificity could be attributed to potential degradation of the protein during storage and transportation.

Patients completed a detailed questionnaire, provided a blood sample, and underwent a colonoscopy. PBLs were isolated and analyzed with Western blot, a technique that detects levels of a protein using antibodies specific to the target protein. Sensitivity and specificity for CD24 were calculated using receiver operating characteristic curves.

In a second validation study of an independent sample of 167 subjects, the blood test yielded improved values for the detection of CRC (sensitivity 92.3%; specificity 83.8%). The values for the detection of normal versus CRC and adenoma patients were 77.1% and 86.8%, respectively.

Dr. Arber said that a goal of further research is to collect data on CD24 levels and polyp size.

When asked what additional research would be needed before the test could be widely offered for CRC detection and surveillance, Dr. Arber said he is focusing on increasing the test's negative predictive values and is exploring whether there are certain subpopulations for whom the test is not predictive.

In its current form, the test, based on Western blot analysis, can be performed in any hospital, Dr. Arber said. He added that he and his colleagues are developing an ELISA (enzyme-linked immunosorbent assay) kit designed to facilitate use of the test in any laboratory worldwide.

Dr. Arber disclosed that he is chief scientist at Micromedic Technologies Ltd., which supported this research. Dr. Arber also is on the review panel for GI View Ltd., which develops gastrointestinal diagnostic devices, and has received research support from Pfizer.

The test can be performed in any hospital, Dr. Nadir Arber said.

Source Courtesy Dr. Nadir Arber