NEW YORK (Reuters Health) - Researchers from Portugal and Greece have developed blood- and tumor-based tests that may help in evaluating breast cancer prognosis, according to the findings from two studies reported in the International Journal of Cancer for February 10.
Dr. Sergio Castedo and colleagues, from the Portuguese Oncology Institute in Porto, developed a new one-step PCR assay for detecting the mammaglobin (MGB1) gene in blood samples from breast cancer patients. Recent reports indicate that the gene is a potentially specific marker for circulating tumor cells.
Unlike previous tests, the researchers’ assay uses specific primers for cDNA synthesis. In the current study, which involved 54 untreated patients with breast cancer, this change resulted in improved sensitivity without a fall in specificity. The MGB1 transcript was detected in 22 of the breast cancer patients, in none of 38 healthy subjects, and in just 1 of 18 patients with a hematologic malignancy.
The likelihood of testing positive for MGB1 was directly related to disease stage. For example, no patients with stage 0 disease tested positive, whereas 8 of 11 (73%) patients with stage IV disease demonstrated this marker (p = 0.003).
“The prognostic and therapeutic implications of MGB1 positivity by one-step RT-PCR in the peripheral blood of breast cancer patients, especially in clinically localized disease...should be evaluated after long-term clinical follow-up of these patients,” the authors note.
In the second study, Dr. Alexandra Giatromanolaki, from the Democritus University of Thrace in Alexandroupolis, Greece, and colleagues used two tests to assess the vascularity of breast tumors and whether malignant cells were present in the blood. The presence of both high tumor vascularity and malignant cells in the blood was referred to as “highly angiogenic and disseminated in the peripheral blood disease” (HAD).
The researchers tested for cytokeratin-19 positive cells in the blood as an indicator of disseminated disease and analyzed tumor specimens to determine the microvessel density (MVD), an indicator of tumor vascularity. In their study of 100 patients, HAD was observed in 25.
Regardless of the chemotherapy regimen used, the relapse rate for HAD patients was about 70%, much higher than the less than 5% rate seen for other patients (p < 0.0001).
“The simultaneous presence of high MVD and CK19-positive cells in the blood of patients with early breast cancer is linked with poor prognosis, which cannot be improved with standard chemotherapy regimens,” the researchers conclude.
Source: Int J Cancer 2004;108:592-595,620-627. [ Google search on this article ]
MeSH Headings:Breast Neoplasms: Neoplasms: Neoplasms by Site: Polymerase Chain Reaction: Reverse Transcriptase Polymerase Chain Reaction: DiseasesCopyright © 2002 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.
