Clinical Utility of Breast Cancer DNA Markers in Plasma

Institution: John Wayne Cancer Institute
Investigator(s): David Hoon, MSc, Ph.D. -
Award Cycle: 1999 (Cycle V) Grant #: 5JB-0045 Award: $372,242
Award Type: IDEAS II
Research Priorities
Detection, Prognosis and Treatment>Imaging, Biomarkers, and Molecular Pathology: improving detection and diagnosis

Initial Award Abstract (1999)
It has become more apparent that in cancer patients, identification of genetic changes in tumors can be highly informative in assessing the outcome of treatments. Multiple genetic changes are required for tumors to start growing, continuing growing and become more aggressive. Although multiple genetic markers in breast cancer have been defined, studies of how they can be used to diagnose breast cancer and predict disease progression are still limited. However, genetic changes (DNA markers) in breast cancer should prove to be valuable as prognostic tools. Traditionally genetic markers are tested only in tumors that have been surgically removed, which limits the assessment of the disease progression to the genetic status of the tumor when it was removed. We have developed an innovative molecular diagnostic assay to assess multiple genetic markers in a small amount of blood (less than 5 ml) from breast cancer patients. This assay provides a unique approach in monitoring genetic changes occurring during tumor progression without the need to obtain tumor tissue through invasive surgical procedures. The assay is highly informative, more tumor-specific than conventional assays, provides an inexpensive means of rapid testing, and offers an improved method for diagnosis and prognosis of breast cancer disease. By correlating these genetic analyses with clinico-pathological factors, the assay provides an exciting new approach for assessing breast cancer progression.

The diagnostic significance of genetic markers for tumor suppressor genes (loss of heterozygosity) in plasma will be assessed in patients undergoing sentinel lymphadenectomy. Sentinel lymphadenectomy removes the first node (sentinel node) to receive metastases from the primary breast tumor. This innovative surgical procedure, which accurately stages disease progression in patients, detects small instances of tumor spreading (micrometastasis), and reduces the side effects associated with standard lymphadenectomy, was pioneered by JWCI and is now used throughout the world. The genetic assay will be conducted in conjunction with the sentinel lymphadenectomy procedure to improve efficacy in diagnosis and prognosis. This provides a highly innovative approach for detecting and understanding disease spreading.

The successful completion of these studies will hopefully provide an assay for diagnosis and prognosis as well as evaluation of therapeutic interventions. To date, the decision about a treatment regimen has been predominantly based on the physical, biochemical and genetic characteristics of the tumor. This assay will provide a new way to use genetic markers as measures of disease progression and potentially improve our ability to tailor the most effective treatment(s) to individual breast cancer patients, thus improving the management of breast cancer disease in California. This study endeavors to achieve this goal by incorporating and combining the fields of surgery, pathology, molecular genetics, medical and radiation oncology, and nursing.

Final Report (2002)
The major objective of the project was to determine if the detection of DNA specific markers in blood can improve diagnosis of breast cancer, provide a genetic insight into the events during the pathogenesis of disease spreading, and provide prognostic insight into disease outcome. The Aims of the study are: Aim I, Analysis of DNA markers in paired serum and tumor biopsies from breast cancer patients of different clinicopathlogical stages. Aim II, Correlation of plasma DNA markers with tumor burden in the axillary lymph nodes. Aim III, Diagnostic significance of serum DNA markers in patients undergoing SLND (sentinel lymph node dissection).

The study involved assessment of 241 early and late stage breast cancer patients' serum for free circulating DNA tumor markers. Techniques and methods were developed to isolate and purify free tumor-related DNA from small amounts of serum. A sensitive assay was developed for detection of circulating DNA markers for genetic instability. A panel of 8 DNA markers representing 6 chromosomal regions that frequently have genetic aberrations in breast were assessed. Respective patients' breast cancer primary tumors and micrometastasis were also assessed by laser capture microdissection. This approach allowed us to isolate DNA from small clusters of tumor cells. A procedure was developed to isolate DNA from small number of tumor cells.

The major findings have been that circulating DNA markers are frequently present in early and late stage breast cancer patients' serum. The number of DNA markers correlated to breast cancer histopathology and disease burden. Certain specific DNA markers were detected more frequently than others. No DNA tumor markers were found in normal healthy women. Patients need to be clinically followed up longer to determining the significance of the DNA tumor marker presence and disease recurrence. Advanced stage cancers were shown to have a different marker profile than earlier stage cancers. Repetitive analysis of patients for these markers may be a valuable surrogate for monitoring treatment.

The impact of these findings is for the first time we have tumor genetic markers that can be assessed in blood in a longitudinal manner repetitively by a non-invasive approach. This provides a highly sensitive approach to routinely monitor breast cancer progression through analysis of informative genetic markers. This would provide a minimally invasive procedure of limited cost for diagnosis and potentially prognosis. Having a non-invasive assay such that it can be routinely provided may allow us to rapidly assess breast cancer patients for early disease recurrence well before clinical signs. This would have a significant medical and economical impact on breast cancer patient management in California.

Microsatellite alterations detected in the serum of early stage breast cancer patients.
Periodical:Annals of the New York Academy of Sciences
Index Medicus: Ann N Y Acad Sci
Authors: Taback B, Giuliano AT, Hansen NM, Hoon DSB.
Yr: 2001 Vol: 945 Nbr: Abs: Pg:22-30