Evaluation of a panel of tumor markers for molecular detection of circulating cancer cells in women with suspected breast cancer.
OBJECTIVE
We examined the feasibility of using molecular characterization of circulating tumor cells as a method for early detection of breast cancer.


METHODS
Women without a prior history of cancer who had a breast abnormality detected on imaging followed by a breast biopsy were enrolled in this study. Density gradient centrifugation and immunomagnetic capture were used to enrich for epithelial cells from approximately 20 mL of blood. Real-time reverse transcription-PCR was used to quantitate the expression levels of the highly breast-specific genes, mammaglobin, gamma-aminobutyric acid type A receptor pi subunit (GABA A(pi)), B305D-C, and B726P in the epithelial cell-enriched samples.


RESULTS
The assay was technically feasible in 154 of 199 accrued patients. From their clinical assessment, 100 patients had benign breast disease, 10 patients had ductal carcinoma in situ, and 44 patients had invasive breast cancer. We constructed a diagnostic test that classified patients with mammaglobin levels of at least 32.2 copies/pg beta-actin (units) in their circulating epithelial cells as positive for invasive breast cancer. This resulted in a sensitivity and specificity of 63.3% and 75.0%, respectively. A diagnostic test that classified patients as positive for invasive breast cancer when either mammaglobin levels were >46.3 units or B305D-C levels were >11.6 units increased the sensitivity and specificity to 70.5% and 81.0%, respectively. In the latter test, 12 of the 14 node-positive breast cancer patients were correctly identified. Including GABA A(pi) and B726P in the test did not increase its diagnostic potential.


CONCLUSIONS
These results suggest that molecular characterization of circulating epithelial cells using mammaglobin and B305D-C offers potential for early detection of invasive breast cancer.
Reinholz
Monica M
MM
Divisions of Experimental Pathology and Biostatistics, and Department of Oncology, Mayo Clinic College of Medicine, Rochester, Minnesota, USA. reinholz.monica@mayo.edu
Nibbe
Andrea
A
Jonart
Leslie M
LM
Kitzmann
Kathleen
K
Suman
Vera J
VJ
Ingle
James N
JN
Houghton
Raymond
R
Zehentner
Barbara
B
Roche
Patrick C
PC
Lingle
Wilma L
WL
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D060785:Mammaglobin A; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D009360:Neoplastic Cells, Circulating; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014598:Uteroglobin / Q000096:biosynthesis* / Q000235:genetics
C502975:B305D-C protein, human; D014408:Biomarkers, Tumor; D060785:Mammaglobin A; D009363:Neoplasm Proteins; C556448:SCGB2A2 protein, human; D014598:Uteroglobin