Detection of breast cancer in nipple aspirate fluid by CpG island hypermethylation.
OBJECTIVE
New approaches to the early detection of breast cancer are urgently needed as there is more benefit to be realized from screening. Nipple aspiration is a noninvasive technique that yields fluid known to contain breast epithelial cells. Silencing of tumor suppressor genes such as p16(INk4a), BRCA1, and hMLH1 have established hypermethylation as a common mechanism for tumor suppressor inactivation in human cancer and as a promising target for molecular detection.


METHODS
Using sensitive methylation-specific PCR, we searched for aberrant promoter hypermethylation in a panel of six normally unmethylated genes: glutathione S-transferase pi 1 (GSTP1); retinoic acid receptor-beta2 (RARbeta2); p16(INk4a); p14(ARF); RAS association domain family protein 1A (RASSF1A); and death-associated protein kinase (DAP-kinase) in 22 matched specimens of tumor, normal tissue, and nipple aspirate fluid collected from breast cancer patients.


RESULTS
Hypermethylation of one or more genes was found in all 22 tumor DNAs (100% diagnostic coverage) and identical gene hypermethylation detected in 18 of 22 (82%) matched aspirate fluid DNAs. In contrast, hypermethylation was absent in benign and normal breast tissue and nipple aspirate DNA from healthy women.


CONCLUSIONS
Promoter hypermethylation of important cancer genes is common in breast cancer and could be detected in matched aspirate DNAs from patients with ductal carcinoma in situ or stage I cancer. Promoter hypermethylation represents a promising marker, and larger studies may lead to its useful application in breast cancer diagnosis and management.
Krassenstein
Rachel
R
Departments of Surgical Oncology and Pathology, Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
Sauter
Edward
E
Dulaimi
Essel
E
Battagli
Cristina
C
Ehya
Hormoz
H
Klein-Szanto
Andres
A
Cairns
Paul
P
D000328:Adult; D000368:Aged; D051017:Apoptosis Regulatory Proteins; D014408:Biomarkers, Tumor / Q000235:genetics; D001707:Biopsy, Needle; D001826:Body Fluids / Q000737:chemistry / Q000166:cytology*; D001943:Breast Neoplasms / Q000175:diagnosis*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000175:diagnosis*; D016022:Case-Control Studies; D018899:CpG Islands; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000032:analysis*; D064550:Death-Associated Protein Kinases; D004847:Epithelial Cells / Q000737:chemistry / Q000473:pathology*; D005240:Feasibility Studies; D005260:Female; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase / Q000235:genetics; D006801:Humans; D007527:Isoenzymes / Q000235:genetics; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000235:genetics; D009558:Nipples; D011401:Promoter Regions, Genetic / Q000235:genetics; D018168:Receptors, Retinoic Acid / Q000235:genetics; D025803:Tumor Suppressor Protein p14ARF / Q000235:genetics; D025521:Tumor Suppressor Proteins / Q000235:genetics
D051017:Apoptosis Regulatory Proteins; D014408:Biomarkers, Tumor; D019941:Cyclin-Dependent Kinase Inhibitor p16; D004273:DNA, Neoplasm; D007527:Isoenzymes; D009363:Neoplasm Proteins; C411762:RASSF1 protein, human; D018168:Receptors, Retinoic Acid; D025803:Tumor Suppressor Protein p14ARF; D025521:Tumor Suppressor Proteins; C082925:retinoic acid receptor beta; C496556:GSTP1 protein, human; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase; D064550:Death-Associated Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases