Jl. Magda et al., POLYMERASE CHAIN REACTION-BASED DETECTION OF CLONALITY AS A NON-MORPHOLOGIC DIAGNOSTIC-TOOL FOR FINE-NEEDLE ASPIRATION OF THE BREAST, CANCER CYTOPATHOLOGY, 84(4), 1998, pp. 262-267
BACKGROUND, Fine-needle aspiration (FNA) of breast specimens can be di
fficult and between 10-25% of the lesions ultimately are classified as
''atypical,'' even by the most experienced cytopathologist. The goal
of this study was to identify a molecular mechanism that reliably dist
inguishes benign and malignant (or premalignant) lesions and that coul
d be used as an adjunct in these morphologically ambiguous cases. METH
ODS. Because all malignancies represent clonal proliferations, assessm
ent of clonality represents a potential molecular mechanism for making
this distinction. Excess material preserved from breast FNAs was exam
ined using the human androgen receptor locus clonality assay. This ass
ay allows determination of clonality on the basis of X chromosome inac
tivation as detected by polymerase chain reaction analysis of genomic
DNA after methylase-sensitive restriction digestion. RESULTS. In this
pilot study, 25 cases showed reproducible results. All malignant cases
(9 of 9) were monoclonal, whereas 10 of 12 benign cases were polyclon
al. Of four atypical cases, two were monoclonal and both were found to
be malignant after surgical resection. Monoclonality was observed in
two benign cases that were hyperplastic lesions. CONCLUSIONS. These pr
eliminary results suggest that this test may provide a non-morphologic
molecular mechanism for the objective categorization of breast FNAs,
Cancer (Cancer Cytopathol) 1998;84:262-7. (C) 1998 American Cancer Soc
iety.