Autor(es):
Reis Filho, Jorge S. 
; Milanezi, Fernanda ; Amendoeira, Isabel ; Albergaria, André ; Schmitt, Fernando C.
Data: 2003
Identificador Persistente: http://hdl.handle.net/1822/1956
Origem: RepositóriUM - Universidade do Minho
Assunto(s): p63; Fine-needle aspiration; Myoepithelial cells; Breast; Myoepithelium; Immunocytochemistry; Naked nuclei
Descrição
BACKGROUND. The presence of myoepithelial cells (MECs) in fine-needle aspiration
biopsies (FNAB) of the breast constitute an important criterion used to
diagnose benign breast lesions. However, MECs sometimes have a distorted cytomorphology,
and most of the previously evaluated myoepithelial markers do not
have satisfactory sensitivity and specificity. p63, a recently characterized p53
homolog, is a nuclear transcription factor that is expressed in basal cells of
multilayered epithelia and myoepithelial cells of the breast. The authors analyzed
the immunocytochemical distribution of p63 in a series of 82 breast FNABs (30
benign lesions and 52 malignant breast lesions).
METHODS. Eighty-two archival, Papanicolaou-stained smears of breast lesions were
retrieved from the files of the authors’ institutions. Immunocytochemistry was
performed according to the streptavidin-biotin-peroxidase complex technique using
the antibody 4A4 (against all p63 isoforms). Two pathologists evaluated the
distribution of p63 positive cells. Only nuclear reactivity was considered specific.
RESULTS. In benign lesions, p63 decorated the nuclei of MECs in all samples. p63
also stained naked nuclei in fibroadenomas. In malignant lesions, p63 was positive
in MECs overlying malignant cell clusters in all 8 samples of ductal carcinoma in
situ (DCIS), in 9 of 16 samples of pure invasive carcinomas (IC), and in 16 of 20
samples that contained both DCIS and IC. In 18 samples (36%), a variable population
of p63 positive, malignant cells was observed. p63 failed to decorate stromal,
neural, adipocytic, and smooth muscle cells in all samples.
CONCLUSIONS. p63 is a reliable nuclear marker of MECs in breast aspirates. Regardless
of the fact that variable proportions of p63 positive, malignant cells were
observed in 36% of breast carcinoma aspirates, p63 may be a useful adjunct
antibody to confirm the presence of MECs in FNABs of benign breast lesions.
