Non-operative breast pathology: apocrine lesions.

Apocrine metaplasia is a very common finding in the female breast after the age of 25. It is so common that many people regard it as a normal component of the breast. This, however, is only really the case in apocrine sweat glands of the axilla and in the peri-areolar apocrine glands. The apocrine cell does, however, contribute to a number of different breast lesions, some of which are very taxing diagnostically; apocrine variants of both in-situ and invasive cancer are encountered. This review considers the common apocrine metaplastic lesions seen in fibrocystic change as well as apocrine adenoma, apocrine change within sclerosing adenosis, atypical apocrine lesions and apocrine malignancies.

Androgen receptor expression in ductal carcinoma in situ of the breast: relation to oestrogen and progesterone receptors.

AIMS: Ductal carcinoma in situ (DCIS) of the breast has been diagnosed increasingly since the advent of mammographic screening. In contrast to the situation in invasive breast carcinoma, there are no reports on androgen receptor (AR) status in DCIS and few reports on oestrogen (ER) and progesterone (PR) receptors. METHODS: AR expression was examined in 57 cases of DCIS of the breast and correlated to the degree of differentiation and ER/PR status using immunohistochemical methods. RESULTS: AR positivity was noted in 19 of the cases, whereas the other 38 cases were negative. There was no significant association between AR expression and the degree of differentiation of DCIS; three of the 13 well differentiated DCIS cases, 10 of the 19 intermediately differentiated cases, and six of the 25 poorly differentiated cases were positive (p = 0.093). However, a strong association was shown between the expression of ER (p < 0.0001) and PR (p = 0.002) and the degree of differentiation of DCIS. In addition, no significant association was found between the expression of AR and the expression of ER (p = 0.26) or PR (p = 0.57) in DCIS of the breast. CONCLUSIONS: A large number of cases of DCIS of the breast express AR and this may be associated with apocrine differentiation, which may impact on accurate typing of DCIS. Moreover, the expression of AR (but not ER or PR) in DCIS does not appear to be associated with the degree of differentiation.

Immunohistochemical localization of gross cystic disease fluid protein-15, -24 and -44 in ductal carcinoma in situ of the breast: relationship to the degree of differentiation.

AIMS: Three major proteins present in breast gross cystic disease fluid and expressed by the cyst lining apocrine epithelium are gross cystic disease fluid protein-15 (GCDFP-15), apolipoprotein-D (APO-D; GCDFP-24) and zinc alpha2-glycoprotein (ZnGP; GCDFP-44). The aim of this study was to investigate the expression of these proteins in ductal carcinoma in situ (DCIS) of the breast and to relate their expression with the degree of differentiation of DCIS. METHODS AND RESULTS: An immunohistochemical study of these proteins was performed in 57 cases of DCIS and nine cases of morphologically apocrine DCIS. Positivity was seen in 24/57 (42.1%) cases with anti-GCDFP-15, 20/57 (35.1%) cases with anti-GCDFP-24 and 22/57 (38.6%) cases with anti-GCDFP-44. GCDFP-15 positivity was noted in 5/13 (38.5%) of the well-differentiated, 11/19 (57.9%) intermediately differentiated and 8/25 (32.0%) of the poorly differentiated cases (P=0.217). GCDFP-24 positivity was seen in 3/13 (23.0%) well-differentiated, 9/19 (47.4%) intermediately differentiated and 8/25 (32.0%) poorly differentiated cases (P=0.336). GCDFP-44 was detected in 5/13 (38.5%) of well-differentiated cases, 11/19 (57.9%) intermediately differentiated and 6/25 (24.0%) poorly differentiated cases (P=0.074). In the nine cases of apocrine DCIS, GCDFP-15 positivity was detected in seven (77.8%), while five (55.6%) and six (66.7%) cases were positive for GCDFP-24 and GCDFP-44, respectively. CONCLUSIONS: The results indicate that there is no significant association between the expression of the studied proteins and the degree of differentiation of DCIS of the breast. Moreover, some morphologically apocrine DCIS cases appear to lose expression of these proteins.

Loss of heterozygosity and allelic imbalance in apocrine adenosis of the breast.

Recently, there have been studies suggesting that apocrine adenosis of the breast is a putative precancerous lesion, despite the generally held view that apocrine adenosis is benign. Because apocrine adenosis is almost always present as a small area or areas, it cannot be easily studied by conventional methods. In this study, areas of apocrine adenosis were microdissected from archival paraffin-embedded tissue to examine loss of heterozygosity and allelic imbalance compared with normal breast tissue epithelium from the same patients. Seventeen cases of apocrine adenosis, four associated with carcinoma, were analyzed using polymorphic microsatellite markers and polymerase chain reaction for loss of heterozygosity/allelic imbalance at eight loci that were reported to show allele loss or imbalance in invasive and in situ breast cancer. Loss of heterozygosity/allelic imbalance was detected in six of 17 cases of apocrine adenosis; three of 12 (25%) informative cases at 1p (MYCL1), two of seven (28.6%) at 11q (INT2), one of three (33.3%) at 13q (D13S267), two of 12 (16.7%) at 16q (D16S539), and two of 10 (20%) at 17q (D17S250). Neither loss of heterozygosity nor allelic imbalance has been identified at 1p (D1S252), 17p (TP53), or 17p (D17S513). In two of the four cases associated with carcinoma, loss of heterozygosity/allelic imbalance was seen in the same allele as in the synchronous carcinoma. These results suggest that molecular alterations, such as loss of heterozygosity and allelic imbalance, identified in apocrine adenosis may constitute an early event in the pathogenesis of breast cancer; reinforcing the possibility of apocrine adenosis being a putative precancerous lesion.

c-erbB2 oncoprotein expression, gene amplification, and chromosome 17 aneusomy in apocrine adenosis of the breast.

Amplification of the c-erbB2 oncogene and numerical aberrations of chromosome 17 occur in human breast carcinomas. Apocrine adenosis (AA) of the breast has been shown occasionally to have c-erbB2 overexpression and a possible premalignant potential, but little is known about cellular level genetic alterations in AA of the breast. Fluorescence in situ hybridization (FISH) is a new approach to detect these. In this study, a series of AA was studied by immunohistochemistry for c-erbB2 protein expression and by FISH using dual colour DNA probes for the c-erbB2 gene and the centromeric region of chromosome 17. Cell membrane immunostaining was seen in 10/18 (55.6%) AA cases, but unequivocal c-erbB2 gene amplification or chromosome 17 aneusomy was not seen. The results of this study suggest that c-erbB2 overexpression without amplification may occur early in breast oncogenesis. Amplification and numerical chromosome aberrations may occur later in the pathogenesis of apocrine-derived breast carcinomas.