<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>Apocrine carcinoma of the breast is a rare subtype of breast carcinoma, which only presents as 4% among patients with breast cancer. The percentage varies based on the diagnostic criteria used by each institution to classify apocrine carcinoma. Several confusing terms used in previous studies, including apocrine ductal carcinoma in situ (ADCIS), apocrine morphology in lobular carcinoma in situ (Apocrine LCIS), apocrine-like invasive carcinoma, pure apocrine carcinoma, molecular apocrine tumors (MATs), and triple-negative apocrine carcinoma of the breast (TNAC). The treatment, prognosis, and molecular profiles are also diverse. Pure apocrine carcinoma has stricter criteria for diagnosis, requiring more than 90% of cells showing apocrine morphology and classic IHC characteristics of ER-negative, PR-negative, and AR-positive in at least 10% of tumor cell nuclei. Research related to prognosis is diverse due to the difficulty of unifying the diagnostic criteria. Current evidence of treatment is geared toward the use of neoadjuvant chemotherapy and anti-androgen therapy when AR is present, accompanied by other treatments if biomarkers are present, such as HER2, PI3K, or CDK4/6. This article focuses on clearly summarizing different subtypes and management of apocrine carcinoma of the breast.</p>
</abstract>

Apocrine carcinoma of the breast is a rare subtype of breast carcinoma, which only presents as 4% among patients with breast cancer. The percentage varies based on the diagnostic criteria used by each institution to classify apocrine carcinoma. Several confusing terms used in previous studies, including apocrine ductal carcinoma in situ (ADCIS), apocrine morphology in lobular carcinoma in situ (Apocrine LCIS), apocrine-like invasive carcinoma, pure apocrine carcinoma, molecular apocrine tumors (MATs), and triple-negative apocrine carcinoma of the breast (TNAC). The treatment, prognosis, and molecular profiles are also diverse. Pure apocrine carcinoma has stricter criteria for diagnosis, requiring more than 90% of cells showing apocrine morphology and classic IHC characteristics of ER-negative, PR-negative, and AR-positive in at least 10% of tumor cell nuclei. Research related to prognosis is diverse due to the difficulty of unifying the diagnostic criteria. Current evidence of treatment is geared toward the use of neoadjuvant chemotherapy and anti-androgen therapy when AR is present, accompanied by other treatments if biomarkers are present, such as HER2, PI3K, or CDK4/6. This article focuses on clearly summarizing different subtypes and management of apocrine carcinoma of the breast.

Apocrine carcinoma of the breast: Review

Riverside, School of Medicine, Internal Medicine

Forum of Clinical Oncology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

{"article-title":"Apocrine carcinoma of the breast: Review"}

Apocrine carcinoma of the breast is a rare subtype of breast carcinoma, which only presents as 4% among patients with breast cancer. The percentage varies...

CLASSIFICATION	INTERVENTION
ATYPICAL APOCRINE LESIONS (AA)	No intervention +− Core needle biopsy
APOCRINE DCIS (ADCIS)	Mastectomy or conservative surgery +/− adjuvant radiation therapy
APOCRINE CARCINOMA	Neoadjuvant chemotherapy + surgery +/− radiation therapy + anti-androgen therapy (if AR+) + anti-HER2 antibodies (if HER2+) +/− PI3 kinase inhibition and CDK4/6 inhibitors (if biomarkers detected)

IMMUNOHISTOLOGY MARKERS	PURE APOCRINE CARCINOMA	ADCIS	INVOLVING PATHWAY
ER, PR (−), AR (+)	100% strictly match to AR (+,) ER(−), PR (−) criteria	>90%	AR pathway
HER-2	1/3 positive, 2/3 negative	47.1%	HER2 signaling pathway
GCDFP-15	75%	96.4%	AR pathway
AMACR	> 90%	> 90%	Oxidative degradation pathways
ER-A36	94.7%	94.7% (classified with pure apocrine carcinoma)	MAPK/ERK signaling pathway EGFR/Src/ERK signaling pathway
PIK3CA	>80%	100%	PI3K/mTOR pathway
P53	46–50%	61.8%	PI3K/mTOR/p53 pathway
PD-L1	10–40%	N/A	PD-1/PD-L1 pathway
AR-V7	57%	N/A	AR pathway

Apocrine carcinoma of the breast: Review

Article Category: Review

Published Online: Sep 15, 2023

Page range: 52 - 61

Received: Jun 07, 2023

Accepted: Jul 31, 2023

DOI: https://doi.org/10.2478/fco-2023-0007

Keywords
Apocrine carcinoma, breast cancer, androgen receptor

© 2023 Chieh Yang et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Figure 1:

Figure 2:

Figure 3:

Treatment recommendation from the literature review.

Immunohistology characteristics of ADCIS and pure apocrine carcinoma.

Apocrine carcinoma of the breast: Review

Article Category: Review

Published Online: Sep 15, 2023

Page range: 52 - 61

Received: Jun 07, 2023

Accepted: Jul 31, 2023

DOI: https://doi.org/10.2478/fco-2023-0007

KeywordsApocrine carcinoma, breast cancer, androgen receptor

© 2023 Chieh Yang et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Figure 1:

Figure 2:

Figure 3:

Treatment recommendation from the literature review.

Immunohistology characteristics of ADCIS and pure apocrine carcinoma.

Keywords
Apocrine carcinoma, breast cancer, androgen receptor