Recommendations for human epidermal growth factor receptor 2 testing in breast cancer: american society of clinical oncology/college of american pathologists clinical practice guideline update

PURPOSE: To update the American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guideline recommendations for human epidermal growth factor receptor 2 (HER2) testing in breast cancer to improve the accuracy of HER2 testing and its utility as a predictive marker in invasive breast cancer. METHODS: ASCO/CAP convened an Update Committee that included coauthors of the 2007 guideline to conduct a systematic literature review and update recommendations for optimal HER2 testing. RESULTS: The Update Committee identified criteria and areas requiring clarification to improve the accuracy of HER2 testing by immunohistochemistry (IHC) or in situ hybridization (ISH). The guideline was reviewed and approved by both organizations. RECOMMENDATIONS: The Update Committee recommends that HER2 status (HER2 negative or positive) be determined in all patients with invasive (early stage or recurrence) breast cancer on the basis of one or more HER2 test results (negative, equivocal, or positive). Testing criteria define HER2-positive status when (on observing within an area of tumor that amounts to > 10% of contiguous and homogeneous tumor cells) there is evidence of protein overexpression (IHC) or gene amplification (HER2 copy number or HER2/CEP17 ratio by ISH based on counting at least 20 cells within the area). If results are equivocal (revised criteria), reflex testing should be performed using an alternative assay (IHC or ISH). Repeat testing should be considered if results seem discordant with other histopathologic findings. Laboratories should demonstrate high concordance with a validated HER2 test on a sufficiently large and representative set of specimens. Testing must be performed in a laboratory accredited by CAP or another accrediting entity. The Update Committee urges providers and health systems to cooperate to ensure the highest quality testing. This guideline was developed through a collaboration between the American Society of Clinical Oncology and the College of American Pathologists and has been published jointly by invitation and consent in both Journal of Clinical Oncology and the Archives of Pathology & Laboratory Medicine

Tubulopapillary carcinoma of the mammary gland in a maned wolf (Chrysocyon brachyurus): histopathological and immunophenotypical analysis

A maned female wolf (Chrysocyon brachyurus) showed nodules in the inguinal and left abdominal cranial mammary glands. The mammary gland was surgically excised, and microscopic analysis revealed epithelial cell proliferation in a tubular and papillary pattern; delicate fibrovascular stalks presenting numerous layers of moderately pleomorfic epithelial cells were observed. This histologic appearance was compatible with a diagnosis of mammary tubulopapillary carcinoma. The immunohistochemical profile revealed nuclear positivity for estrogen (70%) and progesterone (at least 90% of the neoplastic cells). The myoepithelium-associated with neoplastic cells lacked integrity, as evidenced by failed smooth muscle alpha actin reactivity in microinvasive areas. A low proliferation index was observed (3.4%). To the authors' knowledge, the present case represents the first finding of female tubulopapillary carcinoma in a mammary gland in this species