Immunohistochemical assessment of HRAS Q61R mutations in breast adenomyoepitheliomas.

AIMS: Breast adenomyoepitheliomas (AMEs) are uncommon tumours. Most oestrogen receptor (ER)-positive AMEs have mutations in phosphoinositide 3-kinase (PI3K) pathway genes, whereas ER-negative AMEs usually harbour concurrent mutations affecting the HRAS Q61 hotspot and PI3K pathway genes. Here, we sought to determine the sensitivity and specificity of RAS Q61R immunohistochemical (IHC) analysis for detection of HRAS Q61R mutations in AMEs. METHODS AND RESULTS: Twenty-six AMEs (14 ER-positive; 12 ER-negative) previously subjected to massively parallel sequencing (n = 21) or Sanger sequencing (n = 5) of the HRAS Q61 hotspot locus were included in this study. All AMEs were subjected to IHC analysis with a monoclonal (SP174) RAS Q61R-specific antibody, in addition to detailed histopathological analysis. Nine ER-negative AMEs harboured HRAS mutations, including Q61R (n = 7) and Q61K (n = 2) mutations. Five of seven (71%) AMEs with HRAS Q61R mutations were immunohistochemically positive, whereas none of the AMEs lacking HRAS Q61R mutations (n = 17) were immunoreactive. RAS Q61R immunoreactivity was restricted to the myoepithelium in 80% (4/5) of cases, whereas one case showed immunoreactivity in both the epithelial component and the myoepithelial component. RAS Q61R immunohistochemically positive AMEs were associated with infiltrative borders (P < 0.001), necrosis (P < 0.01) and mitotic index in the epithelial (P < 0.05) and myoepithelial (P < 0.01) components. RAS Q61R IHC assessment did not reveal Q61K mutations (0/2). CONCLUSIONS: IHC analysis of RAS Q61R shows high specificity (100%) and moderate sensitivity (71%) for detection of HRAS Q61R mutations in breast AMEs, and appears not to detect HRAS Q61K mutations. IHC analysis of RAS Q61R may constitute a useful technique in the diagnostic workup of ER-negative AMEs.

Systemic therapy for patients with advanced human epidermal growth factor receptor 2-positive breast cancer: American Society of Clinical Oncology clinical practice guideline.

PURPOSE: To provide evidence-based recommendations to practicing oncologists and others on systemic therapy for patients with human epidermal growth factor receptor 2 (HER2) -positive advanced breast cancer. METHODS: The American Society of Clinical Oncology convened a panel of medical oncology, radiation oncology, guideline implementation, and advocacy experts and conducted a systematic literature review from January 2009 to October 2012. Outcomes of interest included overall survival, progression-free survival (PFS), and adverse events. RESULTS: A total of 16 trials met the systematic review criteria. The CLEOPATRA trial found survival and PFS benefits for docetaxel, trastuzumab, and pertuzumab in first-line treatment, and the EMILIA trial found survival and PFS benefits for trastuzumab emtansine (T-DM1) in second-line treatment. T-DM1 also showed a third-line PFS benefit. One trial reported on duration of HER2-targeted therapy, and three others reported on endocrine therapy for patients with HER-positive advanced breast cancer. RECOMMENDATIONS: HER2-targeted therapy is recommended for patients with HER2-positive advanced breast cancer, except for those with clinical congestive heart failure or significantly compromised left ventricular ejection fraction, who should be evaluated on a case-by-case basis. Trastuzumab, pertuzumab, and taxane for first-line treatment and T-DM1 for second-line treatment are recommended. In the third-line setting, clinicians should offer other HER2-targeted therapy combinations or T-DM1 (if not previously administered) and may offer pertuzumab, if the patient has not previously received it. Optimal duration of chemotherapy is at least 4 to 6 months or until maximum response, depending on toxicity and in the absence of progression. HER2-targeted therapy can continue until time of progression or unacceptable toxicities. For patients with HER2-positive and estrogen receptor-positive/progesterone receptor-positive breast cancer, clinicians may recommend either standard first-line therapy or, for selected patients, endocrine therapy plus HER2-targeted therapy or endocrine therapy alone.

Recommendations on disease management for patients with advanced human epidermal growth factor receptor 2-positive breast cancer and brain metastases: American Society of Clinical Oncology clinical practice guideline.

PURPOSE: To provide formal expert consensus-based recommendations to practicing oncologists and others on the management of brain metastases for patients with human epidermal growth factor receptor 2 (HER2) -positive advanced breast cancer. METHODS: The American Society of Clinical Oncology (ASCO) convened a panel of medical oncology, radiation oncology, guideline implementation, and advocacy experts and conducted a systematic review of the literature. When that failed to yield sufficiently strong quality evidence, the Expert Panel undertook a formal expert consensus-based process to produce these recommendations. ASCO used a modified Delphi process. The panel members drafted recommendations, and a group of other experts joined them for two rounds of formal ratings of the recommendations. RESULTS: No studies or existing guidelines met the systematic review criteria; therefore, ASCO conducted a formal expert consensus-based process. RECOMMENDATIONS: Patients with brain metastases should receive appropriate local therapy and systemic therapy, if indicated. Local therapies include surgery, whole-brain radiotherapy, and stereotactic radiosurgery. Treatments depend on factors such as patient prognosis, presence of symptoms, resectability, number and size of metastases, prior therapy, and whether metastases are diffuse. Other options include systemic therapy, best supportive care, enrollment onto a clinical trial, and/or palliative care. Clinicians should not perform routine magnetic resonance imaging (MRI) to screen for brain metastases, but rather should have a low threshold for MRI of the brain because of the high incidence of brain metastases among patients with HER2-positive advanced breast cancer.