α-Methylacyl-CoA racemase: a useful immunohistochemical marker of breast carcinoma with apocrine differentiation.

Carcinoma with apocrine differentiation is an androgen receptor (AR)-positive subset of triple-negative breast carcinomas. In addition to carcinoma with apocrine differentiation, other AR-positive triple-negative breast carcinomas occur, albeit less frequently. We found that α-methylacyl-CoA racemase (AMACR), also known as P504S, is overexpressed in carcinoma with apocrine differentiation and non-neoplastic apocrine metaplasia. We aimed to evaluate AMACR as a possible marker of carcinoma with apocrine differentiation. We immunohistochemically examined the expression of AMACR in carcinoma with apocrine differentiation and nonapocrine carcinomas and compared it with that of gross cystic disease fluid protein-15 (GCDFP-15). In total, 212 breast carcinomas were evaluated: 39 carcinomas with apocrine differentiation, 28 ductal carcinomas in situ with apocrine morphology (ADCIS), and 145 nonapocrine breast carcinomas. AMACR was expressed in 38 of 39 (97.4%) carcinomas with apocrine differentiation and in 27 of 28 (96.4%) ADCIS, consistent with the expression of GCDFP-15. However, in nonapocrine carcinomas, AMACR expression was observed in 32 of 145 (22.0%) lesions, whereas GCDFP-15 expression was observed in 91 of 145 (62.7%) lesions. For carcinoma with apocrine differentiation, AMACR was as sensitive as GCDFP-15 (both 97.1%) but more specific (77.9% versus 37.2%). In selected cases, AMACR messenger RNA (mRNA) levels were quantitatively determined relative to that of TATA-binding protein mRNA, and they comprised 5.23, 1.33, and 0.60 for carcinomas with apocrine differentiation, nonapocrine carcinomas, and normal breast tissue, respectively. CONCLUSION: Our findings demonstrate that AMACR expression may be used for differentiating carcinoma with apocrine differentiation from nonapocrine carcinomas and indicate that AMACR is a more sensitive carcinoma with apocrine differentiation marker than GCDFP-15.

A multicenter, observational study of metastatic breast cancer patients who were treated with eribulin mesylate or taxane-based regimens.

AIM: This multicenter, observational study aimed to investigate the survival benefit of eribulin as well as that of taxane-based regimens in Japanese patients with metastatic breast cancer (MBC) in a real-world setting. METHODS: This study enrolled women with MBC who received eribulin or taxane-based regimens with or without bevacizumab in routine clinical practice from July 2011 to March 2014. Patients were followed until September 2015. The primary endpoint was overall survival (OS). Secondary endpoints included progression-free survival (PFS), post-progression survival (PPS) and adverse events. Efficacy findings were adjusted according to demographics. RESULTS: In total, 216 patients receiving eribulin monotherapy (n = 101), taxane monotherapy (n = 73) or taxane plus bevacizumab (n = 42) were followed for a median time of 15.4 months. Median OS, PFS and PPS were 22.3, 8.1 and 14 months in the eribulin monotherapy group; 13.2, 3.6 and 7.6 months in the taxane monotherapy group; and 12.9, 5.7 and 6.3 months, in the taxane plus bevacizumab group, respectively. The incidence of neutropenia was 67.3, 41.1 and 16.7%, and the incidence of grade 4 neutropenia was 1.0, 8.2 and 7.1% in the eribulin monotherapy, taxane monotherapy and taxane plus bevacizumab groups, respectively. One patient (1.0%) discontinued eribulin and 18 patients (15.7%) discontinued taxane-based regimens because of adverse events. CONCLUSION: In Japanese MBC patients in a real-world setting, eribulin showed a survival benefit and tolerability similar to that in previous reports.