Background Sentinel lymph node biopsy is a standard staging procedure for early axillary lymph node‐negative breast cancer. As an alternative to the currently used radioactive tracers for sentinel lymph node (SLN) detection during the surgical procedure, a number of studies have shown promising results using superparamagnetic iron oxide (SPIO) nanoparticles. Here, we developed a new handheld, cordless, and lightweight magnetic probe for SPIO detection. Methods Resovist (SPIO nanoparticles) were detected by the newly developed handheld probe, and the SLN detection rate was compared to that of the standard radioisotope (RI) method using radioactive colloids (99mTc) and a blue dye (indigo carmine). This was a multicenter prospective clinical trial that included 220 patients with breast cancer scheduled for sentinel node biopsy after a clinical diagnosis of negative axillary lymph node from three facilities in Japan. Results Of the 210 patients analyzed, SLN was detected in 94.8% (199/210 cases, 90% confidence interval [CI]) with our magnetic method and in 98.1% (206/210 cases, 90% CI) with the RI method. The magnetic method exceeded the threshold identification rate of 90%. Conclusion This was the first clinical study to use a novel handheld magnetometer to detect SLN, which we demonstrate to be not inferior to the RI method.

Current immunohistochemistry methods for diagnosing abnormal cells, such as cancer cells, require multiple steps and can be relatively slow compared with intraoperative frozen hematoxylin and eosin staining, and are therefore rarely used for intraoperative examination. Thus, there is a need for novel rapid detection methods. We previously demonstrated that functionalized fluorescent ferrite beads (FF beads) magnetically promoted rapid immunoreactions. The aim of this study was to improve the magnetically promoted rapid immunoreaction method using antibody-coated FF beads and a magnet subjected to a magnetic field. Using frozen sections of xenograft samples of A431 human epidermoid cancer cells that express high levels of epidermal growth factor receptor (EGFR) and anti-EGFR antibody-coated FF beads, we reduced the magnetically promoted immunohistochemistry procedure to a 1-min reaction and 1-min wash. We also determined the optimum magnetic force for the antibody reaction (from 7.79 × 10−15 N to 3.35 × 10−15 N) and washing (4.78 × 10−16 N), which are important steps in this technique. Furthermore, we stained paraffin-embedded tissue arrays and frozen sections of metastatic breast cancer lymph nodes with anti-pan-cytokeratin antibody-coated FF beads to validate the utility of this system in clinical specimens. Under optimal conditions, this ultra-rapid immunostaining method may provide an ancillary method for pathological diagnosis during surgery. (J Histochem Cytochem 58:XXX–XXX, 2010)

The proportions of Japanese women with dense breasts were high. In addition, the false-negative rate for women with dense breasts was also high. Owing to this, Japanese women with dense breasts may need to commonly undergo additional tests to ensure detection of breast cancer in the screening MMG.

BRCAness is defined as a phenotypic copy of germline BRCA mutations, which describes presence of homologous recombination defects in sporadic cancers. We detected BRCAness by multiplex ligation-dependent probe amplification (MLPA) and explored whether BRCAness can be used as a predictor of prognosis. BRCAness status was classified for total 121 breast cancer patients. Forty-eight patients (39.7%) were identified as BRCAness positive. Tumors of BRCAness were more likely to be hormone receptors negative (95.8% vs. 50.7%, P < 0.001), nuclear grade III (76.1% vs. 48.4%, P = 0.001) and triple-negative breast cancer subtype (91.6% vs. 42.5%, P < 0.001). Five-year disease free survival (DFS) (54.0% vs. 88.0%, P < 0.001) and overall survival (OS) (76.3% vs. 93.1%, P = 0.002) were significantly lower in BRCAness patients. In neoadjuvant chemotherapy subgroup analysis, clinical response rate for taxane-based regimen was significantly lower in BRCAness patients (58.3% vs. 77.8%, P = 0.041). Cox regression multivariate analysis showed that BRCAness was the independent prognostic factor for DFS (HR 2.962, 95%CI 1.184–7.412, P = 0.020), but not for OS (HR 2.681, 95%CI 0.618–11.630, P = 0.188). BRCAness is associated with specific characteristics and may suggest resistance to taxane-based chemotherapy. BRCAness can be used as a negative prognostic indicator for breast cancer.

Accurate pre-operative localization of nonpalpable lesions plays a pivotal role in guiding breast-conserving surgery (BCS). In this multicenter feasibility study, nonpalpable breast lesions were localized using a handheld magnetic probe (TAKUMI) and a magnetic marker (Guiding-Marker System®). The magnetic marker was preoperatively placed within the target lesion under ultrasound or stereo-guidance. Additionally, a dye was injected subcutaneously to indicate the extent of the tumor excision. Surgeons checked for the marker within the lesion using a magnetic probe. The magnetic probe could detect the guiding marker and accurately localize the target lesion intraoperatively. All patients with breast cancer underwent wide excision with a safety margin of ≥5 mm. The presence of the guiding-marker within the resected specimen was the primary outcome and the pathological margin status and re-excision rate were the secondary outcomes. Eighty-seven patients with nonpalpable lesions who underwent BCS, from January to March of 2019 and from January to July of 2020, were recruited. The magnetic marker was detected in all resected specimens. The surgical margin was positive only in 5/82 (6.1%) patients; these patients underwent re-excision. This feasibility study demonstrated that the magnetic guiding localization system is useful for the detection and excision of nonpalpable breast lesions.