Purpose: Detection of sentinel lymph node (SLN) metastasis in breast cancer patients has conventionally been determined by intraoperative histopathologic examination of frozen sections followed by definitive postoperative examination of permanent sections. The purpose of this study is to develop a more efficient method for intraoperative detection of lymph node metastasis. Experimental Design: Cutoff values to distinguish macrometastasis, micrometastasis, and nonmetastasis were determined by measuring cytokeratin 19 (CK19) mRNA in histopathologically positive and negative lymph nodes using one-step nucleic acid amplification (OSNA). In an intraoperative clinical study involving six facilities, 325 lymph nodes (101 patients), including 81 SLNs, were divided into four blocks. Alternate blocks were used for the OSNA assay with CK19 mRNA, and the remaining blocks were used for H&E and CK19 immunohistochemistryb ased three-level histopathologic examination. The results from the two methods were then compared. Results: We established CK19 mRNA cutoff values of 2.5 Â 10 2 and 5 Â 10 3 copies/AL. In the clinical study, an overall concordance rate between the OSNA assay and the three-level histopathology was 98.2 %. Similar results were obtained with 81 SLNs. The OSNA assay discriminated macrometastasis from micrometastasis. No false positive was observed in the OSNA assay of 144 histopathologically negative lymph nodes from pN0 patients, indicating an extremely low false positive for the OSNA assay. Conclusion: The OSNA assay of half of a lymph node provided results similar to those of three-level histopathology. Clinical results indicate that the OSNA assay provides a useful intraoperative detection method of lymph node metastasis in breast cancer patients.Sentinel lymph node (SLN) biopsy has recently become a standard surgical procedure in the treatment of breast cancer patients (1 -10). This procedure can predict metastasis to the regional lymph nodes with high accuracy and avoids unnecessary removal of axillary lymph nodes and subsequent morbidity associated with axially clearance in node negative breast cancer patients.SLN metastasis is generally detected by conventional means including the intraoperative H&E-based histopathologic examination of frozen section(s) or cytologic observation of touchimprints, followed by definitive postoperative histopathologic examination of permanent sections (2, 7 -9). However, the sensitivity of these intraoperative methods is not high. Many investigators have reported that the intraoperative H&E-based histopathologic examination has a false-negative rate of 5% to 52% (reviewed in ref. 11). Furthermore, these methods provide subjective rather than objective results, which may differ from one pathologist to another (12). On the other hand, the definitive postoperative histopathologic examination generally requires 5 to 10 days for assessment. If an accurate Imaging, Diagnosis, Prognosis

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Both F10 and BL6 sublines of B16 mouse melanoma cells are metastatic after intravenous injection, but only BL6 cells are metastatic after subcutaneous injection. Retrotransposon insertion was found to produce an N-terminally truncated form (Δγ1) of the B56γ1 regulatory subunit isoform of protein phosphatase (PP) 2A in BL6 cells, but not in F10 cells. We found an interaction of paxillin with PP2A C and B56γ subunits by co-immunoprecipitation. B56γ1 co-localized with paxillin at focal adhesions, suggesting a role for this isoform in targeting PP2A to paxillin. In this regard, Δγ1 behaved similarly to B56γ1. However, the Δγ1-containing PP2A heterotrimer was insufficient for the dephosphorylation of paxillin. Transfection with Δγ1 enhanced paxillin phosphorylation on serine residues and recruitment into focal adhesions, and cell spreading with an actin network. In addition, Δγ1 rendered F10 cells as highly metastatic as BL6 cells. These results suggest that mutations in PP2A regulatory subunits may cause malignant progression.

Purpose: Accurate assessment of metastasis in sentinel lymph nodes (SLN) of breast cancer is important but involves a heavy workload for the pathologist.We conducted a multicenter clinical trial in Japan to evaluate a new automated assay system for cytokeratin 19 mRNA, the one-step nucleic acid amplification (OSNA) assay (Sysmex), to detect lymph node metastasis of breast cancer. Experimental Design: Surgically obtained axillary lymph nodes were sectioned into four pieces, two of which were examined with the OSNA assay. The other two adjacent pieces were examined with H&E and immunohistochemical staining for cytokeratin 19. Serial sections at 0.2-mm intervals were used in trial 1 to determine the specificity of the OSNA assay, and three pairs of sections cut from the sliced surfaces of the pieces were used in trial 2 to compare the accuracy of the OSNA assay with that of a routine pathologic examination for SLNs in Japan. Results: In trial 1, the sensitivity and specificity were 95.0% [95% confidence interval (95% CI), 75.1-99.9 %] and 97.1% (95 % CI, 91.8-99.4%), respectively, for 124 axillary lymph nodes obtained from 34 patients. In trial 2, the agreement between findings of the assay and of the pathologic examination was 92.9% (95% CI, 90.1-95.1%) for 450 axillary lymph nodes obtained from 164 patients. Conclusion: The OSNA assay can detect lymph node metastasis as accurately as can conventional pathology and thus can be an effective addition to or alternative for rapid intraoperative examination of SLNs.Sentinel lymph node (SLN) biopsy for breast cancer is expected to become a standard surgical procedure in the near future, and accurate assessment of metastasis of SLNs is essential for making decisions about the avoidance of unnecessary axillary dissection and the provision of appropriate adjuvant treatment for patients. However, methods for the pathologic examination of SLNs to detect metastasis remain controversial (1 -4). Although more detailed examination of SLNs can provide more accurate information about metastasis (5), to obtain more accurate results, a comparatively greater number of pathologic specimens need to be examined (6). This involves much time for preparation of the specimens and a heavy workload for pathologists to examine them, especially intraoperatively.To overcome these problems, molecular detection of metastasis has been developed as one of the most promising methods for SLN examination. With this procedure, the whole lymph node can be examined during a short time