Understanding and quantifying the mechanical properties of breast tissues has been a subject of interest for the past two decades. This has been motivated in part by interest in modelling soft tissue ...response for surgery planning and virtual-reality-based surgical training. Interpreting elastography images for diagnostic purposes also requires a sound understanding of normal and pathological tissue mechanical properties. Reliable data on tissue elastic properties are very limited and those which are available tend to be inconsistent, in part as a result of measurement methodology. We have developed specialized techniques to measure tissue elasticity of breast normal tissues and tumour specimens and applied them to 169 fresh ex vivo breast tissue samples including fat and fibroglandular tissue as well as a range of benign and malignant breast tumour types. Results show that, under small deformation conditions, the elastic modulus of normal breast fat and fibroglandular tissues are similar while fibroadenomas were approximately twice the stiffness. Fibrocystic disease and malignant tumours exhibited a 3-6-fold increased stiffness with high-grade invasive ductal carcinoma exhibiting up to a 13-fold increase in stiffness compared to fibrogalndular tissue. A statistical analysis showed that differences between the elastic modulus of the majority of those tissues were statistically significant. Implications for the specificity advantages of elastography are reviewed.
CONTEXT Current recommendations for women who have a BRCA1 or BRCA2 mutation are to undergo breast surveillance
from age 25 years onward with mammography annually and clinical breast examination
...(CBE) every 6 months; however, many tumors are detected at a relatively advanced
stage. Magnetic resonance imaging (MRI) and ultrasound may improve the ability
to detect breast cancer at an early stage. OBJECTIVE To compare the sensitivity and specificity of 4 methods of breast cancer
surveillance (mammography, ultrasound, MRI, and CBE) in women with hereditary
susceptibility to breast cancer due to a BRCA1 or BRCA2 mutation. DESIGN, SETTING, AND PARTICIPANTS A surveillance study of 236 Canadian women aged 25 to 65 years with BRCA1 or BRCA2 mutations who underwent
1 to 3 annual screening examinations, consisting of MRI, mammography, and
ultrasound at a single tertiary care teaching hospital between November 3,
1997, and March 31, 2003. On the day of imaging and at 6-month intervals,
CBE was performed. MAIN OUTCOME MEASURES Sensitivity and specificity of each of the 4 surveillance modalities,
and sensitivity of all 4 screening modalities vs mammography and CBE. RESULTS Each imaging modality was read independently by a radiologist and scored
on a 5-point Breast Imaging Reporting and Data System scale. All lesions with
a score of 4 or 5 (suspicious or highly suspicious for malignancy) were biopsied.
There were 22 cancers detected (16 invasive and 6 ductal carcinoma in situ).
Of these, 17 (77%) were detected by MRI vs 8 (36%) by mammography, 7 (33%)
by ultrasound, and 2 (9.1%) by CBE. The sensitivity and specificity (based
on biopsy rates) were 77% and 95.4% for MRI, 36% and 99.8% for mammography,
33% and 96% for ultrasound, and 9.1% and 99.3% for CBE, respectively. There
was 1 interval cancer. All 4 screening modalities combined had a sensitivity
of 95% vs 45% for mammography and CBE combined. CONCLUSIONS In BRCA1 and BRCA2 mutation
carriers, MRI is more sensitive for detecting breast cancers than mammography,
ultrasound, or CBE alone. Whether surveillance regimens that include MRI will
reduce mortality from breast cancer in high-risk women requires further investigation.
Early alterations in textural characteristics of quantitative ultrasound spectral parametric maps, in conjunction with changes in their mean values, are demonstrated here, for the first time, to be ...capable of predicting ultimate clinical/pathologic responses of breast cancer patients to chemotherapy. Mechanisms of cell death, induced by chemotherapy within tumor, introduce morphological alterations in cancerous cells, resulting in measurable changes in tissue echogenicity. We have demonstrated that the development of such changes is reflected in early alterations in textural characteristics of quantitative ultrasound spectral parametric maps, followed by consequent changes in their mean values. The spectral/textural biomarkers derived on this basis have been demonstrated as non-invasive surrogates of breast cancer chemotherapy response. Particularly, spectral biomarkers sensitive to the size and concentration of acoustic scatterers could predict treatment response of patients with up to 80% of sensitivity and specificity (p=0.050), after one week within 3-4 months of chemotherapy. However, textural biomarkers characterizing heterogeneities in distribution of acoustic scatterers, could differentiate between treatment responding and non-responding patients with up to 100% sensitivity and 93% specificity (p=0.002). Such early prediction permits offering effective alternatives to standard treatment, or switching to a salvage therapy, for refractory patients.
Aims
Technical limitations in conventional pathological evaluation of breast lumpectomy specimens may reduce diagnostic accuracy in the assessment of margin and focality. A novel technique based on ...whole‐mount serial sections enhances sampling while preserving specimen conformation and orientation. The aim of this study was to investigate assessment of focality and margin status by the use of whole‐mount serial sections versus simulated conventional sections in lumpectomies.
Methods and results
Two pathologists interpreted whole‐mount serial sections and simulated conventional sections for 58 lumpectomy specimens by reporting the closest margin and focality. Measurements were compared by the use of McNemar's chi‐squared test. Statistically significant differences were observed in the assignment of both margin positivity (P = 0.014) and multifocality (P = 0.021). A positive margin or multifocal disease was identified by the use of whole‐mount serial sections but missed in the simulated conventional assessment in 10.3% and 17.2% of all cases, respectively. There was no case in which a positive margin was detected only in the simulated conventional assessment.
Conclusions
The whole‐mount technique is more sensitive than conventional assessment for identifying a positive margin or multifocal disease in breast lumpectomy specimens. Undersampling in conventional sections was implicated in almost all cases of discordance. The majority of positive margins or secondary foci identified only in whole‐mount serial sections concerned in‐situ disease.
Aims
Multiplexed immunofluorescence is a powerful tool for validating multigene assays and understanding the complex interplay of proteins implicated in breast cancer within a morphological context. ...We describe a novel technology for imaging an extended panel of biomarkers on a single, formalin‐fixed paraffin‐embedded breast sample and evaluating biomarker interaction at a single‐cell level, and demonstrate proof‐of‐concept on a small set of breast tumours, including those which co‐express hormone receptors with Her2/neu and Ki‐67.
Methods and results
Using a microfluidic flow cell, reagent exchange was automated and consisted of serial rounds of staining with dye‐conjugated antibodies, imaging and chemical deactivation. A two‐step antigen retrieval process was developed to satisfy all epitopes simultaneously, and key parameters were optimized. The imaging sequence was applied to seven breast tumours, and compared with conventional immunohistochemistry. Single‐cell correlation analysis was performed with automated image processing.
Conclusions
We have described a novel platform for evaluating biomarker co‐localization. Expression in multiplexed images is consistent with conventional immunohistochemistry. Automation reduces inconsistencies in staining and positional shifts, while the fluorescent dye cycling approach dramatically expands the number of biomarkers which can be visualized and quantified on a single tissue section.
BCA2 is an E3 ligase linked with hormone responsive breast cancers. We have demonstrated previously that the RING E3 ligase BCA2 has autoubiquitination activity and is a very unstable protein. ...Previously, only Rab7, tetherin, ubiquitin and UBC9 were known to directly interact with BCA2.
Here, additional BCA2 binding proteins were found using yeast two-hybrid and bacterial-II-hybrid screening techniques with Human breast and HeLa cDNA libraries. Co-expression of these proteins was analyzed through IHC of TMAs. Investigation of the molecular interactions and effects were examined through a series of in vivo and in vitro assays.
Ten unique BCA2 interacting proteins were identified, two of which were hHR23a and 14-3-3sigma. Both hHR23a and 14-3-3sigma are co-expressed with BCA2 in breast cancer cell lines and patient breast tumors (n = 105). hHR23a and BCA2 expression was significantly correlated (P = < 0.0001 and P = 0.0113) in both nucleus and cytoplasm. BCA2 expression showed a statistically significant correlation with tumor grade. High cytoplasmic hHR23a trended towards negative nodal status. Binding to BCA2 by hHR23a and 14-3-3sigma was confirmed in vitro using tagged partner proteins and BCA2. hHR23a and 14-3-3sigma effect the autoubiquitination and auto-degradation activity of BCA2. Ubiquitination of hHR23a-bound BCA2 was found to be dramatically lower than that of free BCA2, suggesting that hHR23a promotes the stabilization of BCA2 by inactivating its autoubiquitination activity, without degradation of hHR23a. On the other hand, phosphorylated BCA2 protein is stabilized by interaction with 14-3-3sigma both with and without proteasome inhibitor MG-132 suggesting that BCA2 is regulated by multiple degradation pathways.
The interaction between BCA2 and hHR23a in breast cancer cells stabilizes BCA2. High expression of BCA2 is correlated with grade in breast cancer, suggesting regulation of this E3 ligase is important to cancer progression.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract PURPOSE: Ultrasound elastography is a new imaging technique that can be used to assess tissue stiffness. The aim of this study was to investigate the potential of ultrasound elastography for ...monitoring treatment response of locally advanced breast cancer patients undergoing neoadjuvant therapy. METHODS: Fifteen women receiving neoadjuvant chemotherapy had the affected breast scanned before, 1, 4, and 8 weeks following therapy initiation, and then before surgery. Changes in elastographic parameters related to tissue biomechanical properties were then determined and compared to clinical and pathologic tumor response after mastectomy. RESULTS: Patients who responded to therapy demonstrated a significant decrease ( P < .05) in strain ratios and strain differences 4 weeks after treatment initiation compared to non-responding patients. Mean strain ratio and mean strain difference for responders was 81 ± 3% and 1 ± 17% for static regions of interest (ROIs) and 81 ± 3% and 6 ± 18% for dynamic ROIs, respectively. In contrast, these parameters were 102±2%, 110±17%, 101±4%, and 109±30% for non-responding patients, respectively. Strain ratio using static ROIs was found to be the best predictor of treatment response, with 100% sensitivity and 100% specificity obtained 4 weeks after starting treatment. CONCLUSIONS: These results suggest that ultrasound elastography can be potentially used as an early predictor of tumor therapy response in breast cancer patients.
To develop and validate improved processing methods for producing diagnostic-quality, whole-mount serial sections for 3-dimensional imaging of whole-breast histopathologic studies, we subjected ...4-mm-thick whole-specimen slices to a 38-hour microwave-assisted protocol. Morphologic features, antigenicity, and tissue shrinkage were evaluated. A schedule using the tissue processor was optimized by evaluating the serial section yield for 3 schedules. The microwave-based processing schedule is adequate for producing diagnostic-quality whole-mount breast serial sections of an area up to 6,000 mm(2) and is compatible with a variety of immunohistochemical stains. A mean +/- SE total tissue shrinkage of 8.4% +/- 0.2% resulted. For the tissue processor, optimal results are obtained using a 59-hour schedule. Total fixation and processing time for whole-mount serial breast sections has been reduced from 21 days to 38 hours, with microwave assistance, and to 59 hours without. No adverse effects of microwaves on morphologic features, antigenicity, or gross tissue dimensions were observed.
Clarke G M, Peressotti C, Holloway C M B, Zubovits J T, Liu K & Yaffe M J (2011) Histopathology59, 116–128
Development and evaluation of a robust algorithm for computer‐assisted detection of sentinel ...lymph node micrometastases
Aims: Increasing the sectioning rate for breast sentinel lymph nodes can increase the likelihood of detecting micrometastases. To make serial sectioning feasible, we have developed an algorithm for computer‐assisted detection (CAD) with digitized lymph node sections.
Methods and results: K‐means clustering assigned image pixels to one of four areas in a colourspace (representing tumour, unstained background, counterstained background and microtomy artefacts). Four filters then removed ‘false‐positive’ pixels from the tumour cluster. A set of 43 sections containing tumour (a total of 259 foci) and 59 sections negative for malignancy was defined by two pathologists, using light microscopy, and CAD was applied. For the clinically relevant task of identifying the largest focus in each section (micrometastasis in 22/43 sections), the sensitivity and specificity were 100%. Isolated tumour cells (ITCs) were identified in one slide initially considered to be negative. Identification of all 259 foci yielded sensitivities of 57.5% for ITCs (<0.200 mm), 89.5% for micrometastases, and 100% for larger metastases, with one false‐positive. Reduced sensitivity was ascribed to variable staining. Nine additional metastases (<0.01–0.3 mm) that were not initially identified were detected by CAD.
Conclusions: This algorithm is well suited to the task of sentinel lymph node evaluation and may enhance the detection of occult micrometastases.
Summary We examined the effect of lateral spatial resolution and reader specialty on the accuracy of detection of breast cancer. The motivation for this pilot study was the need to acquire and ...display very large data sets in whole-specimen 3D digital breast histopathology imaging. The ultimate goal is to determine the minimum resolution adequate for detection of malignancy. Twenty-three histologic slides were selected from breast pathology cases and digitized at 2 sampling distances (3.2 and 1.9 μ m pixels). Images were viewed by 14 pathologists, of whom 5 had breast pathology as their primary specialty. The readers assessed the likelihood of malignancy on a 5-point Likert scale, and provided a provisional diagnosis. For the detection task, sensitivity, specificity, overall accuracy of detection, and area under the receiver-operator curve were calculated. An overall diagnostic score, and scores grouped by malignancy type, were also computed. Outcome measures were examined for significant resolution and specialty effects. Increasing the lateral resolution significantly improved accuracy in diagnosis ( P = .004) but no effect was found for detection. Breast specialists achieved significantly higher scores for all outcome measures except specificity. Differences in performance between the 2 groups of readers tended to be greater for the diagnostic task compared to detection, especially at the higher resolution. However, specimen coverage may also be a significant factor. Factors related to the readers may have also affected performance in this study. Based on these results, a more comprehensive study should examine pixel sizes between 0.7 and 1.9 μ m.
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