Nancy Wang

Diagnosing breast cancer using Raman spectroscopy: prospective analysis

We present the first prospective test of Raman spectroscopy in diagnosing normal, benign, and malignant human breast tissues. Prospective testing of spectral diagnostic algorithms allows clinicians to accurately assess the diagnostic information contained in, and any bias of, the spectroscopic measurement. In previous work, we developed an accurate, internally validated algorithm for breast cancer diagnosis based on analysis of Raman spectra acquired from fresh-frozen in vitro tissue samples. We currently evaluate the performance of this algorithm prospectively on a large ex vivo clinical data set that closely mimics the in vivo environment. Spectroscopic data were collected from freshly excised surgical specimens, and 129 tissue sites from 21 patients were examined. Prospective application of the algorithm to the clinical data set resulted in a sensitivity of 83%, a specificity of 93%, a positive predictive value of 36%, and a negative predictive value of 99% for distinguishing cancerous from normal and benign tissues. The performance of the algorithm in different patient populations is discussed. Sources of bias in the in vitro calibration and ex vivo prospective data sets, including disease prevalence and disease spectrum, are examined and analytical methods for comparison provided.

Diagnosing breast cancer using diffuse reflectance spectroscopy and intrinsic fluorescence spectroscopy

Using diffuse reflectance spectroscopy and intrinsic fluorescence spectroscopy, we have developed an algorithm that successfully classifies normal breast tissue, fibrocystic change, fibroadenoma, and infiltrating ductal carcinoma in terms of physically meaningful parameters. We acquire 202 spectra from 104 sites in freshly excised breast biopsies from 17 patients within 30 min of surgical excision. The broadband diffuse reflectance and fluorescence spectra are collected via a portable clinical spectrometer and specially designed optical fiber probe. The diffuse reflectance spectra are fit using modified diffusion theory to extract absorption and scattering tissue parameters. Intrinsic fluorescence spectra are extracted from the combined fluorescence and diffuse reflectance spectra and analyzed using multivariate curve resolution. Spectroscopy results are compared to pathology diagnoses, and diagnostic algorithms are developed based on parameters obtained via logistic regression with cross-validation. The sensitivity, specificity, positive predictive value, negative predictive value, and overall diagnostic accuracy (total efficiency) of the algorithm are 100, 96, 69, 100, and 91%, respectively. All invasive breast cancer specimens are correctly diagnosed. The combination of diffuse reflectance spectroscopy and intrinsic fluorescence spectroscopy yields promising results for discrimination of breast cancer from benign breast lesions and warrants a prospective clinical study.

Lysosomal membrane permeabilization during apoptosis--involvement of Bax?

Bcl‐2 family members have long been known to control permeabilization of the mitochondrial membrane during apoptosis, but involvement of these proteins in lysosomal membrane permeabilization (LMP) was not considered until recently. The aim of this study was to investigate the mechanism underlying the release of lysosomal proteases to the cytosol seen during apoptosis, with special emphasis on the role of Bax. In human fibroblasts, exposed to the apoptosis‐inducing drug staurosporine (STS), the release of the lysosomal protease cathepsin D to the cytosol was observed by immunocytochemistry. In response to STS treatment, there was a shift in Bax immunostaining from a diffuse to a punctate pattern. Confocal microscopy showed co‐localization of Bax with both lysosomes and mitochondria in dying cells. Presence of Bax at the lysosomal membrane was confirmed by immuno‐electron microscopy. Furthermore, when recombinant Bax was incubated with pure lysosomal fractions, Bax inserted into the lysosomal membrane and induced the release of lysosomal enzymes. Thus, we suggest that Bax is a mediator of LMP, possibly promoting the release of lysosomal enzymes to the cytosol during apoptosis.

Mutation of the HEXIM1 Gene Results in Defects During Heart and Vascular Development Partly Through Downregulation of Vascular Endothelial Growth Factor

Our previous studies and those of others indicated that the transcription factor Hexamethylene-bis-acetamide-inducible protein 1 (HEXIM1) is a tumor suppressor and cyclin-dependent kinase inhibitor, and that these HEXIM1 functions are mainly dependent on its C-terminal region. We provide evidence here that the HEXIM1 C-terminal region is critical for cardiovascular development. HEXIM1 protein was detected in the heart during critical time periods in cardiac growth and chamber maturation. We created mice carrying an insertional mutation in the HEXIM1 gene that disrupted its C-terminal region and found that this resulted in prenatal lethality. Heart defects in HEXIM11 to 312 mice included abnormal coronary patterning and thin ventricular walls. The thin myocardium can be partly attributed to increased apoptosis. Platelet endothelial cell adhesion molecular precursor-1 staining of HEXIM11 to 312 heart sections revealed decreased vascularization of the myocardium despite the presence of coronary vasculature in the epicardium. The expression of vascular endothelial growth factor (VEGF), known to affect angioblast invasion and myocardial proliferation and survival, was decreased in HEXIM11 to 312 mice compared with control littermates. We also observed decreased fibroblast growth factor 9 (FGF9) expression, suggesting that effects of HEXIM1 in the myocardium are partly mediated through epicardial FGF9 signaling. Together our results suggest that HEXIM1 plays critical roles in coronary vessel development and myocardial growth. The basis for this role of HEXIM1 is that VEGF is a direct transcriptional target of HEXIM1, and involves attenuation a repressive effects of C/EBP&agr; on VEGF gene transcription.

Evidence for Transformation of Fibroadenoma of the Breast to Malignant Phyllodes Tumor

Fibroadenoma (FA) and phyllodes tumor (PT) of the breast are biphasic tumors composed of variable proportions of epithelial and stromal cells. We identified a case of synchronous FA and PT in the same breast mass. Using laser capture microdissection, loss of heterozygosity analysis was performed on these components to gain potential insight into the histogenetic relationship between FA and PT. Genomic DNA was analyzed at 10 microsatellite loci by polymerase chain reaction. Both tumors showed allelic loss at D7S522. In addition, phylloid tumor showed allelic loss at TP53 and D22S264, not observed in FA. Our data suggest that FA and PT are clonally related and allelic loss at TP53 and D22S264 may be implicated in the progression of FA to phyllode tumor.

Significance of histiocytes on otherwise-normal cervical smears from postmenopausal women: A retrospective study of 108 cases

OBJECTIVE To evaluate the significance of histiocytes on normal cervical smears from postmenopausal women and correlate them with endometrial pathology. STUDY DESIGN Histiocytes were classified into three types. The clinical history was obtained from cytologic and surgical reports. RESULTS Among 108 cervical smears, 13 had large, foamy histiocytes (type A), 88 had histiocytes resembling superficial endometrial stromal cells (type B), and 7 had variably sized histiocytes alone or in association with inflammatory or multinucleated cells (type C). Endometrial pathology was identified in 13 patients (12.0%): 4/13 with type A histiocytes (2 endometrial adenocarcinomas, 2 endometrial polyps), 8/88 with type B histiocytes (8 endometrial polyps) and 1/7 with type C histiocytes (endometrial polyp). Among 70 patients with no clinical indications for endometrial sampling except for the presence of histiocytes, 4 demonstrated endometrial pathology (all endometrial polyps). In contrast, endometrial pathology was identified in 9/38 with clinical indications for endometrial sampling. Among the 13 patients with endometrial pathology, 9 had a significant clinical history (sensitivity of 69.2%), and 4 had histiocytes as the only indication for endometrial biopsy (sensitivity of 30.8%). CONCLUSION A significant clinical history is more predictive of endometrial pathology and outweighs the significance of histiocytes as an indication for endometrial biopsy.

Segregation of Radiographic Calcifications in Stereotactic Core Biopsies of Breast: Is It Necessary?

Abstract:  Stereotactic‐needle core biopsy (SNCB) is increasingly being used for the evaluation of mammographic calcifications. Radiography of SNCB specimens is essential to confirm the presence of calcifications within the biopsy material. To aid and direct the pathologist, it has been recommended that SNCBs be separated into those with and without radiographic calcifications and separately embedded. However, the utility of this separation to the pathologist has not been established. We reviewed 80 consecutive 11 gauge vacuum‐assisted SNCB procedures performed for mammographic calcifications. The core biopsies were separated by the radiologist into those with and without radiographic calcifications (“calcs” and “no calcs”). Twenty‐nine of 80 (36%) of the “calcs” cores were atypical or malignant, while 23 of 80 (29%) of the “no calcs” cores were atypical or malignant (χ2 = 0.63, p = NS). The same diagnosis was rendered in the “calcs” and “no calcs” specimens in 61/80 cases (76%). Two cases of ductal carcinoma in situ, four cases of atypical ductal hyperplasia and 13 cases of fibroadenoma were diagnosed in the “calcs” cores only. However, in all cases where the pathologic lesion was seen in the “calcs” core only, the pathologic lesion was present on initial H&E levels and would have been diagnosed even in the absence of core segregation. Deeper sections were deemed necessary in seven of the 80 cases. No change in diagnosis was made on the basis of these deeper sections, even in the cases where histologic calcifications appeared on deeper sections. Separate embedding of SNCBs into those with and without radiographic calcifications does not appear to be of great utility to the pathologist. Equal attention should be given to all cores in the setting of SNCBs for mammographic calcifications.