Breast-specific gamma imaging as an adjunct modality for the diagnosis of invasive breast cancer with correlation to tumour size and grade.

OBJECTIVES: The purpose of this study was to determine the sensitivity of breast-specific gamma imaging (BSGI) in the detection of invasive breast cancers and to characterise the sensitivity of BSGI based on tumour size and pathological grade. METHODS: 139 females with invasive carcinoma who underwent BSGI were retrospectively reviewed. Patients were injected in the antecubital vein with 20-30 mCi (925-1110 MBq) of (99m)Tc-sestamibi. Images were obtained with a high-resolution, breast-specific gamma camera (Dilon 6800; Dilon Technologies, Newport News, VA) and were categorised based on radiotracer uptake as normal, normal with heterogeneous uptake, probably abnormal and abnormal. For a positive examination, the region of the area of increased uptake had to correlate with the laterality and location of the biopsy-proven cancer. RESULTS: 149 invasive cancers in 139 patients with a mean size of 1.8 cm (0.2-8.5 cm) were included. 146 were identified with BSGI (98.0%). All cancers which measured ≥ 0.7 cm (n = 123) as well as all cancers grade 2 or higher (n = 102), regardless of tumour size, were identified with BSGI (100%). There were 6 cancers that were pathological grade 1 and measured <7 mm, of which 50% (3/6) were identified with BSGI. The overall sensitivity of BSGI for the detection of invasive breast cancer is 98.0%. The sensitivity for subcentimetre cancers is 88.5% (23/26). CONCLUSION: BSGI has a high sensitivity for the detection of invasive breast cancer. Our results demonstrate that BSGI detected all invasive breast cancers pathological grade 2 and higher regardless of size and all cancers which measured ≥ 7 mm regardless of grade. BSGI can reliably detect invasive breast cancers and is a useful adjunct imaging modality for the diagnosis of breast cancer.

DNA breakage and cell cycle checkpoint abrogation induced by a therapeutic thiopurine and UVA radiation.

The frequency of squamous cell skin carcinoma in organ transplant patients is around 100-fold higher than normal. This dramatic example of therapy-related cancer reflects exposure to sunlight and to immunosuppressive drugs. Here, we show that the interaction between low doses of UVA, the major ultraviolet component of incident sunlight, and 6-TG, a UVA chromophore that is introduced into DNA by one of the most widely prescribed immunosuppressive drugs, causes DNA single- and double-strand breaks (DSB). S phase cells are particularly vulnerable to this DNA breakage and cells defective in rejoining of S-phase DSB are hypersensitive to the combination of low-dose UVA and DNA 6-TG. 6-TG/UVA-induced DNA lesions provoke canonical DNA damage responses involving activation of the ATM/Chk2 and ATR/Chk1 pathways and appropriate cell cycle checkpoints. Higher levels of photochemical DNA damage induce a proteasome-mediated degradation of Chk1 and checkpoint abrogation that is consistent with persistent unrepaired DNA damage. These findings indicate that the interaction between UVA and an immunosuppressant drug causes photochemical DNA lesions, including DNA breaks, and can compromise cell cycle checkpoints. These two properties could contribute to the high risk of sunlight-related skin cancer in long-term immunosuppressed patients.

Inhibition of proliferation by 1-8U in interferon-alpha-responsive and non-responsive cell lines.

Interferon (IFN)-inducible proteins of the 1-8 gene family mediate homotypic adhesion and transduction of antiproliferative signals. Their induction correlates with inhibition of cell growth while they are often repressed in the course of malignant transformation and tumor development. Ras-mediated transformation of mouse mast cells is associated with downregulation of 1-8U expression and interferon-alpha (IFN-alpha) treatment reverts the proliferation rate to normal levels together with induction of 1-8U. Conversely, the antiproliferative responses of IFN-alpha in sensitive human melanoma cells are accompanied by 1-8U induction. Here we provide direct evidence that recombinant expression of 1-8U in human cell lines is sufficient to block cell proliferation. Based on the abundant expression and subcellular localization to the plasma membrane and exosome-like structures, we propose a model capable of explaining the pleiotropic functions of 1-8 family proteins in tumor cells and during normal development.

Fourteen-gauge ultrasonographically guided large-core needle biopsy of breast masses.

OBJECTIVE: Large-core needle biopsy of the breast can be performed with stereotactic or ultrasonographic guidance. However, ultrasonographically guided large-core needle biopsy has notable advantages, including the absence of ionizing radiation, increased patient comfort, and greater cost-effectiveness. The purpose of this study was to evaluate the accuracy of ultrasonographically guided large-core needle biopsy for the diagnosis of breast cancer in palpable and nonpalpable breast masses. METHODS: The study was a retrospective review of consecutive ultrasonographically guided large-core needle biopsies for indeterminate breast masses. A total 424 ultrasonographically guided core biopsies were performed in 367 patients with 1 or more breast masses. Ultrasonographically guided core biopsy was performed with a 14-gauge spring-loaded needle and a freehand technique. Correlation of ultrasonographically guided core biopsy pathologic findings with subsequent surgical pathologic findings or long-term imaging follow-up was performed. RESULTS: Of 424 indeterminate breast lesions for which histopathologic findings were obtained by ultrasonographically guided core biopsy, 234 cancers were diagnosed. Twenty-eight additional lesions had either questionable but not definitively malignant pathologic features (n = 11) or radiologic-pathologic discordance (n = 17) and were surgically excised. Of these, 8 additional cancers were diagnosed. Patients or surgeons chose excision of 41 additional lesions that were benign on ultrasonographically guided core biopsy No cancer was found in these surgical specimens. One additional cancer was diagnosed at a 6-month imaging follow-up because of interval growth. On the basis of surgical and long-term imaging follow-up, the sensitivity of ultrasonographically guided core biopsy for the diagnosis of breast carcinoma was 99.2% (95% confidence interval, 95.6%-99.9%) in 173 palpable breast masses and 93.2% (95% confidence interval, 87.1%-97%) in 251 nonpalpable masses. In cancers diagnosed on the basis of immediate surgical excision as a result of ultrasonographically guided core biopsy that showed either questionable pathologic features or radiologic-pathologic discordance, the sensitivity of ultrasonographically guided core biopsy for the diagnosis of breast cancer was 99.2%. CONCLUSIONS: Ultrasonographically guided large-core needle biopsy is a sensitive percutaneous biopsy method for the diagnosis of breast cancer in palpable and nonpalpable breast masses.

Identification of metastasis-associated genes by transcriptional profiling of a metastasizing versus a non-metastasizing human melanoma cell line.

In order to identify genes associated with the metastatic phenotype we have compared the expression pattern of 6800 genes in a metastatic (NMCL-1) versus a non-metastatic (530) human melanoma cell line making use of DNA microarrays. The differentially expressed genes identified are involved in control of transcription, regulation of the cell-cycle, proteolysis, cell adhesion, immune response and signaling. A remarkable feature of the system under investigation is the consistent down-regulation of MHC-related and cell adhesion mediating genes in the metastatic cell line.

Global analysis of differential gene expression after transformation with the v-H-ras oncogene in a murine tumor model.

Mouse PB-3c mast cells stably transfected with the v-H-ras oncogene induce tumor formation in vivo when implanted into mice. Such tumor cells are characterized by an autocrine IL-3 loop. DNA microarrays allow simultaneous transcript imaging of several thousand genes and the technique was applied in this tumor model to analyse gene expression following malignant transformation. Using three independent tumor lines derived from the same precursor the expression of about 400 out of 11 000 genes was modulated in each tumor. A subset of only 75 genes (0.68%) is shared and up- or downregulated in all three lines. A significant portion of this gene pool possesses functions related to tumorigenesis such as cell adhesion, signaling or transcriptional regulation. Apart from a number of expressed sequence tags (EST's) we find downregulation of four interferon-inducible genes in the tumor lines. Finally, when we extrapolate our data to the complete mouse genome, we estimate that about 500 genes are differentially expressed in tumor cells compared to the precursor cell PB-3c.

Nonpalpable breast cancer: percutaneous diagnosis with 11- and 8-gauge stereotactic vacuum-assisted biopsy devices.

PURPOSE: To compare the accuracy of diagnosis of invasive breast cancer with 11- and 8-gauge stereotactic vacuum-assisted biopsy (SVAB) devices and to correlate lesion diameter and accuracy of breast cancer diagnosis at SVAB. MATERIALS AND METHODS: During a 22-month period, 489 SVAB procedures were performed with an 11-gauge probe and 305 with an 8-gauge probe. SVAB and surgical pathologic results of 104 breast carcinomas were reviewed and correlated with lesion size, number of specimens obtained, and type of SVAB probe used. RESULTS: Four of 38 ductal carcinoma in situ (DCIS) lesions diagnosed with 11-gauge SVAB demonstrated invasion at surgery, whereas one of 23 DCIS lesions diagnosed with 8-gauge SVAB demonstrated invasion at surgery (P =.6). A mean of 12 specimens per lesion were obtained in each group. In lesions 30 mm or larger, the underestimation rate for DCIS was 43% (three of seven) with 11-gauge SVAB and 17% (one of six) with 8-gauge SVAB (P =.6). Overall, the rate of underestimation for DCIS was significantly higher in lesions 30 mm or larger (four of 13) than in smaller lesions (one of 48, P =.006). CONCLUSION: This study demonstrated no difference in breast cancer diagnosis with the 8- and 11-gauge SVAB systems, but the accuracy of breast cancer diagnosis was greater in lesions smaller than 30 mm than in larger lesions.

Reliability of histologic diagnosis of breast cancer with stereotactic vacuum-assisted biopsy.

The purpose of this study was to determine the accuracy of 11-gauge stereotactic vacuum-assisted breast biopsy (SVAB) for the diagnosis of breast cancer. Percutaneous biopsies of 426 suspicious breast lesions in 365 patients using 11-gauge SVAB were performed between September 1996 and June 1998. Of these biopsies 59 (13.8%) resulted in a diagnosis of breast carcinoma and 56 (95%) were surgically excised. These 56 lesions constitute the basis of this study. Pathology of SVAB and surgically excised tissue of the 56 carcinomas as well as imaging findings were correlated. At percutaneous biopsy 34 (61%) lesions demonstrated ductal carcinoma in situ (DCIS) and 22 (39%) invasive carcinomas. Surgical excision demonstrated the presence of an invasive cancer in three lesions percutaneously diagnosed as DCIS (9%; confidence interval 2-24%). No residual carcinoma was surgically demonstrated in seven (12.5%) lesions. Sensitivity of 11-gauge SVAB for the diagnosis of invasion in breast cancer was 88 per cent. Using SVAB the diagnosis of invasive carcinoma is reliable. However, a percutaneous finding of DCIS does not exclude the presence of invasion in 9 per cent of cases as confirmed by subsequent surgery. Using SVAB 12.5% of carcinomas are completely excised.

Stereotactic breast biopsy of nonpalpable lesions: determinants of ductal carcinoma in situ underestimation rates.

PURPOSE: To measure the effect of biopsy device, probe size, mammographic lesion type, lesion size, and number of samples obtained per lesion on the ductal carcinoma in situ (DCIS) underestimation rate. MATERIALS AND METHODS: Nonpalpable breast lesions at 16 institutions received a histologic diagnosis of DCIS after 14-gauge automated large-core biopsy in 373 lesions and after 14- or 11-gauge directional vacuum-assisted biopsy in 953 lesions. The presence of histopathologic invasive carcinoma was noted at subsequent surgical biopsy. RESULTS: By performing the chi(2) test, independent significant DCIS underestimation rates by biopsy device were 20.4% (76 of 373) of lesions diagnosed at large-core biopsy and 11.2% (107 of 953) of lesions diagnosed at vacuum-assisted biopsy (P <.001); by lesion type, 24.3% (35 of 144) of masses and 12.5% (148 of 1,182) of microcalcifications (P <.001); and by number of specimens per lesion, 17.5% (88 of 502) with 10 or fewer specimens and 11.5% (92 of 799) with greater than 10 (P <.02). DCIS underestimations increased with lesion size. CONCLUSION: DCIS underestimations were 1.9 times more frequent with masses than with calcifications, 1.8 times more frequent with large-core biopsy than with vacuum-assisted biopsy, and 1.5 times more frequent with 10 or fewer specimens per lesion than with more than 10 specimens per lesion.

Radiologist detection of microcalcifications with and without computer-aided detection: a comparative study.

AIM: To compare the sensitivity and specificity of microcalcification detection by radiologists alone and assisted by a computer-aided detection (CAD) system. MATERIALS AND METHODS: Films of 106 patients were masked, randomized, digitized and analysed by the CAD-system. Five readers interpreted the original mammograms and were blinded to demographics, medical history and earlier films. Forty-two mammograms with malignant microcalcifications, 40 with benign microcalcifications and 24 normal mammograms were included. Results were recorded on a standardized image interpretation form. The mammograms with suspicious areas flagged by the CAD-system were displayed on mini-monitors and immediately re-reviewed. The interpretation was again recorded on a new copy of the standard form and classified according to six groups. RESULTS: Forty-one out of 42 (98%) malignant microcalcifications and 32 of 40 (80%) benign microcalcifications were flagged by the CAD-system. There was an average of 1.2 markers per image. The sensitivity for malignant microcalcifications detection by mammographers without and with the CAD-system ranged from 81% to 98% and from 88% to 98%, respectively. The mean difference without and with CAD-system was 2.2% (range 0-7%). CONCLUSION: No statistically significant changes in sensitivity were found when experienced mammographers were assisted by the CAD-system, with no significant compromise in specificity.

Focal fibrosis of the breast: imaging characteristics and histopathologic correlation.

PURPOSE: To characterize mammographic and ultrasonographic (US) features of focal fibrosis of the breast (FFB), to compare the radiologic and histopathologic findings, to investigate the incidence of FFB, and to determine if histopathologic diagnosis of FFB is an acceptable diagnosis for specific mammographic and US findings. MATERIALS AND METHODS: Retrospective review of findings from 1,268 surgical excisional and 796 percutaneous breast biopsies (290 US-guided, 370 stereotactically guided, and 136 vacuum-assisted stereotactically-guided) revealed 44 (2.1%) diagnoses of FFB. Mammographic and US features were correlated with histopathologic types. RESULTS: Thirty-seven (84%) of the 44 lesions diagnosed as FFB were visualized on mammograms and appeared as six (14%) circumscribed masses, two (5%) lobulated masses, one (2%) microlobulated mass, 11 (25%) obscured masses, two (5%) architectural distortions, and 15 (34%) asymmetric densities. Seven palpable lesions were not visualized on mammograms. Thirty-three of the 44 lesions were evaluated at US; 25 (76%) of 33 were visible. Twenty (80%) of 25 were well-defined hypoechoic masses; three (12%), ill-defined masses; and two (8%), marked shadowing without visible mass. At histopathologic examination, 17 (39%) of the 44 lesions were characterized as mass-like fibrosis; 14 (32%), as nodular fibrosis; 12 (27%), as haphazard fibrosis; and one (2%), as septal fibrosis. Histopathologic type and specific imaging findings did not correlate statistically. CONCLUSION: FFB is a histopathologic entity that has a wide spectrum of imaging findings. It is an acceptable histopathologic result of percutaneous breast biopsy, provided that careful radiologic-histopathologic clinical correlation is performed.

Sonographic appearance of ductal carcinoma in situ diagnosed with ultrasonographically guided large core needle biopsy: correlation with mammographic and pathologic findings.

The purpose of this study was to evaluate sonographic features of ductal carcinoma in situ diagnosed percutaneously at ultrasonographically guided large core needle biopsy. Of 619 biopsies, 203 breast carcinomas were diagnosed, of which nine were pure ductal carcinoma in situ. All ductal carcinoma in situ lesions appeared sonographically as hypoechoic masses without a pseudocapsule. Grade 1 lesions (n = 2; mean size, 9.5 mm), grade 2 lesions (n = 4; mean size, 18 mm) and grade 3 lesions (n = 3; mean size, 32 mm) had means of 0, 1, and 5 malignant sonographic features, respectively. Ductal carcinoma in situ appeared mammographically as a mass, with two of four grade 2 lesions and all grade 3 lesions demonstrating suspicious microcalcifications. One grade 3 ductal carcinoma in situ was spiculated. In conclusion, ductal carcinoma in situ lesions tended to show more malignant mammographic and sonographic features as histologic grade and size increased.

The effect of multiple binding modes on empirical modeling of ligand docking to proteins.

A popular approach to the computational modeling of ligand/receptor interactions is to use an empirical free energy like model with adjustable parameters. Parameters are learned from one set of complexes, then used to predict another set. To improve these empirical methods requires an independent way to study their inherent errors. We introduce a toy model of ligand/receptor binding as a workbench for testing such errors. We study the errors incurred from the two state binding assumption--the assumption that a ligand is either bound in one orientation, or unbound. We find that the two state assumption can cause large errors in free energy predictions, but it does not affect rank order predictions significantly. We show that fitting parameters using data from high affinity ligands can reduce two state errors; so can using more physical models that do not use the two state assumption. We also find that when using two state models to predict free energies, errors are more severe on high affinity ligands than low affinity ligands. And we show that two state errors can be diagnosed by systematically adding new binding modes when predicting free energies: if predictions worsen as the modes are added, then the two state assumption in the fitting step may be at fault.

Atypical ductal hyperplasia: histologic underestimation of carcinoma in tissue harvested from impalpable breast lesions using 11-gauge stereotactically guided directional vacuum-assisted biopsy.

OBJECTIVE: This review was undertaken to determine the reliability of the histologic diagnosis of atypical ductal hyperplasia (ADH) made from tissue obtained by 11-gauge stereotactically guided directional vacuum-assisted biopsy of impalpable breast lesions. MATERIALS AND METHODS: Four hundred twenty-two 11-gauge stereotactically guided vacuum-assisted breast biopsies were performed at our institution between November 5, 1996, and June 30, 1998. Biopsies were performed with the patient prone on a dedicated stereotactic biopsy table. A directional vacuum-assisted biopsy device was used. Eight to 24 cores (mean, 13.4) were harvested from each lesion. Radiography of core specimens was performed in cases in which the target lesion contained microcalcifications. Twenty (4.7%) of the 422 biopsies yielded a histopathologic diagnosis of ADH. Surgical excision of 16 of the 20 lesions was subsequently performed. We compared the histopathologic results of the core extracted and the corresponding surgically excised tissue. RESULTS: Of the 16 surgically excised lesions, four (25.0%) retained the diagnosis of ADH. Four (25%) were upgraded to carcinoma: Two (12.5%) were ductal carcinoma in situ without comedonecrosis, one (6.3%) was invasive carcinoma, and one (6.3%) was tubular carcinoma. Of the remaining eight surgically excised lesions, six (37.5%) were interpreted as benign fibrocystic changes with ductal hyperplasia without atypia, and two (12.5%) were interpreted as lobular carcinoma in situ. CONCLUSION: Because ADH was underdiagnosed in 25% of the lesions, we recommend that surgical excision be performed whenever ADH is found in tissue obtained from 11-gauge directional vacuum-assisted breast biopsy.

Contributions of orientation and hydrogen bonding to catalysis in Asn229 mutants of thymidylate synthase.

We have determined structures of binary and ternary complexes of five Asn229 variants of thymidylate synthase (TS) and related their structures to the kinetic constants measured previously. Asn229 forms two hydrogen bonds to the pyrimidine ring of the substrate 2'-deoxyuridine-5'-monophosphate (dUMP). These hydrogen bonds constrain the orientation of dUMP in binary complexes with dUMP, and in ternary complexes with dUMP and the TS cofactor, 5,10-methylene-5,6,7,8-tetrahydrofolate. In N229 mutants, where these hydrogen bonds cannot be made, dUMP binds in a misoriented or more disordered fashion. Most N229 mutants exhibit no activity for the dehalogenation of 5-bromo-dUMP, which requires correct orientation of dUMP against Cys198. Since bound dUMP forms the binding surface against which the pterin ring of cofactor binds, misorientation of dUMP results in higher Km values for cofactor. At the same time, binding of the cofactor aids in ordering and positioning dUMP for catalysis. Hydrophobic mutants, such as N229I, favor an arrangement of solvent molecules and side-chains around the ligands similar to that in a proposed transition state for ternary complex formation in wild-type TS, and kcat values are similar to the wild-type value. Smaller, more hydrophilic mutants favor arrangements of the solvent and side-chains surrounding the ligands that do not resemble the proposed transition state. These changes correspond to decreases in kcat of up to 2000-fold, with only modest increases in Km or Kd. These results are consistent with the proposal that the hydrogen-bonding network between water, dUMP and side-chains in the active-site cavity contributes to catalysis in TS. Asn229 has the unique ability to maintain this critical network, without sterically interfering with dUMP binding.

Diffusion imaging of human breast.

It is shown that diffusion-weighted imaging is possible in the human breast. Diffusion constants were measured in the breast parenchyma of four volunteers with no known breast lesions. The apparent diffusion constant of water measured in regions of interest chosen in normal human breast fibroglandular tissue was 1.64 +/- 0.19 x 10(-5) cm2/S and that measured in the area of fatty breast tissue was 0.32 +/- 0.18 x 10(-5) cm2/S. The resulting images indicate that fibroglandular tissue and fat can be clearly distinguished in diffusion-weighted as well as in absolute diffusion images of the breast. Potential future applications of this technology for the study of breast pathologies are suggested.