Highlights d Lapatinib-resistant breast cancer cells upregulate CD36 expression for survival d Ta... more Highlights d Lapatinib-resistant breast cancer cells upregulate CD36 expression for survival d Targeting CD36 re-sensitizes lapatinib-resistant cells to HER2-inhibition d Deletion of Cd36 significantly attenuates MMTV-neu-driven mammary tumor growth d CD36 is induced by HER2-targeted therapy and predicts poor clinical prognosis
We previously described the expression of CD36 and lipoprotein lipase (LPL) by breast cancer (BC)... more We previously described the expression of CD36 and lipoprotein lipase (LPL) by breast cancer (BC) cells and tissues, and the growth-promoting effect of very low-density lipoprotein (VLDL) supplementation observed in BC cell lines only in the presence of LPL. We now describe the deployment of LPL by BC cells. Our data support a model in which LPL is bound to a heparin-like heparan sulfate proteoglycan motif on the BC cell surface and acts in concert with the VLDL receptor to rapidly internalize intact lipoproteins via receptor-mediated endocytosis. We further observe substantial alterations in gene expression programs related to pathways for lipid acquisition (synthesis vs. uptake) in response to each the availability of exogenous triglyceride in tissue culture media and LPL expression status. Current literature emphasizes de novo fatty acid synthesis as the paramount mechanism for lipid acquisition by cancer cells. Our findings indicate that exogenous lipid uptake can serve as an im...
International journal of clinical and experimental pathology, 2016
The ubiquitin E3 ligase MDM2 is best known for its ability to suppress the tumor suppressor p53. ... more The ubiquitin E3 ligase MDM2 is best known for its ability to suppress the tumor suppressor p53. However, MDM2 also targets other proteins for proteasomal degradation and accumulating evidence strongly suggests p53-independent roles of MDM2 in cancer. We previously reported that MDM2 promotes degradation of another ubiquitin E3 ligase HUWE1 by ubiquitination, particularly, which confers HER2 breast cancer cells resistance to the HER2 inhibitor lapatinib. However, it remains unclear whether such a mechanism can operate in other cell types, independently of HER2 inhibitors. Moreover, evidence that supports HUWE1 degradation by MDM2 is missing. In the current study, we performed immunohistochemistry (IHC) to analyze expression levels of MDM2 and HUWE1 in normal organs, two breast cancer cohorts (A, n = 137 and B, n = 27), and a liposarcoma cohort (n = 45). Our results show that HUWE1 is ubiquitously expressed in healthy organs, where the oncoprotein MDM2 is undetectable. Likewise, in t...
Wire-localized excision of nonpalpable breast cancer is imprecise, resulting in positive margins ... more Wire-localized excision of nonpalpable breast cancer is imprecise, resulting in positive margins 25-30% of the time. Patients underwent preoperative supine magnetic resonance imaging (MRI). A radiologist outlined the tumor edges on consecutive images, creating a three-dimensional (3D) view of its location. Using 3D printing, a bra-like plastic form (the Breast Cancer Locator [BCL]) was fabricated, with features that allowed a surgeon to (1) mark the edges of the tumor on the breast surface; (2) inject blue dye into the breast 1 cm from the tumor edges; and (3) place a wire in the tumor at the time of surgery. Nineteen patients with palpable cancers underwent partial mastectomy after placement of surgical cues using patient-specific BCLs. The cues were in place in <5 min and no adverse events occurred. The BCL accurately localized 18/19 cancers. In the 18 accurately localized cases, all 68 blue-dye injections were outside of the tumor edges. Median distance from the blue-dye cente...
In the original paper by Dr. Poller 6 describing the morphologic criteria for the Van Nuys classi... more In the original paper by Dr. Poller 6 describing the morphologic criteria for the Van Nuys classification, he defined in detail three nuclear grades (high, intermediate, and low). Identical morphologic criteria were subsequently used, in combination with tumor size and margin ...
Analytical and Quantitative Cytology and Histology the International Academy of Cytology and American Society of Cytology, Jun 1, 2004
To analyze the microvasculature and tissue type ratios in normal vs. benign and malignant breast ... more To analyze the microvasculature and tissue type ratios in normal vs. benign and malignant breast tissue to establish a baseline for expected values against which future imaging studies can be benchmarked. Using computer-assisted techniques on immunostained breast tissue (normal [n = 28], fibrocystic [n = 37], fibroadenomas [n = 19], invasive carcinomas [n = 19]), values were obtained for microvessel density (MVD), mean vessel area (MVA), vessel orientation (shape) and epithelial:stromal ratio (E:S). Measurement reproducibility and the effects of fibroadenoma stromal hyalinization and fibrocystic disease severity were also tested. Value ranges for the 4 diagnostic groups were significantly different (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001). For invasive breast carcinomas, E:S and MVD were significantly higher (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001) but MVA was smaller as compared to that in fibroadenomas. Peripherally vs. centrally there was no significant difference in MVD, MVA or vessel shape in the neoplasms. Decreases in E:S and MVD correlated with fibroadenoma stromal hyalinization. Increases in E:S and MVA correlated with more severe fibrocystic disease. Correlation coefficients for measurement reproducibility were high across the diagnostic categories. This study established a specific, reproducible, computer-assisted technique and baseline of expected values for morphologic criteria in normal, benign and malignant breast tissue that may be used in the future to correlate new breast imaging responses with these underlying biologic properties.
Melanoma is one of the most aggressive types of skin cancer. The purpose of this study was to eva... more Melanoma is one of the most aggressive types of skin cancer. The purpose of this study was to evaluate the use of two biomarkers, ProEx C and glucose transporter isoform 1 (GLUT1), in the diagnosis and prognostication of melanoma. We analyzed 129 melanomas and 59 benign nevi in a tissue microarray using immunohistochemical method with antibodies to topoisomerase IIα (TOP2A) and minichromosome maintenance complex component 2 (MCM2) using ProEx C and to GLUT1. The average proliferative index by ProEx C immunostain was significantly higher in melanomas (37.5%) compared to benign nevi (1.9%) as was the expression of GLUT1 (p<0.0001 respectively). Dermal mitosis was found to correlate positively with both ProEx C and GLUT1 (p=0.003 and p<0.001, respectively). Ulceration and tumor thickness positively correlated with GLUT1 expression (p=0.013 and p=0.033, respectively), but not with ProEx C staining. There was a significant association between increasing ProEx C index and stronger e...
Analytical and Quantitative Cytology and Histology the International Academy of Cytology and American Society of Cytology, Aug 1, 2009
OBJECTIVETo assess how optical scatter properties in breast tissue, as measured by phase contrast... more OBJECTIVETo assess how optical scatter properties in breast tissue, as measured by phase contrast microscopy and interpreted pathophysiologically, might be exploited as a diagnostic tool to differentiate cancer from benign tissue.STUDY DESIGNWe evaluated frozen human breast tissue sections of adipose tissue, normal breast parenchyma, benign fibroadenoma tumors and noninvasive and invasive malignant cancers by phase contrast microscopy through quantification of grayscale values, using multiple regions of interest (ROI). Student’s t tests were performed on phase contrast measures across diagnostic categories testing data from individual cases; all ROI data were used as separate measures.RESULTSStroma demonstrated significantly higher scatter intensity than did epithelium, with lower scattering in tumor-associated stroma as compared with normal or benign-associated stroma. Measures were comparable for invasive and noninvasive malignant tumors but were higher than those found in benign tumors and were lowest in adipose tissue.CONCLUSIONSignificant differences were found in scatter coefficient properties of epithelium and stroma across diagnostic categories of breast tissue, particularly between benign and malignant-associated stroma. Improved understanding of how scatter properties correlate with morphologic criteria used in routine pathologic diagnoses could have a significant clinical impact as developing optical technology allows macroscopic in situ phase contrast imaging.
Spot 14 (S14) is a nuclear protein that communicates the status of dietary fuels and fuel-related... more Spot 14 (S14) is a nuclear protein that communicates the status of dietary fuels and fuel-related hormones to genes required for long-chain fatty acid synthesis. In mammary gland, S14 is important for both epithelial proliferation and milk fat production. The S14 gene is amplified in some breast cancers and is strongly expressed in most. High expression of S14 in primary invasive breast cancer is conspicuously predictive of recurrence. S14 mediates the induction of lipogenesis by progestin in breast cancer cells and accelerates their growth. Conversely, S14 knockdown impairs de novo lipid synthesis and causes apoptosis. We found that breast cancer cells do not express lipoprotein lipase (LPL) and hypothesize that they do not have access to circulating lipids unless the local environment supplies it. This may explain why primary breast cancers with low S14 do not survive transit from the LPL-rich mammary fat pad to areas devoid of LPL, such as lymph nodes, and thus do not appear as distant metastases. Thus, S14 is a marker for aggressive breast cancer and a potential target as well. Future effort will center on validation of S14 as a therapeutic target and producing antagonists of its action.
Clinical chemistry and laboratory medicine, Jan 12, 2016
Molecular technologies have allowed laboratories to detect and establish the profiles of human ca... more Molecular technologies have allowed laboratories to detect and establish the profiles of human cancers by identifying a variety of somatic variants. In order to improve personalized patient care, we have established a next-generation sequencing (NGS) test to screen for somatic variants in primary or advanced cancers. In this study, we describe the laboratory quality management program for NGS testing, and also provide an overview of the somatic variants identified in over 1000 patient samples as well as their implications in clinical practice. Over the past one-and-a-half years, our laboratory received a total of 1028 formalin-fixed, paraffin-embedded (FFPE) tumor tissues, which consisted of non-small-cell lung carcinomas (NSCLCs), colon adenocarcinomas, glioma/glioblastomas, melanomas, breast carcinomas, and other tumor types. During this time period, we implemented a series of quality control (QC) checks that included (1) pre-DNA extraction, (2) DNA quantification, (3) DNA quality...
The authors describe what is, to the best of their knowledge, the first quantitative hemoglobin c... more The authors describe what is, to the best of their knowledge, the first quantitative hemoglobin concentration images of the female breast that were formed with model-based reconstruction of near-infrared intensity-modulated tomographic data. The results in 11 patients, including two with breast tumors with pathologic correlation, are summarized. Hemoglobin concentration appears to correlate with tumor vascularity without the need for exogenous contrast material and thereby has intrinsic diagnostic value.
The 2013 American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guid... more The 2013 American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guideline updates lowered the threshold for HER2 positivity and altered the equivocal category. The goal of this study was to evaluate the impact of these changes on the distribution of HER2 fluorescence in situ hybridization (FISH) status. The utility of reflex HER2 immunohistochemistry (IHC) for FISH equivocal cases was also examined. We retrospectively reviewed all invasive breast cancers analyzed for HER2 via dual-probe FISH (PathVysion; Abbott Laboratories. Abbott Park, IL) 12 months before and after the HER2 guidelines updates were implemented. Reflex HER2 IHC results were recorded for HER2 FISH equivocal cases. There was a significant increase in the number of HER2 FISH equivocal results after the guideline updates (4.9% vs 1.4%, P = .0087) that was independent of specimen type (core vs surgical, P = .6). All 17 FISH equivocal cases after the updates had reflex HER2 IHC: two (12%) of ...
Background: USP18 (ubiquitin-specific protease 18) removes ubiquitin-like modifier interferon sti... more Background: USP18 (ubiquitin-specific protease 18) removes ubiquitin-like modifier interferon stimulated gene 15 (ISG15) from conjugated proteins. USP18 null mice in a FVB/N background develop tumors as early as 2 months of age. These tumors are leiomyosarcomas and thus represent a new murine model for this disease. Methods: Heterozygous USP18 +/− FVB/N mice were bred to generate wild-type, heterozygous and homozygous cohorts. Tumors were characterized immunohistochemically and two cell lines were derived from independent tumors. Cell lines were karyotyped and their responses to restoration of USP18 activity assessed. Drug testing and tumorigenic assays were also performed. USP18 immunohistochemical staining in a large series of human leiomyosacomas was examined. Results: USP18 −/− FVB/N mice spontaneously develop tumors predominantly on the back of the neck with most tumors evident between 6-12 months (80 % penetrance). Immunohistochemical characterization of the tumors confirmed they were leiomyosarcomas, which originate from smooth muscle. Restoration of USP18 activity in sarcoma-derived cell lines did not reduce anchorage dependent or independent growth or xenograft tumor formation demonstrating that these cells no longer require USP18 suppression for tumorigenesis. Karyotyping revealed that both tumor-derived cell lines were aneuploid with extra copies of chromosomes 3 and 15. Chromosome 15 contains the Myc locus and MYC is also amplified in human leiomyosarcomas. MYC protein levels were elevated in both murine leiomyosarcoma cell lines. Stabilized P53 protein was detected in a subset of these murine tumors, another feature of human leiomyosarcomas. Immunohistochemical analyses of USP18 in human leiomyosarcomas revealed a range of staining intensities with the highest USP18 expression in normal vascular smooth muscle. USP18 tissue array analysis of primary leiomyosarcomas from 89 patients with a clinical database revealed cases with reduced USP18 levels had a significantly decreased time to metastasis (P = 0.0441). Conclusions: USP18 null mice develop leiomyosarcoma recapitulating key features of clinical leiomyosarcomas and patients with reduced-USP18 tumor levels have an unfavorable outcome. USP18 null mice and the derived cell lines represent clinically-relevant models of leiomyosarcoma and can provide insights into both leiomyosarcoma biology and therapy.
Highlights d Lapatinib-resistant breast cancer cells upregulate CD36 expression for survival d Ta... more Highlights d Lapatinib-resistant breast cancer cells upregulate CD36 expression for survival d Targeting CD36 re-sensitizes lapatinib-resistant cells to HER2-inhibition d Deletion of Cd36 significantly attenuates MMTV-neu-driven mammary tumor growth d CD36 is induced by HER2-targeted therapy and predicts poor clinical prognosis
We previously described the expression of CD36 and lipoprotein lipase (LPL) by breast cancer (BC)... more We previously described the expression of CD36 and lipoprotein lipase (LPL) by breast cancer (BC) cells and tissues, and the growth-promoting effect of very low-density lipoprotein (VLDL) supplementation observed in BC cell lines only in the presence of LPL. We now describe the deployment of LPL by BC cells. Our data support a model in which LPL is bound to a heparin-like heparan sulfate proteoglycan motif on the BC cell surface and acts in concert with the VLDL receptor to rapidly internalize intact lipoproteins via receptor-mediated endocytosis. We further observe substantial alterations in gene expression programs related to pathways for lipid acquisition (synthesis vs. uptake) in response to each the availability of exogenous triglyceride in tissue culture media and LPL expression status. Current literature emphasizes de novo fatty acid synthesis as the paramount mechanism for lipid acquisition by cancer cells. Our findings indicate that exogenous lipid uptake can serve as an im...
International journal of clinical and experimental pathology, 2016
The ubiquitin E3 ligase MDM2 is best known for its ability to suppress the tumor suppressor p53. ... more The ubiquitin E3 ligase MDM2 is best known for its ability to suppress the tumor suppressor p53. However, MDM2 also targets other proteins for proteasomal degradation and accumulating evidence strongly suggests p53-independent roles of MDM2 in cancer. We previously reported that MDM2 promotes degradation of another ubiquitin E3 ligase HUWE1 by ubiquitination, particularly, which confers HER2 breast cancer cells resistance to the HER2 inhibitor lapatinib. However, it remains unclear whether such a mechanism can operate in other cell types, independently of HER2 inhibitors. Moreover, evidence that supports HUWE1 degradation by MDM2 is missing. In the current study, we performed immunohistochemistry (IHC) to analyze expression levels of MDM2 and HUWE1 in normal organs, two breast cancer cohorts (A, n = 137 and B, n = 27), and a liposarcoma cohort (n = 45). Our results show that HUWE1 is ubiquitously expressed in healthy organs, where the oncoprotein MDM2 is undetectable. Likewise, in t...
Wire-localized excision of nonpalpable breast cancer is imprecise, resulting in positive margins ... more Wire-localized excision of nonpalpable breast cancer is imprecise, resulting in positive margins 25-30% of the time. Patients underwent preoperative supine magnetic resonance imaging (MRI). A radiologist outlined the tumor edges on consecutive images, creating a three-dimensional (3D) view of its location. Using 3D printing, a bra-like plastic form (the Breast Cancer Locator [BCL]) was fabricated, with features that allowed a surgeon to (1) mark the edges of the tumor on the breast surface; (2) inject blue dye into the breast 1 cm from the tumor edges; and (3) place a wire in the tumor at the time of surgery. Nineteen patients with palpable cancers underwent partial mastectomy after placement of surgical cues using patient-specific BCLs. The cues were in place in <5 min and no adverse events occurred. The BCL accurately localized 18/19 cancers. In the 18 accurately localized cases, all 68 blue-dye injections were outside of the tumor edges. Median distance from the blue-dye cente...
In the original paper by Dr. Poller 6 describing the morphologic criteria for the Van Nuys classi... more In the original paper by Dr. Poller 6 describing the morphologic criteria for the Van Nuys classification, he defined in detail three nuclear grades (high, intermediate, and low). Identical morphologic criteria were subsequently used, in combination with tumor size and margin ...
Analytical and Quantitative Cytology and Histology the International Academy of Cytology and American Society of Cytology, Jun 1, 2004
To analyze the microvasculature and tissue type ratios in normal vs. benign and malignant breast ... more To analyze the microvasculature and tissue type ratios in normal vs. benign and malignant breast tissue to establish a baseline for expected values against which future imaging studies can be benchmarked. Using computer-assisted techniques on immunostained breast tissue (normal [n = 28], fibrocystic [n = 37], fibroadenomas [n = 19], invasive carcinomas [n = 19]), values were obtained for microvessel density (MVD), mean vessel area (MVA), vessel orientation (shape) and epithelial:stromal ratio (E:S). Measurement reproducibility and the effects of fibroadenoma stromal hyalinization and fibrocystic disease severity were also tested. Value ranges for the 4 diagnostic groups were significantly different (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001). For invasive breast carcinomas, E:S and MVD were significantly higher (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001) but MVA was smaller as compared to that in fibroadenomas. Peripherally vs. centrally there was no significant difference in MVD, MVA or vessel shape in the neoplasms. Decreases in E:S and MVD correlated with fibroadenoma stromal hyalinization. Increases in E:S and MVA correlated with more severe fibrocystic disease. Correlation coefficients for measurement reproducibility were high across the diagnostic categories. This study established a specific, reproducible, computer-assisted technique and baseline of expected values for morphologic criteria in normal, benign and malignant breast tissue that may be used in the future to correlate new breast imaging responses with these underlying biologic properties.
Melanoma is one of the most aggressive types of skin cancer. The purpose of this study was to eva... more Melanoma is one of the most aggressive types of skin cancer. The purpose of this study was to evaluate the use of two biomarkers, ProEx C and glucose transporter isoform 1 (GLUT1), in the diagnosis and prognostication of melanoma. We analyzed 129 melanomas and 59 benign nevi in a tissue microarray using immunohistochemical method with antibodies to topoisomerase IIα (TOP2A) and minichromosome maintenance complex component 2 (MCM2) using ProEx C and to GLUT1. The average proliferative index by ProEx C immunostain was significantly higher in melanomas (37.5%) compared to benign nevi (1.9%) as was the expression of GLUT1 (p<0.0001 respectively). Dermal mitosis was found to correlate positively with both ProEx C and GLUT1 (p=0.003 and p<0.001, respectively). Ulceration and tumor thickness positively correlated with GLUT1 expression (p=0.013 and p=0.033, respectively), but not with ProEx C staining. There was a significant association between increasing ProEx C index and stronger e...
Analytical and Quantitative Cytology and Histology the International Academy of Cytology and American Society of Cytology, Aug 1, 2009
OBJECTIVETo assess how optical scatter properties in breast tissue, as measured by phase contrast... more OBJECTIVETo assess how optical scatter properties in breast tissue, as measured by phase contrast microscopy and interpreted pathophysiologically, might be exploited as a diagnostic tool to differentiate cancer from benign tissue.STUDY DESIGNWe evaluated frozen human breast tissue sections of adipose tissue, normal breast parenchyma, benign fibroadenoma tumors and noninvasive and invasive malignant cancers by phase contrast microscopy through quantification of grayscale values, using multiple regions of interest (ROI). Student’s t tests were performed on phase contrast measures across diagnostic categories testing data from individual cases; all ROI data were used as separate measures.RESULTSStroma demonstrated significantly higher scatter intensity than did epithelium, with lower scattering in tumor-associated stroma as compared with normal or benign-associated stroma. Measures were comparable for invasive and noninvasive malignant tumors but were higher than those found in benign tumors and were lowest in adipose tissue.CONCLUSIONSignificant differences were found in scatter coefficient properties of epithelium and stroma across diagnostic categories of breast tissue, particularly between benign and malignant-associated stroma. Improved understanding of how scatter properties correlate with morphologic criteria used in routine pathologic diagnoses could have a significant clinical impact as developing optical technology allows macroscopic in situ phase contrast imaging.
Spot 14 (S14) is a nuclear protein that communicates the status of dietary fuels and fuel-related... more Spot 14 (S14) is a nuclear protein that communicates the status of dietary fuels and fuel-related hormones to genes required for long-chain fatty acid synthesis. In mammary gland, S14 is important for both epithelial proliferation and milk fat production. The S14 gene is amplified in some breast cancers and is strongly expressed in most. High expression of S14 in primary invasive breast cancer is conspicuously predictive of recurrence. S14 mediates the induction of lipogenesis by progestin in breast cancer cells and accelerates their growth. Conversely, S14 knockdown impairs de novo lipid synthesis and causes apoptosis. We found that breast cancer cells do not express lipoprotein lipase (LPL) and hypothesize that they do not have access to circulating lipids unless the local environment supplies it. This may explain why primary breast cancers with low S14 do not survive transit from the LPL-rich mammary fat pad to areas devoid of LPL, such as lymph nodes, and thus do not appear as distant metastases. Thus, S14 is a marker for aggressive breast cancer and a potential target as well. Future effort will center on validation of S14 as a therapeutic target and producing antagonists of its action.
Clinical chemistry and laboratory medicine, Jan 12, 2016
Molecular technologies have allowed laboratories to detect and establish the profiles of human ca... more Molecular technologies have allowed laboratories to detect and establish the profiles of human cancers by identifying a variety of somatic variants. In order to improve personalized patient care, we have established a next-generation sequencing (NGS) test to screen for somatic variants in primary or advanced cancers. In this study, we describe the laboratory quality management program for NGS testing, and also provide an overview of the somatic variants identified in over 1000 patient samples as well as their implications in clinical practice. Over the past one-and-a-half years, our laboratory received a total of 1028 formalin-fixed, paraffin-embedded (FFPE) tumor tissues, which consisted of non-small-cell lung carcinomas (NSCLCs), colon adenocarcinomas, glioma/glioblastomas, melanomas, breast carcinomas, and other tumor types. During this time period, we implemented a series of quality control (QC) checks that included (1) pre-DNA extraction, (2) DNA quantification, (3) DNA quality...
The authors describe what is, to the best of their knowledge, the first quantitative hemoglobin c... more The authors describe what is, to the best of their knowledge, the first quantitative hemoglobin concentration images of the female breast that were formed with model-based reconstruction of near-infrared intensity-modulated tomographic data. The results in 11 patients, including two with breast tumors with pathologic correlation, are summarized. Hemoglobin concentration appears to correlate with tumor vascularity without the need for exogenous contrast material and thereby has intrinsic diagnostic value.
The 2013 American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guid... more The 2013 American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guideline updates lowered the threshold for HER2 positivity and altered the equivocal category. The goal of this study was to evaluate the impact of these changes on the distribution of HER2 fluorescence in situ hybridization (FISH) status. The utility of reflex HER2 immunohistochemistry (IHC) for FISH equivocal cases was also examined. We retrospectively reviewed all invasive breast cancers analyzed for HER2 via dual-probe FISH (PathVysion; Abbott Laboratories. Abbott Park, IL) 12 months before and after the HER2 guidelines updates were implemented. Reflex HER2 IHC results were recorded for HER2 FISH equivocal cases. There was a significant increase in the number of HER2 FISH equivocal results after the guideline updates (4.9% vs 1.4%, P = .0087) that was independent of specimen type (core vs surgical, P = .6). All 17 FISH equivocal cases after the updates had reflex HER2 IHC: two (12%) of ...
Background: USP18 (ubiquitin-specific protease 18) removes ubiquitin-like modifier interferon sti... more Background: USP18 (ubiquitin-specific protease 18) removes ubiquitin-like modifier interferon stimulated gene 15 (ISG15) from conjugated proteins. USP18 null mice in a FVB/N background develop tumors as early as 2 months of age. These tumors are leiomyosarcomas and thus represent a new murine model for this disease. Methods: Heterozygous USP18 +/− FVB/N mice were bred to generate wild-type, heterozygous and homozygous cohorts. Tumors were characterized immunohistochemically and two cell lines were derived from independent tumors. Cell lines were karyotyped and their responses to restoration of USP18 activity assessed. Drug testing and tumorigenic assays were also performed. USP18 immunohistochemical staining in a large series of human leiomyosacomas was examined. Results: USP18 −/− FVB/N mice spontaneously develop tumors predominantly on the back of the neck with most tumors evident between 6-12 months (80 % penetrance). Immunohistochemical characterization of the tumors confirmed they were leiomyosarcomas, which originate from smooth muscle. Restoration of USP18 activity in sarcoma-derived cell lines did not reduce anchorage dependent or independent growth or xenograft tumor formation demonstrating that these cells no longer require USP18 suppression for tumorigenesis. Karyotyping revealed that both tumor-derived cell lines were aneuploid with extra copies of chromosomes 3 and 15. Chromosome 15 contains the Myc locus and MYC is also amplified in human leiomyosarcomas. MYC protein levels were elevated in both murine leiomyosarcoma cell lines. Stabilized P53 protein was detected in a subset of these murine tumors, another feature of human leiomyosarcomas. Immunohistochemical analyses of USP18 in human leiomyosarcomas revealed a range of staining intensities with the highest USP18 expression in normal vascular smooth muscle. USP18 tissue array analysis of primary leiomyosarcomas from 89 patients with a clinical database revealed cases with reduced USP18 levels had a significantly decreased time to metastasis (P = 0.0441). Conclusions: USP18 null mice develop leiomyosarcoma recapitulating key features of clinical leiomyosarcomas and patients with reduced-USP18 tumor levels have an unfavorable outcome. USP18 null mice and the derived cell lines represent clinically-relevant models of leiomyosarcoma and can provide insights into both leiomyosarcoma biology and therapy.
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Papers by Wendy Wells