Designing a Collaborative Breast Radiology Training Program to Tackle Tanzania's Breast Cancer Crisis.

Breast cancer incidence and mortality continue to increase in Africa. In Tanzania, breast cancer is the second leading cause of cancer death for women, and breast cancer incidence and mortality are projected to increase by 80% by 2030. Education gaps among health care workers, delayed presentation, limited screening, and low health literacy all pose significant challenges to providing optimal breast cancer care. Considering these factors, it is imperative to train expert breast radiologists. We present a collaborative breast radiology training program in Tanzania aimed at building local capacity to address national breast cancer challenges. Although cancer control in Africa faces many challenges, developing customized training programs for breast radiology, in conjunction with national cancer programs, may represent a key strategy for addressing breast cancer.

Patient Experience of Women With Dense Breasts Undergoing Screening Contrast-Enhanced Mammography.

OBJECTIVE: We investigated patient experience with screening contrast-enhanced mammography (CEM) to determine whether a general population of women with dense breasts would accept CEM in a screening setting. METHODS: In this institutional review board-approved prospective study, patients with heterogeneous and extremely dense breasts on their mammogram were invited to undergo screening CEM and complete pre-CEM and post-CEM surveys. On the pre-CEM survey, patients were asked about their attitudes regarding supplemental screening in general. On the post-CEM survey, patients were asked about their experience undergoing screening CEM, including causes and severity of any discomfort and whether they would consider undergoing screening CEM again in the future or recommend it to a friend. RESULTS: One hundred sixty-three women were surveyed before and after screening CEM. Most patients, 97.5% (159/163), reported minimal or no unpleasantness associated with undergoing screening CEM. In addition, 91.4% (149/163) said they would probably or very likely undergo screening CEM in the future if it cost the same as a traditional screening mammogram, and 95.1% (155/163) said they would probably or very likely recommend screening CEM to a friend. Patients in this study, who were all willing to undergo CEM, more frequently reported a family history of breast cancer than a comparison cohort of women with dense breasts (58.2% vs 47.1%, P = .027). CONCLUSION: Patients from a general population of women with dense breasts reported a positive experience undergoing screening CEM, suggesting screening CEM might be well received by this patient population, particularly if the cost was comparable with traditional screening mammography.

Factors Associated With Breast Cancer Screening Behaviors Among Women With Dense Breasts.

OBJECTIVE: We sought to identify patient factors associated with patient-reported screening behaviors in women with dense breasts. METHODS: An IRB-approved survey study of women with dense breasts presenting for annual screening mammography at an outpatient imaging center was previously conducted from March 2017 to February 2018. The survey included questions regarding mammographic screening frequency and recent participation in supplemental screening. These survey data were combined post hoc with clinical and demographic data and socioeconomic data imputed from census data. Logistic regression was used to identify patient factors associated with reported screening behaviors. RESULTS: Surveys were completed by 508 women (median age, 59.0 years; range, 31.0-86.0 years) with dense breasts. Multivariable analysis demonstrated an independent association of undergoing mammographic screening annually with a history of discussing breast density with a doctor (adjusted odds ratio [AOR], 2.60; P = 0.019). Undergoing supplemental screening in the previous three years was independently associated with younger age (AOR, 1.59; P = 0.004), strong family history of breast cancer (AOR, 3.84; P = 0.027), higher perceived personal risk for breast cancer (AOR, 3.47; P = 0.004), and increased concern about radiation associated with screening examinations (AOR, 3.31; P = 0.006). CONCLUSION: Women with dense breasts who had discussed breast density with a doctor were more likely to report undergoing annual screening mammography, while younger women and women with a strong family history of breast cancer, higher perceived personal risk for breast cancer, or greater concern about radiation were more likely to report recently undergoing supplemental screening.

2D or Synthetic 2D? A Reader Study of Visualization of Amorphous Calcifications.

OBJECTIVE: Some vendors have created algorithms that generate synthetic 2D (s2D) images from a digital breast tomosynthesis (DBT) dataset to reduce the radiation from obtaining a separate 2D digital mammography (DM). This study evaluated the visibility of amorphous calcifications on 2D DM versus s2D on screening mammography. METHODS: This IRB-approved, retrospective, reader study included screening mammograms from 36 women who received screening DBT exams where both 2D DM and s2D images were obtained: 28 screening mammograms that were eventually given BI-RADS category 4 or 5 for amorphous calcifications and 8 BI-RADS category 1 or 2 screening exams. Two rounds of interpretation were conducted with a six-week washout period. Cases were randomized to display either the 2D DM or s2D images, which were then alternated in the second round. Four fellowship-trained breast radiologists determined whether a study merited recall for calcifications. If so, they rated calcification visibility on a scale of 1 to 5. McNemar chi-square tests were conducted to assess differences in recall rates and Wilcoxon signed rank tests were used to examine shifts in visibility. RESULTS: There was no difference in detection rates of amorphous calcifications between 2D DM and s2D, which were 75.9% and 75.0%, respectively (P = 1.000). Collectively, amorphous calcifications were more visible on s2D than 2D DM, with mean visibility scores of 3.4 versus 3.0, respectively (P = 0.005). CONCLUSION: Synthetic 2D did not change identification of amorphous calcifications compared to 2D DM, and readers considered them more visible on average.

Benign breast papillomas without atypia diagnosed with core needle biopsy: Outcome of surgical excision and imaging follow-up.

PURPOSE: To evaluate the surgical upgrade rate to malignancy and high-risk lesions in cases of papilloma without atypia diagnosed with imaging-guided percutaneous core needle biopsy (CNB) and to determine whether any lesion imaging features, biopsy techniques, and pathological factors can predict lesion upgrade to help guide clinical management. MATERIALS AND METHODS: Benign papillomas without atypia (n = 399) diagnosed with CNB were retrospectively reviewed. The surgical upgrade rate to malignancy or high-risk lesion (atypical ductal hyperplasia, atypical lobular hyperplasia, lobular carcinoma in-situ, flat epithelial atypia and atypical papilloma) was determined. Detection modality (i.e. mammography, ultrasonography (US), magnetic resonance imaging (MRI)), lesion type and size, biopsy-guidance modality (US, stereotactic, MRI), biopsy needle size (<14 G vs ≥14 G), use of vacuum assistance, and presenting symptoms were statistically analyzed. The reference standard for evaluation of upgrade was either excision or at least 24 months of imaging follow-up. Chi Square test and Fisher exact tests were performed for categorical variables, and the Mann-Whitney-U test was used for continuous variables. RESULTS: Ultrasound was the predominant biopsy modality (78.4 %, p < 0.001). Of the 399 benign papilloma lesions in 329 women, 239 (59.9 %) were excised and 93 others were followed for at least 24 months (total of 332). Of these 332 lesions, 7 (2.1 %) were upgraded to ductal carcinoma in-situ and 41 (12.3 %) to high-risk lesions at excision. Larger lesion size (≥15 mm, p = 0.009), smaller biopsy needle size (≥14 G, p = 0.027), and use of spring-loaded biopsy device (p = 0.012) were significantly associated with upgrade to atypia. Only lesion size (≥15 mm, p = 0.02) was associated with upgrade to cancer. CONCLUSION: Upgrade to malignancy of biopsy-proven benign papillomas without atypia at the time of surgery was sufficiently low (2.1 %) to support non-operative management. Surgery may be performed for selected cases- those with larger lesion size and those whose biopsies were performed with smaller spring-loaded biopsy needles.

Breast ultrasound utilization in a safety net emergency department.

PURPOSE: The purpose of this study is to (1) assess the diagnostic yield of ultrasounds performed in the emergency department for suspected breast abscess and determine the rates of reimaging, discordance, and emergent intervention in a large, busy safety net hospital and (2) determine clinical factors significantly associated with abscess as a way to improve patient selection for emergent breast ultrasounds. METHODS: A total of 581 consecutive breast ultrasounds performed in the emergency department for suspected abscess over 15 months were retrospectively reviewed for imaging, demographics, laboratory data, and physical exam findings. Breast abscess was confirmed by combining imaging, clinical, and laboratory data. Linear logistic regression analysis estimated the likelihood of abscess, and the cross-validated area under the receiver operating characteristic curve (AUC) evaluated diagnostic performance. RESULTS: Final diagnoses included abscess (153/581, 26%), cancer (29/581, 5%), granulomatous mastitis (41/581, 7%), normal (120/581, 21%), and other/indeterminate (238/581, 41%). Factors associated with abscess included induration, fluctuance, erythema, drainage, smoking, diabetes, and Black race. Based on these factors, the AUC of the characteristics predictive of abscess was 0.77 (CI, 0.72-0.81). Six breast cancers were not diagnosed on ultrasound. 40% of ultrasounds (231/581) were considered incomplete/inadequate. CONCLUSION: 74% (428/581) of emergent breast ultrasounds in our population were negative for abscess, while 21% (6/29) of cancers were not diagnosed, and 40% (231/581) of exams were incomplete/inadequate. Patient selection for emergent ultrasounds can be improved, allowing patients with a low likelihood of abscess to be imaged in a more optimal setting.

Multimodality Imaging-based Evaluation of Single-Lumen Silicone Breast Implants for Rupture.

Breast implants are frequently encountered on breast imaging studies, and it is essential for any radiologist interpreting these studies to be able to correctly assess implant integrity. Ruptures of silicone gel-filled implants often occur without becoming clinically obvious and are incidentally detected at imaging. Early diagnosis of implant rupture is important because surgical removal of extracapsular silicone in the breast parenchyma and lymphatics is difficult. Conversely, misdiagnosis of rupture may prompt a patient to undergo unnecessary additional surgery to remove the implant. Mammography is the most common breast imaging examination performed and can readily depict extracapsular free silicone, although it is insensitive for detection of intracapsular implant rupture. Ultrasonography (US) can be used to assess the internal structure of the implant and may provide an economical method for initial implant assessment. Common US signs of intracapsular rupture include the "keyhole" or "noose" sign, subcapsular line sign, and "stepladder" sign; extracapsular silicone has a distinctive "snowstorm" or echogenic noise appearance. Magnetic resonance (MR) imaging is the most accurate and reliable means for assessment of implant rupture and is highly sensitive for detection of both intracapsular and extracapsular rupture. MR imaging findings of intracapsular rupture include the keyhole or noose sign, subcapsular line sign, and "linguine" sign, and silicone-selective MR imaging sequences are highly sensitive to small amounts of extracapsular silicone. ©RSNA, 2017.

Immune-mediated Disease in Ipilimumab Immunotherapy of Melanoma with FDG PET-CT.

RATIONALE AND OBJECTIVES: The purposes of this study were to provide a case-based overview of various immune-mediated side effects detected by 18F-Fluorodeoxyglucose (F-18 FDG) positron emission tomography-computed tomography (PET-CT) in the patients receiving ipilimumab immunotherapy for treatment of malignant melanoma, and discuss the importance of recognizing immune-mediated side effects in the use of F-18 FDG PET-CT for monitoring therapeutic effects of ipilimumab on metastatic melanoma. MATERIALS AND METHODS: This is a retrospective case series study of the patients diagnosed with melanoma who were subjected to immunomodulating therapy with ipilimumab. F-18 FDG PET-CT findings were reviewed, and the patients with immune-mediated side effects were selected for further analysis, in conjunction with review of clinical progress notes, the results of laboratory tests, and findings of other imaging tests. RESULTS: Four patients with immune-mediated side effects were identified among the patients being treated with ipilimumab and subjected to F-18 FDG PET-CT for monitoring therapeutic effects. These immune mediated side effects include new findings of abnormal increased FDG uptake associated with immune-mediated pancreatitis and hypophysitis, as well as immune-mediated thyroiditis and colitis reported previously. CONCLUSIONS: Various immune-mediated side effects were detected by F-18 FDG PET-CT in the patients subjected to immunomodulating therapy with ipilimumab. It is essential for the interpreting provider to recognize and differentiate abnormal FDG uptake associated with immune-mediated side effects from hypermetabolic malignant lesions when using F-18 FDG PET-CT for monitoring therapeutic effects of ipilimumab on melanoma lesions.

An Inv(16)(p13.3q24.3)-encoded CBFA2T3-GLIS2 fusion protein defines an aggressive subtype of pediatric acute megakaryoblastic leukemia.

To define the mutation spectrum in non-Down syndrome acute megakaryoblastic leukemia (non-DS-AMKL), we performed transcriptome sequencing on diagnostic blasts from 14 pediatric patients and validated our findings in a recurrency/validation cohort consisting of 34 pediatric and 28 adult AMKL samples. Our analysis identified a cryptic chromosome 16 inversion (inv(16)(p13.3q24.3)) in 27% of pediatric cases, which encodes a CBFA2T3-GLIS2 fusion protein. Expression of CBFA2T3-GLIS2 in Drosophila and murine hematopoietic cells induced bone morphogenic protein (BMP) signaling and resulted in a marked increase in the self-renewal capacity of hematopoietic progenitors. These data suggest that expression of CBFA2T3-GLIS2 directly contributes to leukemogenesis.

Genomic analysis reveals few genetic alterations in pediatric acute myeloid leukemia.

Pediatric de novo acute myeloid leukemia (AML) is an aggressive malignancy with current therapy resulting in cure rates of only 60%. To better understand the cause of the marked heterogeneity in therapeutic response and to identify new prognostic markers and therapeutic targets a comprehensive list of the genetic mutations that underlie the pathogenesis of AML is needed. To approach this goal, we examined diagnostic leukemic samples from a cohort of 111 children with de novo AML using single-nucleotide-polymorphism microarrays and candidate gene resequencing. Our data demonstrate that, in contrast to pediatric acute lymphoblastic leukemia (ALL), de novo AML is characterized by a very low burden of genomic alterations, with a mean of only 2.38 somatic copy-number alterations per leukemia, and less than 1 nonsynonymous point mutation per leukemia in the 25 genes analyzed. Even more surprising was the observation that 34% of the leukemias lacked any identifiable copy-number alterations, and 28% of the leukemias with recurrent translocations lacked any identifiable sequence or numerical abnormalities. The only exception to the presence of few mutations was acute megakaryocytic leukemias, with the majority of these leukemias being characterized by a high number of copy-number alterations but rare point mutations. Despite the low overall number of lesions across the patient cohort, novel recurring regions of genetic alteration were identified that harbor known, and potential new cancer genes. These data reflect a remarkably low burden of genomic alterations within pediatric de novo AML, which is in stark contrast to most other human malignancies.

Association of the germline TP53 R337H mutation with breast cancer in southern Brazil.

BACKGROUND: The germline TP53-R337H mutation is strongly associated with pediatric adrenocortical tumors (ACT) in southern Brazil; it has low penetrance and limited tissue specificity in most families and therefore is not associated with Li-Fraumeni syndrome. However, other tumor types, mainly breast cancer, have been observed in carriers of several unrelated kindreds, raising the possibility that the R337H mutation may also contribute to breast tumorigenesis in a genetic background-specific context. METHODS: We conducted a case-control study to determine the prevalence of the R337H mutation by sequencing TP53 exon 10 in 123 women with breast cancer and 223 age- and sex-matched control subjects from southern Brazil. Fisher's test was used to compare the prevalence of the R337H. RESULTS: The R337H mutation was found in three patients but in none of the controls (p = 0.0442). Among the carriers, two had familial history of cancer meeting the Li-Fraumeni-like criteria. Remarkably, tumors in each of these three cases underwent loss of heterozygosity by eliminating the mutant TP53 allele rather than the wild-type allele. Polymorphisms were identified within the TP53 (R72P and Ins16) and MDM2 (SNP309) genes that may further diminish TP53 tumor suppressor activity. CONCLUSION: These results demonstrate that the R337H mutation can significantly increase the risk of breast cancer in carriers, which likely depends on additional cooperating genetic factors. These findings are also important for understanding how low-penetrant mutant TP53 alleles can differentially influence tumor susceptibility.

Copy number gains in EGFR and copy number losses in PTEN are common events in osteosarcoma tumors.

BACKGROUND: Osteosarcoma cell lines and tumors have been shown to express epidermal growth factor receptor (EGFR) and harbor amplifications at the EGFR locus. In this study, the authors further analyzed the genomic features of EGFR in osteosarcoma tumors and investigated whether they correlate with phosphatase and tensin homolog (PTEN) expression and copy number status. METHODS: EGFR and PTEN expression was assessed by immunohistochemistry (n = 28), and copy number alterations at the EGFR and PTEN loci were surveyed using Affymetrix (Santa Clara, Calif) 50K single nucleotide polymorphism (SNP) arrays (n = 31) and fluorescence in situ hybridization (FISH) (n = 27). The EGFR tyrosine kinase domain was sequenced to survey for activating mutations (n = 34). In addition, EGFRvIII expression was assessed using reverse transcriptase polymerase chain reaction (n = 24). Results were correlated with available clinical information on 59 patients, with a median age of 14.1 years (range, 5-23 years) and median follow-up of 4.4 years. RESULTS: EGFR expression was detected in the majority of osteosarcoma tumors surveyed (23 of 28; 82%). SNP arrays revealed evidence of frequent copy number gains at 7p11.2 and losses at 10q23.21. A sizeable subset (16 of 27 cases; 59%) showed gains at the EGFR locus using FISH (amplification in 4 of 27 [15%] and balanced chromosome 7 polysomy in 12 of 27 [44%]), and 12 cases showed deletions at the PTEN locus (biallelic deletions in 4 of 27 [15%] and monoallelic deletion in 9 of 27 [33%]). No activating mutations in the EGFR tyrosine kinase domain, EGFRvIII expression, or association with clinical findings were detected. CONCLUSIONS: EGFR expression and genomic gains at the EGFR locus are prevalent in osteosarcoma tumors, which also commonly harbor deletions at the PTEN locus.

Vitreous modulation of gene expression in low-passage human retinal pigment epithelial cells.

PURPOSE: In proliferative vitreoretinopathy (PVR), retinal pigment epithelial (RPE) cells enter the vitreous and proliferate. They become fibroblast-like and participate in the formation of contractile membranes, which can lead to retinal detachment. Vitreous treatment of RPE cells in vitro results in similar morphologic changes. This study was conducted to examine vitreous-induced modulation of gene expression in RPE cells. METHODS: Low-passage human RPE cell lines derived from three donors were each treated for 6, 12, 24, or 48 hours with complete medium or complete medium containing 25% vitreous. Changes in mRNA levels were examined by using microarrays. Real-time quantitative PCR (qPCR) was used to measure mRNA expression of a subset of genes in cells from three additional donors. Immunohistochemistry and immunoblot analysis were used to examine protein expression. RESULTS: Vitreous treatment caused a progressive reprogramming of gene expression. qPCR confirmed vitreous modulation of mRNA levels of 10 of 10 genes. Changes consistent with a transition from an epithelial to a mesenchymal phenotype were observed. Downregulated genes included genes associated with differentiated RPE cells. Upregulated genes included genes associated with stress and inflammation. Pathway analysis indicated that the transforming growth factor-beta/bone morphogenetic protein (BMP) pathway and the focal adhesion pathway may play a role in this process. BMP-2 protein and mRNA were increased. CONCLUSIONS: Despite the biological variation in vitreous and RPE donors, vitreous reproducibly modulated a limited number of mRNAs. Many of these changes were consistent with the more fibroblast-like appearance of vitreous-treated cells and with the pathobiology of PVR. TGF-beta and BMP-2 may be important modulators of vitreous-induced changes in gene expression.

Vitreous induces heme oxygenase-1 expression mediated by transforming growth factor-beta and reactive oxygen species generation in human retinal pigment epithelial cells.

PURPOSE: When human retinal pigment epithelial (RPE) cells come in contact with vitreous, they undergo changes in gene expression that include inflammatory and anti-oxidant responses. The effects of vitreous on expression of heme oxygenase-1 (HO-1), metallothionein (MT) -1a and -2a, and c-fos were investigated. Activator protein-1 (AP-1) binding sites are located in the promoter region of HO-1 and MT genes and the effects of vitreous on c-fos activity were investigated. METHODS: Low passage cultures of human RPE cells were grown in the presence or absence of vitreous or transforming growth factor-beta (TGF-beta). The expression of HO-1 and MTs was measured by real time PCR and, in the case of HO-1, by immunoblotting and immunofluorescence microscopy. Specific inhibitors were used to investigate possible signaling pathways. The effect of vitreous on activation of AP-1 transcription factor was determined by immunoblotting, electrophoretic mobility shift assays, or immunofluorescence microscopy. RESULTS: Incubation of RPE cells with vitreous resulted in increased expression of HO-1, MT-1a and MT-2a. TGF-beta caused an increase in HO-1 expression, although not to the extent mediated by vitreous, but had little effect on MT expression. Addition of inhibitors of TGF-beta signaling (SB431542 or TGF-beta-neutralizing antibodies) decreased the vitreous induction of HO-1. Several reactive oxygen species (ROS) quenchers inhibited the TGF-beta-induced or vitreous-induced elevation of HO-1 mRNA but had no effect on vitreous-mediated induction of MT expression. Inhibitors of the mitogen-activated protein kinase (p38MAPK; SB203580) and Jun N-terminal kinase (JNK; SP600125) pathways inhibited vitreous-induction of HO-1. C-fos, a component of AP-1 transcription factor complexes, exhibited increased expression and activation in the presence of vitreous. CONCLUSIONS: TGF-beta, a known component of vitreous, can account for some but not all of the regulation of the anti-oxidant, anti-inflammatory HO-1 gene in human RPE cells, but it does not participate in the vitreous-mediated upregulation of MTs. Both vitreous and TGF-beta signals increased HO-1 expression via ROS but the latter were not involved in vitreous-mediated MT expression. Increased p38, JNK, and c-fos activation may be implicated in vitreous modulation of HO-1.

Expression and genomic status of EGFR and ErbB-2 in alveolar and embryonal rhabdomyosarcoma.

Both epidermal growth factor receptor (EGFR) and ErbB-2 play an important role in cancer biology and constitute promising molecular targets of therapy. EGFR and ErbB-2 expression has been observed in rhabdomyosarcoma cell lines but not analyzed systematically in rhabdomyosarcoma tumors. Tissue microarray sections representing 66 rhabdomyosarcoma tumors (34 embryonal rhabdomyosarcoma, 32 alveolar rhabdomyosarcoma) were surveyed by immunohistochemistry using antibodies specific for EGFR and ErbB-2. Immunostains were assessed for intensity (0: no immunostaining; 1: weak; 2: moderate; 3: strong) and percentage of at least 500 neoplastic cells exhibiting membranous or membranous and cytoplasmic immunostaining. EGFR and ErbB-2 expression was considered positive if the product of intensity and percentage was greater than 10. Patients had a median age of 5.7 years (range 8 months-19.1 years), and of 65/66 patients, 38 were males and 27 were females. Expression of ErbB-2 was identified in 22/66 (33%) cases and tended to be more frequent in the alveolar subtype (13/32, 41%, vs 9/34, 26%, P=0.30). Expression of EGFR was identified in 31/66 (47%) cases and correlated with the embryonal subtype (26/34, 76%, vs 5/32, 16%, P<0.0001) independent of stage, age, and gender. Coexpression of EGFR and ErbB-2 was identified in eight tumors, of which six were embryonal rhabdomyosarcoma. None of the cases exhibited EGFR or ErbB-2 gene amplification, as assessed using fluorescence in situ hybridization. Furthermore, analysis of 11 additional rhabdomyosarcoma tumors (six alveolar; five embryonal) revealed no evidence of mutations in EGFR exons 18, 19, 20, and 21. In summary, expression of EGFR and/or ErbB-2 is detected in a sizeable subset of rhabdomyosarcoma tumors without evidence of EGFR or ErbB-2 amplification or mutations in the EGFR tyrosine kinase domain. Notably, expression of EGFR correlates with the embryonal subtype, which is also more likely to coexpress EGFR and ErbB-2.

Vitreous induces components of the prostaglandin E2 pathway in human retinal pigment epithelial cells.

PURPOSE: To investigate the alterations in gene expression when human retinal pigment epithelial (RPE) cells in culture are treated with vitreous as a model for the changes that occur in proliferative vitreoretinopathy. METHODS: Human RPE cells were cultured with or without human vitreous or collagen. RNA was extracted and reverse transcribed. The RNAs expressed were compared by using DNA macroarrays. Messenger RNA levels were also measured using real-time reverse transcription polymerase chain reaction. Protein expression was examined by immunoblot analysis. Immunoassays were used to determine levels of prostaglandin E(2). RESULTS: Vitreous treatment of RPE cells resulted in increased expression of two critical enzymes in the synthesis of prostaglandin E(2): membrane-associated prostaglandin E-synthase (mPGES) and cyclooxygenase (COX)-2. Increased levels of mPGES RNA and protein were still present at 48 hours of treatment, but the increase in COX-2 mRNA and protein was transient. The increase in the expression of mPGES was associated with an increase in the production of prostaglandin E(2) that was observed at 12 and 24 hours of treatment but not at 48 hours. Treatment with 100 microg collagen I per ml medium did not cause increased expression of mPGES and COX-2, even though both collagen- and vitreous-treatment caused a morphologic change in the RPE cells to a more fibroblast-like phenotype. CONCLUSIONS: Treatment of human RPE cells with vitreous induces changes in gene expression that are indicative of an inflammatory response.

Metallothionein protects retinal pigment epithelial cells against apoptosis and oxidative stress.

The retina expresses metallothionein (MT) which has been reported to protect cells against oxidative stress and apoptosis. The types of MT expressed by human retinal cells were identified by laser capture microdissection and RT--PCR and it was found that MT-2a is expressed by retinal pigment epithelial (RPE) cells, photoreceptor cells, inner nuclear layer cells and ganglion cells while MT-1a is expressed by RPE cells and MT-3 by cells of the neural retina. MT is induced in cultured human RPE cells under stress conditions such as the presence of glucocorticoids, interleukin-1/TNF alpha, oxygen and TGF beta 1. Cultured human D407 RPE cells were transfected with plasmids that allowed the expression of MT to be controlled via the tet operator protein by the level of tetracycline in the medium. These experiments showed that elevation of MT levels by transfection of RPE cells protects them against toxic levels of cadmium, heme- and iron-induced oxidation and UV light-induced apoptosis.