Although mutation of APC or CTNNB1 (beta-catenin) is rare in breast cancer, activation of Wnt signalling is nonetheless thought to play an important role in breast tumorigenesis, and epigenetic ...silencing of Wnt antagonist genes, including the secreted frizzled-related protein (SFRP) and Dickkopf (DKK) families, has been observed in various tumours. In breast cancer, frequent methylation and silencing of SFRP1 was recently documented; however, altered expression of other Wnt antagonist genes is largely unknown. In the present study, we found frequent methylation of SFRP family genes in breast cancer cell lines (SFRP1, 7 out of 11, 64%; SFRP2, 11 out of 11, 100%; SFRP5, 10 out of 11, 91%) and primary breast tumours (SFRP1, 31 out of 78, 40%; SFRP2, 60 out of 78, 77%; SFRP5, 55 out of 78, 71%). We also observed methylation of DKK1, although less frequently, in cell lines (3 out of 11, 27%) and primary tumours (15 out of 78, 19%). Breast cancer cell lines express various Wnt ligands, and overexpression of SFRPs inhibited cancer cell growth. In addition, overexpression of a beta-catenin mutant and depletion of SFRP1 using small interfering RNA synergistically upregulated transcriptional activity of T-cell factor/lymphocyte enhancer factor. Our results confirm the frequent methylation and silencing of Wnt antagonist genes in breast cancer, and suggest that their loss of function contributes to activation of Wnt signalling in breast carcinogenesis.
E-cadherin (E-cad) and its associated intracellular molecules, catenins, are critical for intercellular epithelial adhesion and are often expressed in non-small-cell lung carcinomas (NSCLCs). We ...constructed tissue microarrays (TMAs) to investigate the expression of cadherins and catenins and their prognostic significance in NSCLC.
Tumor tissue samples from 193 patients with stages I to III NSCLC were obtained from the University of Colorado Cancer Center and Johns Hopkins Medical Institutions. Viable tumor was sampled in triplicate for the TMAs, and slides were stained by immunohistochemistry with antibodies against E-cad, N-cadherin, alpha (alpha)-, beta (beta)-, and gamma (gamma)-catenin, p120, p27, and adenomatous polyposis coli (APC) gene product. Clinical data were collected by the tumor registries. Patients were followed for a median period of 51 months (range, 18 to 100 months).
Absent or severely reduced membranous expression for E-cad, alpha-, beta-, and gamma-catenin, and p120 were observed in 10%, 17%, 8%, 31%, and 61% of the cases, respectively. Tumor cell dedifferentiation correlated with reduced expression for E-cad, beta-catenin, gamma-catenin, and p120 in squamous cell carcinomas but not in adenocarcinomas. There was an inverse correlation between nodal metastasis and expression of E-cad and gamma-catenin. Besides the traditional clinical prognostic variables, E-cad and alpha-, beta-, and gamma-catenin expression were of positive prognostic value in univariate survival analyses. In multivariate analysis, E-cad expression was the only independent prognostic factor for survival in addition to age, node status, tumor status, and pathologic surgical margins.
Reduced expression of E-cad and catenins is associated with tumor cell dedifferentiation, local invasion, regional metastasis, and reduced survival in NSCLC. E-cad is an independent prognostic factor for NSCLC survival.
Aims: Ezrin–radixin–moesin‐binding phosphoprotein 50 (EBP50) is a post synaptic density‐95/Disk‐large/ZO‐1 homologous domain‐containing protein that is involved in the linkage of integral membrane ...proteins to the cytoskeleton and plays an important role in cell signalling. To gain insights into its biological relevance, this study examined expression of EBP50 in two cohorts of breast carcinoma.
Methods and results: Forty‐nine breast carcinoma tissue specimens were first examined by both immunohistochemistry and RNA in situ hybridization. EBP50 expression was correlated with various clinicopathological variables. The relative abundance of EBP50 mRNA in breast carcinomas and their corresponding normal tissue was compared using reverse transcriptase‐polymerase chain reaction (RT‐PCR). EBP50 immunoreactivity was then further independently validated in 120 breast carcinomas on tissue microarrays. EBP50 immunoreactivity was observed in morphologically normal and cancerous epithelial cells contrasting with the adjacent immunonegative stromal cells. An elevated cytoplasmic accumulation of EBP50 protein was readily detected in 73.5–80% of breast carcinomas. EBP50 immunoreactivity was significantly associated with tumour stage, lymph node and oestrogen receptor status. These immunohistochemical observations were further validated using RNA in situ hybridization and RT‐PCR. EBP50 immunoreactivity was significantly correlated with the mRNA expression level.
Conclusion: Oestrogen‐responsive EBP50 may play an important role in tumour progression and might be a potential marker of invasiveness for breast cancer.
Neoadjuvant PD-1 Blockade in Resectable Lung Cancer Forde, Patrick M; Chaft, Jamie E; Smith, Kellie N ...
New England journal of medicine/The New England journal of medicine,
05/2018, Volume:
378, Issue:
21
Journal Article
Peer reviewed
Open access
Antibodies that block programmed death 1 (PD-1) protein improve survival in patients with advanced non-small-cell lung cancer (NSCLC) but have not been tested in resectable NSCLC, a condition in ...which little progress has been made during the past decade.
In this pilot study, we administered two preoperative doses of PD-1 inhibitor nivolumab in adults with untreated, surgically resectable early (stage I, II, or IIIA) NSCLC. Nivolumab (at a dose of 3 mg per kilogram of body weight) was administered intravenously every 2 weeks, with surgery planned approximately 4 weeks after the first dose. The primary end points of the study were safety and feasibility. We also evaluated the tumor pathological response, expression of programmed death ligand 1 (PD-L1), mutational burden, and mutation-associated, neoantigen-specific T-cell responses.
Neoadjuvant nivolumab had an acceptable side-effect profile and was not associated with delays in surgery. Of the 21 tumors that were removed, 20 were completely resected. A major pathological response occurred in 9 of 20 resected tumors (45%). Responses occurred in both PD-L1-positive and PD-L1-negative tumors. There was a significant correlation between the pathological response and the pretreatment tumor mutational burden. The number of T-cell clones that were found in both the tumor and peripheral blood increased systemically after PD-1 blockade in eight of nine patients who were evaluated. Mutation-associated, neoantigen-specific T-cell clones from a primary tumor with a complete response on pathological assessment rapidly expanded in peripheral blood at 2 to 4 weeks after treatment; some of these clones were not detected before the administration of nivolumab.
Neoadjuvant nivolumab was associated with few side effects, did not delay surgery, and induced a major pathological response in 45% of resected tumors. The tumor mutational burden was predictive of the pathological response to PD-1 blockade. Treatment induced expansion of mutation-associated, neoantigen-specific T-cell clones in peripheral blood. (Funded by Cancer Research Institute-Stand Up 2 Cancer and others; ClinicalTrials.gov number, NCT02259621 .).
Activation of fatty acid synthase (FAS) expression and fatty acid synthesis is a common event in human breast cancer. Sterol regulatory element binding proteins (SREBPs) are a family of transcription ...factors that regulate genes involved in lipid metabolism, including FAS. SREBP-1c expression is induced in liver and adipose tissue by insulin and by fasting/refeeding and is critical for nutritional regulation of lipogenic gene expression. In contrast, upregulation of fatty acid metabolism during in vitro transformation of human mammary epithelial cells and in breast cancer cells was driven by increased MAP kinase and PI 3-kinase signaling, which increased SREBP-1 levels. SREBP-1a was more abundant than SREBP-1c in many proliferative tissues and cultured cells and was thus a candidate to regulate lipogenesis for support of membrane synthesis during cell growth. We now show that SREBP-1c and FAS mRNA were both increased by H-
ras transformation of MCF-10a breast epithelial cells and were both reduced by exposure of MCF-7 breast cancer cells to the MAP kinase inhibitor, PD98059, or the PI 3-kinase inhibitor, wortmannin, while SREBP-1a and SREBP-2 showed less variation. Similarly, the mRNA levels for FAS and SREBP-1c in a panel of primary human breast cancer samples showed much greater increases than did those for SREBP-1a and SREBP-2 and were significantly correlated with each other, suggesting coordinate regulation of SREBP-1c and FAS in clinical breast cancer. We conclude that regulation of FAS expression in breast cancer is achieved through modulation of SREBP-1c, similar to the regulation in liver and adipose tissue, although the upstream regulation of liopgenesis differs in these tissues.
Neoadjuvant anti-PD-1 may improve outcomes for patients with resectable NSCLC and provides a critical window for examining pathologic features associated with response. Resections showing major ...pathologic response to neoadjuvant therapy, defined as ≤10% residual viable tumor (RVT), may predict improved long-term patient outcome. However, %RVT calculations were developed in the context of chemotherapy (%cRVT). An immune-related %RVT (%irRVT) has yet to be developed.
The first trial of neoadjuvant anti-PD-1 (nivolumab, NCT02259621) was just reported. We analyzed hematoxylin and eosin-stained slides from the post-treatment resection specimens of the 20 patients with non-small-cell lung carcinoma who underwent definitive surgery. Pretreatment tumor biopsies and preresection radiographic ‘tumor’ measurements were also assessed.
We found that the regression bed (the area of immune-mediated tumor clearance) accounts for the previously noted discrepancy between CT imaging and pathologic assessment of residual tumor. The regression bed is characterized by (i) immune activation—dense tumor infiltrating lymphocytes with macrophages and tertiary lymphoid structures; (ii) massive tumor cell death—cholesterol clefts; and (iii) tissue repair—neovascularization and proliferative fibrosis (each feature enriched in major pathologic responders versus nonresponders, P<0.05). This distinct constellation of histologic findings was not identified in any pretreatment specimens. Histopathologic features of the regression bed were used to develop ‘Immune-Related Pathologic Response Criteria’ (irPRC), and these criteria were shown to be reproducible amongst pathologists. Specifically, %irRVT had improved interobserver consistency compared with %cRVT median per-case %RVT variability 5% (0%–29%) versus 10% (0%–58%), P=0.007 and a twofold decrease in median standard deviation across pathologists within a sample (4.6 versus 2.2, P=0.002).
irPRC may be used to standardize pathologic assessment of immunotherapeutic efficacy. Long-term follow-up is needed to determine irPRC reliability as a surrogate for recurrence-free and overall survival.
Rodents are among the most widespread and problematic invasive animals on islands worldwide contributing to declining endemic island biota through predation and disruption of mutualisms. Identifying ...what rodents eat is critically important to understanding their effects on ecosystems. We used DNA metabarcoding to identify the diets of three invasive rodents in Hawaiian forests: house mouse (
Mus musculus
), black rat (
Rattus rattus
), and Pacific rat (
Rattus exulans
). These rodents primarily eat invertebrates and plants, but previous diet studies have provided only a limited understanding of the diet breadth by relying on morphological identification methods. We opportunistically collected fecal samples from rodents trapped at seven forest sites across Oʻahu, Hawaiʻi for two years. Plant and invertebrate diet items were identified from DNA extracted from fecal samples using
rbc
L and COI primers, respectively. Intact seeds were identified using a dissecting microscope to quantify potential contributions to seed dispersal. All rodent species ate primarily plants and invertebrates of introduced species. However, some native taxa of conservation importance were identified. Neither the rodent species nor the sites drove patterns of diet composition, suggesting that diet variation may be determined by opportunistic foraging or intraspecific variation. Black rat fecal samples contained intact seeds more frequently than house mouse samples, but surprisingly, when samples contained seeds, black rats and house mice both defecated hundreds of introduced seeds, likely contributing to seed dispersal. Conservation efforts targeting invasive rodent control should specifically include house mice and should monitor introduced prey items to prevent predation release of unwanted introduced species.
Many common human cancer tissues express high levels of fatty acid synthase (FAS), the primary enzyme for the synthesis of fatty acids, and the differential expression of FAS between normal and ...neoplastic tissues has led to the consideration of FAS as a target for anticancer therapy. To investigate the potential of targeting FAS for the treatment of pleural mesothelioma, we first determined whether FAS is overexpressed in human mesothelioma. By immunohistochemistry, we found 22 of 30 human mesothelioma tissue samples tested to express significantly increased levels of FAS compared with normal tissues, including mesothelium. To further explore FAS as a therapeutic target in mesothelioma, we established a nude mouse xenograft model for human mesothelioma using the H-Meso cell line. The i.p. xenografts of this cell line have high levels of FAS expression and fatty acid synthesis pathway activity and grow along mesothelial surfaces in a manner similar to the growth pattern of human mesothelioma. Growth of these tumor xenografts was essentially abolished in mice treated with weekly i.p. injections of C75, a synthetic, small molecule inhibitor of FAS, at levels that resulted in no significant systemic toxicity except for reversible weight loss. These results suggest that FAS may be an effective target for pharmacological therapy in a high proportion of human mesotheliomas.
Loss of heterozygosity (LOH) of chromosomal arm 8p has been reported to occur at high frequency for a number of common forms of human cancer, including breast cancer. The objectives of this study ...were to define the regions on this chromosomal arm that are likely to contain breast cancer tumor suppressor genes and to determine when loss of chromosomal arm 8p occurs during breast cancer progression. For mapping the tumor suppressor gene loci, we evaluated 60 cases of infiltrating ductal cancer for allelic loss using 14 microsatellite markers mapped to this chromosomal arm and found LOH of 8p in 36 (60%) of the tumors. Whereas most of these tumors had allelic loss at all informative markers, five tumors had partial loss of 8p affecting two nonoverlapping regions. LOH for all but one of the tumors with 8p loss involved the region between markers D8S560 and D8S518 at 8p21.3-p23.3, suggesting that this is the locus of a breast cancer tumor suppressor gene. We then studied LOH of 8p in 38 cases of ductal carcinoma in situ (DCIS) with multiple individually microdissected tumor foci evaluated for each case. LOH of 8p was found in 14 of the DCIS cases (36%), including 6 of 16 cases of low histological grade and 8 of 22 cases of intermediate or high histological grade. In four of these DCIS cases, 8p LOH was seen in some but not all of the multiple tumor foci examined. These data suggest that during the evolution of these tumors, LOH of 8p occurred after loss of other chromosomal arms that were lost in all tumor foci. Thus, LOH of 8p, particularly 8p21.3-p23, is a common genetic alteration in infiltrating and in situ breast cancer. Although 8p LOH is common even in low histological grade DCIS, this allelic loss often appears to be preceded by loss of other alleles in the evolution of breast cancer.
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