Human SMC2 is part of the condensin complex, which is responsible for tightly packaging replicated genomic DNA prior to segregation into daughter cells. Engagement of the WNT signaling pathway is ...known to have a mitogenic effect on cells, but relatively little is known about WNT interaction with mitotic structural organizer proteins. In this work, we described the novel transcriptional regulation of SMC2 protein by direct binding of the β-catenin·TCF4 transcription factor to the SMC2 promoter. Furthermore, we identified the precise region in the SMC2 promoter that is required for β-catenin-mediated promoter activation. Finally, we explored the functional significance of down-regulating SMC2 protein in vivo. Treatment of WNT-activated intestinal tumor cells with SMC2 siRNA significantly reduced cell proliferation in nude mice, compared with untreated controls (p = 0.02). Therefore, we propose that WNT signaling can directly activate SMC2 transcription as a key player in the mitotic cell division machinery. Furthermore, SMC2 represents a new target for oncological therapeutic intervention.
Condensin SMC proteins are frequently overexpressed in WNT-activated hyperplastic cells.
The SMC2 promoter is a novel target on the β-catenin·TCF4 transcription complex.
β-Catenin·TCF4 may drive production of condensin in hyperplastic cells. SMC2 is required to ensure cellular mitosis and fast proliferation.
Down-regulation of SMC2 expression can repress cell proliferation in WNT-activated cells and represents a new therapeutic target in cancer treatment.
Summary Lynch syndrome (LS), the most frequent form of hereditary colorectal cancer syndrome, is caused by germ-line mutations in the mismatch repair system genes. Recently, a new mechanism involving ...the epithelial cell adhesion molecule ( EPCAM )/ TACSTD1 gene has been shown to be responsible in cases with abnormal MSH2 expression. Of interest, 3′ exons deletions of the EPCAM gene, which is located upstream of MSH2 in chromosome 2, are associated with MSH2 promoter hypermethylation. EPCAM protein, expressed in epithelial tissues, is encoded by the EPCAM/TACSTD1 gene. Our study's aim was to explore EPCAM expression in colorectal carcinomas of MSH2 -associated LS cases to evaluate the usefulness of EPCAM protein expression in the algorithm approach to LS population screening. We included a total of 19 MSH2-negative colorectal carcinomas from 14 different patients in whom we were able to perform a complete germ-line analysis. Nine patients showed a deleterious germ-line mutation that involved the MSH2 gene in 3 instances and the EPCAM gene exon 9 in 6 instances. All patients harboring the EPCAM mutation belonged to the same family. Of the 19 colorectal carcinomas, EPCAM expression loss was seen in only 5 tumors, all of them from patients showing a germ-line EPCAM deletion. Of interest, 6 tumors from 3 different patients carrying the same germ-line EPCAM deletion showed normal EPCAM expression. In conclusion, owing to the high specificity of EPCAM protein expression to identify LS patients carrying an EPCAM deletion, we recommend adding EPCAM immunohistochemistry to the LS diagnostic algorithm in MSH2-negative colorectal carcinoma.
Microsatellite instability (MSI) defines a specific type of genetic instability. Although consensus diagnostic criteria for MSI definition in colorectal cancer have been established, their utility in ...other tumor types remain to be proven. Previously we developed a mathematical model for MSI definition in colorectal cancer. The aim of this study was to establish diagnostic criteria for MSI evaluation in human gastric cancer. We designed an algorithm for the efficient characterization of MSI and used it to analyze data on 7 microsatellite markers in 35 gastric carcinomas. Theoretical models considering 1, 2, or 3 populations were tested against the data collected. Also, hypermethylation of
hMLH1 gene promoter and hMLH1 protein expression were studied. The observed frequencies of MSI in our series of samples best fit a 2-population model: stable and unstable, defined by instability in 2 or more of a minimum of 7 markers analyzed. MSI was observed in 29% of the tumors. Misclassification rate was <4% when any 7 loci were analyzed. MSI(+) tumors inversely associated with p53 protein overexpression. A good correlation between hMLH1 status (either protein or promoter hypermethylation) and MSI classification was observed. We have developed a simple, sensitive, and specific approach to assess the presence of MSI in gastric cancer that may have clinical applications.
This update of the consensus of the Spanish Society of Medical Oncology (Sociedad Española de Oncología Médica - SEOM) and the Spanish Society of Pathology (Sociedad Española de Anatomía Patológica - ...SEAP), reviews the advances in the analysis of biomarkers in advanced colorectal cancer (CRC) as well as susceptibility markers of hereditary CRC and molecular biomarkers of localized CRC. Recently published information on the essential determination of KRAS, NRAS and BRAF mutations and the possible benefits of determining the amplification of human epidermal growth factor receptor 2 (HER2), the expression of proteins in the DNA repair pathway and the study of NTRK fusions are also evaluated. From a pathological point of view, the importance of analysing the tumour budding and poorly differentiated clusters and its prognostic value in CRC is reviewed, as well as the impact of molecular lymph node analysis on lymph node staging in CRC. The incorporation of pan-genomic technologies, such as next-generation sequencing (NGS) and liquid biopsy in the clinical management of patients with CRC is also outlined. All these aspects are developed in this guide which, like the previous one, will be revised when necessary in the future.
Primary renal cell carcinoma (RCC) is the most frequent kidney cancer. In renal transplant patients, RCC more commonly arise in the native kidneys, whereas allograft involvement has been just ...occasionally reported. In these latter cases, a graft origin of tumor cells should be considered and other recipients from the same donor should be investigated. So far, genetic studies to trace the origin of cancer cells have always confirmed the donor origin of these tumors.
A 58-year-old man developed an RCC in the grafted kidney 14 years after transplantation. Histologic and immunohistochemical studies diagnosed a clear cell RCC with sarcomatoid changes. A nine microsatellite DNA assay was used to compare renal tumor cells with donor's (graft parenchyma) and recipient's (lymph nodes and blood) cells.
Of the nine microsatellites analyzed, four turned out to be noninformative and the other five (D1S2734, D1S214, D1S199, D19S219, and Humara) showed different band profiles in donor's and recipient's cells DNA. Tumor and blood profile matching confirmed the recipient origin of neoplastic cells.
We report the first case of a grafted-kidney RCC whose recipient's cell origin has been proved by microsatellite analysis. An origin from the recipient's kidney or bone marrow stem cells is proposed as the more plausible hypothesis.
Tumour budding (TB) correlates with increased local invasion in various neoplasms. Certain basal cell carcinomas (BCCs) exhibit local aggressiveness. Detecting adverse prognostic factors in partial ...biopsies could aid in identifying cases with heightened local risk. The absolute number of TB (≤ 3 tumour cells) in excision specimens of 271 infiltrative BCCs (0: absent; 1: 1–2 foci; 2: ≥ 3 foci; 3: ≥ 10 foci), the histopathological subtype and depth of infiltration, perineural invasion, and other histological features were evaluated. A significant correlation was found between TB and both depth of infiltration (rho 0.445, p < 0.001) and perineural invasion (p = 0.009). In the multivariate analysis of depth and perineural invasion (multiple regression, stepwise), TB was identified as a significant covariate together with diameter, inflammation, and perineural invasion for the former, and depth for the latter. Conversely, no correlation existed between the WHO histological subtypes (infiltrating, sclerosing, and micronodular), and depth of infiltration or perineural invasion. This study demonstrates the value of TB as a biomarker for local invasiveness in BCC. In routine practice, a count of ≥ 3 TB foci in lesions incompletely excised or with narrow tumour-free surgical margins would be a straightforward and reproducible method to guide BCC treatment.
Abstract
High-throughput genomic technologies are increasingly used in personalized cancer medicine. However, computational tools to maximize the use of scarce tissues combining distinct molecular ...layers are needed. Here we present a refined strategy, based on the R-package ‘conumee’, to better predict somatic copy number alterations (SCNA) from deoxyribonucleic acid (DNA) methylation arrays. Our approach, termed hereafter as ‘conumee-KCN’, improves SCNA prediction by incorporating tumor purity and dynamic thresholding. We trained our algorithm using paired DNA methylation and SNP Array 6.0 data from The Cancer Genome Atlas samples and confirmed its performance in cancer cell lines. Most importantly, the application of our approach in cancers of unknown primary identified amplified potentially actionable targets that were experimentally validated by Fluorescence in situ hybridization and immunostaining, reaching 100% specificity and 93.3% sensitivity.
Background & Aims There are few validated biomarkers that can be used to predict outcomes for patients with colorectal cancer. Part of the challenge is the genetic and molecular heterogeneity of ...colorectal tumors not only among patients, but also within tumors. We have explored intratumor heterogeneity at the epigenetic level, due to its dynamic nature. We analyzed DNA methylation profiles of the digestive tract surface and the central bulk and invasive front regions of colorectal tumors. Methods We determined the DNA methylation profiles of >450,000 CpG sites in 3 macrodissected regions of 79 colorectal tumors and 23 associated liver metastases, obtained from 2 hospitals in Spain. We also analyzed samples for KRAS and BRAF mutations, 499,170 single nucleotide polymorphisms, and performed immunohistochemical analyses. Results We observed differences in DNA methylation among the 3 tumor sections; regions of tumor−host interface differed the most from the other tumor sections. Interestingly, tumor samples collected from areas closer to the gastrointestinal transit most frequently shared methylation events with metastases. When we calculated individual coefficients to quantify heterogeneity, we found that epigenetic homogeneity was significantly associated with short time of relapse-free survival (log-rank P = .037) and short time of overall survival (log-rank P = .026) in patients with locoregional colorectal cancer. Conclusions In an analysis of 79 colorectal tumors, we found significant heterogeneity in patterns of DNA methylation within each tumor; the level of heterogeneity correlates with times of relapse-free and overall survival.
Gastric metaplasia in colonic mucosa with inflammatory bowel disease (IBD) develops as an adaptation mechanism. The association between gastric metaplasia and nonconventional and/or conventional ...dysplasia as precursors of colitis-associated colorectal cancer is unknown. To address this question, we retrospectively reviewed a series of 33 IBD colectomies to identify gastric metaplasia in 76 precursor lesions. We obtained 61 nonconventional and 15 conventional dysplasias. Among nonconventional dysplasia, 31 (50.8 %) were low-grade (LGD), 4 (6.5 %) were high-grade (HGD), 9 (14.8 %) had both LGD and HGD, and 17 (27.9 %) had no dysplasia (ND), while 14 (93 %) conventional dysplasias had LGD, and 1 (7 %) had LGD and HGD. Gastric metaplasia was assessed by concomitant immunoexpression of MUC5AC and loss of CDX2 staining. Expression of a p53-mut pattern was considered as a surrogate for gene mutation, and complete loss of MLH1 staining as presence of MLH1 hypermethylation. In nonconventional dysplasia, MUC5AC immunoexpression decreased as the degree of dysplasia increased, being 78 % in LGD and 39 % in HGD (p = 0.006). CDX2 was lost in epithelial glands with high expression of MUC5AC (p < 0.001). The p53-mut pattern was observed in 77 % HGD, 45 % LGD, and in 6 % with ND (p < 0.001). Neither nonconventional nor conventional dysplasia showed complete loss of MLH1 staining. Gastric metaplasia was also present in mucosa adjacent to nonconventional dysplasia with chronic changes or active inflammation. Our results show that gastric metaplasia appears in IBD-inflamed colon mucosa, it is the substrate of most nonconventional dysplasia and occurs prior to p53 alterations.
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