High Concordance and Negative Prognostic Impact of RAS/BRAF/PIK3CA Mutations in Multiple Resected Colorectal Liver Metastases.

Background: The prevalence and clinical implications of genetic heterogeneity in patients with multiple colorectal liver metastases remain largely unknown. In a prospective series of patients undergoing resection of colorectal liver metastases, the aim was to investigate the inter-metastatic and primary-to-metastatic heterogeneity of mutations in KRAS, NRAS, BRAF, and PIK3CA and their prognostic impact.

Patients And Methods: We analyzed the mutation status among 372 liver metastases and 78 primary tumors from 106 patients by methods used in clinical routine testing, by Sanger sequencing, by next-generation sequencing (NGS), and/or by droplet digital polymerase chain reaction.

Truncated PPM1D impairs stem cell response to genotoxic stress and promotes growth of APC-deficient tumors in the mouse colon.

Protein phosphatase magnesium-dependent 1 delta (PPM1D) terminates cell response to genotoxic stress by negatively regulating the tumor suppressor p53 and other targets at chromatin. Mutations in the exon 6 of the PPM1D result in production of a highly stable, C-terminally truncated PPM1D. These gain-of-function PPM1D mutations are present in various human cancers but their role in tumorigenesis remains unresolved.

Exploratory analyses of consensus molecular subtype-dependent associations of mutations with immunomodulation and prognosis in colorectal cancer.

Background: Accumulating evidence suggests immunomodulatory and context-dependent effects of mutations in cancer. We performed an exploratory analysis of the transcriptional, immunobiological and prognostic associations of mutations within the gene expression-based consensus molecular subtypes (CMSs) of colorectal cancer (CRC).

Materials And Methods: In a single-hospital series of 401 stage I-IV primary CRCs, we sequenced the whole coding region of and analysed CMS-dependent transcriptional consequences of the mutations by gene expression profiling.

Gene expression profiles of CMS2-epithelial/canonical colorectal cancers are largely driven by DNA copy number gains.

About 80% of colorectal cancers (CRCs) have chromosomal instability, which is an integral part of aggressive malignancy development, but the importance of specific copy number aberrations (CNAs) in modulating gene expression, particularly within the framework of clinically relevant molecular subtypes, remains mostly elusive. We performed DNA copy number profiling of 257 stage I-IV primary CRCs and integrative gene expression analysis in 151 microsatellite stable (MSS) tumors, focusing on high-level amplifications and the effect of CNAs on the characteristics of the gene expression-based consensus molecular subtypes (CMS). The results were validated in 323 MSS tumors from TCGA.

Transcriptional and functional consequences of TP53 splice mutations in colorectal cancer.

TP53 mutations are common in colorectal cancer (CRC). Most TP53 sequencing studies have been restricted to coding regions, but recent studies have revealed that splice mutations can generate transcript variants with distinct tumorigenic and prognostic properties. Here, we performed unrestricted sequencing of all coding sequences and splice regions of TP53 in a single-hospital series of 401 primary CRCs.

Inferior survival for patients with malignant peripheral nerve sheath tumors defined by aberrant TP53.

Malignant peripheral nerve sheath tumor is a rare and aggressive disease with poor treatment response, mainly affecting adolescents and young adults. Few molecular biomarkers are used in the management of this cancer type, and although TP53 is one of few recurrently mutated genes in malignant peripheral nerve sheath tumor, the mutation prevalence and the corresponding clinical value of the TP53 network remains unsettled. We present a multi-level molecular study focused on aberrations in the TP53 network in relation to patient outcome in a series of malignant peripheral nerve sheath tumors from 100 patients and 38 neurofibromas, including TP53 sequencing, high-resolution copy number analyses of TP53 and MDM2, and gene expression profiling.

Colorectal Cancer Consensus Molecular Subtypes Translated to Preclinical Models Uncover Potentially Targetable Cancer Cell Dependencies.

Response to standard oncologic treatment is limited in colorectal cancer. The gene expression-based consensus molecular subtypes (CMS) provide a new paradigm for stratified treatment and drug repurposing; however, drug discovery is currently limited by the lack of translation of CMS to preclinical models. We analyzed CMS in primary colorectal cancers, cell lines, and patient-derived xenografts (PDX).

Multi-omics of 34 colorectal cancer cell lines - a resource for biomedical studies.

Background: Colorectal cancer (CRC) cell lines are widely used pre-clinical model systems. Comprehensive insights into their molecular characteristics may improve model selection for biomedical studies.

Methods: We have performed DNA, RNA and protein profiling of 34 cell lines, including (i) targeted deep sequencing (n = 612 genes) to detect single nucleotide variants and insertions/deletions; (ii) high resolution DNA copy number profiling; (iii) gene expression profiling at exon resolution; (iv) small RNA expression profiling by deep sequencing; and (v) protein expression analysis (n = 297 proteins) by reverse phase protein microarrays.

Drug sensitivity and resistance testing identifies PLK1 inhibitors and gemcitabine as potent drugs for malignant peripheral nerve sheath tumors.

Patients with malignant peripheral nerve sheath tumor (MPNST), a rare soft tissue cancer associated with loss of the tumor suppressor neurofibromin (NF1), have poor prognosis and typically respond poorly to adjuvant therapy. We evaluated the effect of 299 clinical and investigational compounds on seven MPNST cell lines, two primary cultures of human Schwann cells, and five normal bone marrow aspirates, to identify potent drugs for MPNST treatment with few side effects. Top hits included Polo-like kinase 1 (PLK1) inhibitors (volasertib and BI2536) and the fluoronucleoside gemcitabine, which were validated in orthogonal assays measuring viability, cytotoxicity, and apoptosis.

CpG island methylator phenotype identifies high risk patients among microsatellite stable BRAF mutated colorectal cancers.

The prognostic value of CpG island methylator phenotype (CIMP) in colorectal cancer remains unsettled. We aimed to assess the prognostic value of this phenotype analyzing a total of 1126 tumor samples obtained from two Norwegian consecutive colorectal cancer series. CIMP status was determined by analyzing the 5-markers CAGNA1G, IGF2, NEUROG1, RUNX3 and SOCS1 by quantitative methylation specific PCR (qMSP).

Multilevel genomics of colorectal cancers with microsatellite instability-clinical impact of JAK1 mutations and consensus molecular subtype 1.

Background: Approximately 15% of primary colorectal cancers have DNA mismatch repair deficiency, causing a complex genome with thousands of small mutations-the microsatellite instability (MSI) phenotype. We investigated molecular heterogeneity and tumor immunogenicity in relation to clinical endpoints within this distinct subtype of colorectal cancers.

Methods: A total of 333 primary MSI+ colorectal tumors from multiple cohorts were analyzed by multilevel genomics and computational modeling-including mutation profiling, clonality modeling, and neoantigen prediction in a subset of the tumors, as well as gene expression profiling for consensus molecular subtypes (CMS) and immune cell infiltration.

Somatic POLE proofreading domain mutation, immune response, and prognosis in colorectal cancer: a retrospective, pooled biomarker study.

Background: Precision cancer medicine depends on defining distinct tumour subgroups using biomarkers that may occur at very modest frequencies. One such subgroup comprises patients with exceptionally mutated (ultramutated) cancers caused by mutations that impair DNA polymerase epsilon (POLE) proofreading.

Methods: We examined the association of POLE proofreading domain mutation with clinicopathological variables and immune response in colorectal cancers from clinical trials (VICTOR, QUASAR2, and PETACC-3) and colorectal cancer cohorts (Leiden University Medical Centre 1 and 2, Oslo 1 and 2, Bern, AMC-AJCC-II, and Epicolon-1).

Portrait of the PI3K/AKT pathway in colorectal cancer.

PI3K/AKT signaling leads to reduced apoptosis, stimulates cell growth and increases proliferation. Under normal conditions, PI3K/AKT activation is tightly controlled and dependent on both extracellular growth signals and the availability of amino acids and glucose. Genetic aberrations leading to PI3K/AKT hyper-activation are observed at considerable frequency in all major nodes in most tumors.

Methylated RASSF1A in malignant peripheral nerve sheath tumors identifies neurofibromatosis type 1 patients with inferior prognosis.

Background: Malignant peripheral nerve sheath tumor (MPNST) is a rare and highly aggressive disease with no evidence of effect from adjuvant therapy. It is further associated with the hereditary syndrome neurofibromatosis type 1 (NF1). Silencing of the tumor suppressor gene RASSF1A through DNA promoter hypermethylation is known to be involved in cancer development, but its impact in MPNSTs remains unsettled.

A tissue-based comparative effectiveness analysis of biomarkers for early detection of colorectal tumors.

Objectives: We recently identified a six-gene methylation-based biomarker panel suitable for early detection of colorectal cancer (CRC). In this study, we compared the performance of this novel epi-panel with that of previously identified DNA methylation markers in the same clinical tissue sample sets.

Methods: Quantitative methylation-specific PCR was used to analyze the promoter region of SEPT9 and VIM in a total of 485 tissue samples, divided into test and validation sets.

MiR-9, -31, and -182 deregulation promote proliferation and tumor cell survival in colon cancer.

Several microRNAs (miRNAs) are known to be deregulated in colon cancer, but the mechanisms behind their potential involvement on proliferation and tumor cell survival are unclear. The present study aimed to identify miRNAs with functional implications for development of colon cancer. The cell proliferation and apoptosis were examined following perturbations of miRNA levels by employing a comprehensive miRNA library screen.

NEDD4 is overexpressed in colorectal cancer and promotes colonic cell growth independently of the PI3K/PTEN/AKT pathway.

Ubiquitination controls multiple cellular processes relevant to cancer pathogenesis. Using Gene Set Enrichment Analysis of an mRNA transcriptome dataset, we have identified genes encoding components of the ubiquitin system that are differentially expressed in colorectal cancers as compared to normal colonic mucosa. Among the significantly overexpressed genes was NEDD4 (neural precursor cell-expressed developmentally down-regulated 4), the prototype member of the HECT (homologous to E6AP C-terminus) E3 ubiquitin ligase family.

Phospholipase C isozymes are deregulated in colorectal cancer--insights gained from gene set enrichment analysis of the transcriptome.

Colorectal cancer (CRC) is one of the most common cancer types in developed countries. To identify molecular networks and biological processes that are deregulated in CRC compared to normal colonic mucosa, we applied Gene Set Enrichment Analysis to two independent transcriptome datasets, including a total of 137 CRC and ten normal colonic mucosa samples. Eighty-two gene sets as described by the Kyoto Encyclopedia of Genes and Genomes database had significantly altered gene expression in both datasets.

TCF21 and PCDH17 methylation: An innovative panel of biomarkers for a simultaneous detection of urological cancers.

The three main types of urological cancers are mostly curable by surgical resection, if early detected. We aimed to identify novel DNA methylation biomarkers common to these three urological cancers, potentially suitable for non-invasive testing. From a candidate list of markers created after gene expression assessment of pharmacologically treated cell lines and tissue samples, two genes were selected for further validation.

Identification of an epigenetic biomarker panel with high sensitivity and specificity for colorectal cancer and adenomas.

Background: The presence of cancer-specific DNA methylation patterns in epithelial colorectal cells in human feces provides the prospect of a simple, non-invasive screening test for colorectal cancer and its precursor, the adenoma. This study investigates a panel of epigenetic markers for the detection of colorectal cancer and adenomas.

Methods: Candidate biomarkers were subjected to quantitative methylation analysis in test sets of tissue samples from colorectal cancers, adenomas, and normal colonic mucosa.

DNA methylation analyses of the connexin gene family reveal silencing of GJC1 (Connexin45) by promoter hypermethylation in colorectal cancer.

Gap junctions are specialized plasma membrane domains consisting of channels formed by members of the connexin protein family. Gap junctional intercellular communication is often lost in cancers due to aberrant localization or downregulation of connexins, and connexins are therefore suggested to act as tumor suppressor genes in various tissues. The aim of this study was to investigate the expression pattern and DNA promoter methylation status of connexins in colorectal cancer.

DNA sequence profiles of the colorectal cancer critical gene set KRAS-BRAF-PIK3CA-PTEN-TP53 related to age at disease onset.

The incidence of colorectal cancer (CRC) increases with age and early onset indicates an increased likelihood for genetic predisposition for this disease. The somatic genetics of tumor development in relation to patient age remains mostly unknown. We have examined the mutation status of five known cancer critical genes in relation to age at diagnosis, and compared the genomic complexity of tumors from young patients without known CRC syndromes with those from elderly patients.

Colorectal carcinomas with microsatellite instability display a different pattern of target gene mutations according to large bowel site of origin.

Background: Only a few studies have addressed the molecular pathways specifically involved in carcinogenesis of the distal colon and rectum. We aimed to identify potential differences among genetic alterations in distal colon and rectal carcinomas as compared to cancers arising elsewhere in the large bowel.

Methods: Constitutional and tumor DNA from a test series of 37 patients with rectal and 25 patients with sigmoid carcinomas, previously analyzed for microsatellite instability (MSI), was studied for BAX, IGF2R, TGFBR2, MSH3, and MSH6 microsatellite sequence alterations, BRAF and KRAS mutations, and MLH1 promoter methylation.

Three epigenetic biomarkers, GDF15, TMEFF2, and VIM, accurately predict bladder cancer from DNA-based analyses of urine samples.

Purpose: To identify a panel of epigenetic biomarkers for accurate bladder cancer (BlCa) detection in urine sediments.

Experimental Design: Gene expression microarray analysis of BlCa cell lines treated with 5-aza-2'-deoxycytidine and trichostatin A as well as 26 tissue samples was used to identify a list of novel methylation candidates for BlCa. Methylation levels of candidate genes were quantified in 4 BlCa cell lines, 50 BlCa tissues, 20 normal bladder mucosas (NBM), and urine sediments from 51 BlCa patients and 20 healthy donors, 19 renal cancer patients, and 20 prostate cancer patients.

Germline and somatic NF1 mutations in sporadic and NF1-associated malignant peripheral nerve sheath tumours.

Malignant peripheral nerve sheath tumours (MPNSTs) are a malignancy occurring with increased frequency in patients with neurofibromatosis type 1 (NF1). In contrast to the well-known spectrum of germline NF1 mutations, the information on somatic mutations in MPNSTs is limited. In this study, we screened NF1, KRAS, and BRAF in 47 MPNSTs from patients with (n = 25) and without (n = 22) NF1.