Paediatric diffuse leptomeningeal tumor with glial and neuronal differentiation harbouring chromosome 1p/19q co-deletion and <Emphasis Type="Italic">H3.3 K27M</Emphasis> mutation: unusual molecular profile and its therapeutic implications

Diffuse leptomeningeal glioneuronal tumor (DL-GNT) is a newly introduced tumor entity of uncertain prognosis characterised by a primary diffuse leptomeningeal growth pattern, oligodendroglial-like morphology and dual glial/neuronal differentiation. Predominantly occurring in children, these tumors present as chronic meningitis and mimic infectious/inflammatory diseases. They are surgically challenging tumors with a high incidence of delayed morbidity and mortality despite low-grade histology. Their molecular genetic profile is not fully elucidated and few reports have identified chromosome 1p and 19q deletions, and BRAF alterations. We present a rare instance of a DL-GNT in a 13-year-old female who presented with slowly progressive and sequential neurological deficits over a 12-month duration. Imaging showed leptomeningeal thickening and spinal lesions. Biopsy from the spinal mass showed histomorphological features characteristic of DL-GNT. Further molecular analysis revealed 1p and 19q co-deletion and H3K27M mutation, while no mutation were identified in IDH, TERT, or BRAF genes. Patient died 4 months after diagnosis. Only one previous case of DL-GNT has been reported to harbour H3K27M mutation. Although H3K27M mutations have been described in rare examples of low-grade glial and glioneuronal tumors, whether DL-GNTs with H3K27M represent a rare growth pattern of the aggressive H3K27M-mutant diffuse midline gliomas needs further clarification.     

ATRX status correlates with 11 C-methionine uptake in WHO grade II and III gliomas with <Emphasis Type="Italic">IDH1</Emphasis> mutations

Recent studies on gliomas have shown frequent alterations in the alpha-thalassemia/mental retardation syndrome X-linked gene (ATRX). This study was designed to determine whether ATRX status correlates with uptake of ¹¹C-methionine in WHO grades II and III gliomas. Sixty-two patients underwent ¹¹C-methionine positron emission tomography scans prior to histological diagnosis. The tumor-to-normal ratio (T/N) of ¹¹C-methionine uptake was calculated by dividing the maximum standardized uptake value (SUV) for the tumor by the mean SUV of the normal brain. After surgery, tumor samples were subjected to immunohistochemistry for ATRX and IDH1-R132H followed by IDH1/2 sequencing. Twenty-seven of the sixty-two patients were found to have the IDH mutation. Nine of the twenty-seven gliomas harboring IDH mutations exhibited loss of nuclear ATRX expression, which is accompanied with an astrocytic tumor lineage and a poor prognosis. The mean T/N ratio in tumors with loss of nuclear ATRX expression was 2.20?±?0.53, i.e., significantly lower than that of tumors with ATRX retention (3.28?±?1.32, p?=?0.0171, U test). Our study showed ATRX status to correlate with the T/N ratio and the outcomes of WHO grade II and III glioma patients with the IDH1 mutation. Our data provide new information on the biology and imaging characteristics of gliomas.     

Diagnostic revision of 206 adult gliomas (including 40 oligoastrocytomas) based on ATRX,IDH1/2 and 1p/19q status

The diagnosis of 206 low and high grade adult gliomas, including 40 oligoastrocytomas, was revised based on the immunohistochemical reactivity for the ATRX protein, IDH1/2 mutation status and 1p/19q chromosomal status. All oligodendrogliomas kept the initial diagnosis. Astrocytomas did not change diagnosis in 30 of 36 cases (83.3?%); four of 36 (11.1?%) cases were reclassified as oligodendroglioma, one (2.8?%) as DNT and the other (2.8?%) as reactive gliosis. Oligoastrocytomas changed diagnosis in 35 of 40 (87.5?%) cases, being reclassified 22 of 40 (55?%) as astrocytoma, 11 of 40 (27.5?%) as oligodendroglioma and two of 40 (5?%) as reactive gliosis. Four (10?%) remained unclassifiable. In one case only (2.5?%), the diagnosis of oligoastrocytoma could not be excluded since tumor astrocytes and tumor oligodendrocytes coexisted in mixed tumor areas. In the GBM tumor subgroup, GBMO disappeared because they were not substantiated by molecular genetics. Pilocytic astrocytomas retained ATRX expression. Loss of nuclear ATRX protein expression was strongly associated to IDH1/2 mutations (p?=?0.0001) and mutually exclusive with total 1p/19q co-deletion (p?=?0.0001). In astrocytic tumors, loss of immunoreactivity for the ATRX protein was significantly associated to the ALT phenotype (p?=?0.0003). The constitutive ATRX expression in microglia/macrophages may be misleading, especially in the identification of an oligodendroglial tumor infiltration. Of paramount importance in the recognition of oligodendroglial and astrocytic tumor cells were the double immunostainings for ATRX/GFAP, ATRX/IDH1^R132H, ATRX/Iba-1 and ATRX/CD68.     

<Emphasis Type="Italic">IDH1</Emphasis> or -<Emphasis Type="Italic">2</Emphasis> mutations do not predict outcome and do not cause loss of 5-hydroxymethylcytosine or altered histone modifications in central chondrosarcomas

Background

Mutations in isocitrate dehydrogenase (IDH)1 or -2 are found in ~50% of conventional central chondrosarcomas and in up to 87% of their assumed benign precursors enchondromas. The mutant enzyme acquires the activity to convert α-ketoglutarate into the oncometabolite d-2-hydroxyglutarate (d-2-HG), which competitively inhibits α-ketoglutarate dependent enzymes such as histone- and DNA demethylases.

Methods

We therefore evaluated the effect of IDH1 or -2 mutations on histone modifications (H3K4me3, H3K9me3 and H3K27me3), chromatin remodeler ATRX expression, DNA modifications (5-hmC and 5-mC), and TET1 subcellular localization in a genotyped cohort (IDH, succinate dehydrogenase (SDH) and fumarate hydratase (FH)) of enchondromas and central chondrosarcomas (n = 101) using immunohistochemistry.

Results

IDH1 or -2 mutations were found in 60.8% of the central cartilaginous tumours, while mutations in FH and SDH were absent. The mutation status did not correlate with outcome. Chondrosarcomas are strongly positive for the histone modifications H3K4me3, H3K9me3 and H3K27me3, which was independent of the IDH1 or -2 mutation status. Two out of 36 chondrosarcomas (5.6%) show complete loss of ATRX. Levels of 5-hmC and 5-mC are highly variable in central cartilaginous tumours and are not associated with mutation status. In tumours with loss of 5-hmC, expression of TET1 was more prominent in the cytoplasm than the nucleus (p = 0.0001).

Conclusions

In summary, in central chondrosarcoma IDH1 or -2 mutations do not affect immunohistochemical levels of 5-hmC, 5mC, trimethylation of H3K4, -K9 and K27 and outcome, as compared to wildtype.

     

High incidence of <Emphasis Type="Italic">TERT</Emphasis> mutation in brain tumor cell lines

TERT promoter gene mutations are highly recurrent in malignant glioma. However, little information exists regarding their presence in experimental brain tumor models. To better characterize systems in which TERT mutation studies could be appropriately modeled experimentally, the TERT promoter was examined by conventional sequencing in primary brain tumor initiating cells (BTIC), two matched recurrent BTIC lines, a panel of established malignant glioma cell lines, and two meningioma cell lines. Telomerase gene expression was examined by quantitative PCR. We found that all glioblastoma BTIC lines harbored a TERT mutation, which was retained in two patient-matched recurrent BTIC. The TERT C228T or C250T mutation was found in 33/35 (94 %) of established malignant glioma cell lines and both meningioma cell lines examined. Brain tumor cell lines expressed variably high telomerase levels. Thus, a high percentage of glioma cell lines, as well as two meningioma cell lines, harbors TERT mutations. These data characterize tractable, accessible models with which to further explore telomerase biology in these tumor types.     

Enchondromatosis-associated oligodendroglioma: case report and literature review

Enchondromatosis is a rare skeletal disorder characterized by the development of multiple enchondromas, which can also manifest non-cartilage tumors including gliomas. Here, we describe a genetic analysis of a low-grade glioma that developed in an enchondromatosis case. A 32-year-old man with a long history of enchondromatosis developed a left frontal tumor. The histopathological findings of his surgical specimen revealed characteristics of a low-grade glioma with an IDH1 c.395G>A (R132H) mutation and 1p/19q codeletion, which led to a definitive diagnosis of oligodendroglioma. A common point mutation in IDH1 (R132H) was detected in the patient’s enchondroma and glioma-matched pair specimens. To the best of our knowledge, this is the first case of molecularly confirmed oligodendroglioma associated with enchondromatosis. Furthermore, identification of a common IDH1 mutation in enchondroma and oligodendroglioma-matched pair specimens supports the hypothesis that IDH1/2 mosaicism initiates tumorigenesis.     

Molecular subtypes in early colorectal cancer associated with clinical features and patient prognosis

Purpose

After surgical resection, an ample prognosis variability among stages is observed. Multiple prognostic factors are individually studied and some CRC classifiers have been proposed. Not one have been implemented into clinical practice.

Methods/patients

We classified 105 patients with resected CRC (stage I–III) into five molecular subtypes using BRAF^V600E and RAS (KRAS; NRAS) status, and the expression of DNA mismatch repair (MMR) proteins (MLH1 and MSH2). Clinicopathological features and DFS) of distincts groups were evaluated.

Results and conclusions

RAS and BRAF^V600E mutations were detected in 43.8 and 11.4% of patients, respectively. 19% of tumours had lack of expression of any MMR proteins reflecting a system deficiency (dMMR). Patients with any RAS mutation had lower DFS that patients with RAS wild type (wt) (40.23 vs 45.26 months; p value?=?0.035). Of a total of five molecular subtypes, three were MMR proficient (pMMR): RAS mutated (39%), BRAF^V600E mutated (6.7%) and RAS/BRAF^V600E wt (35.2%); and two were dMMR: BRAF^V600E mutated (4.8%) and BRAF^V600E wt (14.3%). Left side tumours were more frequently observed in pMMR/RAS and BRAF^V600E wt subtype, and right side tumours in dMMR subtypes. Among the three pMMR subtypes, a benefit survival was observed for patients without any mutation in BRAF^v600E or RAS oncogenes (median of DFS?=?45.5 vs 40.98 months in RAS mutated group; p?=?0.084 and vs 34.13 in BRAF^v600E mutated group; p?=?0.031). Molecular classification using these biomarkers can be useful to identify groups with differences in prognosis.

     

Assessment of molecular markers demonstrates concordance between samples acquired via stereotactic biopsy and open craniotomy in both anaplastic astrocytomas and glioblastomas

The classification, treatment and prognosis of high-grade gliomas has been shown to correlate with the expression of molecular markers (e.g. MGMT promotor methylation and IDH1 mutations). Acquisition of tumor samples may be obtained via stereotactic biopsy or open craniotomy. Between the years 2009 and 2013, 22 patients initially diagnosed with HGGs via stereotactic biopsy, that ultimately underwent open craniotomy for resection of their tumor were prospectively included in an institutional glioma database. MGMT promotor analysis was performed using methylation-specific (MS)-PCR and IDH1R132H mutation analysis was performed using immunohistochemistry. Three patients (13.7%) exhibited IDH1R132H mutations in samples obtained via stereotactic biopsy. Tissue derived from stereotaxic biopsy was demonstrated to have MGMT promotor methylation in ten patients (45.5%), while a non-methylated MGMT promotor was demonstrated in ten patients (45.5%); inconclusive results were obtained for the remaining two patients (9%) within our cohort. The initial histologic grading, IDH1R132H mutation and MGMT promotor methylation results were confirmed using samples obtained during open craniotomy in all but one patient; here inconclusive MGMT promotor analysis was obtained in contrast to that which was obtained via stereotactic biopsy. Tumor samples acquired via stereotactic biopsy provide accurate information with regard to clinically relevant molecular markers that have been shown to impact patient care decisions. The profile of markers analyzed in our cohort was nearly concordant between those samples obtained via stereotactic biopsy or open craniotomy thereby suggesting that clinical decisions may be based on the molecular profile of the tumor samples obtained via stereotactic biopsy.     

The impact of melanoma genetics on treatment response and resistance in clinical and experimental studies

Recent attempts to characterize the melanoma mutational landscape using high-throughput sequencing technologies have identified new genes and pathways involved in the molecular pathogenesis of melanoma. Apart from mutated BRAF, NRAS, and KIT, a series of new recurrently mutated candidate genes with impact on signaling pathways have been identified such as NF1, PTEN, IDH1, RAC1, ARID2, and TP53. Under targeted treatment using BRAF and MEK1/2 inhibitors either alone or in combination, a majority of patients experience recurrences, which are due to different genetic mechanisms such as gene amplifications of BRAF or NRAS, MEK1/2 and PI3K mutations. In principle, resistance mechanisms converge on two signaling pathways, MAPK and PI3K-AKT-mTOR pathways. Resistance may be due to small subsets of resistant cells within a heterogeneous tumor mass not identified by sequencing of the bulk tumor. Future sequencing studies addressing tumor heterogeneity, e.g., by using single-cell sequencing technology, will most likely improve this situation. Gene expression patterns of metastatic lesions were also shown to predict treatment response, e.g., a MITF-low/NF-κB-high melanoma phenotype is resistant against classical targeted therapies. Finally, more recent treatment approaches using checkpoint inhibitors directed against PD-1 and CTLA-4 are very effective in melanoma and other tumor entities. Here, the mutational and neoantigen load of melanoma lesions may help to predict treatment response. Taken together, the new sequencing, molecular, and bioinformatic technologies exploiting the melanoma genome for treatment decisions have significantly improved our understanding of melanoma pathogenesis, treatment response, and resistance for either targeted treatment or immune checkpoint blockade.     

A case report of adult cerebellar high-grade glioma with H3.1 K27M mutation: a rare example of an H3 K27M mutant cerebellar tumor

Diffuse midline glioma, H3 K27M mutant, is newly recognized as a distinct category, which usually arises in the brain stem, thalamus or spinal cord of children, and young adults. The oncogenic H3 K27M mutation involves H3.3 (encoded by H3F3A) or H3.1 (encoded by HIST1H3B/HIST1H3C), and the incidence of each mutation differs among the primary sites. Recently, several papers have reported that cerebellar high-grade gliomas in both children and adults also harbor H3 K27 mutation. With the exception of one pediatric case, all of the cases carried the mutation in H3.3. We herein present the case of an adult cerebellar high-grade astrocytic tumor with H3.1 K27M mutation in a 45-year-old man, which also involvedTP53 mutation and was immunonegative for ATRX. Some groups have reported that H3.3 and H3.1 K27M mutations define subgroups of diffuse intrinsic pontine gliomas (DIPGs) with different phenotypes as well as genetic alterations. On comparing the findings of the present case, particularly TP53 mutation status and ATRX expression, to the findings of the previous studies on DIPGs, our case seems unusual among the H3.1 K27M mutant subgroup. Further studies are needed to clarify the exact frequency, clinicopathological characteristics, and genomic alterations of cerebellar gliomas harboring H3 K27M mutation.     

A novel high-sensitivity assay to detect a small fraction of mutant <Emphasis Type="Italic">IDH1</Emphasis> using droplet digital PCR

Detection of mutations in the isocitrate dehydrogenase 1 (IDH1) gene is useful for accurate diagnosis of lower grade gliomas, as described in the 2016 World Health Organization classification of tumors of the central nervous system. Conventional analysis tools, including Sanger DNA sequencing and immunohistochemistry, might fail to detect a small fraction of mutant IDH1 owing to their limited sensitivity. Considering that lower grade gliomas are infiltrative in nature, a highly sensitive detection assay for IDH1 mutation is required for their accurate diagnosis. In this study, we successfully established a droplet digital PCR (ddPCR) system to detect a small fraction of IDH1 mutation. We could detect 0.05% of mutant IDH1 allele in 30 ng DNA. Using this assay, we could detect a small fraction of mutant IDH1 in a glioma case, identified as a wildtype tumor according to the conventional assays. Additionally, in a small amount of DNA derived from the cerebrospinal fluid, we could detect an IDH1 mutation. In conclusion, the ddPCR system is useful to identify a small fraction of IDH1 mutation in diffuse infiltrative gliomas. This might be useful for precision medicine of these gliomas in the near future and also for the non-invasive diagnosis of these gliomas.     

Characteristics and outcomes of elderly patients with diffuse gliomas: a multi-institutional cohort study by Kansai Molecular Diagnosis Network for CNS Tumors

Introduction

This study investigates the current state of clinical practice and molecular analysis for elderly patients with diffuse gliomas and aims to elucidate treatment outcomes and prognostic factors of patients with glioblastomas.

Methods

We collected elderly cases (≥?70 years) diagnosed with primary diffuse gliomas and enrolled in Kansai Molecular Diagnosis Network for CNS Tumors. Clinical and pathological characteristics were analyzed retrospectively. Various factors were evaluated in univariate and multivariate models to examine their effects on overall survival.

Results

Included in the study were 140 elderly patients (WHO grade II: 7, III: 19, IV: 114), median age was 75 years. Sixty-seven patients (47.9%) had preoperative Karnofsky Performance Status score of ≥?80. All patients underwent resection (gross-total: 20.0%, subtotal: 14.3%, partial: 39.3%, biopsy: 26.4%). Ninety-six of the patients (68.6%) received adjuvant treatment consisting of radiotherapy (RT) with temozolomide (TMZ). Seventy-eight of the patients (75.0%) received radiation dose of ≥?50 Gy. MGMT promoter was methylated in 68 tumors (48.6%), IDH1/2 was wild-type in 129 tumors (92.1%), and TERT promoter was mutated in 78 of 128 tumors (60.9%). Median progression-free and overall survival of grade IV cases was 8.2 and 13.6 months, respectively. Higher age (≥?80 years) and TERT promoter mutated were associated with shorter survival. Resection and adjuvant RT?+?TMZ were identified as independent factors for good prognosis.

Conclusions

This community-based study reveals characteristics and outcomes of elderly glioma patients in a real-world setting. Elderly patients have several potential factors for poor prognosis, but resection followed by RT?+?TMZ could lengthen duration of survival.

     

Reclassification of 400 consecutive glioma cases based on the revised 2016WHO classification

In this study, we reclassified 400 consecutive glioma cases including pediatric cases, using the revised 2016 WHO classification with samples collected from the Kyushu University Brain Tumor Bank. The IDH1/2, H3F3A, key genetic markers in the 2016 classification, were analyzed using high-resolution melting, with DNA extracted from frozen tissues. The 1p/19q codeletions were evaluated using a microsatellite-based loss of heterozygosity analysis, with 18 markers, to detect loss of the entire chromosome arm. In the integrated diagnosis, 29 oligodendroglioma cases and 28 anaplastic oligodendroglioma cases were diagnosed as “IDH-mutant and 1p/19q-codeleted,” while 2 oligodendroglioma cases and 5 anaplastic oligodendroglioma cases were diagnosed as not otherwise specified (NOS). These “NOS” cases were either IDH-mutants or 1p/19q-codeleted, although characteristic oligodendroglial features were evident histologically. Better overall survival of patients with oligodendroglioma correlated with the molecular characteristic of “IDH-mutant and 1p/19q-codeleted,” rather than the WHO grade. Eleven “glioblastoma, IDH-wild-type” cases were classified as “1p/19q-codeleted”, however, chromosome 10 loss was also detected in 10 out of 11 cases. The 2016 WHO criteria for glioma classification leads to better diagnosis of patients. However, there are technical pitfalls and problems to be solved in the molecular analysis of routine diagnostics.     

The Prognostic Influence of BRAF Mutation and other Molecular,Clinical and Laboratory Parameters in Stage IV Colorectal Cancer

Our aim was to evaluate the predictive and prognostic influence of BRAF mutation and other molecular, clinical and laboratory parameters in stage IV colorectal cancer (CRC). 60 patients were included in this retrospective analysis, and 17 variables were examined for their relation with treatment response and survival. KRAS mutation was identified in 40.3 % of cases, BRAF and PIK3CA in 8.8 % and 10.5 % respectively. 29.8 % of patients responded to treatment. Median survival time was 14.3 months. Weight loss, fever, abdominal metastases, blood transfusion, hypoalbuminaimia, BRAF and PIK3CA mutations, CRP and DNA Index were associated with survival. In multivariate analysis, male patients had 3.8 times higher probability of response, increased DNA Index was inversely correlated with response and one unit raise of DNA Index augmented 6 times the probability of death. Our findings potentiate the prognostic role of BRAF, PIK3CA mutations and ploidy in advanced CRC.     

Detection of the alternative lengthening of telomeres pathway in malignant gliomas for improved molecular diagnosis

Human malignant gliomas exhibit acquisition of either one of two telomere maintenance mechanisms, resulting from either reactivation of telomerase expression or activation of an alternative lengthening of telomeres (ALT) mechanism. In the present study, we analyzed 63 human malignant gliomas for the presence of ALT-specific extrachromosomal circles of telomeric DNA (C-circles) and measured telomerase expression, telomeric DNA content (Telo/Alu method), and telomeric repeat-containing RNAs (TERRA) levels. We also assessed histomolecular markers routinely used in clinical practice. The presence of C-circles significantly correlated with IDH1/2 mutation, MGMT exon 1 methylation, low Ki-67 immunostaining, increased telomeric DNA content, absence of functional ATRX protein and level of HTERT gene expression. In multivariate analysis, we observed a trend to a correlation between elevated TERRA levels and increased survival. Interestingly, the C-circles assay allowed to detect ALT activation in glioblastomas exhibiting wild-type IDH1/2 and ATRX expression. These results suggest that, after the correlations uncovered here have been confirmed on larger numbers of tumors, telomeric markers might be useful in improving diagnosis. They also point out to the utility of using the specific, sensitive and quantitative C-circle and Telo/Alu assays that can work with as few as 30 ng of tumor DNA.     

Prognostication in Philadelphia Chromosome Negative Myeloproliferative Neoplasms: a Review of the Recent Literature

Purpose of Review

The prognosis for patients with Philadelphia chromosome (Ph)-negative myeloproliferative neoplasms (MPNs) is highly variable. All Ph-negative MPNs carry an increased risk for thrombotic complications, bleeding, and leukemic transformation. Several clinical, biological, and molecular prognostic factors have been identified in recent years, which provide important information in guiding management of patients with Ph-negative MPNs. In this review, we critically evaluate the recent published literature and discuss important new developments in clinical and molecular factors that impact survival, disease transformation, and thrombosis in patients with polycythemia vera, essential thrombocythemia, and primary myelofibrosis.

Recent Findings

Recent studies have identified several clinical factors and non-driver mutations to have prognostic impact on Ph-negative MPNs independent of conventional risk stratification and prognostic models. In polycythemia vera (PV), leukocytosis, abnormal karyotype, phlebotomy requirement on hydroxyurea, increased bone marrow fibrosis, and mutations in ASXL1, SRSF2, and IDH2 were identified as additional adverse prognostic factors. In essential thrombocythemia (ET), JAK2 V617F mutation, splenomegaly, and mutations in SH2B3, SF3B1, U2AF1, TP53, IDH2, and EZH2 were found to be additional negative prognostic factors. Bone marrow fibrosis and mutations in ASXL1, SRSF2, EZH2, and IDH1/2 have been found to be additional prognostic factors in primary myelofibrosis (PMF). CALR mutations appear to be a favorable prognostic factor in PMF, which has not been clearly demonstrated in ET.

Summary

The prognosis for patients with PV, ET, and PMF is dependent upon the presence or absence of several clinical, biological, and molecular risk factors. The significance of additional risk factors identified in these recent studies will need further validation in prospective studies to determine how they may be best utilized in the management of these disorders.

     

<Emphasis Type="Italic">BRAF</Emphasis> mutation may have different prognostic implications in early- and late-stage colorectal cancer

The prognostic implication of BRAF mutant colorectal cancer remains paradoxical. Records of BRAF mutant and wild-type colorectal cancer patients at all stages were reviewed. Clinicopathologic features, including microsatellite instability, CpG islands methylator phenotype, and overall survival, of these patients were analyzed. Between 2005 and 2013, 428 colorectal cancer patients were enrolled in this study. The overall survival between BRAF mutant and wild-type patients with early-stage (stages I and II) colorectal cancer differed nonsignificantly (P = 0.99). By contrast, in late-stage (stages III and IV) patients, the median overall survival of BRAF mutant patients (N = 25) was significantly poorer than that of BRAF wild-type (N = 207) patients (BRAF mutant: 21.3 months (95 % confidence interval [CI] 7.1–35.5); BRAF wild-type: 53.5 months (95 % CI 37.5–69.5), P < 0.0001). In early-stage patients, we found that BRAF mutation was significantly associated with CpG island methylator phenotype-positive (P < 0.001), and microsatellite instability-high status (P = 0.0013). Conversely, in late-stage patients, BRAF mutation was significantly associated with CpG island methylator phenotype-positive (P = 0.0015) and the right-side colon (P = 0.014). BRAF mutation may have different prognostic implications in early- and late-stage colorectal cancer.     

Correlations of IGF-1R and COX-2 Expressions with <Emphasis Type="Italic">Ras</Emphasis> and <Emphasis Type="Italic">BRAF</Emphasis> Genetic Mutations,Clinicopathological Features and Prognosis of Colorectal Cancer Patients

This case-control study aims to investigate the correlations of insulin-like growth factor receptor 1 (IGF-1R) and cyclooxygenase 2 (COX-2) expressions with Ras and BRAF genetic mutations, clinicopathological features and prognosis of colorectal cancer (CRC) patients. A total of 213 CRC patients (case group) and 200 healthy individuals (control group) were selected from our hospital. Ras (K-Ras/N-Ras) and BRAF genetic mutations were detected by direct sequencing. The positive expression rates of IGF-IR and COX-2 in CRC and normal tissues were detected using immunohistochemistry. RT-qPCR and Western blotting were applied to detect the mRNA and protein expressions of IGF-IR and COX-2 in CRC tissues and normal tissues. Total mutation rate of N-Ras, BRAF and K-Ras in case group were 5.2%, 12.2% and 47.4%, respectively. The expressions of IGF-IR and COX-2 were higher in CRC tissues with Ras and BRAF mutations than in those without. CRC tissues with Ras mutation showed higher COX-2 expression than those with BRAF mutation. IGF-IR and COX-2 expressions were correlated to infiltration degree, lymphatic metastasis (in CRC tissues with and without Ras and BRAF mutations), and Dukes stages (only in CRC tissues with Ras and BRAF mutations). CRC patients with negative expressions of IGF-IR and COX-2 had significantly higher accumulative survival rate and longer mean survival duration than those with positive expressions of IGF-IR and COX-2. These findings indicate that IGF-1R and COX-2 expressions may be associated with Ras and BRAF genetic mutations, clinicopathological feature and prognosis of CRC patients.