Ana M. Muñoz-Mármol

Immunohistochemical detection of MYC protein correlates with MYC gene status in aggressive B cell lymphomas

Tapia G, Lopez R, Muñoz‐Mármol A M, Mate J L, Sanz C, Marginet R, Navarro J‐T, Ribera J‐M & Ariza A 
(2011) Histopathology59, 672–678

MYC status determination in aggressive B-cell lymphoma: the impact of FISH probe selection

To assess how hybridization probe design may affect MYC status determination in Burkitt lymphoma and diffuse large B‐cell lymphoma.

Rarity of JC virus DNA sequences and early proteins in human gliomas and medulloblastomas: the controversial role of JC virus in human neurooncogenesis

JC virus (JCV), the agent of progressive multifocal leucoencephalopathy (PML), exerts an oncogenic effect in several laboratory animal models. Moreover, JCV genomic DNA and early viral protein T‐antigen have been detected in various types of human central nervous system (CNS) neoplasms. To further explore this association we have studied paraffin‐embedded brain biopsy tissue from 60 neoplasms (55 gliomas and five medulloblastomas) and 15 reactive gliosis cases for the presence of JCV DNA sequences and proteins. Four post mortem cases of HIV‐associated PML were used as positive controls. Samples were assessed by polymerase chain reaction (PCR) amplification of early (large T antigen) and late (virion protein 3) sequences and immunohistochemistry (IHC) with both PAb 2024 and anti‐SV40 large T antigen monoclonal antibodies. Five cases (three neoplasms and two reactive gliosis instances) showed low viral DNA levels when PCR‐tested for VP3 or large T, while no case was immunoreactive for any of the two antibodies used. The four PML cases yielded positive results with both PCR and IHC. Additionally, IHC with both antibodies was applied to a tissue micro‐array including 109 CNS tumours and 21 reactive gliosis samples. No immunoreactivity was detected in any of these tissue micro‐array samples. The rarity of JCV DNA sequences and early proteins in our brain tumours enriches the controversy over the role of JCV in human neurooncogenesis, whose clarification is in need of further molecular and epidemiologic studies.

New brain-specific beta-synuclein isoforms show expression ratio changes in Lewy body diseases

Lewy body diseases (LBDs) include dementia with Lewy bodies (DLB) and Parkinson disease (PD). Alpha-synuclein (AS) aggregation is a key event in the pathogenesis of LBDs and beta-synuclein (BS) inhibits AS aggregation in vitro and in vivo. Recently, BS has been shown to interact directly with AS regulating its functionality and preventing its oligomerization, and a molecular subgroup of pure DLB lacks BS in cortical regions. In this study, we characterized four new BS transcript variants and analyzed their expression in neuronal and non-neuronal tissue, and their differential expression in frozen samples of three areas from brains of patients with pure Lewy body pathology (LBP), common LBP, Alzheimer pathology, and of controls. Relative mRNA expression was determined by real-time PCR with neuron-specific enolase 2 and synaptophysin as housekeeping genes, and expression changes were evaluated by the ΔΔCt method. Two main findings are in concordance with earlier studies. First, all BS isoforms are drastically diminished in the cortex of patients with pure LBP that had presented clinically as DLB but not PD with dementia. Second, an important shift of the isoform expression ratio was observed in the temporal cortex of all LBD cases, and the minor isoforms, normally absent in the midbrain, were detected in the caudate nucleus of all DLB samples. Our results provide further evidence for the role of minor transcript variants in the development of complex diseases and provide new insights into the pathogenesis of LBDs that may be important for the understanding of molecular mechanisms involved in these complex diseases.

Mismatch repair protein immunohistochemistry: a useful population screening strategy for Lynch syndrome.

Lynch syndrome (LS), the most frequent form of hereditary colorectal cancer, shows a highly penetrant, autosomal dominant pattern of inheritance. Distinction of LS colorectal carcinoma instances from the much more common sporadic colorectal carcinoma cases is of paramount importance. Revised Bethesda Guidelines were developed to diagnose LS by evaluating a combination of clinical and pathologic data. The aim of the present study was to evaluate the usefulness of the pathology items included in the Revised Bethesda Guidelines. We have prospectively studied a series of 1624 consecutive colorectal carcinomas with an algorithm including immunohistochemical analysis of mismatch repair proteins and molecular study of microsatellite instability and BRAF c.1799 T > A (p.V600E) gene mutations. Patients with tumors showing LS features were referred for germline mutation analysis. By applying our algorithmic approach, we were able to identify LS features in 89 colorectal cancer patients, of whom only 27 met Revised Bethesda Guidelines pathology criteria. Of the 89 patients, 47 were then studied at the Genetic Counseling Unit, and LS was confirmed in 18, of whom 7 had not been identified by the Revised Bethesda Guidelines. Our study shows that the Revised Bethesda Guidelines failed to detect 70% of patients at risk of LS. Our algorithmic approach is a realistic and effective tool for LS identification. We strongly recommend the implementation of universal population screening for LS among all patients with newly diagnosed colorectal carcinoma.

Improved clonality detection in Hodgkin lymphoma using the BIOMED-2-based heavy and kappa chain assay: a paraffin-embedded tissue study

Tapia G, Sanz C, Mate J L, Muñoz‐Mármol A M & Ariza A 
(2012) Histopathology 60, 768–773
Improved clonality detection in Hodgkin lymphoma using the BIOMED‐2‐based heavy and kappa chain assay: a paraffin‐embedded tissue study

ROS1 copy number alterations are frequent in non-small cell lung cancer

Objectives We aimed to determine the prevalence and partners of ROS1 rearrangements, to explore the correlation between FISH and IHC assays, and to investigate clinical implications of ROS1 copy number alterations (CNAs). Methods A total of 314 NSCLC patients were screened using ROS1 FISH break-apart probes. Of these, 47 surgical tumors were included in TMAs to analyze ROS1 heterogeneity assessed either by FISH and IHC, and chromosome 6 aneusomy. To characterize ROS1 partners, probes for CD74, EZR, SLC34A2 and SDC3 genes were developed. ROS1 positive FISH cases were screened also by IHC. Results Five patients were ROS1 positive (1.8%). We identified two known fusion partners in three patients: CD74 and SLC34A2. Four out of five ROS1 rearranged patients were female, never smokers and with adenocarcinoma histology. Rearranged cases were also positive by IHC as well. According to ROS1 CNAs, we found a prevalence of 37.8% gains/amplifications and 25.1% deletions. Conclusions This study point out the high prevalence of ROS1 CNAs in a large series of NSCLC. ROS1 gains, amplifications and deletions, most of them due to chromosome 6 polysomy or monosomy, were heterogeneous within a tumor and had no impact on overall survival.

Cystatin C is differentially involved in multiple system atrophy phenotypes

As cystatin C (CysC) is involved in some forms of neurodegeneration, we investigated the possible relationship between CysC and multiple system atrophy (MSA), including its parkinsonian (MSAp) and cerebellar (MSAc) phenotypes.