Integrated multidisciplinary community service for chronic obstructive pulmonary disease reduces hospitalisations

BACKGROUND

Hospitalisations for chronic obstructive pulmonary disease (COPD) exacerbation affect patient outcomes and healthcare costs. The long-term impact of an integrated COPD disease-management approach on hospitalisation remains controversial.

AIM

The aim of this study was to evaluate whether a multidisciplinary community service reduces respiratory hospitalisations for COPD patients.

METHODS

A total of 346 patients was followed for a mean duration of 27.3 months. The number of admissions, total bed days for respiratory (COPD exacerbation or pneumonia) or general medical causes and length of stay (LOS) per respiratory admission was compared before and after referral with the service. A secondary multivariate analysis examined which clinical parameters best predict benefit from such service.

RESULTS

The total respiratory admission and hospital bed days after referral were reduced by 31% (288 vs 417, P < 0.001) and 40.4% (1637 vs 2746, P < 0.0001) respectively, compared with the equivalent duration prior. The average LOS for each respiratory admission was also significantly reduced after referral (6.61 vs 5.70, P = 0.02). Overall, 55% patients experienced a reduction in admission frequency and hospital days. The impact on admission frequency and hospital days was the greatest in those with an at least moderate disease (GOLD ≥2, odds ratio (OR): 3.2, 95% confidence interval (CI): 1.2, 8.9; P = 0.019) and those who completed pulmonary rehabilitation (PR) (OR: 1.7, 95% CI: 1.1, 2.8; P = 0.04). In contrast, general medical admissions increased, one-third attributable to a cardiovascular cause both before and after referral.

CONCLUSIONS

The implementation of COPD multidisciplinary community service was associated with reduced respiratory hospitalisations in the long term. Patients with moderate or severe disease and who are able to complete PR are much more likely to benefit.

Identification and characterization of ALK kinase splicing isoforms in non-small-cell lung cancer

INTRODUCTION

Anaplastic lymphoma kinase (ALK) rearrangements are present in an important subset of non-small-cell lung cancer (NSCLC) and predict for response to the tyrosine kinase inhibitor crizotinib. In this study, we evaluated the yet unknown frequency and functional role of ALK splicing isoforms in NSCLC.

METHODS

We analyzed 270 cases of NSCLC for ALK kinase domain splicing aberrations and in addition generated constructs with full-length echinoderm microtubule-associated protein-like 4 (EML4)-ALK (E13;A20) and a splicing isoform.

RESULTS

Splicing isoforms of the kinase domain of ALK-including complete skipping of exon 23 (ALKdel23, ALK p.I1171fs*42) and exon 27 (ALKdel27, ALK p.T1312fs*0)-were identified in 11.1% (30 of 270 cases) of NSCLC, and these changes coexisted with ALK rearrangements, KRAS mutations, and EGFR mutations. ALK splicing isoforms were observed with full-length EML4-ALK in crizotinib-naive and treated NSCLCs. ALK T1312fs*0 was unable to render cells solely dependent on ALK signaling. Unlike EML4-ALK and EML4-ALK p.L1196M, EML4-ALK T1312fs*0 did not autophosphorylate ALK or other phosphotyrosine sites. Coexpression of equal amounts of EML4-ALK T1312fs*0 and EML4-ALK did not result in resistance to crizotinib, whereas coexpression of EML4-ALK L1196M with EML4-ALK resulted in resistance to inhibition of ALK by crizotinib.

CONCLUSIONS

ALK kinase splicing isoforms were present in NSCLC and even if translated seemed to be nonfunctional variants of ALK.

Pharmacogenetics of β2 adrenergic receptor gene polymorphisms, long-acting β-agonists and asthma

Adrenergic β2 receptor (ADRβ2) agonists are widely used in asthma. Approximately 10% of patients have severe, poorly controlled disease despite extensive use of ADRβ2 agonists. Variations in responses to ADRβ2 agonists can, in part, be attributed to genetic variation, with 49 different polymorphisms having been identified for the ADRβ2 gene. Although clear associations exist between ADRβ2 gene polymorphisms, such as +46G>A, and patient response, the importance of these polymorphisms remains controversial. Patient selection, the number of polymorphisms analysed, differences in the type/dose of ADRβ2 agonist, use of inhaled corticosteroids and population sizes have all varied. Most studies were limited to mild or moderate asthmatics using ADRβ2 agonists sparingly. It is difficult to extrapolate from these studies to individual patients who have severe asthma, use a variety of ADRβ2 agonists and do so frequently. The extent to which ADRβ2 gene polymorphisms are relevant to asthma management needs further review, both clinically and at the molecular level. In vitro studies have helped to define the functional changes induced by specific ADRβ2 gene polymorphisms, including 3'-untranslated region poly-C repeat. The resulting ADRβ2 gene haplotypes (rather than genotypes), the interactions among ADRβ2 gene haplotypes and variations in the chemistry of different agonists deserve more detailed assessment. Responses to ADRβ2 agonists depend on effective downstream signalling following ADRβ2 activation and also on receptor regulation. Studies on other regulators of ADRβ2 receptor signalling and trafficking may be equally important in understanding the functional role of ADRβ2 gene polymorphisms. The role of ADRβ2 gene polymorphisms in the pathogenesis and management of severe asthma cannot be clearly defined until more specific and targeted research studies are performed.

A novel KIF5B-ALK variant in nonsmall cell lung cancer

BACKGROUND

The anaplastic lymphoma kinase (ALK) gene is involved frequently in chromosomal translocations, resulting in fusion genes with different partners found in various lymphoproliferative conditions. It was recently reported in nonsmall cell lung cancer (NSCLC) that the fusion protein encoded by echinoderm microtubule-associated protein-like 4-ALK (EML4-ALK) fusion gene conferred oncogenic properties. The objective of the current study was to identify other possible ALK fusion genes in NSCLC.

METHODS

Immunohistochemical analysis was used to screen for aberrant ALK expression in primary NSCLC. The authors used 5' rapid amplification of complementary DNA ends to screen for potential, novel 5' fusion partners of ALK other than EML4-ALK. Reverse transcriptase-polymerase chain reaction and fluorescence in situ hybridization analyses were used to confirm the identity of 5' fusion partners. The genomic breakpoint was verified using genomic sequencing. Overexpression of the novel ALK fusion gene and variants 3a and 3b of EML4-ALK was performed to assess downstream signaling and functional effects.

RESULTS

The authors identified a novel gene resulting from the fusion of kinesin family member 5B (KIF5B) exon 15 to ALK exon 20 in a primary lung adenocarcinoma. Western blot analysis of clinical tumor tissues revealed the expression of a protein whose size correlated with that of the predicted KIF5B-ALK. Overexpression of KIF5B-ALK in mammalian cells led to the activation of signal transducer and activator of transcription 3 and protein kinase B and to enhanced cell proliferation, migration, and invasion.

CONCLUSIONS

The discovery of the novel KIF5B-ALK variant further consolidated the role of aberrant ALK signaling in lung carcinogenesis.

Double EGFR mutants containing rare EGFR mutant types show reduced in vitro response to gefitinib compared with common activating missense mutations

Epidermal growth factor receptor (EGFR) mutations are common in lung adenocarcinomas, especially from nonsmoking women of Asian descent. We have previously shown EGFR mutations occur in >70% of lung adenocarcinoma from nonsmokers in our population with a complex mutational profile, including 13% of EGFR double mutations. In this study, we investigated the in vitro gefitinib response of four EGFR double mutants identified in untreated patients, including Q787R+L858R, E709A+G719C, T790M+L858R, and H870R+L858R. The phosphorylation profiles of EGFR and downstream effectors AKT, STAT3/5, and ERK1/2 were compared by immunoblot analyses among the single and double mutants transfected into H358 cells. Results showed that mutants responded to in vitro gefitinib treatment with different sensitivities. The G719C and L858R single mutants showed the highest gefitinib sensitivity compared with the corresponding coexisting single mutants E709A, Q787R, H870R, and T790M. The double mutants E709A+G719C, Q787R+L858R, and H870R+L858R showed attenuated responses to gefitinib in the EGFR and downstream effector phosphorylation profiles compared with G719C or L858R alone. T790M+L858R showed strong resistance to gefitinib. Clinically, the patient whose tumor contained H870R+L858R showed tumor stabilization by 250 mg oral gefitinib daily but cerebral metastasis developed 6 months later. Correlation with the in vitro phosphorylation profile of H870R+L858R suggested that treatment failure was probably due to inadequate suppression of EGFR signaling by the drug level attainable in the cerebrospinal fluid at the given oral dosage. Overall, the findings suggested that rare types of EGFR substitution mutations could confer relative gefitinib resistance when combined with the common activating mutants.

The EML4-ALK fusion gene is involved in various histologic types of lung cancers from nonsmokers with wild-type EGFR and KRAS

BACKGROUND

The echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) fusion gene resulting from the chromosome inversion inv(2)(p21;p23) recently was identified in nonsmall cell lung cancer (NSCLC). The authors of this study investigated the frequency, genetic and clinicopathologic profiles of EML4-ALK in Chinese patients with NSCLC.

METHODS

EML4-ALK was investigated in 266 resected primary NSCLC, including adenocarcinomas (AD), lymphoepithelioma-like carcinomas, squamous cell carcinomas, mucoepidermoid carcinomas, and adenosquamous carcinomas, by reverse transcriptase-polymerase chain reaction and was verified by sequencing. EML4-ALK protein expression was studied by immunohistochemistry.

RESULTS

Thirteen tumors (4.9%) had EML4-ALK comprising 4 fusion transcript variants with fusion of the variable segments from 5' EML4 to 3' ALK and with preservation of the ALK kinase domain. The most common variant consisted of 8 tumors with variant 3 that involved EML4 exon 6. The others included 2 tumors with variant 1 (exon 13), 2 tumors with variant 2 (exon 20), and 1 tumor with the novel variant 5 (exon 18). There were 11 ADs and 2 unusual carcinomas with mixed squamous and glandular components. Immunohistochemistry demonstrated diffuse ALK fusion proteins in the tumor cell cytoplasm. EML4-ALK was associated with nonsmokers (P = .009). Tumors with the fusion gene had the wild-type epidermal growth factor receptor (EGFR) (P = .001) and v-Ki-ras2/Kirsten rat sarcoma viral oncogene homolog (KRAS) genes. Patients who had EML4-ALK-positive AD had a younger median age (P = .018) compared with patients who did not have the fusion gene.

CONCLUSIONS

The EML4-ALK fusion gene was present in various histologic types of NSCLC. It occurred in mutual exclusion to EGFR and KRAS mutations and was associated with nonsmokers. The authors concluded that EML4-ALK may be useful for predicting the potential response to ALK inhibitors as a therapeutic option for patients with lung cancer.

SRC promotes survival and invasion of lung cancers with epidermal growth factor receptor abnormalities and is a potential candidate for molecular-targeted therapy

Molecular-targeted therapy using tyrosine kinase inhibitors against epidermal growth factor receptor (EGFR) is an effective therapy for non-small cell lung cancer that harbor EGFR mutations. This study aimed to investigate the role of Src, a close EGFR associator, as a drug target in NSCLC cells with different EGFR genomic statuses. Src inhibition was achieved using 4-(4'-Phenoxyanilino)-6,7-dimethoxyquinazolinee (SKI-1) and the specificity of action was verified by RNA interference. The results showed that SKI-1 induced significant apoptosis in a dose-dependent manner in cancer cells with high basal Src activation. Activation of FAK and p130Cas was involved in Src-mediated invasion in SKI-1-sensitive cells. SKI-1 inhibited phosphorylation of EGFR as well as EGFR downstream effectors, such as signal transducers and activators of transcription 3/5, extracellular signal-regulated kinase 1/2 and AKT in the mutant cells but not the wild-type cells. This inhibition profile of EGFR implicates that induction of apoptosis and sensitivity of mutant cells to SKI treatment is mediated by EGFR and EGFR downstream pathways. Cotreatment with SKI-1 and gefitinib enhanced apoptosis in cancer cells that contained EGFR mutation and/or amplification. SKI-1 treatment alone induced significant apoptosis in H1975 cells known to be resistant to gefitinib. Src phosphorylation was shown by immunohistochemistry in around 30% of primary lung carcinomas. In 152 adenocarcinomas studied, p-Src was associated with EGFR mutations (P = 0.029). Overall, the findings indicated that Src could be a useful target for treatment of non-small cell lung cancer. Besides EGFR genomic mutations, other forms of EGFR and related family member abnormalities such as EGFR amplification might enhance SKI sensitivity.

Therapy-related lymphomas in patients with autoimmune diseases after treatment with disease-modifying anti-rheumatic drugs

Ten patients developing lymphomas after disease modifying anti-rheumatic drugs (DMARD) (methotrexate, n = 3, mean cumulative dose = 3.4 g; cyclophosphamide, n = 2, mean dose = 70 g; azathioprine, n = 6, mean dose = 243 g) were investigated. Methotrexate-related lymphomas were Epstein-Barr virus (EBV)-positive, had infrequent aberrant methylation of p15 and p16, and responded well to methotrexate withdrawal or anti-CD20 antibody (rituximab) alone without concomitant chemotherapy, implying that defective immunosurveillance was important in lymphomagenesis. However, 75% of cyclophosphamide/azathioprine-related lymphomas were EBV-negative, had frequent p15 and p16 methylation, and responded poorly to drug withdrawal and chemotherapy, implying that direct drug-induced mutagenesis might be involved in lymphomagenesis.

Worldwide genomic diversity of the high-risk human papillomavirus types 31, 35, 52, and 58, four close relatives of human papillomavirus type 16

Among the more than one hundred formally described human papillomavirus (HPV) types, 18 are referred to as high-risk HPV types due to their association with anogenital cancer. Despite pathogenic similarities, these types form three remotely related taxonomic groups. One of these groups is called HPV species 9 and is formed by HPV-16, the most common and best-studied type, together with HPV-31, -33, -35, -52, -58, and -67. Previous worldwide comparisons of HPV-16 samples showed about 2% nucleotide diversity between isolates, which were subsequently termed variants. The distribution of divergent variants has been found to correlate frequently with the geographic origin and the ethnicity of the infected patients and led to the concept of unique African, European, Asian, and Native American HPV-16 variants. In the current study, we address the question of whether geography and ethnicity also correlate with sequence variations found for HPV-31, -35, -52, and -58. This was done by sequencing the long control region in samples derived from Europe, Asia, and Africa, and from immigrant populations in North and South America. We observed maximal divergence between any two variants within each of these four HPV types ranging from 1.8 to 3.6% based on nucleotide exchanges and, occasionally, on insertions and deletions. Similar to the case with HPV-16, these mutations are not random but indicate a relationship between the variants in form of phylogenetic trees. An interesting example is presented by a 16-bp insert in select variants of HPV-35, which appears to have given rise to additional variants by nucleotide exchanges within the insert. All trees showed distinct phylogenetic topologies, ranging from dichotomic branching in the case of HPV-31 to star phylogenies of the other three types. No clear similarities between these types or between these types and HPV-16 exist. While variant branches in some types were specific for Europe, Africa, or East Asia, none of the four trees reflected human evolution and spread to the extent illustrated by HPV-16. One possible explanation is that the rare HPV types that we studied spread and thereby diversified more slowly than the more abundant HPV-16 and may have established much of today's variant diversity already before the worldwide spread of humans 100,000 years ago. Most variants had prototypic amino acid sequences within the E6 oncoprotein and a segment of the L1 capsid protein. Some had one, two, or three amino acid substitutions in these regions, which might indicate biological and pathogenic diversity between the variants of each HPV type.

Worldwide genomic diversity of the human papillomaviruses-53, 56, and 66, a group of high-risk HPVs unrelated to HPV-16 and HPV-18

Among more than 200 human papillomavirus (HPV) types presumed to exist, 18 "high-risk" HPV types are frequently found in anogenital cancer. The best studied types are HPV-16 and 18, which are only distantly related to one another and form two separate phylogenetic branches, each including six closely related types. HPV-30, 53, 56, and 66 form a third phylogenetic branch unrelated to HPV-16 and 18. Worldwide comparison of HPV-16 and 18 isolates revealed a distribution of variant genomes that correlated with the geographic origin and the ethnicity of the infected cohort and led to the concept of unique African, European, Asian, and Native American HPV-16 and 18 variants. Here, we address the question whether similar phylogenies are found for HPV-53, 56, and 66 by determining the sequence of the long control regions (LCR) of these HPVs in samples from Europe, Asia, and Africa, and from immigrant societies in North and South America. Phylogenetic trees calculated from point mutations and a few insertions/deletions affecting 2-4.2% of the nucleotide sequences were distinct for each of the three HPVs and divergent from HPV-16 and 18. In contrast to the "star-phylogenies" formed by HPV-16 and 18 variants, 44 HPV-53 isolates represented nine variants, which formed two deep dichotomic branches reminiscent of the beginning split into two new taxa, as recently observed for subtypes of HPV-44 and 68. A total of 66 HPV-56 isolates represented 17 variants, which formed three branches preferentially containing European, Asian, and African variants. Variants of a fourth branch, deeply separated from the other three, were characterized by a 25 bp insertion and created a dichotomy rather than star-like phylogeny. As it contained isolates from cohorts in all continents, it may have evolved before the spread of humans into all continents. 18 of 31 HPV-66 isolates represented the prototype clone, which was found in all parts of the world, while the remaining 13 clones formed 11 branches without any geographic association. Our findings confirm the notion of a quantitatively limited genomic diversity of each HPV type with some correlation to the geographic origin of the sample. In addition, we observed in some variants of these three HPV types mutations that affect the amino acid sequence of the E6 oncoproteins and the L1 capsid protein, supporting the possibility of immunogenic and oncogenic diversity between variants of any HPV type.

Papillomavirus subtypes are natural and old taxa: phylogeny of human papillomavirus types 44 and 55 and 68a and -b

A human papillomavirus (HPV) type is defined as an HPV isolate whose L1 gene sequence is at least 10% different from that of any other type, while a subtype is 2 to 10% different from any HPV type. In order to analyze the phylogeny behind the subtype definition, we compared 49 isolates of HPV type 44 (HPV-44) and its subtype HPV-55, previously misclassified as a separate type, and 41 isolates of the subtype pair HPV-68a and -b, sampled from cohorts in four continents. The subtypes of each pair are separated by deep dichotomic branching, and three of the four subtypes have evolved large phylogenetic clusters of genomic variants forming a "star" phylogeny, with some branches specific for ethnically defined cohorts. We conclude that subtypes of HPV types are natural and old taxa, equivalent to types, which either diverged more recently than types or evolved more slowly.

Transformation of diffuse large B-cell lymphoma into pre-B acute lymphoblastic leukemia: clinicopathologic features and clonal relationship

A patient with fibrosing alveolitis developed a diffuse large B-cell (DLBC) lymphoma that expressed CD20 and CD30. After an initial response, the lymphoma relapsed and was salvaged with further chemotherapy. After another remission of 3 years, a pre-B-cell acute lymphoblastic leukemia (ALL), which expressed CD10, CD19, CD22, CD79a, CD34 and terminal deoxyribonucleotidyl transferase, developed and led to death. Molecular analysis of the immunoglobulin heavy-chain gene showed that the initial lymphoma and its relapse were clonally related. At leukemic relapse, 2 clones related to the initial and relapsed lymphoma clones were present. DLBC lymphomas arise from post-follicle center B cells, whereas ALL arises from pregerminal B cells. Therefore, a direct transformation of DLBC lymphoma to ALL appears unlikely. The overall features suggest instead separate lymphoma and leukemic evolution from a common mutated B-cell precursor rather than transformation of DLBC lymphoma to ALL.

Primary B-cell lymphoma and lymphoma-like lesions of the uterine cervix

We present three patients with atypical lymphoid cells on cervical smear screening, with diffuse large-cell B-cell lymphoma diagnosed by morphology on cervical biopsy. One patient with extensive pelvic disease was treated with chemotherapy and radiotherapy and remained in remission 8 years later. Two patients with presumed stage 1E lesions showed spontaneous regression on repeat cervical biopsy, despite light chain restriction and clonal immunoglobulin gene rearrangement. They are without recurrent malignancy 1 and 5 years after their initial diagnosis. The presence of malignant looking lymphoid cells on cervical smear should be investigated by repeated colposcopic biopsies. The reason for the highly skewed atypical B-cell lymphoproliferation in lymphoma-like lesions of the cervix is unknown. With early stage, nonbulky cervical lymphoma in an otherwise healthy patient, a cone biopsy is advised. A number of these lesions may regress even when clonal populations are detected.

Chromosomal aberrations of primary lung adenocarcinomas in nonsmokers

BACKGROUND

Lung carcinoma is a common malignancy, and tobacco carcinogenesis is the major cause. Studies on individual genes or loci have suggested, that in tumors from nonsmokers, different genetic alterations are present compared with tumors from smokers. It is possible that distinct genetic pathways may be involved. However, the targets remain largely unknown; and, to the authors' knowledge, molecular cytogenetics studies on lung carcinomas from nonsmokers have not been reported.

METHODS

Comparative genomic hybridization (CGH) analysis was performed on primary lung adenocarcinoma samples from 32 patients who never smoked to identify loci of frequent aberrations.

RESULTS

Different extents of aberration were found in 31 of the 32 samples studied. The most frequently altered locus was gain of 16p (59% of samples) followed by gain of 20q (44% of samples), with the minimal overlapping regions at 16p13.1-p13.2 and 20q13.2, respectively. Other over-represented loci with > 30% frequency were observed at 5p (34% of samples), 7p (41% of samples), 8q (31% of samples), 17q (34% of samples), and 19q (34% of samples); and high-level DNA amplifications were detected at 1q, 7p, 12q, 19q, and 20q. DNA under-representation was observed less commonly and included 8p (28% of samples), 9p (22% of samples), 13q (28% of samples), and 18q (38% of samples).

CONCLUSIONS

The current study identified targets of frequent genetic aberration in primary adenocarcinomas from nonsmokers. Compared with reported CGH findings in the literature, the current findings suggest that DNA gain at 16p is the distinct aberration involved in these tumors. Other frequently altered loci involve commonly reported oncogenic and tumor suppressor loci, suggesting an overlap with the genetic pathways of tobacco-induced lung carcinogenesis.

Two cases of therapy-related acute promyelocytic leukemia (t-APL) after mantle cell lymphoma and gestational trophoblastic disease

We report two cases of secondary acute promyelocytic leukemia (APL). One patient presented with concurrent APL and missed abortion 1 year after etoposide-based chemotherapy for gestational trophoblastic disease. A prolonged complete remission was achieved with standard chemotherapy. An elderly man developed APL 1 year after alkylator-based chemotherapy for mantle cell lymphoma (MCL). A complete clinical and molecular remission was obtained with chemotherapy and all- trans retinoic acid, followed by arsenic consolidation. Concomitant molecular relapse of APL and MCL clones was detected at 1 year, both of which responded to oral arsenic therapy. High-dose epipodophyllin is a dose risk for secondary APL, but alkylating agents may also be implicated. For patients with a history of active malignancy and heavy previous chemotherapy exposure, the use of nontoxic arsenic therapy appeared to be effective and prudent.

Ewing sarcoma of the small intestine

This report describes a rare case of Ewing sarcoma (ES) of the small intestine. The patient was a 9-year-old girl with progressive abdominal distension. Computed tomography showed a large mass in the small bowel. Histopathologic examination of the resected tumor showed ES with typical histologic, immunohistochemical, and ultrastructural features. The tumor recurred in the pelvic cavity 18 months after the original surgery. Molecular study of the recurrent tumor confirmed a diagnostic EWS-FLI1 gene fusion. This patient illustrates the unique occurrence of ES in the small intestine.

A novel germline 1.8-kb deletion of hMLH1 mimicking alternative splicing: a founder mutation in the Chinese population

We have previously reported that there is a high incidence of microsatellite instability (MSI) and germline mismatch repair gene mutation in colorectal cancer arising from young Hong Kong Chinese. Most of the germline mutations involve hMSH2, which is different from the mutation spectrum in the Western population. It is well known that alternative splicing is common in hMLH1, which complicates RNA based mutation detection methods. In contrast, large deletions in hMLH1, commonly observed in some ethnic groups, tend to escape detection by exon-by-exon direct DNA sequencing. Here we report the detection of a novel germline 1.8 kb deletion involving exon 11 of hMLH1 in a local hereditary non-polyposis colorectal cancer family. This mutation generates a mRNA transcript with deletion of exons 10-11, which is indistinguishable from one of the most common and predominant hMLH1 splice variants. A diagnostic test based on PCR of the breakpoint region led to the identification of an additional young colorectal cancer patient with this mutation. Haplotype analysis suggests that they may share a common ancestral mutation. Our results caution investigators in the interpretation of alternative splicing and have important implications for the design of hMLH1 mutation detection strategy in the Chinese population.

Chromosomal instability and p53 inactivation are required for genesis of glioblastoma but not for colorectal cancer in patients with germline mismatch repair gene mutation

We have previously reported high-frequency microsatellite instability (MSI-H) and germ-line mismatch repair gene mutation in patients with unusually young onset of high-grade glioma. Some of these patients developed metachronous MSI-H colorectal cancer and conformed to the diagnosis of Turcot's syndrome. Frameshift mutation of TGFbetaRII was present in all the colorectal carcinomas but not in brain tumours. We further characterized the genetic pathways of tumour evolution in these metachronous gliomas and colorectal carcinomas. All MSI-H glioblastomas had inactivation of both alleles of the p53 gene and showed over-expression of the p53 protein while none of the colorectal carcinomas had p53 mutation or protein over-expression. Flow cytometry and comparative genomic hybridization revealed that all glioblastomas were chromosomal unstable with aneuploid DNA content, and with a variable number of chromosomal arm aberrations. In contrast, the colorectal carcinomas had diploid or near-diploid DNA content with few chromosomal arm aberrations. The pattern of chromosomal aberrations in the two organs was different. Loss of 9p was consistently observed in all glioblastomas but not in colorectal carcinomas. Epidermal growth factor receptor amplification was absent in all glioblastomas and colorectal carcinomas. Our results suggest that both the frequency of p53 mutation and its effects differ greatly in the two organs. Following loss of mismatch repair function, p53 inactivation and chromosomal instability are not necessary for development of colorectal carcinoma, but are required for genesis of glioblastoma. Oncogene (2000) 19, 4079 - 4083.

Distinct clinical features associated with microsatellite instability in colorectal cancers of young patients

The Hong Kong Chinese population has an unusually high incidence of colorectal cancer in the young, suggestive of hereditary susceptibility. To search for a genetic basis for this predisposition, we studied the incidence of microsatellite instability (MSI) in paraffin-embedded colectomy specimens of 124 young (<50 years old) Chinese colorectal cancer patients referred to the Hong Kong Hereditary Gastrointestinal Cancer Registry from 1995 to 1998. By medical record review and personal interview, we searched for distinct clinical features associated with the manifestation of MSI in this group of patients. For patients with MSI tumours, blood was taken for detection of germline mutation in 2 mismatch repair (MMR) genes. MSI was present in 33 tumours from 23 males and 10 females (26.6%). Ongoing mutation analysis has so far identified MMR gene mutations in 8 patients with MSI tumours. The incidence of MSI increased significantly with decreasing age at cancer diagnosis. For patients aged 30 to 49, MSI tumours were located mainly at the proximal colon. However, for exceptionally young patients (<30 years), MSI tumours tended to be at the distal large bowel. This observation suggested a differential activity of the MMR pathway in colorectal carcinogenesis in different age groups. On multivariate analysis, young age at cancer diagnosis, proximal tumour location, a strong family history of colorectal cancer, and a personal history of metachronous cancer were independent predictors for MSI status. This knowledge may have an impact on the management of young colorectal cancer patients and their families.

The angiopoietins, tie2 and vascular endothelial growth factor are differentially expressed in the transformation of normal lung to non-small cell lung carcinomas

The successful establishment of angiogenesis depends on a complex process of endothelial proliferation and organization. The angiopoietins (Ang-1 and Ang-2) and Tie2 ligand-receptor system is essential for the regulation of vascular maturation and stability during embryonic development. Together with the vascular endothelial growth factor (VEGF)-mediated pathway, they have been implicated in the control of normal physiological angiogenesis. We investigated their potential role and interaction in the development of lung cancers by comparing the expression pattern and inter-relationship of Ang-1 and 2, Tie2 and VEGF levels in 28 pairs of primary non-small cell lung cancers (NSCLC) and normal lung. Using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and in-situ hybridization (ISH), we showed that in NSCLC, there was significantly up-regulated VEGF expression by the tumour cells and an increased intensity of Ang-2 expression in the tumour vessels. The number of Ang-2-expressing vessels also correlated with the grades of tumour cell expression of VEGF. On the other hand, normal lung expressed constitutively high and correlated levels of Ang-1 and Tie2, which were significantly reduced in the carcinomas. The findings suggested a role of the Ang-1/Tie2 pathway in the maintenance of the complex vasculature in normal lung, while collaborative activities between the Ang-2 and VEGF pathways might be important in promoting tumour angiogenesis in NSCLC.

Frequent microsatellite instability and mismatch repair gene mutations in young Chinese patients with colorectal cancer

BACKGROUND

The incidence of colorectal cancer in persons under 46 years of age is substantially higher in Hong Kong than in Scotland and many other countries. Consequently, we examined whether there is a hereditary predisposition for colorectal cancer in this Southern Chinese population.

METHODS

We investigated the incidence of microsatellite instability (MSI) at 10 DNA sites in 117 colorectal cancer specimens from Chinese patients of various ages. Those tumors with new alleles at 40% or more of the sites investigated were identified as highly unstable MSI (MSI-H). In young patients, we also searched for germline mutations in three mismatch repair genes (hMSH2, hMLH1, and hMSH6).

RESULTS

The incidence of MSI-H varied statistically significantly with age, being observed in more than 60% of those younger than age 31 years at diagnosis and in fewer than 15% of those age 46 years or older. In 15 patients (<46 years old) whose colorectal cancers showed MSI-H, eight possessed germline mutations in either hMSH2 or hMLH1. When mutations in hMSH6 were included, more than 80% of Chinese colorectal cancer patients younger than 31 years had germline mutations in mismatch repair genes. We found a novel germline missense mutation in hMSH6 in a 29-year-old man whose tumor showed no MSI. Two patients had a 4-base-pair insertion in exon 10 causing a truncated protein; this insertion is a common polymorphism with a population allele frequency in Chinese of 5.6%.

CONCLUSIONS

Our results indicate that germline mutations in mismatch repair genes contribute substantially to the pathogenesis and high incidence of colorectal cancer in young Hong Kong Chinese. However, because young Chinese and Caucasians show similar proportions of colorectal cancers with MSI-H, despite the higher incidence in the former, additional factors may underlie the high susceptibility of young Chinese to colorectal cancer.

Vascular endothelial growth factor is up-regulated in the early pre-malignant stage of colorectal tumour progression

Angiogenesis is an essential requirement for the development, progression and metastasis of malignant tumours. Studies on transgenic mouse models have shown that angiogenesis begins in the pre-malignant phase of oncogenesis, when dysplastic lesions acquire an increased microvasculature. To investigate the relationship between the expression of vascular endothelial growth factor (VEGF) and colorectal tumour progression, we have studied VEGF expression level and splice variant pattern by semi-quantitative RT-PCR and the cellular source of VEGF expression by in situ hybrization (ISH) in a range of lesions that modelled the tumour-development pathway from normal colon to invasive colorectal adenocarcinomas. Colonic adenomas showed a statistically significant up-regulation of VEGF expression over normal tissues, with a further increase during the development of adenocarcinomas. Tumour cells formed the major source of VEGF expression, with a minor contribution from mononuclear cells in the tumour stroma and enhanced expression in tumour cells around necrotic regions. The comparable expression level in both the in situ and invasive components in the same tumours indicated that a high VEGF expression capacity had been acquired prior to establishment of the invasive phenotype. Our findings support activation of VEGF as the molecular basis for the discrete induction of angiogenesis in the pre-malignant phase of colorectal tumour development.

Vascular endothelial growth factor is up-regulated in the early pre-malignant stage of colorectal tumour progression

Angiogenesis is an essential requirement for the development, progression and metastasis of malignant tumours. Studies on transgenic mouse models have shown that angiogenesis begins in the pre-malignant phase of oncogenesis, when dysplastic lesions acquire an increased microvasculature. To investigate the relationship between the expression of vascular endothelial growth factor (VEGF) and colorectal tumour progression, we have studied VEGF expression level and splice variant pattern by semi-quantitative RT-PCR and the cellular source of VEGF expression by in situ hybrization (ISH) in a range of lesions that modelled the tumour-development pathway from normal colon to invasive colorectal adenocarcinomas. Colonic adenomas showed a statistically significant up-regulation of VEGF expression over normal tissues, with a further increase during the development of adenocarcinomas. Tumour cells formed the major source of VEGF expression, with a minor contribution from mononuclear cells in the tumour stroma and enhanced expression in tumour cells around necrotic regions. The comparable expression level in both the in situ and invasive components in the same tumours indicated that a high VEGF expression capacity had been acquired prior to establishment of the invasive phenotype. Our findings support activation of VEGF as the molecular basis for the discrete induction of angiogenesis in the pre-malignant phase of colorectal tumour development.

Germline hMSH2 and differential somatic mutations in patients with Turcot's syndrome

Turcot's syndrome is characterized clinically by the occurrence of primary brain tumor and colorectal tumor and has in previous reports been shown to be associated with germline mutations in the genes APC, hMLH1, and hPMS2. Here we describe three patients with Turcot's syndrome, each having colorectal adenocarcinoma and malignant glioma. All the colorectal and brain tumors from these patients showed replication errors in most of the microsatellite loci investigated. Search for underlying germline mutations in the nucleotide mismatch repair genes revealed three different hMSH2 mutations. All colorectal tumors showed a frameshift in the A(10) tract in the coding sequence of the transforming growth factor beta type II receptor (TGFBRII) gene, but no such change was detected in any of the brain tumors. Frameshift mutation in the BAX gene was found in one colon carcinoma and mutations in insulin-like growth factor type II receptor (IGFIIR) gene in one glioma. Our data have broadened the possible mutation spectrum of patients with Turcot's syndrome. The difference in the mutation spectrum of TGFBRII, BAX, and IGFIIR between brain and colorectal tumors in these individuals suggests that the mutator phenotype may target different pathogenic pathways in the oncogenic process of the two organs.

A case of oral-facial-digital syndrome with overlapping manifestations of type V and type VI: a possible new OFD syndrome

We report a child with clinical and radiological manifestations characteristic of both V'aradi syndrome (oral-facial-digital syndrome type VI) and Thurston syndrome (oral-facial-digital syndrome type V). The findings have not been reported previously, and we believe that it represents a new variant.

Microsatellite instability, Epstein-Barr virus, mutation of type II transforming growth factor beta receptor and BAX in gastric carcinomas in Hong Kong Chinese

Microsatellite instability (MI), the phenotypic manifestation of mismatch repair failure, is found in a proportion of gastric carcinomas. Little is known of the links between MI and Epstein-Barr virus (EBV) status and clinicopathological elements. Examination of genes mutated through the MI mechanism could also be expected to reveal important information on the carcinogenic pathway. Seventy-nine gastric carcinomas (61 EBV negative, 18 EBV positive) from local Hong Kong Chinese population, an intermediate-incidence area, were examined. Eight microsatellite loci, inclusive of the A10 tract of type II transforming growth factor beta receptor (TbetaR-II), were used to evaluate the MI status. MI in the BAX and insulin-like growth factor II receptor (IGF-IIR) genes were also examined. High-level MI (>40% unstable loci) was detected in ten cases (12.7%) and low-level MI (1-40% unstable loci) in three (3.8%). High-level MI was detected in two EBV-associated cases (11%) and the incidence was similar for the EBV-negative cases (13%). The high-level MIs were significantly associated with intestinal-type tumours (P = 0.03) and a more prominent lymphoid infiltrate (P = 0.04). Similar associations were noted in the EBV-positive carcinomas. The high-level MIs were more commonly located in the antrum, whereas the EBV-associated carcinomas were mostly located in body. Thirteen cardia cases were negative for both high-level MI and EBV. All patients aged below 55 were MI negative (P = 0.049). Of the high-level MIs, 80% had mutation in TbetaR-II, 40% in BAX and 0% in IGF-IIR. Of low-level MIs, 33% also had TbetaR-II mutation. These mutations were absent in the MI-negative cases. Of three lymphoepithelioma-like carcinomas, two cases were EBV positive and MI negative, one case was EBV negative but with high-level MI. In conclusion, high-level MIs were present regardless of the EBV status, and were found in a particular clinicopathological subset of gastric carcinoma patient. Inactivation of important growth regulatory genes observed in these carcinomas confirms the importance of MI in carcinogenesis.

hMLH1 promoter methylation and lack of hMLH1 expression in sporadic gastric carcinomas with high-frequency microsatellite instability

Mutation of DNA mismatch repair genes has rarely been documented in sporadic gastric carcinoma with microsatellite instability (MSI). In sporadic colorectal carcinoma, hMLH1 promoter methylation associated with protein loss is found in the majority of high-frequency MSI cases. We investigated a series of 35 sporadic gastric carcinomas stratified into high-frequency MSI (MSI-H), low-frequency MSI (MSI-L) and microsatellite stable (MSS) groups and found that hypermethylation of the CpG island in the hMLH1 promoter region was present in 100% of MSI-H sporadic gastric carcinomas. In 90% of cases, there was an associated complete loss of hMLH1 protein, as detected by immunohistochemistry, and a markedly lowered hMLH1 mRNA level. This loss of hMLH1 protein occurred in the MSI-H invasive tumor but not in the adjacent carcinoma-in situ or dysplastic components that were MSS. The MSI-L and MSS forms of gastric carcinoma all showed predominantly unmethylated hMLH1 promoter, positive hMLH1 protein and high hMLH1 mRNA level. On the other hand, hMSH2 protein was expressed in all of the tumors irrespective of the MSI status. Our results suggest that high-frequency MSI in sporadic gastric cancer is mostly due to epigenetic inactivation of hMLH1 in association with promoter methylation, and the loss of hMLH1 protein is a significant event in the development of invasive tumor.

Monocyte chemoattractant protein-1 (MCP-1) expression in primary lymphoepithelioma-like carcinomas (LELCs) of the lung

Lymphoepithelioma-like carcinoma (LELC) of the lung is a recently recognized primary non-small cell lung carcinoma with distinct clinicopathological features and an aetiological association with Epstein-Barr virus (EBV) infection. The tumour consists of clusters and sheets of poorly or undifferentiated tumour cells in close association with numerous mononuclear inflammatory cells, including a rich component of tumour-associated macrophages (TAMs). To investigate the molecular mechanism leading to the TAM-rich stroma, the expression of a monocyte-specific chemotactic and activating factor, monocyte chemoattractant protein-1 (MCP-1), was studied by reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ hybridization (ISH), and the presence of TAMs was demonstrated by immunohistochemistry in nine LELCs. The results were compared with those found in 17 conventional non-small cell lung carcinomas. RT-PCR showed specific MCP-1 amplification in both LELCs and non-LELCs, but ISH demonstrated a unique and extensive expression of MCP-1 transcripts by the tumour cells of LELCs only, while TAMs, stromal fibroblasts, and endothelial cells formed the major source of MCP-1 in non-LELCs. TAMs in LELCs were more abundant and showed a close topographical relationship with the MCP-1-expressing tumour cells. The results indicate that tumour cell expression of MCP-1 in LELCs is an important mechanism contributing to their distinctive morphological features. This is the first study that demonstrates the in vivo upregulation of a monocyte-specific chemokine by EBV-related carcinomas, illustrating an interesting aspect of tumour biology in EBV-related neoplasms.

Expression of vascular endothelial growth factor in von Hippel-Lindau syndrome-associated papillary cystadenoma of the epididymis

Vascular endothelial growth factor (VEGF) is a hypoxia inducible angiogenic and vascular permeability factor. Although VEGF expression in glioblastoma is induced by hypoxia, its expression in renal cell carcinoma and hemangioblastoma is thought to be related to mutation of the von Hippel-Lindau (VHL) gene. It is not certain whether other lesions in VHL syndrome are associated with an elevated VEGF level. We report a VHL syndrome patient with multiple hemangioblastomas and bilateral epididymal clear cell papillary cystadenomas. In situ hybridization revealed high levels of VEGF mRNA in the clear cells of the epididymal tumor and the stromal cells of the hemangioblastoma. This lends support to the notion that upregulation of VEGF is caused by loss of the wild-type VHL protein. We postulate that the elevated VEGF levels may account for the cyst formation and vascularized stroma present in these VHL-associated tumors.

Microsatellite instability and mutation of DNA mismatch repair genes in gliomas

Microsatellite instability (MSI) has been identified in various human cancers, particularly those associated with the hereditary nonpolyposis colorectal cancer syndrome. Although gliomas have been reported in a few hereditary nonpolyposis colorectal cancer syndrome kindred, data on the incidence of MSI in gliomas are conflicting, and the nature of the mismatch repair (MMR) defect is not known. We established the incidence of MSI and the underlying MMR gene mutation in 22 patients ages 45 years or less with sporadic high-grade gliomas (17 glioblastomas, 3 anaplastic astrocytomas, and 2 mixed gliomas, grade III). Using five microsatellite loci, four patients (18%) had high level MSI, with at least 40% unstable loci. Germline MMR gene mutation was detected in all four patients, with inactivation of the second allele of the corresponding MMR gene or loss of protein expression in the tumor tissue. Frameshift mutation in the mononucleotide tract of insulin-like growth factor type II receptor was found in one high-level MSI glioma, but none was found in the transforming growth factor beta type II receptor and the Bax genes. There was no family history of cancer in three of the patients, and although one patient did have a family history of colorectal carcinoma, the case did not satisfy the Amsterdam criteria for hereditary nonpolyposis colorectal cancer syndrome. Three patients developed metachronous colorectal adenocarcinomas, fitting the criteria of Turcot's syndrome. Thus, MSI and germline MMR gene mutation is present in a subset of young glioma patients, and these patients and their family members are at risk of developing other hereditary nonpolyposis colorectal cancer syndrome-related tumors, in particular colorectal carcinomas. These results have important implications in the genetic testing and management of young patients with glioma and their families.

p53 overexpression is different in Epstein-Barr virus-associated and Epstein-Barr virus-negative carcinoma

AIMS

Epstein-Barr virus (EBV) is associated with a subset of gastric and head and neck carcinomas. While p53 mutation and overexpression is common in gastric cancer, in nasopharyngeal carcinoma p53 is overexpressed yet mutation is uncommon, leading to a proposed viral mechanism of p53 upregulation. We examined the expression of p53 protein in 18 EBV-associated gastric carcinomas (EBV-GA) and compared it with 29 age and sex matched EBV-negative gastric carcinomas (EBV0-GA) and 23 non-nasopharyngeal EBV-associated carcinomas (EBV-CAs) arising from various head and neck regions.

METHODS AND RESULTS

Using two monoclonal antibodies (DO7 and PAb1801) with microwave pre-treatment, the p53 protein was scored according to the intensity and percentage of positive cells. The EBV0-GA showed a clear cut bimodal distribution of p53 levels, with either homogeneous intense staining of most tumour nuclei, or only very weak expression in a few cells. Nearly all the EBV-GA and EBV-CAs showed a weak to moderate p53 expression, characterized by heterogeneous intensity of staining in a variable proportion of tumour cells.

CONCLUSIONS

The difference in p53 levels in the EBV0-GA and EBV-GA is statistically significant. The heterogeneous level of p53 in the EBV-GA and EBV-CAs and its difference from the EBV0-GA is suggestive of a non-mutational mechanism of p53 upregulation and underscores the role of the virus in the oncogenic pathway.

Tissue-specific expression pattern of vascular endothelial growth factor isoforms in the malignant transformation of lung and colon

Angiogenesis, a prerequisite for tumor growth and progression, results from a shift in the equilibrium between angiogenic factors and angiogenic inhibitors. Vascular endothelial growth factor (VEGF) has been identified as one of the most important factors mediating angiogenesis in physiological and pathological conditions. Through alternative splicing, four isoforms of VEGF are formed, consisting of 206, 189, 165, and 121 amino acids, respectively. VEGF206 and VEGF189 differ from VEGF165 and VEGF121 in their bioavailability, with the longer forms being matrix-bound and the shorter forms freely diffusible. To investigate the relative importance of the VEGF isoforms in neoplastic transformation, we studied the pattern of splice variant expression by reverse transcription polymerase chain reaction (RT-PCR) in 18 lung and 11 colonic carcinomas and their corresponding normal tissues, respectively. The findings showed a significant upregulation of VEGF in both carcinomas, with VEGF165 and VEGF121 being the predominant forms; VEGF189 was significantly expressed in normal lung but not colon; and VEGF206 was not detected in any specimen. The findings indicate that during malignant progression, an angiogenic switch favoring the shorter diffusible isoforms is likely to confer on the tumor a growth advantage. From the differential expression of VEGF isoforms in normal lung and colonic tissues, different functional roles of the splice variants is suggested. In particular, VEGF189 may be important for the maintenance of the vascular integrity of the lung.

Detection of trisomy 3 in primary gastric B-cell lymphoma by using chromosome in situ hybridization on paraffin sections

Recent studies in Western populations have shown that trisomy 3 is the most frequent chromosomal abnormality in primary gastric lymphoma (PGL). To study the incidence of trisomy 3 and its implications for the pathogenesis of PGL in Hong Kong, we have applied the technique of chromosome in situ hybridization in 13 cases of PGL by using archival paraffin-embedded tissue sections. Five cases of chronic gastritis were used as controls. Trisomy 3 was found in 9 (69%) of 13 cases, including cases of low-grade lymphoma and high-grade lymphoma with or without a low-grade component. Our findings are similar to the incidence of trisomy 3 reported in the Western literature. The persistent finding of trisomy 3 in various histologic grades of PGL suggests that it may be useful as a clonal marker in this group of neoplasms. Various molecular events involving chromosome 3 may be related to the pathogenesis of this group of lymphomas.

Presence of Epstein-Barr virus in lymphoepithelioma-like carcinoma of the middle ear

AIM

To examine the association of Epstein-Barr virus (EBV) with carcinoma of the ear.

METHODS

Five non-keratinising squamous cell carcinomas and two undifferentiated carcinomas of the ear were examined. In situ hybridisation was used to localised EBV-encoded RNAs (EBER). Immunohistochemical methods to detect LMP-1 and EBNA2 were performed in the EBER positive cases.

RESULTS

Two cases were EBER positive, including one non-keratinising and one undifferentiated carcinoma. Both showed identical morphology to those arising from the nasopharynx, with abundant lymphoid stroma. They were both negative for LMP-1 and EBNA2.

CONCLUSIONS

EBV associated carcinoma with the morphology of lymphoepithelioma can also arise from the middle ear.

Expression of vascular endothelial growth factor and its receptors in the anaplastic progression of astrocytoma, oligodendroglioma, and ependymoma

Vascular endothelial growth factor (VEGF) is a hypoxia-inducible angiogenic factor, which is known to be upregulated in most cases of glioblastoma multiforme (GBM). The expression of VEGF and its receptors in ependymomas, oligodendrogliomas, and particularly the expression during anaplastic progression of these three types of gliomas has not been studied extensively. Fifty-six gliomas, consisting of 10 ependymomas, 12 oligodendrogliomas, 3 anaplastic oligodendrogliomas, 6 astrocytomas grade II, 5 anaplastic astrocytomas, and 20 glioblastoma multiformes, were investigated for VEGF and receptor expression using in situ hybridization (ISH) and reverse transcription polymerase chain reaction (RT-PCR). Results showed that VEGF was moderately to strongly expressed in 8 of 10 ependymomas and in all anaplastic oligodendrogliomas and glioblastoma multiforme cases. These tumors displayed similar degrees of extensive necrosis and vascular proliferation, with VEGF expression consistently seen in tumor cells around necrotic areas. The VEGF expression, although present at a lower level, also was shown in 4 of 12 oligodendrogliomas, in 3 of 6 astrocytomas grade II, and in 2 of 5 anaplastic astrocytomas, with a regional rather than diffuse pattern of positive result. The findings from the in situ hybridization study correlated with the expression index, as determined by reverse transcription polymerase chain reaction. Expression of VEGF was correlated significantly with vascular proliferation (p < 10(-5)) and necrosis (p < 10(-5)), as well as with microvessel density (p = 0.002, rs = 0.41). The VEGF receptors, kinase domain region (KDR) and Fms-like-tyrosine kinase (Flt-1), also were upregulated in the tumor vasculature of glioblastoma multiforme, anaplastic oligodendrogliomas, and ependymomas with necrosis, whereas the astrocytomas grade II, anaplastic astrocytomas, and oligodendroglioma tumors tended to express a weak to nondetectable signal. Anaplastic progression in all three types of gliomas is heralded by the occurrence of small zones of VEGF-expressing cells and early vascular proliferation, followed by an accelerated phase of angiogenesis closely associated with VEGF induction around areas of necrosis and with the expression of VEGF receptors in the tumor vasculature.

Up-regulation of lysozyme production in colonic adenomas and adenocarcinomas

AIMS

The presence of lysozyme protein in some gastric adenomas and adenocarcinomas has been well documented. There have been relatively few studies investigating the presence of lysozyme in tumours of the large intestine and they show contrasting results. We aim to investigate the cellular source and expression of lysozyme in colonic adenomas and adenocarcinomas.

METHODS AND RESULTS

We randomly selected 29 and 27 colonic adenomas and adenocarcinomas, respectively. Using in-situ hybridization (ISH) and immunohistochemistry (IHC), we found an up-regulation of lysozyme in the dysplastic epithelium of all the adenomas studied, with more than 80% of cases expressing moderate to strong signals. Although the up-regulation of lysozyme was also observed in adenocarcinomas, only 30% of the cases showed moderate to strong signals, mostly with an uneven distribution. Down-regulation of lysozyme in the severely dysplastic and invasive foci were noted in some cases of adenoma with malignant transformation. Normal colonic glands were consistently negative for lysozyme at both the mRNA and the protein level, but inflamed and immature regenerative colonic epithelium at the crypt base showed positive signals in a similar pattern to those observed in the dysplastic epithelium of the adenomas.

CONCLUSIONS

Our results confirm that colonic epithelium can produce lysozyme and its expression is up-regulated in the dysplastic epithelium in adenomas and in invasive cancer cells. It is interesting that regenerative colonic epithelium showed a similar pattern of lysozyme expression as in adenomas. The loss of lysozyme secreting phenotype in most of the invasive tumours suggests that lysozyme may not confer an advantage to tumour progression.

Post-transplantation lymphoproliferative disorder of donor origin in a sex-mismatched renal allograft as proven by chromosome in situ hybridization

We report a case of post-transplantation B-cell lymphoproliferative disorder (PTLPD) associated with Epstein-Barr virus (EBV) that developed in a renal allograft 5 months after transplantation. The lesion had a histologic appearance of diffuse large B-cell lymphoma with monoclonality demonstrated by in situ hybridization (ISH) for kappa and lambda mRNA. Both the male donor and the female recipient were EBV seropositive. The lymphoid cells in this lesion was proven to be of donor origin by ISH for the human Y chromosome on the paraffin-embedded sections of the allograft. The recipient of the other kidney from the same donor did not have evidence of lymphoma, and the patient was also free from disease 2 years after surgical removal of the lymphoma This case is an unusual PTLPD of donor origin; the majority of such lesions in solid organ transplantations are of recipient origin. Our findings demonstrate that the origin of PTLPD can be documented in selected cases using ISH with probes to the Y chromosome.

Expression of vascular endothelial growth factor and its receptors in pilocytic astrocytoma

Vascular endothelial growth factor (VEGF), a potent angiogenic and vascular permeability factor, is important in the angiogenesis of glioblastoma. A major difference between pilocytic astrocytoma, a grade I tumor, and the grade II fibrillary astrocytoma is the vascular proliferation, highly vascularized stroma, and great propensity for cyst formation in the former. In order to explore factors regulating such angiogenesis and cyst formation in pilocytic astrocytoma, we examined expression of VEGF and its receptors (KDR and Flt-1) using in situ hybridization. In all 14 cases a high level of VEGF transcripts could be demonstrated. These were found in specific regions, namely, in the tumor cyst wall, in areas of hyaline cystic degeneration, in stellate reticulated astrocytes around microcysts in the biphasic compact and loose areas, and in tumor cells with degenerative pleomorphic multicoated nuclei. KDR and Flt-1 were expressed in the tumor vasculature, with particularly high levels seen in coiled young proliferating vessels, especially those in the cyst wall. Given the known angiogenic and vascular permeability activities of VEGF, we propose that VEGF plays an important role in molding the characteristic morphologic features of this tumor, namely, the formation of cysts, microcystic pattern, hyaline cystic degeneration, hyaline vessels, and vascular proliferation. Mechanisms that block the VEGF pathway could constitute a potential therapeutic strategy for the treatment of this tumor.

Prevalence of mutations and 30-bp deletion in the C-terminal region of Epstein-Barr virus latent membrane protein-1 oncogene in reactive lymphoid tissue and non-nasopharyngeal EBV-associated carcinomas in Hong Kong Chinese

A specific variant of Epstein-Barr virus (EBV) with a 30-bp deletion in the C-terminal region of the LMP1 gene has been found in some EBV-associated malignancies. To better understand the tumorigenic role of this LMP1 variant, we used PCR and sequencing to examine the LMP1 gene in 38 EBV-associated carcinomas (EBV-CAs) occurring in various organs (6 lung, 10 salivary gland, 5 sino-nasal, 16 gastric and 1 metastatic NPC), 55 reactive lymphoid tissues from tonsils (TON) and 67 EBV-negative tumours in various organs (22 adenolymphoma of salivary gland, 14 gastric and 31 colonic adenocarcinomas), where the virus was demonstrated in lymphocytes. The TON showed prevalence of both deleted and non-deleted variants of LMP1, with dual infection being common. Significantly more of the LMP1 variant was deleted in EBV-CA and in EBV-negative tumours. Sequencing showed that the deleted and non-deleted variants have different sets of amino acid mutation. Mutations in codon 344 and 355 in the non-deleted variant disrupted the 9 nucleotide repeat flanking the deletion and thus may have conferred resistance to the deletion. The prevalence of both variants in the TON, with enrichment for the deleted variant in various organs, argues for the existence of an immune selection pressure in our population. The deleted variant, which may have a higher tumorigenic potential, may contribute to the high incidence of NPC, as well as the occurrence of EBV-CA in organs outside the nasopharynx in our locality.

Monocyte chemoattractant protein-1 expression and macrophage infiltration in gliomas

While the number of reports on macrophage infiltration of gliomas is increasing, the extent and mechanisms of macrophage recruitment remain unclear. To investigate whether monocyte chemoattractant protein-1 (MCP-1) plays a role in this process, in situ hybridisation (ISH) was performed for 22 glioblastomas (GBM), 1 anaplastic astrocytoma (AA) and 4 grade II fibrillary astrocytomas (AII) and reverse transcription-polymerase chain reaction was performed in 13 GBM, 1 AA and 3 AII. High levels of MCP-1 mRNA were detectable in most GBM, while a lower level was detected in AII. Many tumour-associated macrophages (TAM) could be demonstrated by immunohistochemistry (IHC) in most GBM, while the AII contained a lower number of TAM. The positive correlation between the MCP-1 level and abundance of TAM suggested that MCP-1 has a role in TAM recruitment. By combining ISH and IHC, high levels of MCP-1 mRNA were shown both in tumour cells and TAM. Along tumour borders, reactive astrocytes and microglia also expressed MCP-1. In areas with T lymphocyte infiltration, larger numbers of MCP-1-positive cells with an enhanced level of expression could be identified. We propose that the mechanism of macrophage recruitment is, at least partly, effected by constitutive expression and T cell-mediated up-regulation of MCP-1 in tumour cells and TAM. The production of MCP-1 by TAM establishes a positive amplification circuit for macrophage recruitment in gliomas.

Colorectal carcinoma in Hong Kong: epidemiology and genetic mutations

The incidence of colorectal carcinoma is rising at an alarming pace in Asian urban societies such as Hong Kong. Detailed examination of the epidemiological pattern and genetic mutation of colorectal cancer in the Hong Kong Chinese population is overdue. We compared the reported age incidence of colorectal carcinoma in Hong Kong with that of Scotland and other countries. Hong Kong showed a much higher incidence of colorectal carcinoma among the young age groups. By comparison with other countries, this raised incidence among the young appeared to be related to southern Chinese societies. The recent dramatic rise in colorectal cancer in Hong Kong was largely attributable to an increase in the over 50 years age group, while the young incidence remained unchanged. We also defined the mutation spectrum of p53 and Ki-ras in 67 unselected cases by direct DNA sequencing. Interestingly, insertion/deletion mutations in p53 from colorectal carcinoma in Hong Kong showed a significantly higher frequency (17.2%) than the Scottish data (0%) and the world database (6.6%), although the overall frequency of p53 mutation (43%) in Hong Kong was similar to others. The high incidence of colorectal carcinoma in young people and the raised proportion of frameshift mutations in p53 encourage further search for a genetic basis for susceptibility to this disease in the Hong Kong Chinese population.

Interphase cytogenetic study of endometrial stromal sarcoma by chromosome in situ hybridization

Endometrial stromal neoplasms include a heterogenous group of tumors with different clinical behavior and response to treatment. Cytogenetic study of such tumors has been scanty. The aim of this study was to analyze and compare the chromosome composition in low-grade and high-grade endometrial stromal sarcoma using the technique of chromosome in situ hybridization. Eight cases of low-grade stromal sarcoma and three cases of high-grade stromal sarcoma were studied. Biotinylated DNA probes specific for the regions of chromosomes X, 11, 12, and 17 were used on formalin-fixed paraffin embedded material from these tumors. The in situ hybridization signals were visualized by immunoperoxidase technique. Four of the eight low-grade stromal sarcomas retained normal disomy of the chromosomes studied. The other four low-grade sarcomas showed a gain of from one to three chromosomes, whereas all of the three high-grade sarcomas showed polysomies in all of the four chromosomes being studied. No loss of chromosomes was detected. One case of high-grade sarcoma contained coexisting areas of low-grade sarcoma. Although aneusomy was found in the high-grade portion, disomy was noted in the low-grade areas. In the stromal sarcomas studied, there was no definite correlation between the presence of chromosome polysomies and the clinical progress of the tumors. This is the first interphase cytogenetic study of uterine stromal sarcoma, and the results support the concept that complex numerical chromosome abnormalities evolve during anaplastic transformation of endometrial stromal sarcoma.

Mixed low grade and high grade endometrial stromal sarcoma of uterus: differences on immunohistochemistry and chromosome in situ hybridisation

A case of a 64 year old woman with a tumour of the uterus is reported. The patient presented with postmenopausal bleeding and subsequently underwent total hysterectomy and bilateral salpingo-oophorectomy. Sections of the tumour showed a low grade endometrial stromal sarcoma coexisting with areas consistent with high grade sarcoma. The sarcoma cells, in both the low and high grade areas, were positive for vimentin and negative for desmin and cytokeratin on immunohistochemistry. While the sarcoma cells in the low grade region showed immunoreactivity for oestrogen and progestogen receptors, those in the high grade region did not. Using chromosome in situ hybridisation, the low grade portion of the sarcoma was diploid for chromosomes X, 11, 12, and 17, whereas the more anaplastic areas were aneuploid for these chromosomes. This case may represent an example of high grade endometrial stromal sarcoma arising by dedifferentiation from a low grade stromal sarcoma. Adequate sampling is important in identifying such anaplastic changes as the origin of the tumour will affect patient management.