A HER2 selective theranostic agent for surgical resection guidance and photodynamic therapy.

In many cancers early intervention involves surgical resection of small localised tumour masses. Inadequate resection leads to recurrence whereas overzealous treatment can lead to organ damage. This work describes production of a HER2 targeting antibody Fab fragment dual conjugated to achieve both real time near-infrared fluorescent imaging and photodynamic therapy. The use of fluorescence emission from a NIR-dye could be used to guide resection of tumour bulk, for example during endoscopic diagnosis for oesophago-gastric adenocarcinoma, this would then be followed by activation of the photodynamic therapeutic agent to destroy untreated localised areas of cancer infiltration and tumour infiltrated lymph nodes. This theranostic agent was prepared from the Fab fragment of trastuzumab initially by functional disulfide re-bridging and site-specific click reaction of a NIR-dye. This was followed by further reaction with a novel pre-activated form of the photosensitiser chlorin e6 with the exposed fragments' lysine residues. Specific binding of the theranostic agent was observed in vitro with a HER2 positive cell line and cellular near-infrared fluorescence was observed with flow cytometry. Specific photo-activity of the conjugates when exposed to laser light was observed with HER2 positive but not HER2 negative cell lines in vitro, this selectivity was not seen with the unconjugated drug. This theranostic agent demonstrates that two different photo-active functions can be coupled to the same antibody fragment with little interference to their independent activities.

Key differences identified between actinic keratosis and cutaneous squamous cell carcinoma by transcriptome profiling.

BACKGROUND: Cutaneous squamous cell carcinoma (cSCC) is one of the most common malignancies in fair-skinned populations worldwide and its incidence is increasing. Despite previous observations of multiple genetic abnormalities in cSCC, the oncogenic process remains elusive. The purpose of this study was to elucidate key molecular events associated with progression from premalignant actinic keratoses (AKs) to invasive cSCC by transcriptome profiling. METHODS: We combined laser capture microdissection with the Affymetrix HGU133 Plus 2.0 microarrays to profile 30 cSCC and 10 AKs. RESULTS: We identified a core set of 196 genes that are differentially expressed between AK and cSCC, and are enriched for processes including epidermal differentiation, cell migration, cell-cycle regulation and metabolism. Gene set enrichment analysis highlighted a key role for the mitogen activated protein kinase (MAPK) pathway in cSCC compared with AK. Furthermore, the histological subtype of the tumour was shown to influence the expression profile. CONCLUSION: These data indicate that the MAPK pathway may be pivotal to the transition from AK to cSCC, thus representing a potential target for cSCC prevention. In addition, transcriptome differences identified between cSCC subtypes have important implications for future development of targeted therapies for this malignancy.

BRCA2 mutations in primary breast and ovarian cancers.

The second hereditary breast cancer gene, BRCA2, was recently isolated. Germline mutations of this gene predispose carriers to breast cancer, and, to a lesser extent, ovarian cancer. Loss of heterozygosity (LOH) at the BRCA2 locus has been observed in 30-40% of sporadic breast and ovarian tumours, implying that BRCA2 may act as a tumour suppressor gene in a proportion of sporadic cases. To define the role of BRCA2 in sporadic breast and ovarian cancer, we screened the entire gene for mutations using a combination of techniques in 70 primary breast carcinomas and in 55 primary epithelial ovarian carcinomas. Our analysis revealed alterations in 2/70 breast tumours and none of the ovarian carcinomas. One alteration found in the breast cancers was a 2-basepair (bp) deletion (4710delAG) which was subsequently shown to be a germline mutation, the other was a somatic missense mutation (Asp3095Glu) of unknown significance. Our results suggest that BRCA2 is a very infrequent target for somatic inactivation in breast and ovarian carcinomas, similar to the results obtained for BRCA1.

Germline mutations of the BRCA1 gene in breast and ovarian cancer families provide evidence for a genotype-phenotype correlation.

Mutations in the BRCA1 gene, discovered in 1994, are associated with an 80-90% lifetime risk of breast cancer. We have analysed 60 families with a history of breast and/or ovarian cancer for germline mutations in BRCA1. Twenty-two different mutations were detected in 32 families (53%), of which 14 are previously unreported. We observed a significant correlation between the location of the mutation in the gene and the ratio of breast to ovarian cancer incidence within each family. Our data suggest a transition in risk such that mutations in the 3' third of the gene are associated with a lower proportion of ovarian cancer. Haplotype analysis supports previous data which suggest some BRCA1 mutation carriers have common ancestors; however, we have found at least two examples where recurrent mutations appear to have arisen independently.

Localization to Xq27 of a susceptibility gene for testicular germ-cell tumours.

Testicular germ-cell tumours (TGCT) affect 1 in 500 men and are the most common cancer in males aged 15-40 in Western European populations. The incidence of TGCT has risen dramatically over the last century. Known risk factors for TGCT include a history of undescended testis (UDT), testicular dysgenesis, infertility, previously diagnosed TGCT (ref. 7) and a family history of the disease. Brothers of men with TGCT have an 8-10-fold risk of developing TGCT (refs 8,9), whereas the relative risk to fathers and sons is fourfold (ref. 9). This familial relative risk is much higher than that for most other types of cancer. We have collected samples from 134 families with two or more cases of TGCT, 87 of which are affected sibpairs. A genome-wide linkage search yielded a heterogeneity lod (hlod) score of 2.01 on chromosome Xq27 using all families compatible with X inheritance. We obtained a hlod score of 4.7 from families with at least one bilateral case, corresponding to a genome-wide significance level of P=0.034. The proportion of families with UDT linked to this locus was 73% compared with 26% of families without UDT (P=0.03). Our results provide evidence for a TGCT susceptibility gene on chromosome Xq27 that may also predispose to UDT.

Continual monitoring of intraepithelial lymphocyte immunophenotype and clonality is more important than snapshot analysis in the surveillance of refractory coeliac disease.

OBJECTIVE: An aberrant immunophenotype and monoclonality of intraepithelial lymphocytes (IELs) are frequently found in refractory coeliac disease (RCD). However, the utility of continual monitoring of IEL immunophenotype and clonality in the surveillance of RCD remains to be studied. DESIGN: The diagnostic and follow-up biopsies from 33 patients with CD, 7 with suspected RCD, 41 with RCD and 20 with enteropathy-associated T cell lymphoma (EATL) (including 11 evolved from RCD) were investigated by CD3epsilon/CD8 double immunohistochemistry and PCR-based clonality analysis of the rearranged T cell receptor (TCR) genes. RESULTS: An aberrant immunophenotype (CD3epsilon(+)CD8(-) IELs > or =40%) and monoclonality were detected occasionally in CD biopsies, either transiently in patients with CD not compliant with a gluten-free diet or in those who subsequently developed suspected RCD, RCD or EATL. In contrast, the aberrant immunophenotype and monoclonality were found in 30 of 41 (73%) and 24 of 37 (65%) biopsies, respectively, at the time of RCD diagnosis. Among the patients with RCD who did not show these abnormalities in their diagnostic biopsies, 8 of 10 (80%) and 5 of 11 (45%) cases gained an aberrant immunophenotype and monoclonality, respectively, during follow-up. Irrespective of whether detected in diagnostic or follow-up biopsies, persistence of both abnormalities was characteristic of RCD. Importantly, the presence of concurrent persistent monoclonality and aberrant immunophenotype, especially > or =80% CD3epsilon(+)CD8(-) IELs, was a strong predictor of EATL development in patients with RCD (p=0.001). CONCLUSIONS: Continual monitoring of both immunophenotype and clonality of IELs is more important than snapshot analysis for RCD diagnosis and follow-up, and could provide a useful tool for surveillance of patients at risk of EATL.

A20 deletion is associated with copy number gain at the TNFA/B/C locus and occurs preferentially in translocation-negative MALT lymphoma of the ocular adnexa and salivary glands.

The genetic basis of MALT lymphoma is largely unknown. Characteristic chromosomal translocations are frequently associated with gastric and pulmonary cases, but are rare at other sites. We compared the genetic profiles of 33 ocular adnexal and 25 pulmonary MALT lymphomas by 1 Mb array-comparative genomic hybridization (CGH) and revealed recurrent 6q23 losses and 6p21.2-6p22.1 gains exclusive to ocular cases. High-resolution chromosome 6 tile-path array-CGH identified NF-kappaB inhibitor A20 as the target of 6q23.3 deletion and TNFA/B/C locus as a putative target of 6p21.2-22.1 gain. Interphase fluorescence in situ hybridization showed that A20 deletion occurred in MALT lymphoma of the ocular adnexa (8/42=19%), salivary gland (2/24=8%), thyroid (1/9=11%) and liver (1/2), but not in the lung (26), stomach (45) and skin (13). Homozygous deletion was observed in three cases. A20 deletion and TNFA/B/C gain were significantly associated (p<0.001) and exclusively found in cases without characteristic translocation. In ocular cases, A20 deletion was associated with concurrent involvement of different adnexal tissues or extraocular sites at diagnosis (p=0.007), a higher proportion of relapse (67% versus 37%) and a shorter relapse-free survival (p=0.033). A20 deletion and gain at TNFA/B/C locus may thus play an important role in the development of translocation-negative MALT lymphoma.

Conditional expression of mutated K-ras accelerates intestinal tumorigenesis in Msh2-deficient mice.

K-ras mutation occurs in 40-50% of human colorectal adenomas and carcinomas, but its contribution to intestinal tumorigenesis in vivo is unclear. We developed K-ras(V12) transgenic mice that were crossed with Ah-Cre mice to generate K-ras(V12)/Cre mice, which showed beta-naphthoflavone-induction of Cre-mediated LoxP recombination that activated intestinal expression of K-ras(V12) 4A and 4B transcripts and proteins. Only very occasional intestinal adenomas were observed in beta-naphthoflavone-treated K-ras(V12)/Cre mice aged up to 2 years, suggesting that mutated K-ras expression alone does not significantly initiate intestinal tumourigenesis. To investigate the effects of mutated K-ras on DNA mismatch repair (MMR)-deficient intestinal tumour formation, these mice were crossed with Msh2(-/-) mice to generate K-ras(V12)/Cre/Msh2(-/-) offspring. After beta-naphthoflavone treatment, K-ras(V12)/Cre/Msh2(-/-) mice showed reduced average lifespan of 17.3+/-5.0 weeks from 26.9+/-6.8 (control Msh2(-/-) mice) (P<0.01). They demonstrated increased adenomas in the small intestine from 1.41 (Msh2(-/-) controls) to 7.75 per mouse (increased fivefold, P<0.01). In the large intestine, very few adenomas were found in Msh2(-/-) mice (0.13 per mouse) whereas K-ras(V12)/Cre/Msh2(-/-) mice produced 2.70 adenomas per mouse (increased 20-fold, P<0.01). Over 80% adenomas from K-ras(V12)/Cre/Msh2(-/-) mice showed transgene recombination with expression of K-ras(V12) 4A and 4B transcripts and proteins. Sequencing of endogenous murine K-ras showed mutations in two out of 10 tumours examined from Msh2(-/-) mice, but no mutations in 17 tumours from K-ras(V12)/Cre/Msh2(-/-) mice. Expression of K-ras(V12) in tumours caused activation of the mitogen-activated protein kinase and Akt/protein kinase B signaling pathways, demonstrated by phosphorylation of p44MAPK, Akt and GSK3beta, as well as transcriptional upregulation of Pem, Tcl-1 and Trap1a genes (known targets of K-ras(V12) expression in stem cells). Thus, mutated K-ras cooperates synergistically with MMR deficiency to accelerate intestinal tumorigenesis, particularly in the large intestine.

Fusion of splicing factor genes PSF and NonO (p54nrb) to the TFE3 gene in papillary renal cell carcinoma.

We demonstrate that the cytogenetically defined translocation t(X;1)(p11.2;p34) observed in papillary renal cell carcinomas results in the fusion of the splicing factor gene PSF located at 1p34 to the TFE3 helix-loop-helix transcription factor gene at Xp11.2. In addition we define an X chromosome inversion inv(X)(p11.2;q12) that results in the fusion of the NonO (p54nrb) gene to TFE3. NonO (p54nrb), the human homologue of the Drosophila gene NonAdiss which controls the male courtship song, is closely related to PSF and also believed to be involved in RNA splicing. In each case the rearrangement results in the fusion of almost the entire splicing factor protein to the TFE3 DNA-binding domain. These observations suggest the possibility of intriguing links between the processes of RNA splicing, DNA transcription and oncogenesis.

Fluorescent BAT-25 and BAT-26 analysis of T cell prolymphocytic leukaemia.

T cell prolymphocytic leukaemia (T-PLL) is a chronic mature T cell malignancy with many random cytogenetic abnormalities. These imply that maintenance of genomic integrity is impaired. This is supported by the recent finding that the ataxia telangiectasia gene, ATM, which contributes to maintaining genomic integrity, is frequently mutated in this disease. To evaluate in T-PLL the role of other genes with comparable function, a fluorescence-based semi-automated assay was developed for BAT-25 and BAT-26. These markers contain sequences that are particularly unstable in cells with DNA mismatch repair defects. Application of the assay to 20 T-PLL cases found no evidence for such defects.

Anaplastic large cell lymphoma-propagating cells are detectable by side population analysis and possess an expression profile reflective of a primitive origin.

Cancer stem cells or tumour-propagating cells (TPCs) have been identified for a number of cancers, but data pertaining to their existence in lymphoma so far remain elusive. We show for the first time that a small subset of cells purified from human anaplastic lymphoma kinase (ALK)-positive and -negative, anaplastic large cell lymphoma cell lines and primary patient tumours using the side population (SP) technique have serial tumour-propagating capacity both in vitro and in vivo; they give rise to both themselves and the bulk tumour population as well as supporting growth of the latter through the production of soluble factors. In vivo serial dilution assays utilising a variety of model systems inclusive of human cell lines, primary human tumours and nucleophosmin (NPM)-ALK-induced murine tumours demonstrate the TPC frequency to vary from as many as 1/54 to 1/1336 tumour cells. In addition, the SP cells express higher levels of pluripotency-associated transcription factors and are enriched for a gene expression profile consistent with early thymic progenitors. Finally, our data show that the SP cells express higher levels of the NPM-ALK oncogene and are sensitive to an ALK inhibitor.

An improved high throughput heteroduplex mutation detection system for screening BRCA2 mutations-fluorescent mutation detection (F-MD).

We describe an improved, fast, automated method for screening large genes such as BRCA2 for germline genomic mutations. The method is based on heteroduplex analysis, and has been adapted for a high throughput application by combining the fluorescent technology of automated sequencers and robotic sample handling. This novel approach allows the entire BRCA2 gene to be screened with appropriate overlaps in four lanes of an ABI 377 gel. The method will detect all types of mutations, especially point mutations, more reliably and robustly than other commonly used conformational sensitive methods (e.g. CSGE). In addition we show that this approach, which relies on band shift detection, is able to detect single base substitutions that have hitherto only been detectable by direct sequencing methods.

Molecular and cytogenetic analysis of glioblastoma multiforme.

Glioblastoma multiforme (GBM) is the most common primary tumor occurring in the central nervous system of adults. Although progress has been made in clinical management of this tumor, little is known about the molecular defects underlying the initiation and progression of GBM. To address these issues, we have characterized five cases of GBM using cytogenetics, comparative genomic hybridization (CGH), fluorescence in situ hybridization (FISH), and direct sequencing. All of these tumors were observed to have clonal chromosome aberrations. Complicated chromosome translocations including der(18)t(2;4;12;18), der(X)t(X;10)(q27.1;p12.1) and der(10)t(10;15)(p11.23;q11.2), and der(1) (:1p31-->1q44::7q11. 3-->7qter) were seen in three tumors. Loss of the CDKN2 gene was noted in four tumors. A gain of copy number of the Cathepsin L gene was seen in two tumors. Amplification of the CDK4, MDM2, and GLI/CHOP genes was noted in two tumors, and amplification of the PDGFR gene was detected in one tumor. Mutation of exon 5 of the TP53 gene was found in three tumors. No mutation of the BCL10 gene was detected in five cases of GBM analyzed, although deletion of chromosome 1p was seen in two tumors. These results provide information for further investigation of GBM.

Molecular and cytogenetic analysis of lymphoblastoid and colon cancer cell lines from cotton-top tamarin (Sagiunus oedipus).

The cotton-top tamarin (CTT) (Sagiunus oedipus) has been used as an animal model to investigate the etiology and pathophysiology of several human diseases, including ulcerative colitis and its associated colorectal carcinoma (CRC). Little is known, however, about genetic synteny between CTT and humans, and about chromosome aberrations in CTT CRC. To address these issues, we have analyzed CTT lymphoblastoid and CRC cell lines using cytogenetics, fluorescence in situ hybridization (Zoo-FISH), and direct sequencing. The CTT lymphocytes had pseudodiploid chromosomes of 46. The CTT CRC cells showed near-diploid chromosomes of 45. Several clonal structural aberrations were observed, including der(1), a marker chromosome, and double minutes. Zoo-FISH using human chromosome 2, 3, 5, 6, 9, 11, 13, 15, 16, 17, 19, 22, and X paints identified homologous chromosomes and subchromosomal regions in the CTT genome. Fluorescence in situ hybridization with human telomeric probe also detected a homologous sequence in CTT genome. Direct sequencing of CTT genomic DNA using primers amplifying exons 4 and 15 of the human APC gene identified DNA sequences in CTT genome with 99% and 95% homology, respectively. These results provide a basis for further comparative studies of CTT and human genome.

Allelotype of uterine leiomyomas.

Uterine leiomyomas are the most common benign tumor that arise from smooth muscle cells of the myometrium. Little is known about the etiology and pathogenesis of this tumor. To investigate the molecular pathogenesis of these tumors, we have conducted an allelotype of 102 leiomyomas from 12 patients, using 67 fluorescently-tagged oligonucleotide primers amplifying microsatellite loci covering all autosomes. No areas of the genome showed frequent loss of heterozygosity (LOH); however, the highest rate of LOH (9%) was observed on 7q, consistent with previous cytogenetic observations. Uterine leiomyomas are sometimes multiple. In general, multiplicity of other types of neoplasm is associated with genetic predisposition to the disease. Because multiple tumors were available from each of the 12 patients studied, we looked for evidence of allele-specific LOH, which might indicate the presence of an underlying predisposition gene. However, no evidence for allele-specific LOH was detected, indicating that if cases of multiple uterine leiomyoma are due to an underlying predisposition gene, it is unlikely to be a recessive oncogene.

Association between the GCG polymorphism of the selenium dependent GPX1 gene and the risk of young onset prostate cancer.

Epidemiological studies have suggested an association between low selenium levels and the development of prostate cancer. Human cellular glutathione peroxidase I (hGPX1) is a selenium-dependent enzyme that protects against oxidative damage and its peroxidase activity is a plausible mechanism for cancer prevention by selenium. The GPX1 gene has a GCG repeat polymorphism in exon 1, coding for a polyalanine tract of five to seven alanine residues. To test if the GPX1 GCG repeat polymorphism associates with the risk of young-onset prostate cancer we conducted a case-control study. The GPX1Ala genotypes were determined for 267 prostate cancer cases and 260 control individuals using polymerase chain reaction (PCR) amplification with fluorescently labelled primers and an ABI 377 automated genotyper. Associations between specific genotypes and the risk of prostate cancer were examined by logistic regression. We found no significant association between the GPX1 genotypes and prostate cancer. There was however an increased frequency of the GPX1Ala6/Ala6 genotype in the prostate cancer cases compared to controls (OR: 1.67; 95% CI: 0.97-2.87). The result of this study suggests that the GPX1 genotype is unlikely to be associated with the risk of developing prostate cancer.

Differential expression of NF-kappaB target genes in MALT lymphoma with and without chromosome translocation: insights into molecular mechanism.

Mucosa-associated lymphoid tissue (MALT) lymphoma is characterized by t(11;18)(q21;q21)/API2-MALT1, t(1;14)(p22;q32)/BCL10-IGH and t(14;18)(q32;q21)/IGH-MALT1, which commonly activate the nuclear factor (NF)-kappaB pathway. Gastric MALT lymphomas harboring such translocations usually do not respond to Helicobacter pylori eradication, while most of those without translocation can be cured by antibiotics. To understand the molecular mechanism of these different MALT lymphoma subgroups, we performed gene expression profiling analysis of 21 MALT lymphomas (13 translocation-positive, 8 translocation-negative). Gene set enrichment analysis (GSEA) of the NF-kappaB target genes and 4394 additional gene sets covering various cellular pathways, biological processes and molecular functions have shown that translocation-positive MALT lymphomas are characterized by an enhanced expression of NF-kappaB target genes, particularly toll like receptor (TLR)6, chemokine, CC motif, receptor (CCR)2, cluster of differentiation (CD)69 and B-cell CLL/lymphoma (BCL)2, while translocation-negative cases were featured by active inflammatory and immune responses, such as interleukin-8, CD86, CD28 and inducible T-cell costimulator (ICOS). Separate analyses of the genes differentially expressed between translocation-positive and -negative cases and measurement of gene ontology term in these differentially expressed genes by hypergeometric test reinforced the above findings by GSEA. Finally, expression of TLR6, in the presence of TLR2, enhanced both API2-MALT1 and BCL10-mediated NF-kappaB activation in vitro. Our findings provide novel insights into the molecular mechanism of MALT lymphomas with and without translocation, potentially explaining their different clinical behaviors.

Chlamydia psittaci is variably associated with ocular adnexal MALT lymphoma in different geographical regions.

Infectious agents play a critical role in MALT lymphoma development. Studies from Italy showed Chlamydia psittaci infection in 87% of ocular adnexal MALT lymphomas and complete or partial regression of the lymphoma after C. psittaci eradication in four of nine cases. However, C. psittaci was not demonstrated in ocular adnexal MALT lymphomas from the USA. This study was thus designed to investigate further the role of C. psittaci, and other infectious agents commonly associated with chronic eye disease, in the development of ocular adnexal MALT lymphoma. The presence of C. psittaci, C. trachomatis, C. pneumoniae, herpes simplex virus 1 and 2 (HSV1, HSV2), and adenovirus 8 and 19 (ADV8, ADV19) was assessed separately by polymerase chain reaction in 142 ocular adnexal MALT lymphomas, 53 non-marginal zone lymphomas, and 51 ocular adnexal biopsies without a lymphoproliferative disorder (LPD), from six geographical regions. C. psittaci was detected at similar low frequencies in non-LPD and non-marginal zone lymphoma groups from different geographical regions (0-14%). Overall, the prevalence of C. psittaci was significantly higher in MALT lymphomas (22%) than in non-LPD (10%, p=0.042) and non-marginal zone lymphoma cases (9%, p=0.033). However, the prevalence of C. psittaci infection in MALT lymphoma showed marked variation among the six geographical regions examined, being most frequent in Germany (47%), followed by the East Coast of the USA (35%) and the Netherlands (29%), but relatively low in Italy (13%), the UK (12%), and Southern China (11%). No significant differences in the detection of C. pneumoniae, C. trachomatis, HSV1, HSV2, ADV8, and ADV19 were found between lymphomas and controls from different geographical regions. In conclusion, our results show that C. psittaci, but not C. pneumoniae, C. trachomatis, HSV1, HSV2, ADV8 or ADV19, is associated with ocular adnexal MALT lymphoma and that this association is variable in different geographical areas.