A phase II study of sunitinib in recurrent and/or metastatic adenoid cystic carcinoma (ACC) of the salivary glands: current progress and challenges in evaluating molecularly targeted agents in ACC.

BACKGROUND: Vascular endothelial growth factor (VEGF) and c-kit are highly expressed in adenoid cystic carcinoma (ACC) and associated with biologic aggressiveness. This study aimed to assess the antitumor activity of sunitinib, a multi-targeted inhibitor of vascular endothelial growth factor receptor, c-kit, platelet-derived growth factor receptor, ret proto-oncogene (RET) and FMS-like tyrosine kinase 3 (FLT3), in ACC of the salivary gland. PATIENTS AND METHODS: Patients with progressive, recurrent and/or metastatic ACC were treated with sunitinib 37.5 mg daily in this single-arm, two-stage phase II trial. Response was assessed every 8 weeks. RESULTS: Fourteen patients were enrolled on to the study. Among 13 assessable patients, there were no objective responses, 11 patients had stable disease (SD), 8 patients had SD ≥ 6 months and 2 patients had progressive disease as best response. Median time to progression was 7.2 months. Median overall survival was 18.7 months. Toxic effects occurring in at least 50% of patients included fatigue, oral mucositis and hypophosphatemia usually of mild to moderate severity. CONCLUSIONS: Although no responses were observed, sunitinib was well tolerated, with prolonged tumor stabilization of ≥ 6 months in 62% of assessable patients. The lack of responses is comparable with other trials of molecularly targeted agents in ACC and highlights the need for novel strategies in phase II clinical trial design.

Integrative analysis of array-comparative genomic hybridisation and matched gene expression profiling data reveals novel genes with prognostic significance in oesophageal adenocarcinoma.

BACKGROUND AND AIMS: The incidence of oesophageal adenocarcinoma (OAC) has been increasing rapidly with a dismal survival rate of less than 20%. Understanding the genomic aberrations and biology of this cancer may enhance disease interventions. This study aimed to use genome-wide genomic and expression data to enhance the understanding of OAC pathogenesis and identify groups with differential outcomes. METHODS: Array-comparative genomic hybridisation (aCGH) analysis was carried out on 56 fresh frozen OAC resection samples with long-term clinical follow-up data. Samples with aberrations were further analysed with whole-genome single-nucleotide polymorphism arrays to confirm aCGH findings. Matched gene expression microarray data were used to identify genes with high copy number-expression correlations. Nested-multiplex PCR on DNA from microdissected specimens and fluorescence in situ hybridisation assays were used for target validation. Immunohistochemistry on the same cohort and independent samples (n=371) was used for subsequent validation. Kaplan-Meier survival analyses were performed based on aCGH data after unsupervised K-means clustering (K=5, 50 iterations) and immunohistochemistry data. RESULTS: aCGH identified 17 common regions (>5% samples) of gains and 11 common regions of losses, including novel regions in OAC (loci 11p13 and 21q21.2). Integration of aCGH data with matched gene expression microarray data highlighted genes with high copy number-expression correlations: two deletions (p16/CDKN2A, MBNL1) and four gains (EGFR, WT1, NEIL2, MTMR9). Immunohistochemistry demonstrated protein over-expression of targets with gains: EGFR (10%), WT1 (20%), NEIL2 (14%) and MTMR9 (25%). These targets individually (p<0.060) and in combination had prognostic significance (p=0.008). On the genomic level, K-means clustering identified a cluster (32% of cohort) with differential log(2) ratios of 16 CGH probes (p<4×10(-7)) and a worse prognosis (median survival=1.37 years; p=0.015). CONCLUSIONS: Integration of aCGH and gene expression data identified copy number aberrations and novel genes with prognostic potential in OAC.

The NRG1 gene is frequently silenced by methylation in breast cancers and is a strong candidate for the 8p tumour suppressor gene.

Neuregulin-1 (NRG1) is both a candidate oncogene and a candidate tumour suppressor gene. It not only encodes the heregulins and other mitogenic ligands for the ERBB family, but also causes apoptosis in NRG1-expressing cells. We found that most breast cancer cell lines had reduced or undetectable expression of NRG1. This included cell lines that had translocation breaks in the gene. Similarly, expression in cancers was generally comparable to or less than that in various normal breast samples. Many non-expressing cell lines had extensive methylation of the CpG island at the principal transcription start site at exon 2 of NRG1. Expression was reactivated by demethylation. Many tumours also showed methylation, whereas normal mammary epithelial fragments had none. Lower NRG1 expression correlated with higher methylation. Small interfering RNA (siRNA)-mediated depletion of NRG1 increased net proliferation in a normal breast cell line and a breast cancer cell line that expressed NRG1. The short arm of chromosome 8 is frequently lost in epithelial cancers, and NRG1 is the most centromeric gene that is always affected. NRG1 may therefore be the major tumour suppressor gene postulated to be on 8p: it is in the correct location, is antiproliferative and is silenced in many breast cancers.

Assessment of erlotinib pharmacodynamics in tumors and skin of patients with head and neck cancer.

BACKGROUND: The purpose of the study was to evaluate the effects of erlotinib on epidermal growth factor receptor (EGFR)-related signaling elements in tumor and skin from patients with advanced squamous cell carcinoma of the head and neck (HNSCC) and seek relationships between relevant clinical, biological, and pharmacokinetic parameters. PATIENTS AND METHODS: Immunostaining for EGFR, p-EGFR, p-ERK, p-Akt, and p27 were analyzed semiquantitatively in serial tumor and skin samples from participating patients. Steady-state trough concentrations of erlotinib and its metabolite OSI-420 were also determined. RESULTS: Of 25 patients enrolled, 20 (80%) paired pre- and posttreatment skin biopsies and seven (28%) paired tumor biopsies were evaluable for at least one immunohistochemical parameter. The severity of skin toxicity related to time to progression (TTP) (P = 0.048) and overall survival (P < 0.001). C(ss,min) values for erlotinib and OSI-420 also related to TTP (P = 0.042 and 0.036, respectively). Erlotinib treatment was associated with decreased p-EGFR expression in 66% of evaluable tumor samples, which seemed related to increased TTP and survival, and p27 was up-regulated in 59% of evaluable skin biopsy samples following treatment. CONCLUSIONS: The feasibility of obtaining serial evaluable biopsies of HNSCC was suboptimal. Nevertheless, erlotinib inhibited p-EGFR in HNSCC tumors, which appeared associated to clinical benefit, and induced p27 in biopsies of normal skin.

Cross-platform array comparative genomic hybridization meta-analysis separates hematopoietic and mesenchymal from epithelial tumors.

A series of studies have been published that evaluate the chromosomal copy number changes of different tumor classes using array comparative genomic hybridization (array CGH); however, the chromosomal aberrations that distinguish the different tumor classes have not been fully characterized. Therefore, we performed a meta-analysis of different array CGH data sets in an attempt to classify samples tested across different platforms. As opposed to RNA expression, a common reference is used in dual channel CGH arrays: normal human DNA, theoretically facilitating cross-platform analysis. To this aim, cell line and primary cancer data sets from three different dual channel array CGH platforms obtained by four different institutes were integrated. The cell line data were used to develop preprocessing methods, which performed noise reduction and transformed samples into a common format. The transformed array CGH profiles allowed perfect clustering by cell line, but importantly not by platform or institute. The same preprocessing procedures used for the cell line data were applied to data from 373 primary tumors profiled by array CGH, including controls. Results indicated that there is no apparent feature related to the institute or platform and that array CGH allows for unambiguous cross-platform meta-analysis. Major clusters with common tissue origin were identified. Interestingly, tumors of hematopoietic and mesenchymal origins cluster separately from tumors of epithelial origin. Therefore, it can be concluded that chromosomal aberrations of tumors from hematopoietic and mesenchymal origin versus tumors of epithelial origin are distinct, and these differences can be picked up by meta-analysis of array CGH data. This suggests the possibility of prospectively using combined analysis of diverse copy number data sets for cancer subtype classification.

p300 is required for orderly G1/S transition in human cancer cells.

The role of the transcriptional coactivator p300 in cell cycle control has not been analysed in detail due to the lack of appropriate experimental systems. We have now examined cell cycle progression of p300-deficient cancer cell lines, where p300 was disrupted either by gene targeting (p300(-) cells) or knocked down using RNAi. Despite significant proliferation defects under normal growth conditions, p300-deficient cells progressed rapidly through G1 with premature S-phase entry. Accelerated G1/S transition was associated with early retinoblastoma (RB) hyperphosphorylation and activation of E2F targets. The p300-acetylase activity was dispensable since expression of a HAT-deficient p300 mutant reversed these changes. Co-immunoprecipitation showed p300/RB interaction occurs in vivo during G1, and this interaction has two peaks: in early G1 with unphosphorylated RB and in late G1 with phosphorylated RB. In vitro kinase assays showed that p300 directly inhibits cdk6-mediated RB phosphorylation, suggesting p300 acts in early G1 to prevent RB hyperphosphorylation and delay premature S-phase entry. Paradoxically, continued cycling of p300(-) cells despite prolonged serum depletion was observed, and this occurred in association with persistent RB hyperphosphorylation. Altogether, these results suggest that p300 has an important role in G1/S control, possibly by modulating RB phosphorylation.

Using array-comparative genomic hybridization to define molecular portraits of primary breast cancers.

We analysed 148 primary breast cancers using BAC-arrays containing 287 clones representing cancer-related gene/loci to obtain genomic molecular portraits. Gains were detected in 136 tumors (91.9%) and losses in 123 tumors (83.1%). Eight tumors (5.4%) did not have any genomic aberrations in the 281 clones analysed. Common (more than 15% of the samples) gains were observed at 8q11-qtel, 1q21-qtel, 17q11-q12 and 11q13, whereas common losses were observed at 16q12-qtel, 11ptel-p15.5, 1p36-ptel, 17p11.2-p12 and 8ptel-p22. Patients with tumors registering either less than 5% (median value) or less than 11% (third quartile) total copy number changes had a better overall survival (log-rank test: P=0.0417 and P=0.0375, respectively). Unsupervised hierarchical clustering based on copy number changes identified four clusters. Women with tumors from the cluster with amplification of three regions containing known breast oncogenes (11q13, 17q12 and 20q13) had a worse prognosis. The good prognosis group (Nottingham Prognostic Index (NPI)

Comparative genomic hybridization of esophageal adenocarcinoma and squamous cell carcinoma cell lines.

We compared whole genomic changes in cell lines generated from esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC). To do so, we investigated chromosomal DNA copy number changes in four EAC cell lines and three ESCC cell lines using comparative genomic hybridization (CGH). Frequent gains of chromosome 5p, 8q, and 20q occurred in both ESCC and EAC cell lines, but gains of 3q, 5q, and 9q were mainly seen in ESCC cell lines; gain of chromosome 10q25-qtel was mainly seen in EAC cell lines. It was noticeable that 18q12 loss existed in 2 EAC and 1 ESCC cell lines in our study. The chromosomal abnormalities common to all of the cell lines may help to identify candidate genes related to both EAC and ESCC. The chromosome aberrations mainly seen in either EAC or ESCC cell lines are in keeping with their known different etiology and may lead to the identification of genes important for disease specific pathogenesis.

Impaired transforming growth factor beta signalling in Barrett's carcinogenesis due to frequent SMAD4 inactivation.

BACKGROUND AND AIMS: Transforming growth factor beta (TGF-beta) is frequently involved in gastrointestinal carcinogenesis although its contribution to oesophageal adenocarcinoma (AC) and its precursor Barrett's oesophageal epithelium (BE) metaplasia are unclear. METHODS: Expression of TGF-beta signalling components was assessed by reverse transcription-polymerase chain reaction (PCR), western blot, and immunohistochemistry in oesophageal endoscopic biopsies and cell lines. Genomic alterations in SMAD4 were characterised by fluorescence in situ hybridisation, methylation specific PCR, and sequencing. Functional integrity of TGF-beta signalling was assessed by characterisation of p21 and proliferation status. Smad4 negative BIC-1 cells were transiently transfected with smad4 and TGF-beta responsiveness evaluated. RESULTS: smad4 mRNA expression was progressively reduced in the metaplasia-dysplasia-adenocarcinoma sequence (p<0.01). A quarter of AC samples displayed an abnormal Smad4 protein isoform, with no corresponding changes in gene sequence or organisation. Methylation of smad4 has not been described previously but we found promoter methylation in 70% of primary AC samples. In 6/8 oesophageal cell lines, chromosomal rearrangements affected the smad4 locus. Lack of smad4 expression in BIC-1 cells occurred secondary to loss of one copy and extensive deletion of the second allele's promoter region. TGF-beta dependent induction of p21 and downregulation of minichromosome maintenance protein 2 was lost in >80% of BE and AC. TGF-beta failed to inhibit proliferation in 5/8 oesophageal cell lines. In BIC-1, the antiproliferative response was restored following transient transfection of smad4 cDNA. CONCLUSIONS: In BE carcinogenesis, downregulation of Smad4 occurs due to several different mechanisms, including methylation, deletion, and protein modification. Frequent alterations in TGF-beta signalling lead to a functionally significant impairment of TGF-beta mediated growth suppression.

A simple and reliable pretreatment protocol facilitates fluorescent in situ hybridisation on tissue microarrays of paraffin wax embedded tumour samples.

AIMS: To describe a robust pretreatment protocol for preparing paraffin wax embedded tissues on tissue microarrays for fluorescence in situ hybridisation (FISH). The newly developed pretreatment protocol described here was compared with the commonly used sodium thiocyanate based protocol and two different heating methods used in standard antigen unmasking protocols for immunohistochemistry (pressure cooking and microwaving in citrate acid buffer). METHODS: Dewaxed tissue sections were incubated in 10mM citric acid buffer at 80 degrees C for 30 minutes to two hours, followed by a short pepsin digestion (1-5 mg/ml). Pretreated tissues were co-denatured with DNA probes at 80 degrees C for 10 minutes, followed by hybridisation at 37 degrees C for 48-72 hours. RESULTS: The three protocols using citrate acid buffer produced FISH signals with superior signal to noise ratios compared with sodium thiocyanate pretreatment. Most importantly, the best tissue attachment was achieved using the newly developed pretreatment protocol: on tissue microarrays less than 1% of cores were lost. To date, a total of 30 probes have been successfully hybridised on to breast tissue and multi-tissue microarrays. CONCLUSION: This pretreatment protocol is easy, reproducible, and facilitates FISH on tissue microarrays, with potential for widespread application in cancer research.

Degenerate oligonucleotide primed-polymerase chain reaction-based array comparative genomic hybridization for extensive amplicon profiling of breast cancers : a new approach for the molecular analysis of paraffin-embedded cancer tissue.

We have developed a protocol for degenerate oligonucleotide-primed-polymerase chain reaction-based array comparative genomic hybridization (array CGH) that, when combined with a laser microdissection technique, allows the analysis of cancer cell populations isolated from routine, formalin-fixed, paraffin-embedded tissue samples. Comparison of copy number changes detected by degenerate oligonucleotide-primed-polymerase chain reaction-based array CGH to those detected by conventional array CGH or fluorescence in situ hybridization, demonstrated that amplifications can be reliably detected. Using a genomic microarray containing 57 oncogenes, we screened a total of 28 breast cancer samples and obtained a detailed amplicon profile that is the most comprehensive to date in human breast cancer. The array CGH method described here will allow the genetic analysis of paraffin-embedded human cancer materials for example in the context of clinical trials.

Absence of rearrangements in the BRCA2 gene in human cancers.

Mutations of BRCA2 in sporadic breast and ovarian carcinomas are exceedingly rare. This led to the suggestion that large genomic rearrangements could be involved. We performed Southern blots in genomic DNA from 130 primary breast cancers and 83 cancer cell lines (breast, ovarian, pancreatic and small cell lung carcinomas) and found no genomic rearrangements. These results suggest that a gene other than BRCA2 is the target of the frequent 13q12.3 allelic deletions in human cancers.

Molecular cytogenetic analysis of breast cancer cell lines.

The extensive chromosome rearrangements of breast carcinomas must contribute to tumour development, but have been largely intractable to classical cytogenetic banding. We report here the analysis by 24-colour karyotyping and comparative genomic hybridization (CGH) of 19 breast carcinoma cell lines and one normal breast epithelial cell line, which provide model examples of karyotype patterns and translocations present in breast carcinomas. The CGH was compared with CGH of 106 primary breast cancers. The lines varied from perfectly diploid to highly aneuploid. Translocations were very varied and over 98% were unbalanced. The most frequent in the carcinomas were 8;11 in five lines; and 8;17, 1;4 and 1;10 in four lines. The most frequently involved chromosome was 8. Several lines showed complex multiply-translocated chromosomes. The very aneuploid karyotypes appeared to fall into two groups that evolved by different routes: one that steadily lost chromosomes and at one point doubled their entire karyotype; and another that steadily gained chromosomes, together with abnormalities. All karyotypes fell within the range seen in fresh material and CGH confirmed that the lines were broadly representative of fresh tumours. The karyotypes provide a resource for the cataloguing and analysis of translocations in these tumours, accessible at http://www.path.cam.ac.uk/ approximately pawefish.

Mutations truncating the EP300 acetylase in human cancers.

The EP300 protein is a histone acetyltransferase that regulates transcription via chromatin remodelling and is important in the processes of cell proliferation and differentiation. EP300 acetylation of TP53 in response to DNA damage regulates its DNA-binding and transcription functions. A role for EP300 in cancer has been implied by the fact that it is targeted by viral oncoproteins, it is fused to MLL in Leukaemia and two missense sequence alterations in EP300 were identified in epithelial malignancies. Nevertheless, direct demonstration of the role of EP300 in tumorigenesis by inactivating mutations in human cancers has been lacking. Here we describe EP300 mutations, which predict a truncated protein, in 6(3%) of 193 epithelial cancers analysed. Of these six mutations, two were in primary tumours (a colorectal cancer and a breast cancer) and four were in cancer cell lines (colorectal, breast and pancreatic). In addition, we identified a somatic in-frame insertion in a primary breast cancer and missense alterations in a primary colorectal cancer and two cell lines (breast and pancreatic). Inactivation of the second allele was demonstrated in five of six cases with truncating mutations and in two other cases. Our data show that EP300 is mutated in epithelial cancers and provide the first evidence that it behaves as a classical tumour-suppressor gene.

Cell cycle checkpoint evasion and protracted cell cycle arrest in X-irradiated small-cell lung carcinoma cells.

PURPOSE: To determine the longevity and dose-dependence of acute X-irradiation-induced cell cycle perturbations in a panel of seven small-cell lung carcinoma (SCLC) cell lines (COR-L32B, COR-L51B, COR-L88B, COR-L96C, COR-L103, COR-L266B, COR-L279), assessed for TP53 tumour suppressor gene status and showing characteristically long population doubling periods. MATERIALS AND METHODS: Cell lines were screened for abnormalities in TP53. Cell cycle arrest and nuclear fragmentation were determined by flow cytometry under culture conditions that minimized the propensity of SCLC cells to form multicellular aggregates. A faster growing SCLC cell line (NCI-H69) and two breast tumour cell lines were used as controls. RESULTS: NCI-H69 and five of the COR-SCLC cell lines showed clear evidence of TP53 abnormalities and the cycle arrest responses of the breast tumour cell lines established the effects of TP53 mutation on G1/S checkpoint loss. All SCLC lines, at 24 h after low dose irradiation, showed abrogation of the G1/S checkpoint together with a range of expression of a protracted G2/M delay. G2/M delay progressed in all panel cell lines up to 48 h post-irradiation while NCI-H69 showed significant recovery for the dose range 75-600cGy. Only NCI-H69 and one panel line showed dose-dependent progression to complete nuclear DNA fragmentation. CONCLUSIONS: The culture method permits the measurement of cell cycle effects that reflect the TP53 status of SCLC cells. G1/S checkpoint failure, long-term radiation-induced G2 arrest, highly muted apoptotic responses and delayed recovery appear to be typical responses of the recently derived COR-SCLC lines. The results imply that low levels of unrepaired DNA damage, induced at clinically relevant doses, can persist for days in SCLC cells with long cell cycle traverse times, and can remain capable of checkpoint activation with implications for S phase-targeted therapies.

Fatal occupational injuries associated with forklifts, United States, 1980-1994.

BACKGROUND: This paper describes deaths of American workers involving forklifts during the 15-year period from January 1, 1980 to December 31, 1994. METHODS: Death certificate data were obtained from the National Institute for Occupational Safety and Health's (NIOSH's) National Traumatic Occupational Fatality (NTOF) surveillance system. The narrative fields on the death certificate were searched for keywords indicating that a powered industrial vehicle (PIV) or forklift was involved in the death. This study examined the circumstances of the forklift-related deaths, the nature of the injury, and the decedent's age, gender, race, occupation, and industry. Average annual employment data from the Bureau of the Census were used to calculate civilian fatality rates by age, gender, industry, and occupation. RESULTS: A total of 1,021 deaths were identified. The average age of the fatally injured worker was 38 years; the 1,021 forklift-related deaths resulted in a total of 27,505 years of productive life lost. The three most common circumstances of the fatalities were forklift overturns (22%), pedestrian struck by forklifts (20%), and worker crushed by forklift (16%). The greatest proportion of the fatalities (37%) occurred to workers in Manufacturing, followed by Transportation, Communication, and Public Utilities, (TCPU), (17%), Construction (16%), Wholesale Trade (8%), and Agriculture, Forestry, and Fishing (AFF) (7%). The highest forklift-related fatality rates per ten million workers occurred among transport operatives (34.0) and laborers (32.0). CONCLUSIONS: Many of the fatalities resulting from forklift "overturns" might have been prevented if the operator had been restrained with a lap/shoulder belt. Careful consideration should be given to separating pedestrian and forklift traffic, and restricting the use of forklifts near time clocks, exits, and other areas where large numbers of pedestrians pass through an area in a short time. Additionally, systematic traffic control, including rules for pedestrian and forklift traffic, will be necessary to reduce the enormous injury and death toll associated with forklifts. Am. J. Ind. Med. 36:504-512, 1999. Published 1999 Wiley-Liss, Inc.

MLL2, the second human homolog of the Drosophila trithorax gene, maps to 19q13.1 and is amplified in solid tumor cell lines.

The Mixed Lineage Leukemia (MLL) gene is commonly involved in translocations in infantile leukemia and is amplified in some cases of adult myeloid leukemia. A homolog of MLL denoted MLL2, which represents the second human homolog of the Drosophila trithorax gene, was characterized by assembling ESTs, the KIAA0304 cDNA clone, RT - PCR fragments and a new clone isolated from a cDNA phage library and compared to the available genomic sequence. The MLL2 gene maps to 19q13.1, a region of frequent rearrangement or amplification in solid tumors. MLL2 consists of an 8.5 - 9 kb transcript and spans 20 kb of genomic DNA. The predicted MLL2 protein possesses all of the major domains defined in MLL and the two genes have a similar genomic structure. We find that MLL2 is amplified in two of 14 pancreatic carcinoma cell lines and one of five glioblastoma cell lines and is a likely critical gene in 19q13.1 amplifications. It is also a candidate for chromosomal rearrangements involving this chromosome locus. MLL2 is one additional mammalian trithorax-group gene with involvement in human cancer.

Lymphocyte subsets in systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterised by increased B cell activity and depressed T cell function. However, the contribution of the immunoregulatory system to its pathogenesis is still unclear. The recent development in the production of monoclonal antibodies and the availability of bench-top flow cytometers have allowed rapid quantitation of peripheral blood lymphocyte subsets. We analysed the distribution of the lymphocyte subsets in 24 patients with active SLE and 18 with inactive SLE. The distribution of immunoregulatory cells in 72 normal volunteers was used as control. Statistical analysis showed that there were significant differences between both the SLE groups and the normal controls, for total lymphocytes, T cells, B cells, T helper cells, T suppressor cells, T helper/suppressor ratio and natural killer cells. There was a significant difference for T helper cells between active and inactive SLE. T helper cells levels were found to be low in inactive SLE and lower in active SLE. It appears that treatment-induced remissions did not restore the levels of immunoregulatory cells to normal. Thus, T helper cell levels reflect disease activity and longitudinal assays of T helper cells may serve as an indicator of disease reactivation.

Unexpected Epithelial Membrane Antigen (EMA) and Cytokeratin Expression in a Case of Infantile Acute Monoblastic Leukaemia.

A previously healthy eleven month old male Malay infant presented with fever, upper respiratory tract infection and right knee swelling. Pallor, bilateral proptosis, hepatosplenomegaly, multiple scalp swellings and a right cheek swelling were observed. Investigations revealed that he had acute monoblastic leukemia or FAB M5a. Immunophenotyping by flow cytometry showed that the blast cells were positive for CD45, CD13, CD33, HLA-DR, CDllc, CD71, EMA, and Cytokeratin. They were negative for CD34, CD19, CD10, CD22, CD2, CD3, CD4, CD7, CD8, CD61, NK, Glycophorin A, and CD14. The monoblasts were used to evaluate anti-EMA and anti-cytokeratin. They were unexpectedly found to be positive. Acute monoblastic leukaemias are well known to show extramedullary infiltration and this may be their primary mode of presentation. Thus, in immunochemostry, when using EMA and cytokeratin expression in the differential diagnosis of neoplastic diseases, it is important to consider that monoblasts may express these markers as illustrated by this case.

Protection of conjugated linoleic acids against 2-amino-3- methylimidazo[4,5-f]quinoline-induced colon carcinogenesis in the F344 rat: a study of inhibitory mechanisms.

Grilled ground beef contains a number of heterocyclic amine carcinogens, such as 2-amino-3-methylimidazo[4,5-f] quinoline (IQ), as well as anticarcinogenic conjugated linoleic acids (CLA). In the present study, CLA was administered to male F344 rats by gavage on alternating days in weeks 1-4, while IQ was given by gavage every other day in weeks 3 and 4 (100 mg/kg body wt). Rats were killed 6 h after the final carcinogen dose 16 in order to score colonic aberrant crypt foci (ACF). In the ACF study, CLA had no effect on the size of the foci, but inhibited significantly (P < 0.05) the number of ACF/colon, from 4.3 +/- 2.4 in controls to 1.1 +/- 1.3 in CLA-treated rats (mean +/- SD, n = 10). Rats given CLA also had significantly lower IQ-DNA adducts in the colon as determined by 32P-postlabeling analysis; relative adduct labeling levels (RAL x 10(7) for the major adduct were 9.13 +/- 2.6 in controls versus 5.42 +/- 1.8 in CLA-treated animals (P < 0.05). Mechanism studies indicated that CLA and other fatty acids interact with certain heterocyclic amines in a manner consistent with substrate-ligand binding. However, no such interaction occurred with IQ, and CLA failed to inhibit significantly the mutagenicity of N-hydroxy-IQ in the Salmonella assay. Liver microsomes from CLA-treated rats exhibited lower activities for dealkylation of 7-ethoxyresorufin and methoxyresorufin and activated IQ to DNA binding species less effectively than microsomes from control animals. Direct addition of CLA to the in vitro incubation inhibited IQ-DNA binding and was associated with increased recovery of unmetabolized parent compound. In the Salmonella assay, CLA inhibited the mutagenic activity of IQ in the presence of S9 or ram seminal vesicle microsomes. Collectively, these results support a mechanism involving inhibition of carcinogen activation by CLA, as opposed to direct interaction with the procarcinogen, scavenging of electrophiles or selective induction of phase I detoxification pathways.