FAS system deregulation in T-cell lymphoblastic lymphoma

The acquisition of resistance towards FAS-mediated apoptosis may be required for tumor formation. Tumors from various histological origins exhibit FAS mutations, the most frequent being hematological malignancies. However, data regarding FAS mutations or FAS signaling alterations are still lacking in precursor T-cell lymphoblastic lymphomas (T-LBLs). The available data on acute lymphoblastic leukemia, of precursor origin as well, indicate a low frequency of FAS mutations but often report a serious reduction in FAS-mediated apoptosis as well as chemoresistance, thus suggesting the occurrence of mechanisms able to deregulate the FAS signaling pathway, different from FAS mutation. Our aim at this study was to determine whether FAS-mediated apoptotic signaling is compromised in human T-LBL samples and the mechanisms involved. This study on 26 T-LBL samples confirms that the FAS system is impaired to a wide extent in these tumors, with 57.7% of the cases presenting any alteration of the pathway. A variety of mechanisms seems to be involved in such alteration, in order of frequency the downregulation of FAS, the deregulation of other members of the pathway and the occurrence of mutations at FAS. Considering these results together, it seems plausible to think of a cumulative effect of several alterations in each T-LBL, which in turn may result in FAS/FASLG system deregulation. Since defective FAS signaling may render the T-LBL tumor cells resistant to apoptotic cell death, the correct prognosis, diagnosis and thus the success of anticancer therapy may require such an in-depth knowledge of the complete scenario of FAS-signaling alterations.

FGF receptor genes and breast cancer susceptibility: results from the Breast Cancer Association Consortium

BACKGROUND

Breast cancer is one of the most common malignancies in women. Genome-wide association studies have identified FGFR2 as a breast cancer susceptibility gene. Common variation in other fibroblast growth factor (FGF) receptors might also modify risk. We tested this hypothesis by studying genotyped single-nucleotide polymorphisms (SNPs) and imputed SNPs in FGFR1, FGFR3, FGFR4 and FGFRL1 in the Breast Cancer Association Consortium.

METHODS

Data were combined from 49 studies, including 53 835 cases and 50 156 controls, of which 89 050 (46 450 cases and 42 600 controls) were of European ancestry, 12 893 (6269 cases and 6624 controls) of Asian and 2048 (1116 cases and 932 controls) of African ancestry. Associations with risk of breast cancer, overall and by disease sub-type, were assessed using unconditional logistic regression.

RESULTS

Little evidence of association with breast cancer risk was observed for SNPs in the FGF receptor genes. The strongest evidence in European women was for rs743682 in FGFR3; the estimated per-allele odds ratio was 1.05 (95% confidence interval=1.02-1.09, P=0.0020), which is substantially lower than that observed for SNPs in FGFR2.

CONCLUSION

Our results suggest that common variants in the other FGF receptors are not associated with risk of breast cancer to the degree observed for FGFR2.

Phenotypic characterization of hereditary epithelial ovarian cancer based on a tissue microarray study

The pathologic and immunohistochemical features of familial epithelial ovarian cancers are not well understood. We have carried out a comprehensive immunohistochemical study of familial ovarian carcinomas from women with and without BRCA1 or BRCA2 mutations, in order to identify specific and/or common features among these different familial case groups (BRCA1, BRCA2 and non-BRCA1/2) and to identify markers of diagnostic value that might help to select more specific treatments. 73 familial primary ovarian carcinomas were analyzed for the expression of 40 antibodies involved in different genetic pathways using a tissue microarray. Serous carcinomas comprised the majority of all three familial case groups. On the other hand, BRCA1 and BRCA2 carcinomas have similar histopathologic features; i.e. they are often high-grade and are usually diagnosed at a more advanced FIGO stage than non-BRCA1/2 carcinomas. In our series, BRCA1 carcinomas had better clinical evolution and they also more frequently over-expressed PR and P53 than BRCA2 and non-BRCA1/2 carcinomas. Unsupervised cluster analysis and survival analysis identified ERCC1 as a potential marker of better clinical outcome for hereditary epithelial ovarian cancer.

Association of PHB 1630 C>T and MTHFR 677 C>T polymorphisms with breast and ovarian cancer risk in BRCA1/2 mutation carriers: results from a multicenter study

BACKGROUND

The variable penetrance of breast cancer in BRCA1/2 mutation carriers suggests that other genetic or environmental factors modify breast cancer risk. Two genes of special interest are prohibitin (PHB) and methylene-tetrahydrofolate reductase (MTHFR), both of which are important either directly or indirectly in maintaining genomic integrity.

METHODS

To evaluate the potential role of genetic variants within PHB and MTHFR in breast and ovarian cancer risk, 4102 BRCA1 and 2093 BRCA2 mutation carriers, and 6211 BRCA1 and 2902 BRCA2 carriers from the Consortium of Investigators of Modifiers of BRCA1 and BRCA2 (CIMBA) were genotyped for the PHB 1630 C>T (rs6917) polymorphism and the MTHFR 677 C>T (rs1801133) polymorphism, respectively.

RESULTS

There was no evidence of association between the PHB 1630 C>T and MTHFR 677 C>T polymorphisms with either disease for BRCA1 or BRCA2 mutation carriers when breast and ovarian cancer associations were evaluated separately. Analysis that evaluated associations for breast and ovarian cancer simultaneously showed some evidence that BRCA1 mutation carriers who had the rare homozygote genotype (TT) of the PHB 1630 C>T polymorphism were at increased risk of both breast and ovarian cancer (HR 1.50, 95%CI 1.10-2.04 and HR 2.16, 95%CI 1.24-3.76, respectively). However, there was no evidence of association under a multiplicative model for the effect of each minor allele.

CONCLUSION

The PHB 1630TT genotype may modify breast and ovarian cancer risks in BRCA1 mutation carriers. This association need to be evaluated in larger series of BRCA1 mutation carriers.

Phenotypic and histologic characteristics of cutaneous melanoma in patients with melanocortin-1 receptor polymorphisms

BACKGROUND

The melanocortin-1 receptor (MC1R) is an important risk factor for melanoma due to its role in the production of melanin in response to sun exposure.

OBJECTIVES

To analyze the phenotypic and histologic characteristics of cutaneous melanoma in patients carrying mutations in MC1R and assess the influence of sun exposure on the occurrence of melanoma.

MATERIAL AND METHODS

A total of 224 patients with a diagnosis of melanoma seen in the Department of Dermatology at Hospital General Universitario Gregorio Marañón in Madrid, Spain between September 2004 and December 2009 were included in the study. The genomic sequence of MC1R was analyzed by polymerase chain reaction.

RESULTS

At least one of the following MC1R variants was present in 58% of the patients: V60L, V92M, I155T, R160W, D294H, and R163Q. Carriers of those variants had a history of sunburn (P=.018) and melanomas located on areas with intermittent sun exposure (P=.019), and the majority had a diagnosis of superficial spreading melanoma. These associations were especially significant in patients with the R160W and D294H variants. Carriers of R160W also had melanomas associated with melanocytic nevi (P=.028).

CONCLUSIONS

The results of our study suggest that there may be a relationship between the expression of certain MC1R variants and sun exposure, history of sunburn, and skin type. They also indicate a higher frequency of superficial spreading melanomas and melanomas associated with melanocytic nevi in patients carrying certain mutations in MC1R.

Evaluation of the XRCC1 gene as a phenotypic modifier in BRCA1/2 mutation carriers. Results from the consortium of investigators of modifiers of BRCA1/BRCA2

BACKGROUND

Single-nucleotide polymorphisms (SNPs) in genes involved in DNA repair are good candidates to be tested as phenotypic modifiers for carriers of mutations in the high-risk susceptibility genes BRCA1 and BRCA2. The base excision repair (BER) pathway could be particularly interesting given the relation of synthetic lethality that exists between one of the components of the pathway, PARP1, and both BRCA1 and BRCA2. In this study, we have evaluated the XRCC1 gene that participates in the BER pathway, as phenotypic modifier of BRCA1 and BRCA2.

METHODS

Three common SNPs in the gene, c.-77C>T (rs3213245) p.Arg280His (rs25489) and p.Gln399Arg (rs25487) were analysed in a series of 701 BRCA1 and 576 BRCA2 mutation carriers.

RESULTS

An association was observed between p.Arg280His-rs25489 and breast cancer risk for BRCA2 mutation carriers, with rare homozygotes at increased risk relative to common homozygotes (hazard ratio: 22.3, 95% confidence interval: 14.3-34, P<0.001). This association was further tested in a second series of 4480 BRCA1 and 3016 BRCA2 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1 and BRCA2.

CONCLUSIONS AND INTERPRETATION

No evidence of association was found when the larger series was analysed which lead us to conclude that none of the three SNPs are significant modifiers of breast cancer risk for mutation carriers.

Clinical and genetic characterization of classical forms of familial adenomatous polyposis: a Spanish population study

BACKGROUND

Classical familial adenomatous polyposis (FAP) is characterized by the appearance of >100 colorectal adenomas.

PATIENTS AND METHODS

We screened the APC and MUTYH genes for mutations and evaluated the genotype-phenotype correlation in 136 Spanish classical FAP families.

RESULTS

APC/MUTYH mutations were detected in 107 families. Sixty-four distinct APC point mutations were detected in 95 families of which all were truncating mutations. A significant proportion (39.6%) had not been previously reported. Mutations were spread over the entire coding region and great rearrangements were identified in six families. Another six families exhibited biallelic MUTYH mutations. No APC or MUTYH mutations were detected in 29 families. These APC/MUTYH-negative families showed clinical differences with the APC-positive families. A poor correlation between phenotype and mutation site was observed.

CONCLUSIONS

Our results highlight that a broad approach in the genetic study must be considered for classical FAP due to involvement of both APC and MUTYH and the heterogeneous spectrum of APC mutations observed in this Spanish population. The scarcely consistent genotype-phenotype correlation does not allow making specific recommendations regarding screening and management. Differences observed in APC/MUTYH-negative families may reflect a genetic basis other than mutations in APC and MUTYH genes for FAP predisposition.

Evaluation of a candidate breast cancer associated SNP in ERCC4 as a risk modifier in BRCA1 and BRCA2 mutation carriers. Results from the Consortium of Investigators of Modifiers of BRCA1/BRCA2 (CIMBA)

Background:

In this study we aimed to evaluate the role of a SNP in intron 1 of the ERCC4 gene (rs744154), previously reported to be associated with a reduced risk of breast cancer in the general population, as a breast cancer risk modifier in BRCA1 and BRCA2 mutation carriers.

Methods:

We have genotyped rs744154 in 9408 BRCA1 and 5632 BRCA2 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA) and assessed its association with breast cancer risk using a retrospective weighted cohort approach.

Results:

We found no evidence of association with breast cancer risk for BRCA1 (per-allele HR: 0.98, 95% CI: 0.93–1.04, P=0.5) or BRCA2 (per-allele HR: 0.97, 95% CI: 0.89–1.06, P=0.5) mutation carriers.

Conclusion:

This SNP is not a significant modifier of breast cancer risk for mutation carriers, though weak associations cannot be ruled out.

Gene expression profiling integrated into network modelling reveals heterogeneity in the mechanisms of BRCA1 tumorigenesis

BACKGROUND

Gene expression profiling has distinguished sporadic breast tumour classes with genetic and clinical differences. Less is known about the molecular classification of familial breast tumours, which are generally considered to be less heterogeneous. Here, we describe molecular signatures that define BRCA1 subclasses depending on the expression of the gene encoding for oestrogen receptor, ESR1.

METHODS

For this purpose, we have used the Oncochip v2, a cancer-related cDNA microarray to analyze 14 BRCA1-associated breast tumours.

RESULTS

Signatures were found to be molecularly associated with different biological processes and transcriptional regulatory programs. The signature of ESR1-positive tumours was mainly linked to cell proliferation and regulated by ER, whereas the signature of ESR1-negative tumours was mainly linked to the immune response and possibly regulated by transcription factors of the REL/NFkappaB family. These signatures were then verified in an independent series of familial and sporadic breast tumours, which revealed a possible prognostic value for each subclass. Over-expression of immune response genes seems to be a common feature of ER-negative sporadic and familial breast cancer and may be associated with good prognosis. Interestingly, the ESR1-negative tumours were substratified into two groups presenting slight differences in the magnitude of the expression of immune response transcripts and REL/NFkappaB transcription factors, which could be dependent on the type of BRCA1 germline mutation.

CONCLUSION

This study reveals the molecular complexity of BRCA1 breast tumours, which are found to display similarities to sporadic tumours, and suggests possible prognostic implications.

Effect of common NAT2 variant alleles in the acetylation of the major clonazepam metabolite, 7-aminoclonazepam

We investigated the role of NAT2 on clonazepam acetylation, using transiently expressed human NAT2 alleles. The NAT25*B and the NAT2*6A variant alleles cause a 20 and 22-fold reduction in the Vmax, respectively. We conclude that NAT2 is responsible for 7-aminoclonazepam acetylation and that NAT2 gene polymorphisms impair such metabolic pathway.

SLC45A2: a novel malignant melanoma-associated gene

Human pigmentation appears to be one of the strongest risk factors for malignant melanoma (MM). In humans, there is a long list of genes known to be involved in rare pigmentary disorders such as albinism. These genes explain most of the variation in pigmentation phenotypes seen in human populations, and they do this by regulating the level of synthesis, chemical composition, packaging, and distribution of melanin. This Spanish case-control study included 131 consecutive melanoma patients and 245 control subjects frequency-matched for sex and age. A total of 23 SNPs in six candidate genes (ASP, OCA2, TYR, TYRP1, SILV, and SLC45A) belonging to the pigmentation pathway were genotyped. We found that the variant allele of c.1122C>G, p.Phe374Leu (NCBI dbSNP rs16891982) in SLC45A2 (membrane associated transporter previously known as MATP) was associated with protection from MM (OR, 0.41; 95% CI, 0.24-0.70; P=0.008 after adjustment for multiple testing). This association was validated by the consistent link observed with dark hair, dark skin, dark eye color, and the presence of solar lentigins and childhood sunburns. This is the first time SLC45A2 has been described as a melanoma susceptibility gene in a light-skinned population.

The molecular pathology of hereditary breast cancer

Hereditary breast cancer arising in carriers of mutations in the BRCA1 and BRCA2 genes differs from sporadic breast cancer and from non-BRCA1/2 familial breast carcinomas. Most BRCA1 carcinomas have the basal-like phenotype and are high-grade, highly proliferating, estrogen receptor-negative and HER2-negative breast carcinomas, characterized by the expression of basal markers such as basal keratins, P-cadherin and epidermal growth factor receptor. BRCA1 carcinomas frequently carry p53 mutations. The basal-like phenotype is only occasionally found in BRCA2 carcinomas, which tend to be estrogen and progesterone receptor positive. BRCA1 and BRCA2 loss of heterozygosity is found in almost all BRCA1 and BRCA2 carcinomas, respectively. Both genotypes have a low frequency of HER2 expression/amplification. In addition, comparative genomic hybridization and array expression studies have revealed differences in chromosomal gains and losses as well as expression patterns between genotypes. Several studies have shown that hereditary carcinomas that are not attributable to BRCA1/2 mutations are heterogeneous and have phenotypic similarities to BRCA2 tumors. A small group of cases are secondary to mutations in other breast cancer susceptibility genes, such as p53, PTEN or CDH1. As a result of the low frequency of breast carcinomas attributable to mutations in these genes, it is very difficult to establish a specific phenotype for each genotype, other than the association of lobular carcinomas with CDH1 germline mutations. The pathological and molecular features of hereditary breast cancer can drive specific treatments and influence the process of mutation screening.

Current strategies in the search for low penetrance genes in cancer

The genetic etiology of most cancers remains largely unclear and it has been hypothesised that common genetic variants with modest effects on disease susceptibility cause the bulk of this unexplained risk. Case-control association studies are considered the most effective strategy to identify these low-penetrance genes. While traditionally, such studies have focused on putative functional single nucleotide polymorphisms (SNPs) in candidate genes, a more comprehensive approach can now be taken, as a result of a number of recent developments: the mapping of the human genome, including the identification of almost ten million SNPs; and the development of high-throughput genotyping technologies that enable hundreds of thousands of SNPs to be genotyped in a single reaction, in multiple subjects and at an affordable cost. All common genomic variation can be captured by genotyping SNPs in gene-, pathway- or genome-wide-based strategies and these are now being applied to many diseases, including cancer. We present an outline of each of these approaches, including recent published examples, and discuss a number of challenges that remain to be addressed.

Distinct genomic aberration patterns are found in familial breast cancer associated with different immunohistochemical subtypes

Five breast cancer subtypes have been described in sporadic breast cancer (SBC) using expression arrays: basal-like, ERBB2, normal breast-like, luminal A and B. These molecular subtypes show different genomic aberration patterns (GAPs). Recently, our group described these breast cancer subtypes in 50 non-BRCA1/2 familial tumors using immunohistochemistry assays. We extended this study to the other classes of familial breast cancer (FBC), including 62 tumors (18 BRCA1, 16 BRCA2 and 28 non-BRCA1/2), with the same panel of 25 immunohistochemical (IHC) markers and histological grade obtaining a similar classification. We combined these data with results generated by a 1 Mb BAC array-based CGH study to evaluate the genomic aberrations of each group. We found that BRCA1-related tumors are preferentially basal-like, whereas non-BRCA1/2 familial tumors are mainly luminal A subtype. We described distinct GAPs related to each IHC subtype. Basal tumors had a greater number of gains/losses, while luminal B tumors had more high-level DNA amplifications. Our data are similar to those obtained in SBC studies, highlighting the existence of distinct genetic pathways of tumor evolution, common to both SBC and FBC.

Classification of missense variants of unknown significance inBRCA1based on clinical and tumor information

Classification of rare missense variants in disease susceptibility genes as neutral or disease-causing is important for genetic counseling. Different criteria are used to help classify such variants in BRCA1 and BRCA2; however, the strongest evidence tends to come from segregation analysis and observed cooccurrence with known pathogenic mutations, which both require information that is not readily available in most circumstances. A likelihood-based model has been developed, integrating most of the data currently used to classify these variants. We have adapted the original model, including only that information that could be more easily obtained from a cancer genetics laboratory, such as loss of heterozygosity (LOH), grade, and immunohistochemical analysis to assess estrogen receptor (ER) status for the tumors of carriers of these variants. We also considered summary family history (personal or first-degree family history of bilateral breast or ovarian cancer), which was not incorporated into the original model. To test the ability of the modified model to classify missense variants in BRCA1, we analyzed 17 variants, of which 10 have previously been classified as pathogenic mutations or neutral polymorphisms. We also included a prior step consisting of the screening of the variants among 1,000 controls, with which we were able to classify five as neutral, based solely on their observed frequency. We found that combining this relatively easily collected information can be sufficient to classify variants as pathogenic or neutral if tumors from at least three carriers of the same variant can be collected and analyzed.

MC1R: three novel variants identified in a malignant melanoma association study in the Spanish population

The human melanocortin-1 receptor (MC1R) gene, which plays a crucial role in pigmentation, also appears to be important in malignant melanoma (MM). This case-control study in the Spanish population included 116 consecutive MM patients and 188 controls frequency matched for sex and age. Sequence analysis of the entire coding region of MC1R was performed, identifying 21 variants, all of them previously reported except for three novel non-synonymous changes: Ser41Phe, Met128Thr and Asn281Ser. Simulated structural analyses suggested disruption of the local structure around Phenylalanine 41, possible destabilization of the hydrophobic interior of the molecule in Threonine 128 and that Asparagine 281 could be in a region of functional importance. The fact that these three novel variants were not present in 1,000 healthy individuals tested adds further weight to them having putative adverse effects on the functional protein. Six variants, all non-synonymous changes, were individually associated with MM risk (Arg160Trp, Asp294His, Val60Leu, Val92Met, Ile155Thr and Arg163Gln). Carrying two non-synonymous variants was associated with much higher risk of MM (odds ratio: 10.44, 95% confidence interval = 4.48-24.33, P = 5 x 10(-8)) and haplotype analysis, verified by cloning, confirmed that this is predominantly due to carrying each on a different chromosome. Our results suggest that both red hair colour (RHC) and non-red hair colour variants, and possibly other rare non-synonymous variants, in MC1R are implicated in the development of MM. In addition to carrying MC1R variant alleles, having blond/red hair and childhood sunburns were independent risk factors for MM.

A haplotype containing the p53 polymorphisms Ins16bp and Arg72Pro modifies cancer risk in BRCA2 mutation carriers

Germline mutations in the BRCA1 and BRCA2 genes confer a high lifetime risk of developing breast and other cancers; however, remarkable differences exist regarding disease manifestation in mutation carriers. It has been suggested that other genetic and/or environmental factors modify not only the appearance but also the age of onset and type of tumor in BRCA1/2-associated cases. The aim of the present study was to investigate the role of two p53 polymorphisms (c.97-147ins16bp and c.215c>g, p.Arg72Pro) as potential modifiers. For this purpose we investigated the possible association between the two polymorphisms and disease status in 447 BRCA1/2 mutation carriers belonging to 170 Spanish breast and/or ovarian cancer families. Genotype and haplotype analyses revealed that the presence of a specific haplotype carrying the allele without the 16-bp insertion and the variant allele for the Arg72Pro (No Ins-72Pro haplotype) was associated with an earlier age of onset in BRCA2 mutation carriers. We found an increased risk of developing a first primary tumor (breast or ovarian) before 35 years of age for individuals who carried at least one No Ins-72Pro haplotype (OR: 2.69; 95% CI: 1.15-6.29; P=0.022). We confirmed these data by a functional study in which we compared different p53 genotypes in relation to their apoptotic response after cell treatment with a cytotoxic drug (AraC). Our results revealed a decrease in p53 apoptotic rate associated with the No Ins-72Pro haplotype.

FANCD2 associated with sporadic breast cancer risk

Several components of the Fanconi anaemia (FA) family of proteins allow the formation of the DNA repair complex foci formed by proteins such as BRCA1/2 and RAD51. Because the genes that participate in the DNA repair pathway have been described as low-penetrance breast cancer susceptibility genes, we postulated that variants in FA genes could also be associated with sporadic breast cancer risk. We studied seven SNPs in FANCA, FANCL and FANCD2 in a total of 897 consecutive and non-related sporadic breast cancer cases and 1033 unaffected controls from the Spanish population. We observed a statistically significant association with sporadic breast cancer for the variant rs2272125 (L1366L) located on FANCD2 (OR per allele=1.35; 95% C.I. 1.09-1.67; P=0.005). Both haplotype and diplotype analyses confirmed this association, where one haplotype and pooled diplotypes carrying it were associated with more than 4-fold risk (P=0.007 and P=0.006, respectively). Screening for potential causal variants in FANCD2 was performed, detecting one in the putative promoter region, which is located in a phylogenetically conserved motif with consensus binding sites for some transcriptional factors, suggesting a functional implication. Our data indicate that a relationship between FANCD2 and sporadic breast cancer risk may exist.

Increased frequency of rapid acetylator genotypes in patients with brain astrocytoma and meningioma

OBJECTIVES

The arylamine N-acetyltransferase (NAT2) is a polymorphic enzyme involved in deactivation and activation of carcinogens through N- and O-acetylation. We investigated the association between the genetic NAT2 polymorphism and brain tumors by analysis of genomic DNA from 71 brain tumor patients and 258 healthy controls.

MATERIALS AND METHODS

Seven single nucleotide polymorphisms of the NAT2 gene were studied by using allele-specific polymerase chain reaction amplification.

RESULTS

Ten different NAT2 allelic variants were identified in both patient and control groups. A higher number of individuals carrying functional NAT2 genes, and therefore with a rapid acetylation phenotype, was found in brain tumor patients vs healthy volunteers (OR 1.79, 95% CI 1.05-3.05; P < 0.05). This is observed either for patients suffering from meningioma or astrocytoma, and this is due to an increase of the wild-type NAT2*4 allelic variant frequency (OR 1.48, 95% CI 0.99-2.19), and a reduction of the commonest defective allelic variant NAT2*5B in the brain tumor patients, compared with healthy subjects (OR 0.54, 95% CI 0.37-0.80).

CONCLUSIONS

This observation indicates that NAT2 could be considered as a low-penetrance gene for brain tumors, and that individuals carrying rapid acetylation alleles are at increased risk of developing brain tumors.

Differential expression of NF-kappaB pathway genes among peripheral T-cell lymphomas

Nuclear factor kappa B (NF-kappaB) is one important pathway in T-cell proliferation and survival. In a previously reported microarray study, we found NF-kappaB pathway genes differentially expressed between peripheral (PTCL) and lymphoblastic lymphomas. Here, we investigated the expression of NF-kappaB pathway genes using cDNA microarrays in a group of 62 PTCL and in reactive lymph nodes. We found two different subgroups of PTCL based on the expression of NF-kappaB pathway genes. One-third of PTCL showed clearly reduced expression of NF-kappaB genes, while the other group was characterized by high expression of these genes. This distinction was found among all T-cell lymphoma categories analyzed (PTCL unspecified, angioimmunoblastic, cutaneous and natural killer/T lymphomas) with the exception of anaplastic lymphomas (ALCL), which were characterized by reduced NF-kappaB expression in anaplastic cells. Quantitative RT-PCR and immunohistochemical analysis of NF-kappaB-p65 protein confirmed these differences among PTCL subgroups. Importantly, we found that differentiation between NF-kappaB-positive and -negative PTCL could be of clinical interest. The expression profile associated to reduced expression of NF-kappaB genes was significantly associated with shorter survival of patients and seems to be an independent prognostic factor in a multivariate analysis.

Estrogen and progesterone receptor gene polymorphisms and sporadic breast cancer risk: A Spanish case-control study

Estrogens, and to a lesser extent progesterones, influence the proliferation, differentiation and physiology of breast tissue as well as the development and progression of breast cancer. Genetic variants in the steroid hormone receptor genes ESR1 and PGR (belonging to the nuclear receptor superfamily) could therefore modify sporadic breast cancer susceptibility. Two studies have shown a protective effect associated with variants in ESR1 in 2 distinct populations. We studied 4 single nucleotide polymorphisms (SNPs) in ESR1 and 4 in PGR in 550 consecutive and unrelated sporadic Spanish breast cancer patients and 564 healthy Spanish controls. We observed a dominant protective effect for the S10S variant in ESR1, with an estimated odds ratio (OR) of 0.75 (95% CI = 0.58-0.97; p = 0.03) although functional studies did not show changes in the RNA stability. A small subset of individuals carried a haplotype combination that corroborates this protection. No other SNP considered in either gene was found to be associated with sporadic breast cancer. Our results obtained in a European population confirm the protective role of the S10S variant in ESR1, previously reported in an Asian and a European-American population.

Lhermitte-Duclos disease and Cowden disease: clinical and genetic study in five patients with Lhermitte-Duclos disease and literature review

BACKGROUND

Lhermitte-Duclos Disease (LDD) is an infrequent cerebellar disorder characterized by focal or diffuse enlargement of cerebellar folia presenting as a slowly growing mass in the posterior fossa. Over the past decade its association with Cowden disease (CD) has been recognized with increasing frequency. This latter disease is a genetic condition leading to the presence of multiple hamartomas and neoplasias which affect mainly the skin, thyroid, breast and genito-urinary and gastro-intestinal tracts. It has even been hypothesized that LDD and CD constitute a single entity. This work is aimed to analyse to what extent this association was present in patients treated for LDD at our institution.

METHOD

We reviewed the medical records of five patients and performed clinical studies for CD manifestations, among them, genetic investigation for PTEN mutations. The International Cowden Consortium Criteria were applied for the diagnosis of CD.

FINDINGS

Four of the five patients treated for LDD were also diagnosed of CD. The genetic study found PTEN mutations in two of them. Interpretation. LDD has been found to be closely related to CD in this series, in accordance with previous literature. However, the absence of CD diagnosis in one of the patients led us to suggest that, despite the strong association between these two diseases, LDD can also appear as an isolated condition.

Simultaneous detection of the immunophenotypic markers and genetic aberrations on routinely processed paraffin sections of lymphoma samples by means of the FICTION technique

Disciplines such as morphology, immunophenotyping and genetics widely contributed over decades to the understanding of the cellular mechanisms of cancer. To obtain a greater insight into the complex processes of tumorigenesis, scientists have joined their efforts to combine many of the available techniques. Here, we report on the development of a FICTION (Fluorescence Immunophenotyping and Interphase Cytogenetics as a tool for the Investigation of Neoplasms) technique that allows a simultaneous detection of immunophenotypic markers and genetic aberrations on routinely processed lymphoma samples. As the antigen retrieval method seems to play an important role in the final results, we tested the pressure-cooking method at different times (2, 4 and 8 min) using three different buffers (EDTA, Tris-EDTA and citrate), resulting in improved sensitivity for the detection of both immunophenotypic markers and genetic aberrations. We also applied this method to different types of lymphoma using double immunofluorescence assays (including CD30, CD20, CD8 monoclonal antibodies) and several fluorescence in situ hybridization probes to demonstrate that the FICTION technique could be easily applied on paraffin sections in different combinations for the diagnosis and research of cancer.

Characterization of the A673 cell line (Ewing tumor) by molecular cytogenetic techniques

The A673 cell line was established from a patient with a primary rhabdomyosarcoma (RMS), which is referred to in the literature either as a Ewing tumor (ET) or as RMS. Although the two tumoral types are associated with specific and well-characterized translocations, no cytogenetic report on this cell line has been published. We characterized the A673 cell line using a combination of spectral karyotyping (SKY), fluorescence in situ hybridization (FISH), and reverse transcriptase polymerase chain reaction (RT-PCR), which revealed the presence of a complex karyotype and a translocation involving chromosomes 11 and 22 and the fusion of EWS and FLI1 genes, both events being specific to ET. Neither cytogenetics nor molecular alterations specific to RMS were found.

Complex cytogenetic abnormalities including telomeric associations and MEN1 mutation in a pediatric ependymoma

Ependymomas are neuroectodermal tumors of the brain and spinal cord. Some recurrent cytogenetic aberrations have been reported in these tumors, including alterations involving chromosomes 22, 6, and 11. However, consistent molecular alterations have not been identified in ependymal tumors. We studied a recurrent ependymoma in a 3-year-old patient by standard cytogenetic and molecular analysis of TP53 and MEN1 genes. In the present case, we found many of the cytogenetic features previously described as being recurrent in ependymomas, including unstable telomeric alterations. Furthermore, we detected a novel acquired heterozygous mutation in the MEN1 gene. The chromosomal instability produced by the telomeric alterations and the mutation in the MEN1 gene could be important events in the tumorigenesis of ependymomas.

Identification of ins(8;21) with AML1/ETO fusion in acute myelogenous leukemia M2 by molecular cytogenetics

A high percentage of cases of acute myelogenous leukemia (AML) of the M2 subtype show a rearrangement between the AML1 and ETO genes. The detection of the AML1/ETO fusion has clinical relevance because patients with this subtype have a good prognosis. We present the results of conventional and molecular cytogenetic studies in a patient with acute myelogenous leukemia French-American-British M2 classification, who had a complex karyotype involving chromosomes 8 and 21. Dual-color fluorescence in situ hybridization (FISH) using the AML1/ETO probe demonstrated a recombination of both genes on an add(8) chromosome. The use of other FISH probes (CEP8, c-myc and TEL21) and spectral karyotyping indicated that AML1/ETO fusion occurred as a consequence of a previously undescribed ins(8;21)(q22;q22.1q22.3).

Multiplex-polymerase chain reaction assay for the detection of prognostically significant translocations in acute lymphoblastic leukemia

BACKGROUND AND OBJECTIVES

The presence of specific chromosomal translocations in acute lymphoblastic leukemias (ALL) plays an important role in determining the prognosis of the patients. Our aim is to develop a highly sensitive and specific method to screen simultaneously for the four most frequent translocations in ALL: t(9;22), t(1;19), t(4;11), t(12;21).

DESIGN AND METHODS

Our approach uses a multiplex-polymerase chain reaction (PCR) method, which involves two rounds of PCR using fluorescence-labeled nested primers. The chimeric transcripts resulting from these translocations can be identified by agarose gel electrophoresis or by fluorescence analysis. To validate this method we carried out the analysis in 42 pediatric ALL samples previously studied by cytogenetic and fluorescent in situ hybridization (FISH) techniques.

RESULTS

In all samples with a known translocation detected by cytogenetic or FISH techniques, the same translocation was identified by the multiplex-PCR assay. Moreover, with this method we detected rearrangements in five patients in clinical remission and in two patients at diagnosis for whom karyotypes were normal and rearrangements had not been detected. The application of this multiplex-PCR assay was also useful in cases without cytogenetic results.

INTERPRETATION AND CONCLUSIONS

These results show that the multiplex-PCR method allows reliable, sensitive and rapid detection of the prognostically significant translocations in ALL. We believe that this assay combined with cytogenetic analysis should be the strategy of choice for the initial diagnostic phase of acute lymphoblastic leukemia, and that it could be used not only at diagnosis but also to follow-up these alterations in remission samples without previous controls.

Fluorescence in situ hybridization study of TEL/AML1 fusion and other abnormalities involving TEL and AML1 genes. Correlation with cytogenetic findings and prognostic value in children with acute lymphocytic leukemia

BACKGROUND AND OBJECTIVES

The TEL/AML1 fusion is the most common genetic abnormality found in childhood acute lymphoblastic leukemias (ALL). Although it is very difficult to identify by conventional cytogenetic techniques it can be readily detected using fluorescence in situ hybridization (FISH). We carried out cytogenetic and FISH studies on 42 children with ALL in order to know the frequency of this translocation in our population, the incidence of TEL and/or AML1 gene alterations, and their correlation with clinical evolution and prognosis. In addition, we performed reverse transcription polymerase chain reaction (RT-PCR) in some cases, confirming the feasibility of FISH techniques in the detection of this translocation.

DESIGN AND METHODS

Bone marrow samples were obtained from 42 childhood ALL patients. The copy number of AML1 and TEL genes were studied using fluorescent in situ hybridization with a dual color DNA probe specific for the AML1 and TEL genes.

RESULTS

We found a frequency of TEL/AML1 fusion of 17% in our sample. Double TEL/AML1 fusion, lack of TEL signal and extra AML1 signals were frequent additional FISH abnormalities. Duplication of a chromosomal complement, deletion of chromosome 12p arm, and polysomies of chromosome 21 are plausible explanations for these additional FISH findings. However, a relatively high proportion of our cases (9.5%) presented specific amplification of AML1. A statistically significant difference in prognosis was found between patients with and without these additional AML1 or TEL FISH alterations (p<0.02), which could be related to the presence of specific karyotypes.

INTERPRETATIONS AND CONCLUSIONS

The frequency of TEL/AML1 fusion is similar to that found in other populations (17%). We found that FISH analysis of AML and TEL is related to the evolution of the disease. The absence of alterations in these genes revealed by FISH could be indicative of bad prognosis, while the presence of alterations is related to a good evolution. Our results suggest that interphase FISH analysis to search for alterations in AML and TEL genes could be extremely useful for complementing cytogenetic studies and for providing additional information about the possible outcome of the disease in patients with ALL.

Functionally active duplications of the CYP2D6 gene are more prevalent among larynx and lung cancer patients

The cytochrome P450 CYP2D6 is a polymorphic drug-metabolizing enzyme that is involved in the metabolism of several drugs and xenobiotics. Several independent studies indicate that the CYP2D6 metabolic status is a secondary factor in the risk of developing lung cancer, with individuals with high activity being at increased risk. The occurrence of functionally active duplications of the CYP2D6 gene is a phenomenon that affects 3-8% of Caucasians and up to 30% in some ethnic groups. These duplications cause ultrarapid metabolism of CYP2D6 substrates. In order to establish whether the highest CYP2D6 enzyme activity is associated with an increased risk of cancer, we analyzed the frequency of CYP2D6 gene duplications and enzyme-inactivating mutations in 199 Caucasian patients with lung or larynx cancer and in 335 healthy controls. A significantly increased frequency of carriers of the CYP2D6 gene duplication were found among lung and larynx cancer patients (13%), as compared with healthy controls (6.9%; p < 0.02). The frequency of the mutated active CYP2D6*9 allele was increased in lung cancer patients (p < 0.01) but not in larynx cancer patients. Global findings indicate that over 20% patients with lung or larynx cancer show CYP2D6 genotypes leading to ultrarapid metabolism or to the expression of an enzyme with altered kinetics (p < 0.01 vs. healthy controls). This may influence the metabolism of CYP2D6 substrates, including antineoplastic drugs and opioid derivatives used for pain relief in cancer patients. These patients would require higher doses than those considered as standard. We conclude that dosages for CYP2D6 substrates should be adapted to lung and larynx cancer patients.

IgH, TCR-gamma, and TCR-beta gene rearrangement in 80 B- and T-cell non-Hodgkin's lymphomas: study of the association between proliferation and the so-called "aberrant" patterns

The current study analyzes the rearrangement pattern of immunoglobulin H (IgH), T-cell receptor (TCR)-gamma, and TCR-beta genes in a group of 80 non-Hodgkin's lymphomas (NHL) of different histologic subtypes (43 B-cell and 37 T-cell types). The sensitivity and specificity provided by polymerase chain reaction amplification of these loci are evaluated. The association between the proliferation index and the presence of the so-called "aberrant" or "dual" rearrangements is also considered. Ninety-one percent of B-cell NHL showed IgH gene monoclonality, and 21% also exhibited a monoclonal pattern in one of the TCR genes. Among T-cell NHL, the sensitivity of the study was 65% for the TCR-gamma gene and 46% for the TCR-beta gene. The total sensitivity was 76%, amplifying both loci. IgH gene aberrant rearrangements were observed in 16% of T-cell neoplasms. A substantial percentage of dual rearrangements were detected in precursor and mature B- and T-cell NHL. B-cell NHL showed a tendency toward higher values of proliferation when aberrant rearrangements were present; however, this trend was not significant. Furthermore, in the case of T-cell NHL there was a significant negative association between these two variables.

Inhibition of cytochrome P450 2C9 activity in vitro by 5-hydroxytryptamine and adrenaline

In the present study, the occurrence of a modulatory effect of 14 neurotransmitters, precursors and metabolites on the cytochrome P450 2C9 (CYP2C9) enzyme activity, as determined by diclofenac 4-hydroxylation, was studied in human liver microsomes. Two indoleamines, 5-hydroxytryptamine (5-HT) and adrenaline, showed a non-competitive-type inhibitory effect of approximately 90% of the diclofenac 4-hydroxylase activity, with Ki values of 63.5 (0.7 and 156 (89.3 microM, respectively. The rest of substances analysed were weak inhibitors or had no inhibitory effect. CYP2C subfamily is present in human brain, although CYP2C9 isozyme has not yet been identified in this tissue, and CYP2C9 is involved in the metabolism of psychoactive drugs. Therefore, the fact that endogenous compounds could modulate the CYP2C9 activity, suggests that an hypothetical local activity of brain CYP2C9 might be susceptible to regulatory mechanisms. The possible clinical implications of this modulation are discussed.

Construction and characterization of a nonproliferative El Tor cholera vaccine candidate derived from strain 638

In recent clinical assays, our cholera vaccine candidate strain, Vibrio cholerae 638 El Tor Ogawa, was well tolerated and immunogenic in Cuban volunteers. In this work we describe the construction of 638T, a thymidine auxotrophic version of improved environmental biosafety. In so doing, the thyA gene from V. cholerae was cloned, sequenced, mutated in vitro, and used to replace the wild-type allele. Except for its dependence on thymidine for growth in minimal medium, 638T is essentially indistinguishable from 638 in the rate of growth and morphology in complete medium. The two strains showed equivalent phenotypes with regard to motility, expression of the celA marker, colonization capacity in the infant mouse cholera model, and immunogenicity in the adult rabbit cholera model. However, the ability of this new strain to survive environmental starvation was limited with respect to that of 638. Taken together, these results suggest that this live, attenuated, but nonproliferative strain is a new, promising cholera vaccine candidate.

N-acetyltransferase 2 (NAT2) genotype and colorectal carcinoma: risk variability according to tumour site?

BACKGROUND

Dietary heterocyclic aromatic amines (HAAs) are members of a family of chemicals that comprise highly mutagenic compounds related to colon cancer. The polymorphic N-acetyltransferase 2 enzyme (NAT2, E.C. 2.3.1.5) plays a key role in the transformation of HAAs to ultimate carcinogens. NAT2 enzyme activity is expressed in a genotype-dependent manner in colon epithelium. Therefore local activation of HAAs in colon, and hence increased risk to develop colon cancer, is likely to be related to high NAT2 enzyme activity. This study is aimed at analysing the association between genotypes leading to high NAT2 activity and colorectal cancer risk.

METHODS

Genomic DNA from 120 colorectal cancer patients and 258 healthy individuals were analysed for enzyme-inactivating mutations at the coding region of the NAT2 gene by means of a mutation-specific polymerase chain reaction.

RESULTS

Among patients with sigmoid colon cancer, a significant excess of individuals with genotypes leading to high NAT2 activity was observed as compared both to controls and to the rest of patients with colorectal cancer (P < 0.05).

CONCLUSIONS

Our findings, which require independent confirmation, suggest that the NAT2 genotype constitutes a secondary risk factor to develop sigmoid colon cancer.

Progressive deterioration of central components of auditory brainstem responses during postnatal development of the myelin mutant taiep rat

Auditory brainstem responses (ABRs) were evaluated during the postnatal development (P10-P180) of taiep rats, neurological mutants characterized by early abnormal myelin development and subsequent demyelination of the CNS. The disorder is produced by an autosomal recessive mutation trait that affects the oligodendrocytes but not the Schwann cells. After onset of ABRs (P12-P14), taiep rats and their nonaffected heterozygous littermates that served as controls showed a similar pattern of maturation for wave I. The central waves (In-IV) showed significantly longer latencies in the mutants. By P60-P180, the later waves (III and IV) were frequently difficult to discern. From the onset of ABRs, the interpeak latency I-IV, corresponding to the central conduction time (CCT) of the auditory pathway, showed in taiep rats significantly longer values than controls. After an initial reduction, proportional to that of control rats, the CCT value increased progressively during the second month of the mutants' lives. The electrophysiological results of the present study strongly support the hypothesis that mutation in the taiep rat impairs neuromaturation of the central auditory pathway in the brainstem by affecting the myelination process in the CNS.

Use of the mesoridazine/thioridazine ratio as a marker for CYP2D6 enzyme activity

Thioridazine is metabolized in humans by CYP2D6 to mesoridazine, which is an active metabolite. Two or more CYP2D6 substrates are seldom given simultaneously to elderly patients because potentially dangerous metabolic interactions may occur. It may be valuable to know the CYP2D6 metabolic capacity of such patients to avoid drug interactions, which depend on the metabolic phenotype. The goal of this study was to evaluate the use of the mesoridazine/thioridazine ratio for the estimation of CYP2D6 enzyme capacity. A sensitive and reliable method has been developed for the determination of thioridazine and its metabolites, mesoridazine and sulforidazine. Commonly used central nervous system (CNS) comedications do not interfere with the method. A group of 27 chronic patients with mental illness receiving monotherapy with thioridazine were studied. There were 23 men and 4 women between 37 and 80 years old (mean +/- SD: 61.2 +/- 10.2). The thioridazine/mesoridazine ratio correlated with the debrisoquine metabolic ratio (r = 0.74, p < 0.001). Therefore, the authors suggest that the measurement of thioridazine and its metabolite might be a useful tool to assess CYP2D6 activity during treatment.

Suspected sexual abuse: an unusual presentation form of congenital myotonic dystrophy

In children, anal abnormalities due to various causes may be confused with sexual abuse. We present the case of a child in whom the suspicion of abuse due to anal dilatation led to the previously unknown diagnosis of myotonic dystrophy. Myopathic involvement of the perianal musculature is a known feature of congenital myotonic dystrophy that usually appears in late childhood or adolescence.

CONCLUSION

We stress the importance of considering an underlying myopathic condition in the differential diagnosis of anal laxity. Further studies, such as anal ultrasonography, may help when the diagnosis of abuse is not clear.

Pharmacokinetic-Pharmacodynamic Modelling of the antipyretic effect of two oral formulations of ibuprofen

OBJECTIVE

To analyse the population pharmacokinetic-pharmacodynamic relationships of racemic ibuprofen administered in suspension or as effervescent granules with the aim of exploring the effect of formulation on the relevant pharmacodynamic parameters.

DESIGN

The pharmacokinetic model was developed from a randomised, cross-over bioequivalence study of the 2 formulations in healthy adults. The pharmacodynamic model was developed from a randomised, multicentre, single dose efficacy and safety study of the 2 formulations in febrile children.

PATIENTS AND PARTICIPANTS

Pharmacokinetics were studied in 18 healthy volunteers aged 18 to 45 years, and pharmacodynamics were studied in 103 febrile children aged between 4 and 16 years with bodyweight 225kg.

METHODS

The pharmacokinetic study consisted of two 1-day study occasions, each separated by a 1-week washout period. On each occasion ibuprofen 400mg was administered orally as suspension or granules. The time course of the antipyretic effect was evaluated in febrile children receiving a single oral dose of 7 mg/kg in suspension or 200 or 400mg as effervescent granules. During the pharmacodynamic analysis, the predicted typical pharmacokinetic profile (based on the pharmacokinetic model previously developed) was used.

RESULTS

The disposition of ibuprofen was described by a 2-compartment model. No statistical differences (p > 0.05) were found between the 2 formulations in the distribution and elimination parameters. Absorption of ibuprofen from suspension was adequately described by a first-order process; however, a model with 2 parallel first-order input sites was used for the drug given as effervescent granules, leading to time to reach maximum drug concentration (tmax) values of 0.9 and 1.9 hours for suspension and granules, respectively. The time course of the antipyretic effect was best described using an indirect response model. The estimates (with percentage coefficients of variation in parentheses) of Emax (maximum inhibition of the zero-order synthesis rate of the factor causing fever), EC50 (plasma concentration eliciting half of Emax), n (slope parameter) and k(out) (first order rate constant of degradation) were 0.055 (10), 6.16 (14) mg/L, 2.71 (18) and 1.17 (23) h(-1), respectively, where To is the estimate of the basal temperature, 38.8 (1) degrees C. No significant (p > 0.05) covariate effects (including pharmaceutical formulation) were detected in any of the pharmacodynamic parameters.

CONCLUSIONS

Because of the indirect nature of the effect exerted by ibuprofen, the implications of differences found in the plasma drug concentration profiles between suspension and effervescent granules are less apparent in the therapeutic response.

Modulation of midazolam 1-hydroxylation activity in vitro by neurotransmitters and precursors

OBJECTIVE

The aim of this study was to find whether endogenous substances could modulate CYP3A activity. There is evidence that CYP3A, a major phase-I xenobiotic metabolizing enzyme, is present in human brain but, at the present time, endogenous substrates for such an enzyme remain to be identified. A possible linkage between the CYP2D6 enzyme and serotonergic transmission has been recently reported by our group. In the same manner, structurally related enzymes such as CYP3A could also be related to endogenous compounds.

METHODS

CYP3A activity was measured using the enzyme-specific substrate midazolam in human liver microsomes. Several neurotransmitters, precursors, and their metabolites, corresponding to three different metabolic routes, were assayed as putative modulators of CYP3A enzyme activity. These comprised serotonergic, catecolaminergic, and GABAergic transmitters and precursors. The inhibitory capacity of ketoconazole, a competitive inhibitor of CYP3A, was also analyzed for comparison.

RESULTS

The kinetic analysis of the midazolam 1-hydroxylase activity measured in microsomes from five human liver samples indicated Km values (mean +/- SD) of 5.8 +/- 4.9 microM, and Vmax values of 1.7 +/- 1.4 nmol min(-1) per mg microsomal protein in all the samples used in the study. Of the 14 substances analyzed, adrenaline, serotonin, and 5-hydroxytriptofol were full inhibitors of CYP3A enzyme activity (Ki values of 42.3, 26.4, and 43 microM, respectively). The remaining substances were weak inhibitors or had no inhibitory effect.

CONCLUSION

Brain CYP3A activity could be modulated by some neurotransmitters and precursors.