Biomedical subjects

Miguel A Piris

Publications and source records attributed to Miguel A Piris.

At least 19 recordsLinked to original sources

PubMed2007

Extreme sensitivity to Yondelis (Trabectedin, ET-743) in low passaged sarcoma cell lines correlates with mutated p53.

Yondelis (Trabectedin, ET-743) is a marine anticancer agent currently in Phase II/III development in patients with advanced pretreated soft tissue sarcoma. In the present study, we generated a panel of low passaged tumor cell lines from samples explanted from chemonaive sarcoma patients with different tumor types. We assessed in vitro sensitivity/resistance to Trabectedin and doxorubicin in a panel of sarcoma cell lines and examined the correlation between molecular alterations in DNA repair genes and sensitivity to Trabectedin. We treated cell lines with Trabectedin and doxorubicin in both 96-h and clonogenic assays. In both assays, well-defined groups of resistant and sensitive cell lines were observed. Resistance to Trabectedin did not correlate with resistance to doxorubicin, indicating that the two drugs may have different mechanisms of resistance. p53 mutations and deletions correlated with extreme sensitivity (IC50 < 1 nM) to Trabectedin (P < 0.01). In a pair of isogenic cell lines differing only in the presence or absence of wild-type p53, the absence of p53 rendered cells threefold more sensitive to Trabectedin.

Cell Proliferation↗

PubMed2006

Nuclear bcl10 expression characterizes a group of ocular adnexa MALT lymphomas with shorter failure-free survival.

Ocular adnexa B-cell lymphomas are a relatively rare group of extranodal lymphomas, marginal-zone B-cell lymphomas of mucosa-associated lymphoid tissue (MALT lymphomas) being the most frequent type at this location. As with other nongastrointestinal MALT lymphomas, ocular adnexa MALT lymphomas have distinct characteristics from those of the gastric MALT model, implying specific pathogenic events, which could be of interest in the prediction of clinical behavior and the choice between therapeutic options. In a series of 39 cases of ocular adnexa MALT lymphomas, studied using a tissue microarray, we observed that the most frequent alteration was related to apoptosis regulation. Thus, caspase 3 activity was completely abolished, and phosphorylated IkappaBalpha, a marker of NF-kappaB activation, showed increased expression, while cases with an increased number of large cells displayed increased expression of survivin and other cell-cycle-related proteins, such as cyclin A, cyclin E and Ki67, and p16 expression was reduced. There were no occurrences of t(11;18)(q21,q21), while 5/37 cases exhibited t(14;18)(q32;q21). Aberrant nuclear expression of bcl10 was observed in 11 cases, independently of the presence of translocations, and was significantly associated with phosphorylated IkappaBalpha expression and a reduced TdT-mediated biotin-dUTP nicked-end labeling apoptotic index. Moreover, patients with tumoral bcl10 nuclear expression showed shorter failure-free survival.

Adaptor Proteins, Signal Transducing↗

PubMed2006

Tumor microenvironment and mitotic checkpoint are key factors in the outcome of classic Hodgkin lymphoma.

Around 20% to 30% of patients with Hodgkin lymphoma (HL) do not benefit from standard therapies and finally succumb to their disease. The factors that influence the outcome of HL have not been elucidated, underscoring the demand for the identification of biologic risk factors and new therapeutic targets. We analyzed the gene expression profiles of samples from 29 patients with advanced classic HL treated with standard therapy and compared the expression profiles of patients with favorable and unfavorable clinical outcome. Using supervised methods, we identified 145 genes associated with outcome, which were grouped into 4 signatures representing genes expressed by either the tumoral cells (genes involved in the regulation of mitosis and cell growth/apoptosis) or the tumor microenvironment. The relationship between the expression of 8 representative genes and survival was successfully validated in an independent series of 235 patients by quantification of protein expression levels on tissue microarrays. Analysis of centrosomes and mitotic checkpoint confirmed the existence of an abnormal transition through mitosis in HL cells. Therefore, genes related to tumor microenvironment, cell growth/apoptosis, and regulation of mitosis are associated with treatment response and outcome of patients with HL.

Adolescent↗

PubMed2006

Variability in the expression of polycomb proteins in different normal and tumoral tissues. A pilot study using tissue microarrays.

In spite of the known function of polycomb group (PcG) genes in stem cell self-renewal, control of cellular proliferation and differentiation, its role in cancer pathogenesis is still poorly understood. We studied the expression by immunohistochemistry of several PcG-maintenance complex proteins (RING1, RNF2, BMI1, MEL18, HPH1 and RYBP) in nontumoral (154 samples) and tumoral (550 samples) human tissues using Tissue Microarrays. For selected genes (BMI1 and RING1) FISH analysis has been also carried out. PcG proteins had a tissue- and cell-type-specific expression pattern. Some of them were highly selectively expressed, such as HPH1, which was detected in germ cells in testis, pituitary and parathyroid glands and Langerhans islets, and RYBP, which was found in placenta, umbilical cord and thyroid gland. By contrast, RING1 was ubiquitously expressed in every normal tissue analyzed. Changes in expression associated with tumoral transformation have been found for BMI1 and RNF2, which exhibited increased expression in a large series of tumors, including gastrointestinal tumors, pituitary and parathyroid adenomas, and lymphomas, compared with their expression in normal-cell counterparts. The high level of expression of BMI1 protein observed in mantle-cell lymphomas and pituitary adenomas is associated in some cases with amplification of BMI1 locus. These findings imply that upregulation of BMI1 may constitute a malignancy marker in different types of cancer, mainly in lymphoid and endocrine tumors. RING1 was lost in a group of renal-cell carcinomas and testicular germ-cell tumors. Lastly, RYBP is anomalously expressed in Hodgkin's lymphomas and oligodendrogliomas, among others tumors. A significant finding of the study is the identification of unique PcG profiles for some tumors, such as testicular germ-cell tumors, which have high levels of HPH1 expression and loss of RING1 and/or BMI1; pituitary adenomas, which expressed every PcG protein analyzed; and clear-cell renal-cell carcinoma, which was the only tumor other than testicular germ-cell tumors that did not express RING1.

Carrier Proteins↗

PubMed2006

PRDM1/BLIMP-1 expression in multiple B and T-cell lymphoma.

BACKGROUND AND OBJECTIVES: The positive regulatory domain I (PRDM1) protein or BLIMP-1, belonging to the PRDM gene family of transcriptional repressors, is a key regulator of terminal differentiation in B-lymphocytes and is critical for plasma cell differentiation. DESIGN AND METHODS: Here we document the expression of PRDM1 in normal and neoplastic lymphoid cells, through the use of a monoclonal antibody that recognizes the molecule in paraffin-embedded tissue sections. A large series of B and T-cell lymphomas (679 cases) was studied, using tissue microarrays. RESULTS: Multiple myeloma, plasmacytoma and lymphoplasmacytic lymphoma cases (n=19) were positive. Plasmablastic lymphoma, oral mucosa-type (n=15), were also found to be positive. PRDM1 protein was expressed in some cases of B-cell neoplasia, i.e. chronic lymphocytic leukemia/small lymphocytic lymphoma (15%), diffuse large B-cell lymphoma (43%), classical Hodgkin's lymphoma (41%) and also in T-cell lymphoma (23%). INTERPRETATION AND CONCLUSIONS: Most B-neoplastic cells showing plasmablastic differentiation were PRDM1-positive. Unexpectedly, a subset of diffuse large B-cell lymphoma expressed PRDM1, lacked detectable plasmablastic or immunoblastic changes and displayed more aggressive behavior, with a shorter failure-free survival. In contrast to normal B-cells, diffuse large B-cell lymphoma cases with increased PRDM1 expression co-expressed BCL-6 and MUM1/IRF4, confirming that PRDM1 expression in these tumors is insufficient to drive the full genetic program associated with plasmacytic differentiation.

Cell Differentiation↗

PubMed2006

The presence of STAT1-positive tumor-associated macrophages and their relation to outcome in patients with follicular lymphoma.

BACKGROUND AND OBJECTIVES: The presence of tumor-associated macrophages (TAM) is a prognostic factor for survival in follicular lymphoma (FL). Overexpression and/or activation of the signal transducer and activator of transcription 1 (STAT1) in these TAM have also been observed. The aim of this study was to determine the extent to which macrophages are present in FL and to investigate the expression of STAT1 in these cells. DESIGN AND METHODS: We retrospectively analyzed 211 patients with distinct stages and grades of FL. Expression of the CD68 proteins, chosen as a marker for macrophages, and STAT1 was quantified by immunohistochemistry and double immunofluorescence. RESULTS: Automated determinations revealed the presence of CD68-positive macrophages in all FL tissues studied (mean 57.6+/-45.1 cells/field), while STAT1 protein was expressed in 29.94% of cases. Double-fluorescence staining confirmed that STAT1 protein co-localized exclusively with CD68, indicating the presence of a subset of STAT1-expressing TAM localized principally in the vicinity of tumor cells. Multivariate analysis showed that, besides the Follicular Lymphoma International Prognostic Index (FLIPI) classification, expression of STAT1 was an important independent prognostic factor for shorter overall survival in FL. INTERPRETATION AND CONCLUSIONS: These results demonstrate the presence of STAT1-expressing TAM in FL and their association with an adverse outcome, thus emphasizing the relevance of non-tumor cells in the control of the growth and survival of lymphoma cells.

Aged↗

PubMed2005

Mouse cDNA microarray analysis uncovers Slug targets in mouse embryonic fibroblasts.

There is a need to reveal mechanisms that account for maintenance of the mesenchymal phenotype in normal development and cancer. Slug (approved gene symbol Snai2), a member of the Snail gene family of zinc-finger transcription factors, is believed to function in the maintenance of the nonepithelial phenotype. This study identified candidate Slug target genes linked to Slug gene suppression in primary mouse embryonic fibroblasts. Expression analyses were performed with a mouse cDNA microarray (Mousechip-CNIO) containing 15,000 clones. A total of 15 novel Slug target species were validated by real-time PCR or Western analyses. These included self-renewal genes (Bmi1, Nanog, Gfi1), epithelial-mesenchymal genes (Tcfe2a, Ctnb1, Sin3a, Hdac1, Hdac2, Muc1, Cldn11), survival genes (Bcl2, Bbc3), and cell cycle/damage genes (Cdkn1a, Rbl1, Mdm2). Expression patterns were studied in wild-type MEFs and Slug-deficient MEFs. Slug-complementation studies recovered aberrant gene expression in cells lacking Slug, indicating that these genes were regulated directly by Slug. These results highlight their potential roles in mediating Slug function in mesenchymal cells and may help to identify novel therapeutic biomarkers in cancers linked to Slug.

Animals↗

PubMed2005

Splenic marginal zone lymphoma: proposal of new diagnostic and prognostic markers identified after tissue and cDNA microarray analysis.

Splenic marginal zone lymphoma (SMZL) is a newly recognized lymphoma type whose precise molecular pathogenesis is still essentially unknown. This hampers differential diagnosis with other small B-cell malignancies. With the aim of characterizing this tumor more comprehensively, and of identifying new diagnostic and prognostic markers, we performed cDNA microarray expression profiling and tissue microarray (TMA) immunohistochemical studies in a relatively large series of 44 SMZLs. The results were related to immunoglobulin heavy chain variable region (IgV(H)) mutational status and clinical outcome. SMZLs display a largely homogenous signature, implying the existence of a single molecular entity. Of the genes deregulated in SMZLs, special mention may be made of the genes involved in B-cell receptor (BCR) signaling, tumor necrosis factor (TNF) signaling and nuclear factor-kappaB (NF-kappaB) activation, such as SYK, BTK, BIRC3, TRAF3, and LTB. Other genes observed were SELL and LPXN, which were highly expressed in spleen, and lymphoma oncogenes, such as ARHH and TCL1. In contrast, the genes CAV1, CAV2, and GNG11 located in 7q31, a commonly deleted area, were down-regulated in the entire series. A comparison with the genes comprising the signature of other small B-cell lymphomas identified 3 genes whose expression distinguishes SMZL, namely ILF1, SENATAXIN, and CD40. Shorter survival was associated with CD38 expression, naive IgV(H) genes, and the expression of a set of NF-kappaB pathway genes, including TRAF5, REL, and PKCA.

Biomarkers, Tumor↗

PubMed2005

Mantle-cell lymphoma genotypes identified with CGH to BAC microarrays define a leukemic subgroup of disease and predict patient outcome.

To identify recurrent genomic changes in mantle cell lymphoma (MCL), we used high-resolution comparative genomic hybridization (CGH) to bacterial artificial chromosome (BAC) microarrays in 68 patients and 9 MCL-derived cell lines. Array CGH defined an MCL genomic signature distinct from other B-cell lymphomas, including deletions of 1p21 and 11q22.3-ATM gene with coincident 10p12-BMI1 gene amplification and 10p14 deletion, along with a previously unidentified loss within 9q21-q22. Specific genomic alterations were associated with different subgroups of disease. Notably, 11 patients with leukemic MCL showed a different genomic profile than nodal cases, including 8p21.3 deletion at tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor gene cluster (55% versus 19%; P = .01) and gain of 8q24.1 at MYC locus (46% versus 14%; P = .015). Additionally, leukemic MCL exhibited frequent IGVH mutation (64% versus 21%; P = .009) with preferential VH4-39 use (36% versus 4%; P = .005) and followed a more indolent clinical course. Blastoid variants, increased number of genomic gains, and deletions of P16/INK4a and TP53 genes correlated with poorer outcomes, while 1p21 loss was associated with prolonged survival (P = .02). In multivariate analysis, deletion of 9q21-q22 was the strongest predictor for inferior survival (hazard ratio [HR], 6; confidence interval [CI], 2.3 to 15.7). Our study highlights the genomic profile as a predictor for clinical outcome and suggests that "genome scanning" of chromosomes 1p21, 9q21-q22, 9p21.3-P16/INK4a, and 17p13.1-TP53 may be clinically useful in MCL.

Aged↗

PubMed2005

Outcome in Hodgkin's lymphoma can be predicted from the presence of accompanying cytotoxic and regulatory T cells.

PURPOSE: Recent studies of Hodgkin's lymphoma (HL) have suggested that the presence of regulatory T cells in the reactive background may explain the inhibition of the antitumoral host immune response observed in these patients. This study aimed to assess the relevance of regulatory T cells and CTLs present in the background of HL samples in the prognosis of a series of classic HL (cHL) patients. EXPERIMENTAL DESIGN: Expression of granzyme B and TIA-1 (markers for CTL) and FOXP3 (a marker for regulatory T cells) were evaluated independently by immunohistochemistry in tissue microarrays of 257 cHL patients and correlated with patient outcome. RESULTS: The combined influence of the presence of FOXP3(+) and TIA-1(+) cells distinguished three risk groups of patients with 5-year overall survival of 100%, 88%, and 73%. The presence of a small number of FOXP3(+) cells and a high proportion of TIA-1(+) cells in the infiltrate represent an independent prognostic factor that negatively influenced event-free survival and disease-free survival in cHL. Compared with the features at diagnosis, relapsed samples tended to have more TIA-1(+) cells and a lower proportion of FOXP3(+) cells in the reactive background. CONCLUSIONS: These data suggest that low infiltration of FOXP3(+) cells in conjunction with high infiltration of TIA-1(+) cells in cHL may represent biological markers predicting an unfavorable outcome. Moreover, the variation of these markers over the course of the disease implies a possible role for them in the progression of HL cases.

Adolescent↗

PubMed2005

Expression of the NF-kappaB targets BCL2 and BIRC5/Survivin characterizes small B-cell and aggressive B-cell lymphomas, respectively.

Nuclear factor kappa B (NF-kappaB) activation has been proposed as a cardinal feature of tumourigenesis, although the precise mechanism, frequency, relevance, and extent of NF-kappaB activation in lymphomas remain to be fully elucidated. In this study, expression profiling and tissue microarray studies of 209 and 323 non-Hodgkin's lymphomas (NHLs) respectively, including the most frequent sub-types of NHL, were employed to generate a hypothesis concerning the most common NF-kappaB targets in NHL. These analyses showed that NF-kappaB activation is a common phenomenon in NHL, resulting in the expression of distinct sets of NF-kappaB target genes, depending on the cell context. BCL2 and BIRC5/Survivin were identified as key NF-kappaB targets and their expression distinguished small and aggressive B-cell lymphomas, respectively. Interestingly, in the vast majority of B-cell lymphomas, the expression of these markers was mutually exclusive. A set of genes was identified whose expression correlates either with BIRC5/Survivin or with BCL2. BIRC5/Survivin expression, in contrast to BCL2, was associated with a signature of cell proliferation (overexpression of cell cycle control, DNA repair, and polymerase genes), which may contribute to the aggressive phenotype and poor prognosis of these lymphomas. Strikingly, mantle cell lymphoma and chronic lymphocytic leukaemia expressed highly elevated levels of BCL2 protein and mRNA, higher than that observed in reactive mantle zone cells or even in follicular lymphomas, where BCL2 expression is deregulated through the t(14;18) translocation. In parallel with this observation, BIRC5/Survivin expression was higher in Burkitt's lymphoma and diffuse large B-cell lymphoma than in non-tumoural germinal centre cells. In vitro studies confirmed that NF-kappaB activation contributes to the expression of both markers. In cell lines representing aggressive lymphomas, NF-kappaB inhibition resulted in a decrease in BIRC5/Survivin expression. Meanwhile, in chronic lymphocytic leukaemia (CLL)-derived lymphocytes, NF-kappaB inhibition resulted in a marked decrease in BCL2 expression.

Gene Expression Profiling↗

PubMed2005

Transcriptional signature of Ecteinascidin 743 (Yondelis, Trabectedin) in human sarcoma cells explanted from chemo-naive patients.

Ecteinascidin 743 (ET-743; Yondelis, Trabectedin) is a marine anticancer agent that induces long-lasting objective remissions and tumor control in a subset of patients with pretreated/resistant soft-tissue sarcoma. Drug-induced tumor control is achievable in 22% of such patients, but there is no clear indication of the molecular features correlated with clinical sensitivity/resistance to ET-743. Nine low-passage, soft-tissue sarcoma cell lines, explanted from chemo-naive patients with different patterns of sensitivity, have been profiled with a cDNA microarray containing 6,700 cancer-related genes. The molecular signature of these cell lines was analyzed at baseline and at four different times after ET-743 exposure. The association of levels of TP53 mutation and TP73 expression with ET-743 sensitivity and cell cycle kinetics after treatment was also analyzed. Gene expression profile analysis revealed up-regulation of 86 genes and down-regulation of 244 genes in response to ET-743. The ET-743 gene expression signature identified a group of genes related with cell cycle control, stress, and DNA-damage response (JUNB, ATF3, CS-1, SAT, GADD45B, and ID2) that were up-regulated in all the cell lines studied. The transcriptional signature 72 hours after ET-743 administration, associated with ET-743 sensitivity, showed a more efficient induction of genes involved in DNA-damage response and apoptosis, such as RAD17, BRCA1, PAR4, CDKN1A, and P53DINP1, in the sensitive cell line group. The transcriptional signature described here may lead to the identification of ET-743 downstream mediators and transcription regulators and the proposal of strategies by which ET-743-sensitive tumors may be identified.

Antineoplastic Agents, Alkylating↗

PubMed2004

Overexpression of human DNA polymerase mu (Pol mu) in a Burkitt's lymphoma cell line affects the somatic hypermutation rate.

DNA polymerase mu (Pol mu) is a DNA-dependent DNA polymerase closely related to terminal deoxynucleotidyl transferase (TdT), and prone to induce template/primer misalignments and misincorporation. In addition to a proposed general role in non-homologous end joining of double-strand breaks, its mutagenic potential and preferential expression in secondary lymphoid tissues support a role in somatic hypermutation (SHM) of immunoglobulin genes. Here, we show that human Pol mu protein is expressed in the nucleus of centroblasts obtained from human tonsils, forming a characteristic foci pattern resembling that of other DNA repair proteins in response to DNA damage. Overexpression of human Pol mu in Ramos cells, in which the SHM process is constitutive, augmented the somatic mutations specifically at the variable (V) region of the immunoglobulin genes. The nature of the mutations introduced, mostly base substitutions, supports the contribution of Pol mu to mutation of G and C residues during SHM. In vitro analysis of Pol mu misincorporation on specific templates, that mimic DNA repair intermediates and correspond to mutational hotspots, indicated that many of the mutations observed in vivo can be explained by the capacity of Pol mu to induce transient template/primer misalignments.

B-Lymphocytes↗

PubMed2004

Variability in the degree of expression of phosphorylated IkappaBalpha in chronic lymphocytic leukemia cases with nodal involvement.

PURPOSE: Based on previous preliminary observations, we hypothesize that the molecular and clinical variability of chronic lymphocytic leukemia (CLL) reflects differences in the degree of nuclear factor (NF)-kappaB activation, as determined by the expression of phosphorylated IkappaBalpha (p-IkappaBalpha). EXPERIMENTAL DESIGN: The expression profile (mRNA and protein expression) was analyzed with the Centro Nacional de Investigaciones Oncologicas Oncochip, a cDNA microarray containing 6386 cancer-related genes, and a tissue microarray (TMA). The results were correlated with the IgV(H) mutational status, ZAP-70 expression, cytogenetic alterations, and clinical outcome. RESULTS: We found correlations between the presence of p-IkappaBalpha, a surrogate marker of NF-kappaB activation, and changes in the expression profile (mRNA and protein expression) and clinical outcome in a series of CLL cases with lymph node involvement. Activation of NF-kappaB, as determined by the expression of p-IkappaBalpha, was associated with the expression of a set of genes comprising key genes involved in the control of B-cell receptor signaling, signal transduction, and apoptosis, including SYK, LYN, BCL2, CCR7, BTK, PIK3CD, and others. Cases with increased expression of p-IkappaBalpha showed longer overall survival than cases with lower expression. A Cox regression model was derived to estimate some parameters of prognostic interest: IgV(H) mutational status, ZAP-70, and p-IkappaBalpha expression. The multivariate analysis disclosed p-IkappaBalpha and ZAP-70 expression as independent prognostic factors of survival. CONCLUSIONS: A variable degree of activation of NF-kappaB, as determined by the expression of p-IkappaBalpha, is an identifiable event in CLL, and is correlated with changes in the expression profile and overall survival.

Adult↗

PubMed2004

Influence of biologic markers on the outcome of Hodgkin's lymphoma: a study by the Spanish Hodgkin's Lymphoma Study Group.

PURPOSE: Current therapies fail to cure a significant proportion of patients with Hodgkin's lymphoma (HL). Predictive systems for stratification of the disease and selection of treatment based on sets of clinical variables, such as the international prognostic score (IPS), are of relatively small practical value. The predictive use of biologic parameters has so far provided limited and inconsistent results. Here we explore the influence of a set of molecular markers on the outcome of HL. PATIENTS AND METHODS: Forty molecular markers involved in B-cell differentiation and activation, signal transduction, cell cycle, and apoptosis control were analyzed in 259 classic HL patient cases by using tissue microarrays. Univariate analysis was performed to evaluate the influence of markers on favorable outcome (complete remission of > 12 months). Significant variables were included in a multivariate logistic regression analysis, and the probability of favorable outcome was estimated. RESULTS: Univariate analysis revealed four molecular markers that predicted outcome, and the multivariate analysis showed p53, Bcl-X(L), and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labeling (TUNEL) to have independent significance. The combination of these factors determined two groups of patients (group I, zero to one factor; group II, two to three factors) with a probability of a favorable outcome of.948 and.687, respectively. A multivariate Cox's model shows that these biologic risk groups have special predictive power in low-IPS patients. CONCLUSION: The data from this exploratory study suggest that the accumulation of molecular events seems to influence the outcome of HL, particularly in the low-IPS group.

Adolescent↗

PubMed2004

Abnormal PcG protein expression in Hodgkin's lymphoma. Relation with E2F6 and NFkappaB transcription factors.

The Polycomb group (PcG) of proteins comprises a family of repressors of homeobox genes that play key roles in body formation, haematopoiesis and cell cycle control. In this study, a large-scale analysis of PcG protein expression (BMI1, MEL18, PH1, RNF2, RING1, and RYBP) was performed in 321 Hodgkin's lymphoma (HL) biopsies and in reactive lymphoid tissues using tissue microarrays. The relevance of PcG proteins in HL was also investigated by the simultaneous analysis of PcG and other proteins involved in the control of cell cycle, transcription machinery and lymphoid differentiation. The analysis revealed increased expression of a set of PcG proteins (particularly RYBP and BMI1) in tumour cells in comparison with reactive lymphoid tissue. One of the most striking findings was anomalous RYBP expression in 55% of classical HL cases associated with an unfavourable response to treatment and shorter survival. The data obtained in this study also show an association of PcG proteins with E2F6 and NFkappaB transcription factors. The statistical relationship between PcG and NFkappaB activation was further explored in HL-derived cell lines treated with curcumin, an NFkappaB inhibitor, and TNFalpha. Up- or downregulation of MEL18 was paralleled by loss or gain of activated NFkappaB, which suggests that NFkappaB may regulate expression of this protein. Investigation of the relationship between E2F6 and RING1 by immunofluorescence and confocal analysis, in HL cell lines and paraffin sections, revealed co-expression of both proteins in the same tumour cells. These results allow us to propose that the formation of transcription complexes with E2F6 may modify the functional status of PcG proteins in HSR cells.

Apoptosis↗

PubMed2004

Progression in cutaneous malignant melanoma is associated with distinct expression profiles: a tissue microarray-based study.

Cutaneous malignant melanoma remains the leading cause of skin cancer death in industrialized countries. Clinical and histological variables that predict survival, such as Breslow's index, tumor size, ulceration, or vascular invasion have been identified in malignant melanoma. Nevertheless, the potential relevance of biological variables still awaits an in-depth exploration. Using tissue microarrays (TMAs), we retrospectively analyzed 165 malignant melanoma samples from 88 patients corresponding to distinct histological progression phases, radial, vertical, and metastases. A panel of 39 different antibodies for cell cycle, apoptosis, melanoma antigens, transcription factors, DNA mismatch repair, and other proteins was used. Integrating the information, the study has identified expression profiles distinguishing specific melanoma progression stages. Most of the detected alterations were linked to the control of cell cycle G1/S transition; cyclin D1 was expressed in radial cases 48% (12 of 25) with significant lost of expression in vertical cases 14% (9 of 65), P = 0.002; whereas p16(INK4a) (89% in vertical versus 71% in metastatic cases, P = 0.009) and p27(KIP1) (76% in radial versus 45% in vertical cases, P = 0.010) were diminished in advanced stages. The study also defines a combination of biological markers associated with shorter overall survival in patients with vertical growth phase melanoma, that provided a predictor model with four antibodies (Ki67, p16(INK4a), p21(CIP1), and Bcl-6). This predictor model was validated using an independent series of 72 vertical growth phase melanoma patients.

Adult↗

PubMed2004

Building an outcome predictor model for diffuse large B-cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) patients are treated using relatively homogeneous protocols, irrespective of their biological and clinical variability. Here we have developed a protein-expression-based outcome predictor for DLBCL. Using tissue microarrays (TMAs), we have analyzed the expression of 52 selected molecules in a series of 152 DLBCLs. The study yielded relevant information concerning key biological aspects of this tumor, such as cell-cycle control and apoptosis. A biological predictor was built with a training group of 103 patients, and was validated with a blind set of 49 patients. The predictive model with 8 markers can identify the probability of failure for a given patient with 78% accuracy. After stratifying patients according to the predicted response under the logistic model, 92.3% patients below the 25 percentile were accurately predicted by this biological score as "failure-free" while 96.2% of those above the 75 percentile were correctly predicted as belonging to the "fatal or refractory disease" group. Combining this biological score and the International Prognostic Index (IPI) improves the capacity for predicting failure and survival. This predictor was then validated in the independent group. The protein-expression-based score complements the information obtained from the use of the IPI, allowing patients to be assigned to different risk categories.

Adolescent↗