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Biomedical subjects

M Varella-Garcia

Publications and source records attributed to M Varella-Garcia.

At least 19 recordsLinked to original sources
PubMed2006

Epidermal growth factor receptor gene copy number and protein level are not associated with outcome of non-small-cell lung cancer patients treated with chemotherapy.

BACKGROUND: Survival benefit of non-small-cell lung cancer (NSCLC) patients treated with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors is predicted by high EGFR gene copy number and by strong EGFR protein expression. Clinical relevance of these features in patients treated with chemotherapy has not been reported. PATIENTS AND METHODS: This study included 82 NSCLC patients treated with chemotherapy. There were 45% of females, 6% of never smokers and 45% of patients diagnosed with adenocarcinoma. EGFR gene copy number was evaluated by fluorescence in situ hybridization and EGFR protein level by immunohistochemistry. RESULTS: High EGFR gene copy number and protein level were found in 33% and 71% of patients, respectively. Both markers were significantly associated (P = 0.01). For objective response and disease control, there was no difference between patients defined as negative or positive for both EGFR gene copy number (P = 0.39 and P = 1.00, respectively) and for EGFR protein (P = 1.00 and P = 0.80, respectively). There were no differences in progression-free and overall survival according to EGFR gene copy number (P = 0.76 and P = 0.82, respectively) and protein level (P = 0.67 and P = 0.62, respectively). CONCLUSION: In chemotherapy-treated NSCLC patients, EGFR gene copy number was positively associated with protein level but none of the features were predictive for either treatment response or survival.

Adult↗
PubMed2006

Insulin-like growth factor receptor 1 (IGFR-1) is significantly associated with longer survival in non-small-cell lung cancer patients treated with gefitinib.

BACKGROUND: The aim of the study was to assess whether loss of PTEN and expression of insulin-like growth factor receptor 1 (IGFR-1) could be responsible for intrinsic resistance to the tyrosine kinase inhibitor (TKI) gefitinib. PATIENTS AND METHODS: One hundred and twenty-four gefitinib-treated patients with advanced non-small-cell lung cancer (NSCLC) were analyzed for PTEN and IGFR-1 expression by immunohistochemistry. RESULTS: IGFR-1 was evaluated in 77 patients and resulted positive in 30 (39.0%). IGFR-1 expression was not significantly associated with clinical or biological characteristics. No difference in response to gefitinib treatment (16.7% versus 12.8%, P = 0.74) and time to progression (2.6 versus 3.06 months, P = 0.83) was observed between IGFR-1+ and IGFR-1-. Median survival was significantly longer in IGFR-1+ patients (17.8 versus 7.3 months, P = 0.013). PTEN expression was successfully evaluated in 93 cases. Loss of PTEN was detected in 19 tumors (20.4%) and was not associated with any clinical or biological characteristic. No difference in terms of response, time to progression and survival was observed between PTEN+ and PTEN- patients. In multivariable analysis IGFR-1 negative status was significantly associated with higher risk of death (hazard ratio 2.21, P = 0.012). CONCLUSIONS: IGFR-1 expression and loss of PTEN are not associated with intrinsic resistance to gefitinib. Clinical relevance of these two biomarkers as determinant for acquired resistance, and the prognostic role of IGFR-1 expression in patients not exposed to TKIs should be evaluated further.

Adult↗
PubMed2005

HER3 genomic gain and sensitivity to gefitinib in advanced non-small-cell lung cancer patients.

In non-small-cell lung cancer (NSCLC), sensitivity to tyrosine kinase inhibitors (TKIs) is associated with activating mutations and genomic gain of the epidermal growth factor receptor (EGFR). Preclinical data suggested that HER3 overexpression increases sensitivity to TKIs. A total of 82 NSCLC patients treated with gefitinib (250 mg), and previously evaluated for EGFR and HER2 status by fluorescence in situ hybridisation (FISH) and DNA sequencing, and for Phospho-Akt status by immunohistochemistry, were investigated for HER3 genomic gain by FISH. Patients with high polysomy and gene amplification were considered as HER3 FISH positive (+). HER3 FISH+ pattern was significantly associated with female gender (P=0.02) and never smoking history (P=0.02). Patients with HER3+ tumours (26.8%) had a significantly longer time to progression (3.7 vs 2.7, P=0.04) than patients with HER3- tumours, but not a significantly better response rate or survival. Patients with EGFR+/HER3+ tumours had higher objective response rate (36.4 vs 9.9%, P=0.03) and time to progression (7.7 vs 2.7 months, P=0.03) than patients with EGFR- and/or HER3- tumours, but no significantly longer survival. No difference in response was observed according to HER3 status in patients with EGFR+ tumours. Patients with HER2+/HER3+ tumours had similar outcome as patients with HER2- and/or HER3- tumours. Significantly different clinical end points were not observed between patients with HER3+/P-Akt+ and HER3- and/or P-Akt- tumours. Genomic gain for HER3 is not a marker for response or resistance to TKI therapy in advanced NSCLC patients.

Antineoplastic Agents↗
PubMed2005

Cloning and functional characterization of MEF2D/DAZAP1 and DAZAP1/MEF2D fusion proteins created by a variant t(1;19)(q23;p13.3) in acute lymphoblastic leukemia.

We analyzed the TS-2 acute lymphoblastic leukemia (ALL) cell line that contains a t(1;19)(q23;p13.3) but lacks E2A-PBX1 fusion typically present in leukemias with this translocation. We found that the t(1;19) in TS-2 fuses the 19p13 gene DAZAP1 (Deleted in Azoospermia-Associated Protein 1) to the 1q23 gene MEF2D (Myocyte Enhancer Factor 2D), leading to expression of reciprocal in-frame DAZAP1/MEF2D and MEF2D/DAZAP1 transcripts. MEF2D is a member of the MEF2 family of DNA binding proteins that activate transcription of genes involved in control of muscle cell differentiation, and signaling pathways that mediate response to mitogenic signals and survival of neurons and T-lymphocytes. DAZAP1 is a novel RNA binding protein expressed most abundantly in the testis. We demonstrate that MEF2D/DAZAP1 binds avidly and specifically to DNA in a manner indistinguishable from that of native MEF2D and is a substantially more potent transcriptional activator than MEF2D. We also show that DAZAP1/MEF2D is a sequence-specific RNA-binding protein. MEF2D has been identified as a candidate oncogene in murine retroviral insertional mutagenesis studies. Our data implicate MEF2D in human cancer and suggest that MEF2D/DAZAP1 and/or DAZAP1/MEF2D contribute to leukemogenesis by altering signaling pathways normally regulated by wild-type MEF2D and DAZAP1.

Cell Line, Tumor↗
PubMed2005

Glioblastomas in the older old.

CONTEXT: Recent studies have identified fundamental biological differences in the effects of epidermal growth factor receptor (EGFR) amplification on survival in older versus younger patients with glioblastoma multiforme (GBM). Cell cycle labeling indices have also been found to be inordinately high in older GBM patients and may contribute to the known adverse prognosis in this cohort. However, testing has not been conducted on significant numbers of patients of very advanced age, in whom these features might be expected to emerge as even more significant factors. OBJECTIVE: To assess EGFR amplification status and MIB-1 indices in patients with GBM who are older than 75 years. DESIGN: We identified 20 patients (female-male ratio, 11:9; 11 aged 75-79 years and 9 aged 80-87 years) and studied tumor tissue samples with immunohistochemistry for cell cycle labeling index and by fluorescence in situ hybridization for EGFR amplification. Survival data were obtained from the Colorado Tumor Registry. RESULTS: Mean MIB-1 index was high (24.8%), but individual indices did not correlate with survival. EGFR amplification was detected in 25% of cases, with gain of chromosome 7 in all but one of the remaining patients. Ninety-five percent of patients manifested EGFR amplification and/or polysomy of chromosome 7. Heterogeneity was found within a given tumor, with 10% to 60% of cells showing gain of chromosome 7. Overall patient survival was poor (mean, 4.6 months), but was significantly longer in those with EGFR gene amplification (mean, 8.3 months; median, 10.5 months) versus those without (mean, 3.2 months; median, 2.0 months) (P = .04). CONCLUSION: The presence of EGFR amplification is a significant predictor of survival time in older old patients.

Age Factors↗
PubMed2002

Evaluation of HER-2/neu gene amplification and protein expression in non-small cell lung carcinomas.

HER-2/neu gene amplification and cell surface overexpression are important factors in breast cancer for prognosis and prediction of sensitivity to anti-HER-2/neu monoclonal antibody therapy. In lung cancer, the clinical significance of HER-2/neu expression is currently under evaluation. We investigated 238 non-small lung carcinomas for HER-2/neu protein overexpression by immunohistochemistry using the HercepTest. We found 2+ or 3+ overexpression in 39 patients (16%), including 35% in adenocarcinomas and 20% in large cell carcinomas, but only 1% of squamous cell carcinomas. Marked (3+) overexpression was uncommon (4%). The association between protein expression and gene copy number per cell, as determined by fluorescence in situ hybridisation assay, was investigated in 51 of these NSCLC tumours. Twenty-seven tumours (53%) were negative by both tests. Marked (3+) protein expression and gene amplification were present in only 4% of samples. In 11 tumours (21%), gene gain was accompanied by chromosomal aneusomy and did not result in high protein levels while in 7 (14%) the score 2+ was associated with maximum number of signals per cell <9. The prognostic implication of HER-2/neu protein expression was studied in 187 surgically resected tumours. No statistical difference in survival was observed comparing patients with positive (2+/3+) and negative tumours (0/1+), although 3+ patients showed a tendency to shorter survival. The therapeutic implications of protein expression and gene amplification in lung cancer need to be examined in prospective clinical trials.

Aged↗
PubMed2002

Quantitative HOX expression in chromosomally defined subsets of acute myelogenous leukemia.

We used a degenerate RT-PCR screen and subsequent real-time quantitative RT-PCR assays to examine the expression of HOX and TALE-family genes in 34 cases of chromosomally defined AML for which outcome data were available. AMLs with favorable cytogenetic features were associated with low overall HOX gene expression whereas poor prognostic cases had high levels. Characteristically, multiple HOXA family members including HOXA3-HOXA10 were jointly overexpressed in conjunction with HOXB3, HOXB6, MEIS1 and PBX3. Higher levels of expression were also observed in the FAB subtype, AML-M1. Spearmann correlation coefficients indicated that the expression levels for many of these genes were highly inter-related. While we did not detect any significant correlations between HOX expression and complete response rates or age in this limited set of patients, there was a significant correlation between event-free survival and HOXA7 with a trend toward significance for HoxA9, HoxA4 and HoxA5. While patients with elevated HOX expression did worse, there were notable exceptions. Thus, although HOX overexpression and clinical resistance to chemotherapy often coincide, they are not inextricably linked. Our results indicate that quantitative HOX analysis has the potential to add new information to the management of patients with AML, especially where characteristic chromosomal alterations are lacking.

Acute Disease↗
PubMed2001

TSU-Pr1 and JCA-1 cells are derivatives of T24 bladder carcinoma cells and are not of prostatic origin.

We have shown previously that the putative prostate carcinoma cell lines TSU-Pr1 and JCA-1 share a common origin. The observation that these cell lines have p53 and Ha-ras mutations identical to those in bladder carcinoma cell line T24 prompted us to investigate their possible interrelations. We used cytogenetics and DNA profiling to compare the genetic backgrounds of the three cell lines. At least 12 structural chromosomal abnormalities are shared between T24, TSU-Pr1, and JCA-1 cells. DNA profiles were identical for all three cell lines. These results clearly indicate that the cell lines TSU-Pr1 and JCA-1 are not of prostatic origin but are derivatives of the bladder carcinoma cell line T24. TSU-Pr1 and, to a lesser extent, JCA-1 are frequently used as models in prostate cancer research, and numerous publications have appeared based on these lines. Several other T24 cross-contaminants have been identified in the past, and some of these, such as ECV304, continue to be used under the wrong identity. Our findings highlight the insidious problem that can occur when information regarding cross-contamination does not reach individual researchers and/or the importance of the problem is not fully acknowledged.

Chromosome Aberrations↗
PubMed2001

Karyotypic similarity identified by multiplex-FISH relates four prostate adenocarcinoma cell lines: PC-3, PPC-1, ALVA-31, and ALVA-41.

Recently developed molecular cytogenetic techniques for karyotyping are providing new and important insights regarding the chromosomal changes that occur in solid tumors. We used multiplex-FISH to analyze four adenocarcinoma cell lines, PC-3, PPC-1, ALVA-31, and ALVA-41, in which the characterization of a large number of rearranged chromosomes was partially or substantially inconclusive by G-banding. Although the original descriptions of these lines depict them as distinct entities established from different patients, this study demonstrates that these four lines share numerous, highly rearranged chromosomes, strongly supporting the conclusion that they are derived from the same patient material. Our analysis indicates that PPC-1, ALVA-31, and ALVA-41 were derived from PC-3 through mechanisms involving clonal progression represented by sequential changes and clonal diversion represented by differing patterns of changes. Extensive cellular heterogeneity was detected in all four lines, and most rearrangements included segments derived from multiple chromosomes. Each line also showed a set of unique derivative chromosomes. However, a limited number of metaphase cells (approximately 10) was analyzed for each line, and numerous single-cell abnormalities were detected in all of them. Therefore, it is plausible that the number of clonal, shared, and/or unique rearrangements has been underestimated. These cell lines have been utilized as models for understanding the biology of prostate cancer and reportedly differ in their cell physiology. Rather than detracting from their value, a complete understanding of the interrelationships of these lines to one another may provide the opportunity to define the molecular changes that have led to their individual malignant phenotypes.

Adenocarcinoma↗
PubMed2001

Widely used prostate carcinoma cell lines share common origins.

BACKGROUND: Cross-contamination is a persistent problem in the establishment and maintenance of mammalian cell lines. The observation that the cell lines PC-3, ALVA-31, and PPC-1 all have a homozygous deletion of the alpha-catenin gene prompted us to investigate the uniqueness of these and several other widely used prostate carcinoma cell lines. METHODS: The genetic backgrounds of the putative human prostate cell lines (ALVA-31, ALVA-41, BPH-1, DU 145, JCA-1, LAPC-4, LNCaP, NCI-H660, ND-1, PC-3, PC-3MM2, PC-346C, PPC-1, and TSU-Pr1) were analyzed by cytogenetics, mutation analysis, and DNA profiling. RESULTS: Similarities between several groups of cell lines were found. ALVA-31, ALVA-41, PC-3, PC-3MM2, and PPC-1 all have a deletion of a C in codon 138 of the p53 gene and show almost identical DNA profiles. The ND-1 cell line has two p53 mutations that are identical to the mutations found in DU 145. These two cell lines also share a high number of structural chromosomal abnormalities and nearly identical DNA profiles. The cell lines TSU-Pr1 and JCA-1 share an identical p53 mutation in exon 5 and identical DNA profiles. CONCLUSIONS: Several widely used prostate carcinoma cell lines apparently have identities in common. The knowledge that some of these cell lines are derivatives of one another prompts re-evaluation of previously obtained results.

Cell Lineage↗
PubMed2001

Detection of E2A translocations in leukemias via fluorescence in situ hybridization.

Three rearrangements in ALL disrupt E2A and create E2A fusion proteins: the t(1;19)(q23;p13) and E2A-PBX1, t(17;19)(q22;p13) and E2A-HLF and a cryptic inv(19)(p13;q13) and E2A-FB1. While E2A is fused to PBX1 in most ALLs with a t(1;19), 5-10% of cases have translocations that appear identical, but do not affect E2A or PBX1. Because more intensive therapy improves the outcome of patients with E2A-PBX1positive (1;19) translocations, it is critical to identify this subset of patients so that appropriate therapy can be administered. In addition, there are balanced and unbalanced variants of the t(1;19) and controversy exists regarding the clinical significance of this distinction. We have developed a two-color fluorescence in situ hybridization assay that accurately detects E2A translocations in metaphase and interphase cells, distinguishes between balanced and unbalanced variants and identifies patients with a t(1;19) who lack E2A-PBX1 fusion. We found that clonal microheterogeneity is common in patients with E2A translocations and most patients have mixtures of cells with balanced and unbalanced translocations, suggesting that this distinction represents two ends of a continuum rather than distinct biological entities. These reagents should have widespread clinical utility and be useful for translational and basic research studies involving E2A translocations and this region of chromosome 19p13.

Basic Helix-Loop-Helix Proteins↗
PubMed2001

Minimal residual disease (MRD) in remission t(8;21) AML and in vivo differentiation detected by FISH and CD34+ cell sorting.

Many patients with t(8;21) AML have residual positive cells during remission. We previously developed D-FISH probes that detect both derivative chromosomes and the normal alleles. In negative controls, only 2/44,000 (0.0045%) positive signals were observed. To investigate MRD, we examined specimens from 29 patients who had initially obtained CR. In remission patients, 61% had 1-4/2000 positive cells (0.05-0.19%). Higher frequencies were found in two patients in early relapse and in one patient in early remission. However, a negative test did not exclude relapse. Since false positives were negligible and because most t(8;21) AMLs express CD34, we asked whether cell sorting combined with FISH would increase the sensitivity. In one patient, we observed that 80% of CD34+ cells were t(8;21)+ at 2 months from initial clinical and cytogenetic remission. However, by 5 months the pre- and post-sorted populations contained 0.15% and 0.06% t(8;21) cells, respectively. Whereas essentially all t(8;21) cells in the initial specimen expressed CD34, only 0.6% were subsequently CD34+. These results are consistent with in vitro assays showing that residual t(8;21) cells undergo differentiation. Thus, FISH can identify MRD in a majority of t(8;21) patients and, combined with CD34+ selection, may provide an indirect assessment of the differentiation state of residual t(8;21) cells.

Acute Disease↗
PubMed2001

Chromosomal aneuploidy precedes morphological changes and supports multifocality in head and neck lesions.

OBJECTIVE: To identify chromosome changes associated with the transformation of dysplastic lesions and to verify evidence for multifocality in synchronous premalignant lesions associated with head and neck squamous cell carcinoma (HNSCC). STUDY DESIGN: Chromosomal aneuploidy was evaluated in sections of formalin-fixed, paraffin-embedded tissues from 16 patients with HNSCC, including sites with normal squamous mucosa, dysplasia (low- and high-grade), and invasive tumor. METHODS: A panel of 6 centromeric probes (chromosomes 1, 3, 7, 8, 9, and 17) was analyzed in dual-color fluorescence in situ hybridization assays, using matched hematoxylin-eosin-stained sections for histologic correlation. RESULTS: Imbalances for most of the targets tested were found in 20 of 24 invasive carcinoma sites, mainly represented by gain in copy number per cell. However, cell populations with chromosome losses and gains in multimodal patterns were concomitantly observed in a number of tumors, indicating a high degree of chromosome instability. The detection of chromosomal aneuploidy precedes the malignant transformation as indicated by findings of monosomy and trisomy in normal squamous mucosa, and in low-grade and high-grade dysplasia sites. Loss of chromosomes 3 and 17 prevailed in low-grade dysplasias, and gain of chromosomes 7 and 8 were prevalent in high-grade dysplasias. Synchronous low-grade and high-grade dysplastic lesions displayed discordant molecular signatures, suggesting a multifocal origin. CONCLUSIONS: The interphase fluorescence in-situ hybridization (FISH) assay with centromeric may detect early changes in the progression of dyplastic epithelia to invasive carcinoma and supports the field cancerization theory of multifocality.

Adult↗
PubMed2001

Adjusting interphase FISH results in epithelial tissue sections to whole cell complement.

OBJECTIVE: To derive an equation to compensate for the discrepancies between whole cell preparations and tissue sections for more accurate enumeration of fluorescence in situ hybridization (FISH) signals per cell. STUDY DESIGN: Mean centromere signal counts in touch preparations and corresponding 4-6-micron sections of paraffin-embedded tissue were calculated. Mean widest nuclear diameters were also determined from the tissue sections. The observed data were analyzed to define the volumetric relationships between tissue sections and whole cell preparations. RESULTS: Analysis of results from six lung specimens yielded an equation that approximates whole versus sectioned nuclear volume and permits accurate quantification of mean FISH signal count in histologic sections, as follows: [formula: see text].

Carcinoma↗
PubMed2001

Expression of Her-2/neu in human lung cancer cell lines by immunohistochemistry and fluorescence in situ hybridization and its relationship to in vitro cytotoxicity by trastuzumab and chemotherapeutic agents.

Overexpression of the Her-2/neu oncogene and receptor protein was reported in approximately 20% of breast cancers and was associated with a poor prognosis. Her-2/neu expression was a predictor for response to trastuzumab, a monoclonal antibody that recognizes the Her-2/neu cell surface receptor. Data regarding the expression of Her-2/neu in lung cancer are far more limited, and there is little information regarding the influence of Her-2/neu expression and response to trastuzumab alone or in combination with chemotherapeutic agents. In this report we evaluated Her-2/neu gene expression by fluorescence in situ hybridization (FISH) and the cell surface expression of the Her-2/neu receptor by immunohistochemistry using the HercepTest and by FACS analysis in 31 lung cancer cell lines with 5 breast cancer cell lines as controls. By FACS, we found Her-2/neu overexpression (mean fluorescence intensity >8) in 2 of the 22 non-small cell lung cancer (NSCLC) cell lines (9%), none of 11 small cell lung cancer (SCLC) cell lines, and 4 of 5 breast cancer cell lines. A positive HercepTest (2+ or 3+) was found in 6 of 19 NSCLC cell lines (26%, 2+; 5%, 3+), 1 of 3 SCLC cell lines (33%), and 4 of 5 breast cancer cell lines (80%). One of 6 NSCLC cell lines examined (17%) had gene amplification with >32 copies of Her-2/neu/cell and had homogeneous staining regions. One NSCLC cell line had a maximum of 14 copies of Her-2/neu/cell, and 3 had modest increases in Her-2/neu gene copy number without gene amplification (maximum 5-8 copies/cell). None of the SCLC cell lines had more than a maximum of 4 copies/cell, whereas the 2 breast cancer cell lines had maximum Her-2/neu copy numbers of 80 and 5, respectively. Aneusomy rather than true amplification was the major cause of increased Her-2/neu expression in most of the NSCLC cell lines. There was a strong correlation when the results of fluorescence-activated cell sorter, HercepTest results, and FISH were compared in pairs. Furthermore, Trastuzumab produced a G(1) cell cycle arrest and growth inhibition only in cell lines expressing Her-2/neu. The IC(50) for growth inhibition was correlated with cell surface Her-2/neu expression. The combination of trastuzumab and chemotherapeutic agents produced more than additive growth inhibition in cell lines expressing Her-2/neu, but the level of additivity was not related to the amount of Her-2/neu expression. These data indicate that trastuzumab alone and in combination with chemotherapeutic agents should be tested in NSCLC patients and that Her-2/neu should be assessed by both immunohistochemistry and FISH methods in these studies to determine which test is the best predictor of outcome.

Antibodies, Monoclonal↗
PubMed2000

Identification of two new translocations that disrupt the AML1 gene.

The AML1 gene, located at chromosome 21q22, encodes a component (CBFalpha2) of a heterodimeric transcription factor complex termed core binding factor (CBF), which binds to DNA and activates gene expression. Chromosomal rearrangements may lead to disruption of this gene and development of acute leukemia. Twelve AML1 translocations have been identified to date, and include sites on chromosomes 1, 2, 3, 5, 8, 12, 14, 15, 16, 17, 18, and 19. Here we report two new translocations involving AML1 in acute myeloid leukemia, in which the disruption of the AML1 gene was documented by GTG banding cytogenetic studies and metaphase and interphase FISH analysis. These chromosomal breakpoints identified as harboring new fusion partners for AML1 are at 2p11.2 and 20q13.1. The two patients in who these translocation were identified were elderly males with newly diagnosed AML. These patients shared the same poor outcomes reported for other rare AML1 translocations.

Acute Disease↗