| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Regular Articles |
The Johns Hopkins Oncology Center, Baltimore, Maryland 21231
ABSTRACT
E-Cadherin is a transmembrane glycoprotein that mediates Ca2+-dependent intercellular adhesion in normal epithelium. In tumors of epithelial origin, E-cadherin expression frequently is reduced, an event that contributes to tumor invasion and metastasis. The role of E-cadherin in hematopoietic tissues is less clear. In normal bone marrow, E-cadherin is expressed on erythroid progenitors, CD34+ stem cells, and stromal cells, where it likely contributes to intercellular interactions during hematopoiesis. In this study, we used a nested-PCR approach to examine the methylation status of the E-cadherin 5' CpG island in blood and bone marrow samples from normal donors and in bone marrow from patients with acute leukemia. In normal peripheral blood mononuclear cells and bone marrow, Ecadherin was completely unmethylated. In peripheral blood mononuclear cells, expression was evident by reverse transcription-PCR. Immunoblotting confirmed E-cadherin protein expression in two lymphoblastoid cell lines derived from normal donors. In contrast, E-cadherin was aberrantly methylated in 4 of 4 (100%) leukemia cell lines, 14 of 44 (32%) acute myelogenous leukemias, and 18 of 33 (53%) acute lymphoblastic leukemias. Genomic bisulfite sequencing of primary leukemias confirmed dense methylation across the CpG island. Methylation was associated with loss of E-cadherin RNA and protein in leukemia cell lines and primary leukemias. Following treatment with 5-aza-2'deoxycytidine, a methylated leukemia cell line expressed both E-cadherin transcript and protein. Our results show that methylation of E-cadherin occurs commonly in acute leukemia and suggests a hypothesis for E-cadherin down-regulation in leukemogenesis.
INTRODUCTION
Cadherins are a family of transmembrane glycoproteins that mediate
Ca2+-dependent intercellular adhesion. One member
of this family, epithelial (E)-cadherin (120 kDa), is expressed
predominantly on the surface of epithelial cells, where it plays a
major role in the establishment and maintenance of normal tissue
architecture (1)
. Whereas the extracellular domain of
E-cadherin is responsible for both homophilic (E-cadherin/E-cadherin)
and heterophilic binding (E-cadherin/non-Ecadherin) specificities,
the adhesive function of the molecule is ultimately dependent on its
interaction with the actin cytoskeleton through the intracellular
catenins (1)
. ß-Catenin (94 kDa) and 
-catenin (82
kDa) bind directly to the cytoplasmic domain of E-cadherin, whereas
-catenin (102 kDa) binds to ß-catenin and links the complex to a
network of actin microfilaments. ß-Catenin also functions in signal
transduction by binding to T-cell factor/lymphoid enhancer factor
(Tcf/Lef) proteins, forming a complex that translocates to the nucleus
and transactivates specific genes in the wingless/wnt
signaling pathway (2)
. Recently, E-cadherin was shown to
inhibit ß-catenin-mediated transactivation by binding to ß-catenin
and blocking its interaction with Lef-1 (3)
. Thus,
E-cadherin appears to have a dual purpose in the mammalian cell,
participating in both intercellular adhesion and as part of a complex
signaling pathway.
E-cadherin expression frequently is reduced or absent in a variety of epithelial cancers, and loss of normal intercellular junctions is thought to precede tumor invasion and metastasis (4, 5, 6, 7) . There are several mechanisms for abnormal E-cadherin expression in tumors. It has recently been shown that germ-line mutations of the gene (CDH1), although rare, predispose to familial gastric and colorectal cancer (8 , 9) . Similarly, although allelic loss of the E-cadherin locus at 16q22.1 occurs in a variety of different solid tumors, somatic mutations generally are infrequent, with the exception of diffuse gastric carcinomas and lobular breast carcinomas (10) . In contrast, a common mechanism for E-cadherin loss is epigenetic silencing via DNA hypermethylation, occurring in 15–80% of oral, hepatocellular, breast, and prostate cancers (11, 12, 13) . Methylation of the cytosines in CpG dinucleotides within promoter CpG islands is associated with transcriptional repression, an event that normally occurs during genomic imprinting and X-chromosome inactivation (14) . In neoplasia, however, aberrant methylation of CpG islands results in inactivation of tumor suppressor genes and genes that maintain normal cell growth, such as p16 and MLH1 (14 , 15) .
Although the importance of E-cadherin expression to epithelium is well established, its role in hematopoietic tissues has been studied only recently. During normal hematopoiesis, erythroid, myeloid, and lymphoid progenitor cells adhere selectively to stromal cells and the extracellular matrix, allowing them to receive maturation influences from the bone marrow microenvironment (16) . These influences include chemokines, growth factors, and intercellular interactions mediated by adhesion molecules such as the integrins (17) . In addition to regulating the physical interactions of progenitor cells, cell adhesion molecules are believed to influence differentiation by generating intracellular signals (18) . E-Cadherin is in fact one of the adhesion molecules expressed by stromal cells and mononuclear cells in the bone marrow (19) . Furthermore, during erythropoiesis, E-cadherin is selectively expressed by erythroid progenitors at specific stages of maturation, and the addition of anti-Ecadherin antibody to bone marrow mononuclear cells inhibited erythropoiesis in vitro (20 , 21) . Taken together, these data suggest that E-cadherin may contribute to intercellular interactions important for hematopoiesis.
In this study, we investigated the methylation status of the 5' CpG island of E-cadherin in peripheral blood mononuclear cells from normal individuals and in leukemic blasts from patients with de novo acute leukemia.
MATERIALS AND METHODS
Patient Samples, Cell Lines, and Culture Conditions.
The leukemia samples were diagnostic bone marrows obtained from
patients undergoing evaluation and treatment at the Johns Hopkins
Oncology Center (22)
. All patients gave informed consent
for the bone marrow biopsy according to standard protocol.
Lymphoblastoid cell lines were available from the Johns Hopkins
University Genetic Resource Core Facility. The leukemia cell lines KG1A
(AML),4
U937 (AML),
HL-60 (AML), and A301 (T-ALL) were analyzed in this study. Cell
lines were maintained in the appropriate media and treated with
5-Aza-dC (Sigma) at a concentration of 1 µM for
3–5 days to achieve demethylation.
DNA Extraction.
Genomic DNA was isolated from cell lines and primary leukemias by
standard phenol and chloroform extraction with ethanol precipitation.
DNA was isolated from bone marrow slides as described previously
(23)
.
Methylation Analysis.
Methylation patterns within the E-cadherin CpG island in exon 1
(sequence, -126 bp to +144 bp relative to transcription start; GenBank
Accession No. D49685) were determined after the chemical modification
of genomic DNA with sodium bisulfite (Sigma) as described
(24)
. A nested-PCR approach was used. In the first round
of PCR, 100 ng of bisulfite-treated DNA was amplified using sequencing
primers (24)
. The sequencing primers were
5'-GTTTAGTTTTGGGGAGGGGTT-3' (sense) and
5'-ACTACTACTCCAAAAACCCATAACTAA-3' (antisense), and the cycling
conditions consisted of an initial denaturation step at 95°C for 5
min, followed by the addition of 1 unit of Taq polymerase
and then 30 cycles of 95°C for 30 s, 50°C for 30 s, and
72°C for 30 s. The size of the product following this initial
PCR reaction was 270 bp. For the second round of PCR, this product was
diluted 1:50 in water, and 2 µl of the dilution were used for MSP
(25)
. Nested primer sequences for E-cadherin were
5'-TGTAGTTACGTATTTATTTTTAGTGGCGTC-3' (sense) and
5'-CGAATACGATCGAATCGAACCG-3' (antisense) for the methylated
reaction and 5'-TGGTTGTAGTTATGTATTTATTTTTAGTGGTGTT-3' (sense) and
5'-ACACCAAATACAATCAAATCAAACCAAA-3' (antisense) for the
unmethylated reaction. PCR parameters were as above, except that
the annealing temperatures for the methylated and unmethylated
reactions were 64 and 62°C, respectively. The product sizes of the
methylated and unmethylated reactions were 112 and 120 bp,
respectively.
Immunoblotting.
For analysis of cell lines, whole-cell lysates were prepared from
cultured cells using lysis buffer (1x PBS, 1% NP-40, 0.5% sodium
deoxycholate, 0.1% SDS) with complete protease inhibitors added
(Boehringer Mannheim). Protein concentrations were determined using the
BIO-RAD assay (Bio-Rad). Between 10 and 100 µg of protein were
separated by SDS-PAGE, electrotransferred onto Immobilon-P
membrane (Millipore) and incubated with the anti-E-cadherin antibody
HECD-1 (Zymed laboratories, Inc). Immunoreactive bands on blots were
visualized by the ECL method (Amersham). For analysis of primary
leukemias, approximately 1–2 x 106 cells
were lysed in NOVEX NuPAGE sample buffer and resolved using a 4–12%
Bid-Tris gel (NOVEX, San Diego, CA). HECD-1 antibody was used, and
immunoreactive bands were visualized using ECL, as above. The ECL
system has a detection limit in the nanogram range. To further maximize
the sensitivity of detecting E-cadherin, Western blots of the primary
leukemias were subsequently developed with the SuperSignal West Femto
Maximum Sensitivity Substrate (Pierce), which can detect proteins in
the picogram range.
Sodium Bisulfite DNA Sequencing.
Sodium bisulfite-modified DNA was amplified using the E-cadherin
sequencing primers described above. PCR products were cloned into the
TA cloning vector pCR2.1 (Invitrogen), and individual clones were
sequenced (ABI automated sequencing).
E-Cadherin Transcript Analysis.
Cytoplasmic RNA was isolated using TriZOL Reagent (Life Technologies,
Inc.) and reverse-transcribed using SuperScript II (Life Technologies).
The RT-PCR primers for E-cadherin were 5'-GGAAGTCAGTTCAGACTCCAGCC-3'
(sense, exon 1) and 5'-AGGCCTTTTGACTGTAATCACACC-3' (antisense, exon 3).
The size of the RT-PCR product was 352 bp. Glyceraldehyde-3-phosphate
dehydrogenase expression was analyzed as described previously
(26)
.
RESULTS
In this study, primary leukemia samples were available from two main sources: bone marrow specimens that had been Ficoll-enriched for blasts and banked at -80°C, and bone marrow biopsy slides. Whereas genomic DNA isolated from banked samples was consistently suitable for our molecular studies, we found it difficult to reproducibly generate PCR products from material obtained from slides, most likely because of a problem in the quantity and/or quality of DNA substrate (data not shown). Subsequently, in an effort to facilitate the analysis of DNA samples isolated from slides, we developed a nested-PCR approach to study methylation of the E-cadherin promoter. In the first round of PCR, the genomic region encompassing the transcription start site of E-cadherin was amplified using bisulfite-sequencing primers that avoid any CpG dinucleotides, so that methylated and unmethylated DNA are amplified with equal efficiency (27) . This product was then used as a substrate for a second PCR, in which MSP primers were used to distinguish methylated versus unmethylated E-cadherin.
To estimate the sensitivity of nested-MSP for detecting methylation,
DNA from a completely methylated breast cancer cell line, MB-MDA-231,
was mixed at various ratios with DNA from a completely unmethylated
cell line, MCF7, and assayed. With nested-MSP, methylated
alleles were detectable when they comprised as little as 5% of the
total DNA sample (Fig. 1
A), a
sensitivity comparable to previously published results using standard
MSP (27)
. In additional experiments, the sensitivity of
nested-MSP could be greatly enhanced by increasing the cycle number of
the two-step PCR, but with a corresponding loss in specificity (data
not shown). Therefore, the cycling parameters for nested-MSP that we
used were carefully chosen to permit the analysis of DNA collected from
banked samples and slides with equal efficiency and accuracy (see
below).
|
B). In addition, we studied two lymphoblastoid cell lines
that were derived by taking normal lymphocytes and immortalizing them
with EBV. Both of these lines were unmethylated at E-cadherin (data not
shown).
To determine whether E-cadherin methylation occurred in leukemia, we
next studied a series of leukemia cell lines that included both myeloid
(n = 3) and lymphoblastic (n = 1)
phenotypes. By nested-MSP, three of the cell lines (HL-60, U937, and
A301) were fully methylated, and one (KG1a) was predominantly
methylated (Fig. 1
C). Methylation was also observed in
primary acute leukemias of both myeloid and lymphoblastic phenotypes.
In the AML group, 32% (14 of 44) of the samples were methylated at
E-cadherin (Fig. 1
D). The French-American-British
classifications were available for 15 samples, and although all
subtypes (M0–M7) were represented, the sample size was not large
enough to evaluate for any differences in the frequency of E-cadherin
methylation between groups. In the ALL group, 53% (18 of 33) of the
samples were methylated at E-cadherin (Fig. 1
D). The
frequency of methylation was similar between B- and T-cell phenotypes.
Ten of 17 (59%) B-cell leukemias were methylated, whereas 7 of 13
(54%) T-cell leukemias were methylated. Within the mixed-lineage ALLs,
one of three (33%) was methylated. Unlike leukemia cell lines, primary
leukemias always displayed evidence of unmethylated E-cadherin. This
likely reflects the small proportion of normal PBMCs that are
invariably present in primary leukemia samples when they are collected,
and the high sensitivity of MSP for detecting such alleles.
Methylation of E-cadherin correlated with transcriptional silencing of
the gene. The fully methylated cell lines U937 (AML) and A301 (T-ALL)
had undetectable levels of Ecadherin transcript by RT-PCR (Fig. 2
A). E-Cadherin was
detectable only after treatment with the demethylating agent
5Aza-dC. Western blot analysis of U937 confirmed that after
5-Aza-dC treatment, E-cadherin transcription was associated with
E-cadherin protein expression (Fig. 2
B). These data indicate
that methylation is responsible for transcriptional repression of the
gene. After several days, the treated cell lines demonstrated a slower
growth rate and evidence of cell death, likely because of the general
cytotoxic effect of 5-Aza-dC. Because other genes are methylated and
silenced in U937 [for example, p16 (28)
and p73 (29)
], we cannot attribute these
effects solely to demethylation of E-cadherin.
|
C). The low level of E-cadherin transcript detected
in the methylated sample could theoretically reflect either
transcription from contaminating normal PBMCs or minimal transcription
from methylated leukemic alleles. In contrast, expression of E-cadherin
transcript was uniformly evident in normal PBMCs (Fig. 2
D).
These data underscore the fact that methylation-associated silencing of
E-cadherin is a leukemia-specific event.
By Western blot analysis, E-cadherin protein was expressed by normal
lymphoblastoid cell lines, although at relatively lower levels than the
breast cancer epithelial cell line, MCF7 (Fig. 2
B). To
detect E-cadherin bands of comparable intensity, the amount of total
protein loaded for the lymphoblastoid cell lines was roughly 10-fold
greater than for MCF7. Among the primary leukemias, five methylated
samples (three ALLs and two AMLs) initially showed no evidence of
E-cadherin expression (Fig. 2
B). Because our first analysis
of E-cadherin expression had used RT-PCR, which is an exquisitely
sensitive technique for detecting RNA, we sought to increase the
sensitivity of the Western blot to detect minute quantities of
E-cadherin protein. To do this, Western blots of the methylated primary
leukemias were redeveloped with a supersensitive chemiluminescent
reagent that can detect proteins in the picogram range (see
"Materials and Methods"). Under these conditions, we could detect
low-level expression of E-cadherin in the two methylated AMLs (Fig. 2
B). Again, this band could reflect E-cadherin expression
from normal PBMCs contaminating the primary samples or, alternatively,
minimal expression from methylated leukemic alleles.
To further characterize E-cadherin methylation in primary leukemias and
to correlate the density of methylation with expression, genomic
bisulfite sequencing was performed on PBMCs and primary ALLs. Normal
PBMCs were almost completely unmethylated, except for isolated CpG
sites at the 5' and 3' ends of the region sequenced (Fig. 3
, bottom panel). In
contrast, two methylated ALLs (ALL1 and ALL2) demonstrated dense
patterns of methylation in almost every allele, especially toward the
3' end of the region sequenced. In ALL2, which had undetectable levels
of E-cadherin transcript, there was near complete methylation of three
CpG dinucleotides (8, 9, 10)
immediately flanking the transcription
starting point. In ALL1, which expressed very low levels of
E-cadherin transcript, there was relatively less methylation at these
same sites. Thus, CpG methylation observed with genomic sequencing
correlated with transcriptional silencing of E-cadherin.
|
In this report, we found that aberrant methylation of the E-cadherin promoter is a frequent event in both AML and ALL. We used a nested-MSP approach that allowed us to analyze DNA samples obtained from banked leukemia samples and bone marrow slides with excellent reproducibility. Although one potential problem with nested-PCR would be the generation of false positives, the cycling parameters we chose were designed to demonstrate a high degree of sensitivity and specificity for the presence of significant methylation changes. As proof of this, methylation of cell lines and primary leukemias was associated with transcriptional silencing of the gene by RT-PCR. In addition, genomic bisulfite sequencing confirmed dense CpG methylation in those samples detected as methylated by nested-MSP. Because clinical material often is a scarce resource for molecular studies, the ability to analyze methylation changes using DNA from a single bone marrow slide represents a powerful tool.
The biological significance of E-cadherin methylation in acute leukemia is unclear. E-Cadherin has been shown to function during normal erythropoiesis, but its role during myeloid and lymphoid differentiation has not been studied (21) . Although analysis of E-cadherin expression on myeloid and lymphoid precursors was not performed in this study, we did find evidence of E-cadherin expression by mature PBMCs and normal lymphoblastoid cell lines. Our data suggest that E-cadherin expression is not limited to the erythrocyte lineage, but rather is a feature of multi-lineage hematopoiesis. In support of this, it was recently shown that E-cadherin is expressed on CD34+ cells, the pluripotent stem cell that is thought to give rise to erythroid, lymphoid, and myeloid progenitors (19) .
The importance of adhesion mechanisms in the marrow is known from the extensive study of integrins, a family of adhesion molecules expressed by hematopoietic progenitors. During hematopoiesis, ß1- (VLA-4, VLA-5) and ß2-integrins (LFA-1) mediate interactions between progenitors and the bone marrow microenvironment that are thought to be important for normal proliferation, differentiation, and migration (30 , 31) . Interestingly, defects in integrin-mediated adhesion have been reported in B-lineage ALL and chronic myeloid leukemia (32) . One possibility, then, is that E-cadherin represents another type of adhesion molecule that mediates interactions between progenitors and the bone marrow microenvironment. Loss of Ecadherin would contribute to the overall breakdown in adhesion that is a principal feature of leukemia.
In a recent study looking at multiple genes in AML, E-cadherin methylation was also observed (33) . Together with our results, these data raise some intriguing possibilities for the role of epigenetic inactivation of E-cadherin during leukemogenesis. Further studies characterizing E-cadherin expression on myeloid and lymphoid cells at defined stages of maturation should begin to elucidate this role.
FOOTNOTES
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
1 This research was supported by NIH Grants
CA06973 and CA-43318. 
2 Current address: University of Pennsylvania,
Department of Hematology and Oncology, Philadelphia, PA 19104.
3 To whom requests for reprints should be
addressed, at The Johns Hopkins Oncology Center, Tumor Biology, 1650
Orleans Street, Baltimore, MD 21231. Phone: (410) 955-8506; Fax:
(410) 614-9884; E-mail: hermanji{at}jhmi.edu
4 The abbreviations used are: AML, acute
myelogenous leukemia; ALL, acute lymphoblastic leukemia; 5-Aza-dC,
5-aza-2'-deoxycytidine; MSP, methylation-specific PCR; ECL, enhanced
chemiluminescence; GAPDH, glyceraldehyde-3-phosphate dehydrogenase;
RT-PCR, reverse transcription-PCR; PBMC, peripheral blood mononuclear
cell.
Received 3/27/00; revised 6/23/00; accepted 8/24/00.
REFERENCES
This article has been cited by other articles:
|
|
 |
|
  E.-S. Lee, J.-P. Issa, D. B. Roberts, M. D. Williams, R. S. Weber, M. S. Kies, and A. K. El-Naggar Quantitative Promoter Hypermethylation Analysis of Cancer-Related Genes in Salivary Gland Carcinomas: Comparison with Methylation-Specific PCR Technique and Clinical Significance Clin. Cancer Res., May 1, 2008; 14(9): 2664 - 2672. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Shen, Y. Kondo, S. Ahmed, Y. Boumber, K. Konishi, Y. Guo, X. Chen, J. N. Vilaythong, and J.-P. J. Issa Drug Sensitivity Prediction by CpG Island Methylation Profile in the NCI-60 Cancer Cell Line Panel Cancer Res., December 1, 2007; 67(23): 11335 - 11343. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. D. Wren, Y. Wu, and S.-W. Guo A system-wide analysis of differentially expressed genes in ectopic and eutopic endometrium Hum. Reprod., August 1, 2007; 22(8): 2093 - 2102. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Wu, A. Starzinski-Powitz, and S.-W. Guo Trichostatin A, a Histone Deacetylase Inhibitor, Attenuates Invasiveness and Reactivates E-Cadherin Expression in Immortalized Endometriotic Cells Reproductive Sciences, May 1, 2007; 14(4): 374 - 382. [Abstract] [PDF]
|
|
|
|
 |
|
 W. C. Reinhold, M. A. Reimers, A. K. Maunakea, S. Kim, S. Lababidi, U. Scherf, U. T. Shankavaram, M. S. Ziegler, C. Stewart, H. Kouros-Mehr, et al. Detailed DNA methylation profiles of the E-cadherin promoter in the NCI-60 cancer cells Mol. Cancer Ther., February 1, 2007; 6(2): 391 - 403. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Yuan, J. Wang, J. Li, L. Wang, M. Li, Z. Yang, C. Zhang, and J. L. Dai Frequent Epigenetic Inactivation of Spleen Tyrosine Kinase Gene in Human Hepatocellular Carcinoma. Clin. Cancer Res., November 15, 2006; 12(22): 6687 - 6695. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. D. Gore, S. Baylin, E. Sugar, H. Carraway, C. B. Miller, M. Carducci, M. Grever, O. Galm, T. Dauses, J. E. Karp, et al. Combined DNA methyltransferase and histone deacetylase inhibition in the treatment of myeloid neoplasms. Cancer Res., June 15, 2006; 66(12): 6361 - 6369. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. I. de Caceres, C. Battagli, M. Esteller, J. G. Herman, E. Dulaimi, M. I. Edelson, C. Bergman, H. Ehya, B. L. Eisenberg, and P. Cairns Tumor Cell-Specific BRCA1 and RASSF1A Hypermethylation in Serum, Plasma, and Peritoneal Fluid from Ovarian Cancer Patients Cancer Res., September 15, 2004; 64(18): 6476 - 6481. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Dulaimi, I. I. de Caceres, R. G. Uzzo, T. Al-Saleem, R. E. Greenberg, T. J. Polascik, J. S. Babb, W. E. Grizzle, and P. Cairns Promoter Hypermethylation Profile of Kidney Cancer Clin. Cancer Res., June 15, 2004; 10(12): 3972 - 3979. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Takahashi, N. Shivapurkar, J. Reddy, H. Shigematsu, K. Miyajima, M. Suzuki, S. Toyooka, S. Zochbauer-Muller, J. Drach, G. Parikh, et al. DNA Methylation Profiles of Lymphoid and Hematopoietic Malignancies Clin. Cancer Res., May 1, 2004; 10(9): 2928 - 2935. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Dulaimi, R. G. Uzzo, R. E. Greenberg, T. Al-Saleem, and P. Cairns Detection of Bladder Cancer in Urine by a Tumor Suppressor Gene Hypermethylation Panel Clin. Cancer Res., March 15, 2004; 10(6): 1887 - 1893. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Krassenstein, E. Sauter, E. Dulaimi, C. Battagli, H. Ehya, A. Klein-Szanto, and P. Cairns Detection of Breast Cancer in Nipple Aspirate Fluid by CpG Island Hypermethylation Clin. Cancer Res., January 1, 2004; 10(1): 28 - 32. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Battagli, R. G. Uzzo, E. Dulaimi, I. Ibanez de Caceres, R. Krassenstein, T. Al-Saleem, R. E. Greenberg, and P. Cairns Promoter Hypermethylation of Tumor Suppressor Genes in Urine from Kidney Cancer Patients Cancer Res., December 15, 2003; 63(24): 8695 - 8699. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. V. Brock, M. Gou, Y. Akiyama, A. Muller, T.-T. Wu, E. Montgomery, M. Deasel, P. Germonpre, L. Rubinson, R. F. Heitmiller, et al. Prognostic Importance of Promoter Hypermethylation of Multiple Genes in Esophageal Adenocarcinoma Clin. Cancer Res., August 1, 2003; 9(8): 2912 - 2919. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Jeronimo, I. Costa, M. C. Martins, P. Monteiro, S. Lisboa, C. Palmeira, R. Henrique, M. R. Teixeira, and C. Lopes Detection of Gene Promoter Hypermethylation in Fine Needle Washings from Breast Lesions Clin. Cancer Res., August 1, 2003; 9(9): 3413 - 3417. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. G. Corn, M. K. Summers, F. Fogt, A. K. Virmani, A. F. Gazdar, T. D. Halazonetis, and W. S. El-Deiry Frequent hypermethylation of the 5' CpG island of the mitotic stress checkpoint gene Chfr in colorectal and non-small cell lung cancer Carcinogenesis, January 1, 2003; 24(1): 47 - 51. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Mufti, A. F. List, S. D. Gore, and A. Y.L. Ho Myelodysplastic Syndrome Hematology, January 1, 2003; 2003(1): 176 - 199. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Shen, Y. Kondo, J.-P. Issa, G. Garcia-Manero, J. Roman-Gomez, J. A. Castillejo, A. Torres, and A. Jimenez Lack of p21CIP1 DNA methylation in acute lymphocytic leukemia Blood, October 16, 2002; 100(9): 3432 - 3433. [Full Text] [PDF]
|
|
|
|
 |
|
 E. R. Suh, C. S. Ha, E. B. Rankin, M. Toyota, and P. G. Traber DNA Methylation Down-regulates CDX1 Gene Expression in Colorectal Cancer Cell Lines J. Biol. Chem., September 20, 2002; 277(39): 35795 - 35800. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. J. Giles, A. Keating, A. H. Goldstone, I. Avivi, C. L. Willman, and H. M. Kantarjian Acute Myeloid Leukemia Hematology, January 1, 2002; 2002(1): 73 - 110. [Abstract] [Full Text]
|
|
|
|
|
|
P. Cairns, M. Esteller, J. G. Herman, M. Schoenberg, C. Jeronimo, M. Sanchez-Cespedes, N.-H. Chow, M. Grasso, L. Wu, W. B. Westra, et al. Molecular Detection of Prostate Cancer in Urine by GSTP1 Hypermethylation Clin. Cancer Res., September 1, 2001; 7(9): 2727 - 2730. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. G. Corn, E. I. Heath, R. Heitmiller, F. Fogt, A. A. Forastiere, J. G. Herman, and T.-T. Wu Frequent Hypermethylation of the 5' CpG Island of E-Cadherin in Esophageal Adenocarcinoma Clin. Cancer Res., September 1, 2001; 7(9): 2765 - 2769. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Cancer Research | Clinical Cancer Research |
| Cancer Epidemiology Biomarkers & Prevention | Molecular Cancer Therapeutics |
| Molecular Cancer Research | Cancer Prevention Research |
| Cancer Prevention Journals Portal | Cancer Reviews Online |
| Annual Meeting Education Book | Meeting Abstracts Online |
, unmethylated CpG sites; •, methylated CpG
sites.