Biomedical subjects

Asif Rashid

Publications and source records attributed to Asif Rashid.

At least 19 recordsLinked to original sources

PubMed2007

Expression of epidermal growth factor receptor in esophageal and esophagogastric junction adenocarcinomas: association with poor outcome.

BACKGROUND: The prognosis for patients with esophageal and esophagogastric junction (EGJ) adenocarcinoma remains poor, even after surgical resection. Pathologic assessment of depth of invasion and lymph node status are the primary prognostic factors in these patients. In patients with esophageal squamous cell carcinoma, increased epidermal growth factor receptor (EGFR) expression has been associated with a worse prognosis. It is not known whether EGFR plays a similar role in esophageal and EGJ adenocarcinomas. METHODS: To address this issue, the authors studied tumor specimens from 103 patients with surgically resected esophageal and EGJ adenocarcinomas (9 patients with stage I disease, 23 patients with stage II disease, 57 patients with stage III disease, and 14 patients with stage IV disease). The expression of EGFR was assessed by immunohistochemical analysis of tissue microarrays. Tumors were considered positive for EGFR expression when >5% of tumor cells were stained and negative when <or=5% of tumor cells were stained. RESULTS: EGFR was expressed in 33 of 103 adenocarcinomas (32%) and was correlated with higher pathologic tumor (T) classification (P = .02), the presence of lymph node metastasis (P = .01), and higher pathologic tumor, lymph node, metastasis classification (P = .02). EGFR expression also was correlated with shorter disease-free and overall survival in univariate analyses (P = .001 and P = .004, respectively), and there was a trend toward a correlation between EGFR expression and shorter disease-free survival in multivariate analyses (P = .07 and P = .08). The results demonstrated that EGFR expression in esophageal adenocarcinomas was correlated with advanced pathologic tumor classification and lymph node metastasis. EGFR expression also was correlated with poor disease-free and overall survival, but that correlation was not independent of T classification. CONCLUSIONS: The current findings suggested that EGFR expression correlates with poor prognostic factors and may be used to predict patient outcomes.

Adenocarcinoma↗

PubMed2007

Clinical and in vitro studies of imatinib in advanced carcinoid tumors.

PURPOSE: Effective systemic therapy options for carcinoid tumors are lacking. We conducted in vitro studies and a phase II clinical trial to explore the activity of imatinib in carcinoid tumors. EXPERIMENTAL DESIGN: Cells of the human bronchial carcinoid cell line NCI-H727 and the human pancreatic carcinoid cell line BON-1 were treated with increasing concentrations of imatinib using standard procedures to assess in vitro growth-inhibitory activity. A clinical trial using a two-stage phase II design to assess the response rate and safety profile of imatinib at a dose of 400 mg given twice daily in patients with advanced carcinoid tumors was completed. RESULTS: In both cell lines, there was a dose- and time-dependent cytotoxic effect. The clinical trial enrolled 27 evaluable patients. Median duration on trial was 16 weeks. One patient had a partial response, 17 had stable disease, and 9 had progressive disease by the Response Evaluation Criteria in Solid Tumors criteria. Median progression-free survival time was 24 weeks. Median overall survival is 36 months. Seven patients who achieved a biochemical response had a superior progression-free survival time compared with patients without biochemical response (115 weeks compared with 24 weeks; P = 0.003). An increase in plasma basic fibroblast growth factor was associated with a shorter progression-free survival duration (P = 0.02). CONCLUSIONS: Our data suggest that imatinib is active in vitro and has a modest clinical activity in carcinoid patients. Changes in tumor markers may help select patients who are likely to benefit from therapy.

Adult↗

PubMed2007

Excellent interobserver agreement on grading the extent of residual carcinoma after preoperative chemoradiation in esophageal and esophagogastric junction carcinoma: a reliable predictor for patient outcome.

The extent of residual carcinoma in resected esophageal cancer specimens after preoperative chemoradiation is a predictor of survival according to 3 groups: P0 (0% residual carcinoma), P1 (1% to 50% residual carcinoma), and P2 (>50% residual carcinoma). However, the interobserver variation and reliability of this classification has not been evaluated among different pathologists. Histologic hematoxylin and eosin-stained slides from 60 coded cases of esophageal adenocarcinomas treated with preoperative chemoradiation followed by esophagectomy were independently reviewed by 6 pathologists from 4 different institutions for extent of residual carcinoma and ypT stage. Interobserver agreement was analyzed by kappa (kappa) statistics, and grading of extent of residual carcinoma and ypT stage based on individual and consensus gradings were correlated with patients' survival. The interobserver agreement was excellent for extent of residual carcinoma (kappa=0.84, Kendall's W=0.92; P<0.000001) and was good for ypT stage (kappa=0.71, Kendall's W=0.88; P<0.000001). Agreement was excellent for all categories of residual carcinoma: P0 (kappa=0.87), P1 (kappa=0.81), and P2 (kappa=0.85). Extent of residual carcinoma was a significant predictor for overall survival based on individual pathologist grading (all P values <0.03), and consensus grading (13 P0, 32 P1, and 15 P2), P=0.004; independent of ypT and ypN stages in multivariate analysis (P=0.02). Our results indicate that after preoperative chemoradiation in esophageal cancer there is excellent interobserver agreement among pathologists on grading extent of residual carcinoma. The extent of residual carcinoma is a reliable and reproducible predictor of survival; this grading system may allow a novel and early means of comparing outcomes after different neoadjuvant treatment regimens.

Adenocarcinoma↗

PubMed2006

Outcome of gastric cancer patients after successful gastrectomy: influence of the type of recurrence and histology on survival.

BACKGROUND: The effect of the location of disease recurrence after curative (R0) gastrectomy on patient survival has not been elucidated. The authors hypothesized that the location of recurrence would have a significant influence on survival. METHODS: Medical records of all patients who received treatment for gastric cancer at The University of Texas M. D. Anderson Cancer Center between 1985 and 1998 were reviewed. Patients who underwent R0 resection for gastric cancer and subsequently developed localized (anastomotic) recurrence (LR), lymph node (regional) recurrence (NR), or distant metastases (DM) were analyzed for overall survival (OS). All study factors were entered into a Cox proportional hazards model to provide multivariate hazard ratios. The model was adjusted for the effects of primary site of recurrence, histologic grade, patient age, and location of the primary tumor. RESULTS: This retrospective analysis included 227 consecutive patients. The median survival of patients who developed NR (11 months) was similar to that of patients who developed LR (10 months), but both groups had significantly longer median survival compared with patients who developed DM (7 months; log-rank P = .03). Patients who had well differentiated or moderately differentiated tumors had a longer OS (11 months) than patients who had poorly differentiated tumors (8 months; log-rank P = .02). In this cohort, location of the primary cancer and age at recurrence had no significant impact on OS. CONCLUSIONS: The data from this study suggested that, among patients who undergo R0 gastrectomy for gastric cancer, LR and NR versus DM should be considered a valid stratification factor for randomized trials based on significant differences in survival. Determining whether this stratification should apply to histologic differentiation will require further investigation in a larger multicenter cohort.

Female↗

PubMed2006

An inverse correlation between Interleukin-6 and select gene promoter methylation in patients with gastric cancer.

BACKGROUND: Both serum IL-6 levels and CpG island methylation have been shown to have prognostic significance in gastric cancer, it was suggested that an important link existed between IL-6 and methylation of cancers. AIM: To investigate the prognostic value of IL-6 serum level and the association between serum IL-6 levels and CpG island methylation at p16, DAPK, MGMT and E-cadherin in patients with gastric cancer. PATIENTS AND METHODS: Methylation status was assessed by MSP in 75 surgical specimens of gastric adenocarcinoma. IL-6 serum levels were measured by chemiluminescent enzyme immunoassay (CLEIA). RESULTS: Methylation of p16, DAPK, MGMT, and E-cadherin were present in 53, 48, 32, and 59% of patients. Patients with tumors methylated at p16 and DAPK had lower serum levels of IL-6 compared to unmethylated tumors (1.8 vs. 4.8 pg/ml, p = 0.01 for p16; 1.5 vs. 6.2 pg/ml, p = 0.0001 for DAPK). But there was no difference with MGMT and E-cadherin methylation status. Serum IL-6 levels were also associated with TNM stage (p = 0.001), depth of tumor invasion (p = 0.002), lymphatic invasion (p = 0.01), vascular invasion (p = 0.008), metastasis (p = 0.002) and signet cell histology (p = 0.001). CONCLUSION: IL-6 is of prognostic value for patients of gastric cancer. Low serum IL-6 levels were associated with p16 or DAPK gene methylation in patients with gastric cancer.

Adult↗

PubMed2006

The significance of neuroendocrine differentiation in adenocarcinoma of the esophagus and esophagogastric junction after preoperative chemoradiation.

BACKGROUND: Esophageal and esophagogastric junction (EGJ) adenocarcinomas frequently have neuroendocrine (NE) differentiation, but the significance of NE differentiation in patients who have undergone preoperative chemoradiation and resection remains unclear. METHODS: The authors evaluated the presence of NE differentiation in esophageal and EGJ adenocarcinomas by immunohistochemistry for chromogranin A and synaptophysin and evaluated the clinical significance of NE differentiation in 83 patients (10 patients who had a complete tumor response and 73 patients who had residual tumor in resection specimens) who received preoperative chemoradiation. RESULTS: Of 73 patients who had residual tumor after preoperative treatment, 52% showed NE differentiation. The proportion of tumor cells with NE differentiation had increased from 6% +/- 18% in pretreatment biopsy specimens to 47% +/- 42% (P = .00003) in posttreatment resection specimens in 30 patients who had paired pretreatment biopsy and resection specimens available. Disease-free survival (P = .002) and overall survival (P = .006) were significantly better in patients who had a complete tumor response than in patients who had residual tumor. Among patients who had residual tumor after preoperative chemoradiation, disease-free survival (P = .03) and overall survival (P = .045) were significantly better in patients who had residual tumor without NE differentiation than in patients who had residual tumor with NE differentiation. In multivariate analysis, the presence of NE differentiation in residual tumor was a prognostic factor for worse disease-free survival (P = .02) independent of pathologic stage and extent of residual tumor. CONCLUSIONS: The results from this study suggested that tumor cells with NE differentiation were more resistant to neoadjuvant chemoradiation in patients with esophageal and EGJ adenocarcinomas. The presence of NE differentiation in residual tumor was associated with poor survival after preoperative neoadjuvant therapy.

Adenocarcinoma↗

PubMed2006

Expression of annexin A1 in esophageal and esophagogastric junction adenocarcinomas: association with poor outcome.

PURPOSE: Annexin A1 (ANXA1) is a calcium-binding protein involved in arachidonic acid metabolism and epidermal growth factor receptor tyrosine kinase pathway. ANXA1 has been implicated in early squamous cell carcinogenesis of esophagus and correlates with degree of tumor differentiation. However, the role of ANXA1 in esophageal adenocarcinoma is unclear. Our goal was to evaluate ANXA1 expression and determine its prognostic significance in adenocarcinoma of the esophagus and esophagogastric junction. EXPERIMENTAL DESIGN: This study included 104 consecutive patients with primary resected esophageal and esophagogastric junction adenocarcinomas (11 stage I, 24 stage II, 53 stage III, and 16 stage IV). ANXA1 protein expression in each tumor was assessed by immunohistochemical staining of tissue microarrays. ANAX1 expression level was classified as high (>/=25% of tumor cells with cytoplasmic staining), low (<25% of tumor cells with cytoplasmic staining), or negative; and was correlated with clinicopathologic features and patients' outcomes. RESULTS: High ANXA1 expression was present in 39% (41 of 104) of tumors and was associated with higher pathologic T stage (P = 0.03) and distant metastasis (P = 0.04). High ANXA1 expression correlated with increased recurrence rate (P = 0.004) and decreased overall survival (P = 0.003) in univariate analysis. In multivariate analysis, ANXA1 expression and pN stage significantly correlated with recurrence rate (P = 0.008 and P < 0.001, respectively) and overall survival (P = 0.02 and P < 0.001, respectively) independent of T stage. CONCLUSION: Our results indicate that high ANXA1 expression is frequent in esophageal and esophagogastric junction adenocarcinomas, correlates with more advanced pathologic T stage and the presence of distant metastasis, and is an independent prognostic factor for patient survival.

Adenocarcinoma↗

PubMed2006

Tea drinking and the risk of biliary tract cancers and biliary stones: a population-based case-control study in Shanghai, China.

Biliary tract cancers, encompassing tumors of the gallbladder, extrahepatic bile ducts and ampulla of Vater, are rare but highly fatal malignancies. Apart from gallstones, etiologic factors for biliary tract cancer are not clearly defined. Several epidemiologic studies have suggested that consumption of tea, especially green tea, is protective against a variety of cancers, including gastrointestinal malignancies. As part of a large population-based case-control study of biliary tract disease in Shanghai, China, we evaluated the effects of tea consumption on the risk of biliary tract cancers and biliary stones. The study included 627 incident cases with biliary tract cancer, 1,037 cases with biliary stones and 959 randomly selected controls. Study subjects were interviewed to ascertain data on demographic, medical and dietary factors, including tea consumption. Forty-one percent of the controls were ever tea drinkers, defined as those who consumed at least 1 cup of tea per day for at least 6 months. After adjustment for age, education and body mass index, among women, ever tea drinkers had significantly reduced risks of biliary stones (OR = 0.73, 95% CI = 0.54-0.98) and gallbladder cancer (OR = 0.56, 95% CI = 0.38-0.83). The inverse relationship between tea consumption and gallbladder cancer risk was independent of gallstone disease. Among men, tea drinkers were more likely to be cigarette smokers, and the risk estimates were generally below 1.0, but were not statistically significant. Further studies are needed to confirm these results in other populations and clarify the hormonal and other mechanisms that may be involved.

Adult↗

PubMed2006

CYP17 MspA1 polymorphism and risk of biliary tract cancers and gallstones: a population-based study in Shanghai, China.

Biliary tract cancers, encompassing cancers of the gallbladder, extrahepatic bile duct and ampulla of Vater, are rare but highly fatal malignancies. Other than gallstones, little is known about the risk factors for biliary tract cancers. Endogenous estrogens are thought to play a role in the etiology of gallstones and gallbladder cancer, since both conditions predominate in females and are associated with parity and obesity. In view of reports linking the CYP17 MspA1 polymorphism to high circulating levels of estrogens and a predisposition to other hormonally related cancers, we examined the relationship between CYP17 MspA1 variants and risk of biliary disease in a population-based case-control study in Shanghai. The study included 446 cancer cases (254 gallbladder, 139 extrahepatic bile duct, 53 ampullary cancers), 929 biliary stone cases (691 gallbladder, 238 bile duct) and 818 population controls. Genomic DNA from peripheral blood lymphocytes was used for genotyping. Relative to those with the A2/A2 genotype, A1 carriers (A1/A1 and A1/A2 genotypes) had an increased risk of gallbladder cancer (odds ratio (OR) = 1.5, 95% confidence interval (CI) = 1.1-2.1). In addition, women with the A1 allele and high parity (> or =3) had a 3-fold risk of gallbladder cancer (OR = 3.3, 95% CI = 1.6-6.9), compared to those with the A2/A2 genotype and lower parity, with the highest risk seen for those also having biliary stones (OR = 4.6, 95% CI = 1.8-11.7, P(interaction) = 0.04). The A1 allele was not associated with a higher risk of gallstones except among those with body mass index (BMI) greater than 25 kg/m2 (OR = 3.1, 95% CI = 2.0-4.8, P(interaction) = 0.02) and among those with a history of diabetes (OR = 2.5, 95% CI = 1.4-4.3, P interaction = 0.09). No clear relation was seen between the CYP17 polymorphism and cancers of the bile duct or ampulla of Vater. The association of the CYP17 MspA1 polymorphism with an increased risk of gallbladder cancer, as well as biliary stones among overweight and diabetic individuals, suggests an interplay between genetic and hormonal risk factors in gallbladder disease.

Adult↗

PubMed2006

DNA methylation changes after 5-aza-2'-deoxycytidine therapy in patients with leukemia.

5-Aza-2'-deoxycytidine (decitabine) is postulated to have clinical activity in myeloid leukemias via its ability to inhibit DNA methylation. To study this, we examined DNA methylation in patients with leukemia treated with decitabine. Five days after the treatment, total genomic 5-methylcytosine/cytosine decreased on average by 14% (from 4.3% to 3.7%), whereas methylation of repetitive DNA elements showed a mean decrease of 9% and 16% for Alu and long interspersed nucleotide elements, respectively. Methylation decreased linearly with increasing doses between 5 and 20 mg/m(2)/d (r = 0.88; P = 0.05) but showed a plateau above that. Hypomethylation correlated with response in patients with acute myelogenous leukemia treated with low doses (5-20 mg/m(2)/d), but patients with chronic myelogenous leukemia treated with high doses (100-180 mg/m(2)/d) showed no such correlation. Aberrant methylation of p15 (>10%) was found in 27% of patients, and 80% of these showed a decrease by at least one third, but this did not correlate with response. The imprinted gene H19 showed little change in methylation after decitabine. In conclusion, we show dose-dependent hypomethylation after decitabine at low doses. Increasing the dose, which has been shown previously to result in a reduced response rate, was not accompanied by further hypomethylation.

Adult↗

PubMed2006

The number of lymph nodes with metastasis predicts survival in patients with esophageal or esophagogastric junction adenocarcinoma who receive preoperative chemoradiation.

BACKGROUND: The survival of patients with locoregional adenocarcinoma of the esophagus or the esophagogastric junction (EGJ) who receive preoperative chemoradiation is reported to be better among patients who achieve a pathologic complete response than among patients who have residual tumor, including lymph node (LN) metastasis. However, the prognostic significance of the number of LNs with residual metastasis remains unclear. METHODS: The authors studied 187 consecutive patients who received chemoradiation followed by an esophagectomy. The number of positive LNs and the size of metastatic tumor in each positive LN were examined with regard to overall survival (OS) and recurrence-free survival (RFS). RESULTS: A pathologic complete response was achieved by 29% of patients. No LN metastasis (posttherapy pathologic negative LN status [ypN0]) was present in 49% of patients who had residual carcinoma, and LN metastasis (ypN1) was present in 51% of patients. The 5-year OS and 2-year RFS rates achieved by patients who had 1 positive LN (34% and 45%, respectively) were similar to the rates achieved by patients in the ypN0 group (38% [P = 0.84] and 50% [P = 0.77], respectively) but were significantly better than the rates achieved by patients who had > or = 2 positive LNs (6% [P = 0.02] and 18% [P = 0.01], respectively). The size of metastatic tumor in LNs among patients who had 1 positive LN was a prognostic factor (> or = 4 mm vs. < 4 mm; P = 0.04). In multivariate analysis, OS was better in patients who had 1 LN metastasis among patients in the ypN1 group (P = 0.02) independent of their posttherapy pathologic tumor status. CONCLUSIONS: The current results suggested that the number of LNs with metastasis is an independent prognostic factor in patients with residual adenocarcinoma of the esophagus or the EGJ after preoperative chemoradiation. The authors suggest modification of the tumor-lymph node-metastasis (TNM) staging classification (ypTNM) to include the number of positive LNs in the ypN1 category.

Adenocarcinoma↗

PubMed2006

Genetic alterations in cancer knowledge system: analysis of gene mutations in mouse and human liver and lung tumors.

Mutational incidence and spectra for genes examined in both human and mouse lung and liver tumors were analyzed using the National Institute of Environmental Health Sciences (NIEHS) Genetic Alterations in Cancer (GAC) knowledge system. GAC is a publicly available, web-based system for evaluating data obtained from peer-reviewed studies of genetic changes in tumors associated with exposure to chemical, physical, or biological agents, as well as spontaneous tumors. In mice, mutations in Kras2 and Hras-1 were the most common events reported for lung and liver tumors, respectively, whether chemically induced or spontaneous. There was a significant difference in Kras2 mutation incidence for spontaneous versus induced mouse lung tumors and in Hras-1 mutation incidence and spectrum for spontaneous versus induced mouse liver tumors. The major gene changes reported for human lung and liver tumors were in KRAS2 (lung only) and TP53. The KRAS2 mutation incidence was similar for spontaneous and asbestos-induced human lung tumors, while the TP53 mutation incidence differed significantly. Aflatoxin B1, hepatitis B virus, hepatitis C virus, and vinyl chloride all caused TP53 mutations in human liver tumors, but the mutation spectrum for each agent differed. The incidence of KRAS2 mutations in human compared to mouse lung tumors differed significantly, as did the incidence of Hras and p53 gene mutations in human compared to mouse liver tumors. Differences observed in the mutation spectra for agent-induced compared to spontaneous tumors and similarities in spectra for structurally similar agents support the concept that mutation spectra can serve as a "fingerprint" of exposure based on chemical structure.

Amines↗

PubMed2006

Histopathologic diagnosis of chronic graft-versus-host disease: National Institutes of Health Consensus Development Project on Criteria for Clinical Trials in Chronic Graft-versus-Host Disease: II. Pathology Working Group Report.

This consensus document provides an update for pathologists and clinicians about the interpretation of biopsy results and use of this information in the management of hematopoietic cell transplantation patients. Optimal sampling and tissue preparation are discussed. Minimal criteria for the diagnosis of graft-versus-host disease (GVHD) are proposed, together with specific requirements for the diagnosis of chronic GVHD. Four final diagnostic categories (no GVHD, possible GVHD, consistent with GVHD, and definite GVHD) reflect the integration of histopathology with clinical, laboratory, and radiographic information. Finally, the Working Group developed a set of worksheets to facilitate communication of clinical information to the interpreting pathologist and to aid in clinicopathologic correlation studies. Forms are available at . The recommendations of the Working Group represent a consensus opinion supplemented by evaluation of available peer-reviewed literature. Consensus recommendations and suggested data-capture forms should be validated in prospective clinicopathologic studies.

Biopsy↗

PubMed2006

Associations of Ki-ras proto-oncogene mutation and p53 gene overexpression in sporadic colorectal adenomas with demographic and clinicopathologic characteristics.

In colorectal tumorigenesis, Ki-ras proto-oncogene mutation often occurs early in the adenoma-adenocarcinoma sequence, whereas mutation of the p53 gene is associated with late progression to carcinoma. We evaluated the relationship of demographic and clinicopathologic characteristics to Ki-ras mutation and p53 gene product overexpression in 1,093 baseline sporadic colorectal adenomas from 926 individuals enrolled in a phase III recurrence prevention trial. Ki-ras mutation was found in 14.7% of individuals and p53 overexpression was found in 7.0% of those tested. Multivariate analysis found older age, rectal location, and villous histology to be independently associated with Ki-ras mutation. Individuals with an advanced adenoma (>or=1 cm or high-grade dysplasia or villous histology) had a 4-fold higher likelihood of Ki-ras mutation [odds ratios (OR), 3.96; 95% confidence intervals (CI), 2.54-6.18]. Ki-ras mutations in codon 12 and of the G-to-A transition type were more frequent in older individuals, whereas G-to-T transversion was more frequent in rectal adenomas than in the colon. Multivariate analysis showed that previous history of a polyp (P = 0.03) was inversely associated with p53 overexpression. Large adenoma size (>or=1 cm), high-grade dysplasia, and villous histology were independently associated with p53 overexpression, with the strongest association for advanced adenomas (OR, 7.20; 95% CI, 3.01-17.22). Individuals with a Ki-ras mutated adenoma were more likely to overexpress p53 (OR, 2.46; 95% CI, 1.36-4.46), and 94.8% of adenomas with both alterations were classified as advanced (P <or= 0.0001). Our large cross-sectional study supports the role of both Ki-ras and p53 in the progression of adenomas and shows that their molecular pathogenesis differs by anatomic location, age, and mucosal predisposition as evidenced by previous history of a polyp.

Adenocarcinoma↗

PubMed2006

CpG island methylation in precursors of gastrointestinal malignancies.

Gastrointestinal malignancies account for about 20% of all cancers worldwide. It is widely accepted that cancer evolves through several stepwise morphological stages such as the adenoma-carcinoma and hyperplastic polyp-serrated adenoma-carcinoma sequences in colorectal cancers, and the metaplasia-dysplasia-carcinoma sequences in esophageal and gastric cancers. The morphological progression is associated with the accumulation of multiple genetic and epigenetic events. It is now recognized that epigenetic silencing of gene expression by CpG island methylation is an important alternative mechanism of inactivating tumor suppressor genes. Inflammatory conditions of the gastrointestinal and pancreaticobiliary tracts and liver such as Barrett esophagus, Helicobacter pylori gastritis, inflammatory bowel disease and viral hepatitis, are associated with increased frequency of malignancies and CpG methylation. In addition, CpG methylation is present in aberrant crypt foci and pancreatic intraepithelial neoplasia that are considered putative precursors of colon and pancreatic carcinomas, respectively. Understanding of these early genetic and epigenetic changes allows for the discoveries of potential screening, monitoring and therapeutic strategies. Targeting of the epigenetic changes that occur before the development of frank malignancy offers a potential chemopreventive strategy.

CpG Islands↗

PubMed2005

Prostaglandin-endoperoxide synthase 2 (PTGS2) gene polymorphisms and risk of biliary tract cancer and gallstones: a population-based study in Shanghai, China.

There is evidence that chronic inflammation predisposes to biliary tract cancer and that use of non-steroidal anti-inflammatory drugs (NSAIDs) is protective. Although the mechanisms by which NSAIDs lower cancer risk remain unclear, NSAIDs reduce prostaglandin production by blocking prostaglandin-endoperoxide synthase 2 (PTGS2, commonly known as COX-2), an enzyme induced by proinflammatory stimuli that is often overexpressed in malignant tissue. Since variants in the PTGS2 gene may modify the expression or function of its encoded enzyme to modulate the inflammatory response in the biliary tract, we examined the associations of eight PTGS2 polymorphisms (-645C-->T; Ex3 -8G-->C; IVS5 -275T-->G; IVS7 +111T-->C; Ex10 +127T-->C; Ex10 +686 --->ATTAT-->TTATA; Ex10 +837T-->C; Ex10 -90C-->T) with biliary tract cancer and stones in a population-based case-control study conducted in Shanghai, China. Genotyping was performed for 411 patients with biliary tract cancer (237 gallbladder, 127 extrahepatic bile duct and 47 ampulla of Vater), 895 patients with biliary stones (673 gallbladder, 222 bile duct), and 786 healthy individuals randomly selected from the population. Significant associations were seen only between the Ex10 +837T-->C marker and bile duct cancer risk. Relative to individuals with the TT genotype, those carrying the C allele (TC or CC genotype) had a 1.8-fold (95% confidence interval: 1.2-2.7) risk of bile duct cancer. Inferred haplotypes including this risk-conferring allele were also associated with increased bile duct cancer risk of similar magnitude. Our results suggest that a common PTGS2 variant increases bile duct cancer risk. Further investigation is needed to confirm and extend our findings in studies of biliary tract cancer that more comprehensively examine PTGS2 and other inflammation-related genes.

Age Factors↗

PubMed2005

Mutation of Lkb1 and p53 genes exert a cooperative effect on tumorigenesis.

Peutz-Jeghers syndrome (PJS) is a dominantly inherited disorder characterized by gastrointestinal hamartomatous polyps and mucocutaneous melanin pigmentation. Germ line mutations in LKB1 cause PJS. We have generated mice carrying an Lkb1 exon 2 to 8 deletion by gene targeting in embryonic stem cells. Heterozygotes develop gastric hamartomas that are histologically similar to those found in humans with PJS. LKB1 is also reportedly a mediator of p53-dependent apoptosis. To explore the potential combined effects of p53 and Lkb1 alterations on tumorigenesis, we carried out a series of matings with Lkb1(+/-) and p53 null mice to generate Lkb1(+/-)/p53(+/-) and Lkb1(+/-)/p53(-/-) mice. Similar to the Lkb1(+/-) mice, gastrointestinal hamartomas have also been detected in the mice with these two genotypes. The Lkb1(+/-)/p53(+/-) mice displayed a dramatically reduced life span and increased tumor incidence compared to the mice with either Lkb1 or p53 single gene knockout. The time to onset of polyposis in Lkb1(+/-)/p53(-/-) mice is approximately 2 months earlier than Lkb1(+/-)/p53(+/-) and Lkb1(+/-) mice, whereas the latter two show a similar time to onset which is at approximately 6 months of age. These results strongly suggested that mutations of p53 and Lkb1 gene cooperate in the acceleration of tumorigenesis.

AMP-Activated Protein Kinases↗

PubMed2005

Gene expression profiling of localized esophageal carcinomas: association with pathologic response to preoperative chemoradiation.

PURPOSE: Patients with localized esophageal carcinoma have a 5-year survival rate of less than 20%. Patients are often treated similarly (ie, with preoperative chemoradiotherapy) but the outcomes vary greatly. Chemoradiotherapy and surgery can result in significant undesirable consequences. Currently, however, there are no tools to help select optimum therapy. We hypothesized that gene expression profiling could provide clues and biomarkers for selection of therapy. METHODS: Pretreatment endoscopic cancer biopsies from 19 patients (16 with adenocarcinoma, two with squamous cell carcinoma, and one with adenosquamous carcinoma) enrolled onto a preoperative chemoradiotherapy protocol were profiled using oligonucleotide microarrays. Surgical specimens following therapy were assessed for the degree of pathologic response. On the basis of array data, selected genes were analyzed by polymerase chain reaction. RESULTS: Unsupervised hierarchical cluster analysis segregated the cancers into two molecular subtypes, each consisting 10 and nine specimens, respectively. Most cancers (five of six) that had pathologic complete response (pathCR) clustered in molecular subtype I. Subtype II, with one exception, consisted cancers that had less than pathCR (< pathCR). Using a combination marker approach, levels of PERP, S100A2, and SPRR3 allowed discrimination of pathCR from < pathCR with high sensitivity and specificity (85%). Pathway analysis identified apoptotic pathway as one of the key functions downregulated in molecular type II in comparison with type I. CONCLUSION: These encouraging, albeit preliminary, data suggest that expression profiling may distinguish cancers with different pathologic outcome. This is the first report to show subtypes of esophageal cancers with distinct molecular signatures. The potential of PERP, S100A2, and SPRR3 as biomarkers of pathCR warrants further validation.

Adenocarcinoma↗