Stanley R Hamilton†

BACKGROUND: Sporadic colorectal cancers often arise from a region of cells characterized by a "field defect" that has not been well defined molecularly. DNA methylation has been proposed as a candidate mediator of this field defect. The DNA repair gene O6-methylguanine-DNA methyltransferase (MGMT) is frequently methylated in colorectal cancer. We hypothesized that MGMT methylation could be one of the mediators of field cancerization in the colon mucosa.

METHODS: We studied MGMT promoter ...

PURPOSE: An American Society of Clinical Oncology (ASCO) provisional clinical opinion (PCO), offers timely clinical direction to ASCO's oncologists following publication or presentation of potentially practice-changing data from major studies. This PCO addresses the utility of KRAS gene mutation testing in patients with metastatic colorectal carcinoma to predict response to anti-epidermal growth factor receptor (anti-EGFR) monoclonal antibody (MoAb) therapy with cetuximab or panitumumab ...

The pathologic reports of all 1,020 esophageal biopsy specimens obtained between 1975 and 1981 in patients with symptoms of gastroesophageal reflux were reviewed. Barrett's esophagus was identified in 84 patients (8 percent). The 362 patients seen between 1980 and 1981 were reviewed in detail. The symptoms in patients with Barrett's esophagus differed from those of the patients without Barrett's esophagus. Dysphagia was more often present in the former group (34 percent versus 16 ...

PURPOSE: Early events in colorectal tumorigenesis include mutation of the adenomatous polyposis coli (APC) gene and epigenetic hypermethylation with transcriptional silencing of the O(6)-methylguanine DNA methyltransferase (MGMT), human mut L homologue 1 (hMLH1), and P16/CDKN2A genes. Epigenetic alterations affect genetic events: Loss of MGMT via hypermethylation reportedly predisposes to guanine-to-adenine or cytosine-to-thymine (G:C-->A:T) transition mutations in KRAS and P53, and ...

Signal transducer and activator of transcription 3 (STAT3) has oncogenic potential. The biological effects of STAT3 have not been studied extensively in the pathogenesis of colon cancer, nor has the role of Janus kinase 3 (JAK3), the physiological activator of STAT3, been evaluated. Here, we demonstrate that activated STAT3 (pSTAT3) and activated JAK3 (pJAK3) are expressed constitutively in two colon cancer cell lines, SW480 and HT29. To evaluate the significance of JAK3/STAT3 signaling, ...

BACKGROUND: Colorectal cancer occurs in approximately 150,000 people each year in the United States. Prognostic assessment influences the treatment of patients with colorectal cancer, including decisions about adjuvant therapy. We evaluated chromosome 18q allelic loss, a genetic event associated with tumor progression, as a prognostic marker for this disease.

METHODS: We developed procedures to examine the status of chromosome 18q with microsatellite markers and DNA from formalin-fixed, ...

Carcinoid tumors and pancreatic endocrine tumors are uncommon neuroendocrine neoplasms, and their genetic alterations are not well characterized. These tumors have site-specific differences in neuroendocrine characteristics, clinical course and genetic alterations. We compared clinicopathological features and loss of heterozygosity of chromosomes 11q, 16q and 18, and BRAF gene mutations in 47 patients with neuroendocrine tumors including 16 with pancreatic endocrine tumors, 15 with ...

The prevalence and characteristics of Barrett esophagus in patients with adenocarcinoma of the esophagus or esophagogastric junction are uncertain. We studied 61 consecutive esophagogastrectomy specimens with adenocarcinoma, which were subjected to extensive histopathologic examination. Barrett esophagus was found in 64% of the cases (39 of 61), but had been recognized in only 38% of the patients with Barrett-associated carcinoma who had undergone preoperative endoscopy with biopsy (13 ...

We studied growth factors and their receptors in tumor cells and tumor-associated endothelial cells as the therapeutic targets in colon cancer. Immunohistochemical analysis of 13 surgical specimens of human colon adenocarcinoma revealed that both tumor cells and tumor-associated endothelial cells in 11 of the 13 specimens expressed the epidermal growth factor (EGF), transforming growth factor alpha (TGF-alpha), EGF receptor (EGFR), phosphorylated EGFR (pEGFR), vascular endothelial growth ...

BACKGROUND: Adjuvant chemotherapy improves survival among patients with stage III colon cancer, but no reliable molecular predictors of outcome have been identified.

METHODS: We evaluated loss of chromosomal material (also called loss of heterozygosity or allelic loss) from chromosomes 18q, 17p, and 8p; cellular levels of p53 and p21(WAF1/CIP1) proteins; and microsatellite instability as molecular markers. We analyzed tumor tissue from 460 patients with stage III and high-risk stage II ...

Goblet cell carcinoid is a relatively rare neuroendocrine tumor of the vermiform appendix with poorly understood molecular pathogenesis. We studied the clinicopathologic features and genetic alterations, including allelic loss of chromosomes 11q, 16q, and 18q; sequencing of the K-ras, β-catenin, and DPC4 (SMAD4) genes; and p53 overexpression and loss of DPC4 by immunohistochemistry; in 16 goblet cell carcinoids. We compared the allelic loss in goblet cell carcinoids to those in 18 ...

Gastric cancer is common among the world, but genetic mechanisms of gastric carcinogenesis are not well understood. Gastric polypoid adenomas and flat dysplasias are regarded as precursor lesions. However, a detailed molecular study of these lesions has not been done to determine their role as precancerous lesions. We investigated mutations of the APC, beta-catenin, and K-ras genes, and microsatellite instability (MSI) status in 35 adenomas and 47 flat dysplasias without adenocarcinoma, ...

PURPOSE: To provide recommendations on prevention, screening, genetics, treatment, and management for people at risk for hereditary colorectal cancer (CRC) syndromes. The American Society of Clinical Oncology (ASCO) has a policy and set of procedures for endorsing clinical practice guidelines that have been developed by other professional organizations.

METHODS: The Familial Risk-Colorectal Cancer: European Society for Medical Oncology Clinical Practice Guideline published in 2013 on ...

BACKGROUND: Colon cancers with high-frequency microsatellite instability have clinical and pathological features that distinguish them from microsatellite-stable tumors. We investigated the usefulness of microsatellite-instability status as a predictor of the benefit of adjuvant chemotherapy with fluorouracil in stage II and stage III colon cancer.

METHODS: Tumor specimens were collected from patients with colon cancer who were enrolled in randomized trials of fluorouracil-based adjuvant ...