Colorectal Chemoprevention Pilot Study (SWOG-9041), randomized and placebo controlled: the importance of multiple luminal lesions.

BACKGROUND: Colorectal cancer is common worldwide and chemoprevention has the potential of reducing the number of individuals who may suffer and perish from this disease. METHODS: A randomized placebo controlled pilot study in colorectal cancer patients was performed using calcium carbonate as the test agent in a multi-institutional oncology study group. RESULTS: Two hundred twenty volunteers were randomized in the study. The primary goals of compliance, accrual, and toxicity monitoring are presented. Presence of multiple adenomas at study entry and subsequent development of metachronous adenomas were recorded and found to be associated with synchronous adenomas. The secondary endpoint of recurrent adenomas indicated lower rates of new adenoma in the volunteers randomized to the calcium group. CONCLUSION: This pilot study indicates the feasibility of enrolling survivors of colorectal cancer as study volunteers in a colorectal neoplasm chemoprevention clinical trial and oral calcium continues to be a potentially effective drug in reducing colorectal adenomas.

Phase III study comparing gemcitabine plus cetuximab versus gemcitabine in patients with advanced pancreatic adenocarcinoma: Southwest Oncology Group-directed intergroup trial S0205.

PURPOSE: Patients with advanced pancreas cancer present with disease that is poorly responsive to conventional therapies. Preclinical and early clinical evidence has supported targeting the epidermal growth factor receptor (EGFR) signaling pathway in patients with pancreas cancer. This trial was conducted to evaluate the contribution of an EGFR-targeted agent to standard gemcitabine therapy. Cetuximab is a monoclonal antibody against the ligand-binding domain of the receptor. PATIENTS AND METHODS: Patients with unresectable locally advanced or metastatic pancreatic adenocarcinoma were randomly assigned to receive gemcitabine alone or gemcitabine plus cetuximab. The primary end point was overall survival. Secondary end points included progression-free survival, time to treatment failure, objective response, and toxicity. RESULTS: A total of 745 eligible patients were accrued. No significant difference was seen between the two arms of the study with respect to the median survival time (6.3 months for the gemcitabine plus cetuximab arm v 5.9 months for the gemcitabine alone arm; hazard ratio = 1.06; 95% CI, 0.91 to 1.23; P = .23, one-sided). Objective responses and progression-free survival were similar in both arms of the study. Although time to treatment failure was longer in patients on gemcitabine plus cetuximab (P = .006), the difference in length of treatment was only 2 weeks longer in the combination arm. Among patients who were studied for tumoral EGFR expression, 90% were positive, with no treatment benefit detected in this patient subset. CONCLUSION: In patients with advanced pancreas cancer, the anti-EGFR monoclonal antibody cetuximab did not improve the outcome compared with patients treated with gemcitabine alone. Alternate targets other than EGFR should be evaluated for new drug development.

Acetylcholinesterase supports anchorage independence in colon cancer.

Various roles have been attributed to Acetylcholinesterase (AChE) in cancer. Evidence exists for a pro-apoptotic function, consistent with a protective role of AChE. Because other reports suggested that upregulated AChE in some tumors may control cell adhesion, we tested the effects of AChE on anchorage independence (an essential component of metastasis) of colon tumor cells. Several AChE inhibitors dose-dependently suppressed colony formation of HTB-38 cells in soft agar. This effect of AChE was confirmed with HTB-38 cells stably overexpressing AChE. In contrast, cell proliferation was not altered by the effective doses of these chemical inhibitors or by transfected AChE. Protection from cell cycle arrest consecutive to cancer cell detachment may be conveyed by changes in cell-matrix interactions. Reflective of such changes, the AChE overexpressing cells adhered more strongly to Fibronectin than did the vector controls. The AChE-dependent adhesion was RGD-dependent and accompanied by increased c-Myb DNA-binding, suggesting that AChE upregulates an Integrin receptor via c-Myb. In support of these observations, we find AChE message and protein to be expressed in a large fraction of colon cancers and in all colon tumor cell lines analyzed, but only rarely in normal colon specimens. Our results imply a dual role for AChE in colon cancer. While the anti-apoptotic effects of AChE may be protective against early stages of tumorigenesis, this gene product may support the later stages of transformation by enhancing anchorage independent growth. The induction of Integrins could render the cells independent of microenvironmental cues and override cell cycle arrest after deadhesion.

The RON receptor tyrosine kinase mediates oncogenic phenotypes in pancreatic cancer cells and is increasingly expressed during pancreatic cancer progression.

Pancreatic cancer is an aggressive disease characterized by rapid growth and early metastasis. The recepteur d'origine nantais (RON) receptor tyrosine kinase is overexpressed and/or constitutively active in several epithelial cancers, but its role in pancreatic cancer is unknown. In this study, we have characterized RON expression in both murine and human pancreatic cancer. Immunoblotting indicates that RON is expressed in pancreatic intraepithelial neoplasia (PanIN), primary, and metastatic cell lines both in the human and mouse. Immunostaining revealed that 93% of high-grade PanIN, 79% of primary, and 83% of metastatic lesions from human pancreatic tissue samples expressed RON, with minimal expression in normal ducts and low-grade PanIN (6% and 18%, respectively). Moreover, we show a dose-dependent effect of hepatocyte growth factor-like protein (HGFL), the RON-specific ligand, on pancreatic cancer cell migration and invasion, which was reversed by RON inhibition. Although stimulation with HGFL had no effect on proliferation, concurrent RON receptor blockade and gemcitabine treatment increased apoptosis of RON-expressing pancreatic cancer cells versus gemcitabine treatment alone. Finally, HGFL stimulation of pancreatic cancer cells resulted in increased expression of phospho-mitogen-activated protein kinase and phospho-Akt. Taken together, these findings suggest that RON receptor signaling may contribute to pancreatic carcinogenesis, and that further investigation is warranted to assess the potential of RON-directed therapies in this deadly disease.

Phase II trial of erlotinib in gastroesophageal junction and gastric adenocarcinomas: SWOG 0127.

PURPOSE: A phase II trial of the oral epidermal growth factor receptor (EGFR) inhibitor erlotinib in patients with gastroesophageal adenocarcinomas stratified according to primary tumor location into two groups: gastroesophageal junction (GEJ)/cardia and distal gastric adenocarcinomas. PATIENTS AND METHODS: Patients with a histologically proven diagnosis of adenocarcinoma of the GEJ or stomach (ST) that was unresectable or metastatic; presence of measurable disease; no prior chemotherapy for advanced or metastatic cancer; Zubrod performance status (PS) of 0 to 1; and adequate renal, hepatic, and hematologic function were treated with erlotinib 150 mg/d orally. Patient characteristics were median age, GEJ-63 years, ST-64 years; sex, GEJ-84% male and 16% female, ST-60 male and 40 female; Zubrod PS, GEJ-25 had a PS of 0 and 18 had a PS 1, ST-13 had a PS of 0 and 12 had a PS of 1. RESULTS: Percentage of common toxicities were skin rash, 86% and 72%; fatigue, 51% and 44%; and AST/ALT elevation, 28% and 28%, respectively for GEJ and ST. There has been one confirmed complete response, three confirmed partial responses (PRs) and one unconfirmed PR for an overall response probability of 9% confirmed (95% CI, 3% to 22%), all occurring in GEJ stratum. No responses were observed in ST stratum. The median survival was 6.7 months in GEJ and 3.5 months in ST stratum. Neither intratumoral EGFR, transforming growth factor-alpha or phosphorylated Akt kinase expression nor plasma proteomic analyses were predictive of clinical outcome. No somatic mutations of the EGFR exons 18, 19, or 21 were detected and there was no gross amplification of EGFR by fluorescence in situ hybridization. CONCLUSION: Erlotinib is active in patients with GEJ adenocarcinomas, but appears inactive in gastric cancers. The molecular correlates examined were not predictive of the patient therapeutic response.

beta-Catenin/Wnt signaling regulates expression of the membrane type 3 matrix metalloproteinase in gastric cancer.

Activation of Wnt signaling through beta-catenin dysregulation occurs in numerous human tumors, including gastric cancer. The specific consequences of Wnt signaling in gastric cancer, however, are not well characterized. This study shows that the introduction of mutant beta-catenin into gastric cancer cell lines by adenoviral infection enhances invasiveness and proliferation and up-regulates the expression of the gene encoding the matrix metalloproteinase (MMP) family member membrane type 3 MMP (MT3-MMP). Up-regulation of MT3-MMP is critical to the invasive phenotype as shown by small interfering RNA (siRNA) studies. Immunohistochemical staining also showed that MT3-MMP was highly expressed in gastric cancers with activating beta-catenin mutations. These observations suggest that Wnt activation may contribute to gastric cancer progression by increasing the invasiveness of neoplastic cells in the stomach via up-regulation of MT3-MMP expression.

Cyclin D1b variant influences prostate cancer growth through aberrant androgen receptor regulation.

Cyclin D1 is a multifaceted regulator of both transcription and cell-cycle progression that exists in two distinct isoforms, cyclin D1a and D1b. In the prostate, cyclin D1a acts through discrete mechanisms to negatively regulate androgen receptor (AR) activity and thus limit androgen-dependent proliferation. Accordingly, cyclin D1a is rarely overexpressed in prostatic adenocarcinoma and holds little prognostic value in this tumor type. However, a common polymorphism (A870) known to facilitate production of cyclin D1b is associated with increased prostate cancer risk. Here we show that cyclin D1b is expressed at high frequency in prostate cancer and is up-regulated in neoplastic disease. Furthermore, our data demonstrate that, although cyclin D1b retains AR association, it is selectively compromised for AR regulation. The altered ability of cyclin D1b to regulate the AR was observed by using both in vitro and in vivo assays and was associated with compromised regulation of AR-dependent proliferation. Consistent with previous reports, expression of cyclin D1a inhibited cell-cycle progression in AR-dependent prostate cancer cells. Strikingly, cyclin D1b significantly stimulated proliferation in this cell type. AR-negative prostate cancer cells were nonresponsive to cyclin D1 (a or b) expression, indicating that defects in AR corepressor function yield a growth advantage specifically in AR-dependent cells. In summary, these studies indicate that the altered AR regulatory capacity of cyclin D1b contributes to its association with increased prostate cancer risk and provide evidence of cyclin D1b-mediated transcriptional regulation.

Serrated polyps of the large intestine: a morphologic and molecular review of an evolving concept.

Serrated polyps of the large intestine, including traditional hyperplastic polyps, traditional serrated adenomas, and more recently described sessile serrated adenomas, have gained increased recognition in recent years because of growing evidence that one of these lesions, the sessile serrated adenoma, might be the precursor lesion for some cases of microsatellite unstable colorectal carcinoma. Nevertheless, there has been some reluctance to embrace the concept of sessile serrated adenoma, and numerous diagnostic challenges exist. This article, which grew out of the Roger C. Haggitt Gastrointestinal Pathology Society Forum presented in Vancouver, Canada, March 6, 2004 as part of the annual meeting of the United States-Canadian Academy of Pathology, reviews the morphologic and molecular evidence for the concept of various polyps in the general category of serrated polyps of the large intestine, in particular the lesion known as the sessile serrated adenoma, and provides a conceptual framework for diagnosis of these lesions.

Stability of phosphoprotein as a biological marker of tumor signaling.

PURPOSE: The purpose of the study was to evaluate the stability of phosphoprotein as a marker of signaling activity in human tumors using clinical samples and xenografts. EXPERIMENTAL DESIGN: The expression of phospho-Ser473-Akt (p-Akt) was assessed by immunohistochemistry in paraffin-embedded samples from patients enrolled in a Southwest Oncology Group clinical trial of gastroesophageal junction tumors and by immunohistochemistry and Western blotting in human colon tumor xenografts at various times after removal from the animal. RESULTS: Clinical samples had evaluable p-Akt staining only when obtained as biopsies (9 of 13) and no staining was observed in tumors obtained as surgically resected samples (0 of 15). In HT-29 colon cancer xenografts, p-Akt staining was present in fresh sample but not in tissue that had been allowed to stand for 30 minutes at room temperature. Western blotting of HT-29 tumor xenografts at room temperature showed a slow decrease in total Akt with a half-life of 180 minutes and a rapid decrease in p-Akt with a half-life of 20 minutes. CONCLUSIONS: Caution should be used when using phosphoprotein levels in human tumor specimens to measure intrinsic signaling activity or drug effects because of the potential for rapid dephosphorylation. Rapid processing of biopsies is essential and postoperative surgical samples may be of limited value because of the time to fixation.

Adenoma recurrences after resection of colorectal carcinoma: results from the Southwest Oncology Group 9041 calcium chemoprevention pilot study.

BACKGROUND: Colorectal adenomas are the usual precursors to carcinoma in sporadic and hereditary colorectal cancers (CRC). METHODS: A total of 220 CRC patients (stages 0, I, and II) were randomized prospectively in a double-blind pilot study of calcium chemoprevention by using recurrent colorectal adenomas as a surrogate end point. This trial is still in progress, and we report the preliminary findings on adenoma recurrence rates. RESULTS: Synchronous adenomas were present in 60% of patients, and cancer confined in a polyp was present in 23% of patients. The overall cumulative adenoma recurrence rate was 31% (19% in the first year, 29% for 2 years, and 35% for 3 years). The recurrence rates were greater for patients with synchronous adenomas: 38% at 3 years (P =.01). Lower stage was associated with higher adenoma recurrence rates (P =.04). Factors including age, sex, site of primary cancer, and whether the cancer was confined to a polyp were not significantly associated with differences in adenoma recurrence rates. CONCLUSIONS: The substantial adenoma recurrence rate in patients resected of CRC justifies colonoscopic surveillance on a periodic basis. Patients with higher rates of adenoma recurrences, such as CRC with synchronous adenomas, are ideal subjects for chemoprevention trials.

Microsatellite instability as a predictor of survival in head and neck cancer -- is there a link with colon cancer?

OBJECTIVE: A reliable genetic marker to predict outcome for head and neck cancer is needed. In colon cancer, microsatellite instability (MSI) predicts response to therapy and improved prognosis. Colon cancer patients with MSI have a 60% improvement in survival as compared to patients without MSI. To assess whether MSI is a predictor of improved prognosis in head and neck cancer we used our tumor registry to find 8 patients treated between 1995 and 1998 with head and neck squamous cell carcinoma and either a history of colon cancer or a parent who had colon cancer. As a control, 15 T(2) or T(3) oral cavity cancers were used. METHODS: The tumor specimens were obtained and laser capture microdissected for analysis using the following microsatellite markers: BAT25, BAT26, BAT40, D1S2883, D2S123, D3S1611, D5S346, D7S501 and D8S25. RESULTS: All 8 patients with head and neck cancer and a colon cancer history exhibited MSI or loss of heterozygosity (LOH) at 1 or more of the markers tested. Three patients had 2 abnormal markers, 1 patient had 3 abnormal markers and 1 had 7 abnormal markers. Only 1 of the patients with a colon cancer history, all of whom had MSI, developed recurrent head and neck cancer. Of the 15 control patients, 5 had MSI or LOH and 1 had MSI or LOH at 2 markers. Three of the 5 patients with MSI or LOH had a recurrence; hence MSI and LOH at these markers were uncommon, and there was no relation between MSI and outcome in patients without a history of colon cancer. CONCLUSIONS: These results support a possible alternative mode of carcinogenesis in patients with head and neck cancer and a history of colon cancer and, most significantly, that these cancers are a subgroup of head and neck cancer that may have a better prognosis.

Dysregulation of beta-catenin expression correlates with tumor differentiation in pancreatic duct adenocarcinoma.

BACKGROUND: beta-Catenin functions as an integral part of the E-cadherin/catenin adhesion complex to maintain epithelial cell integrity. beta-Catenin also functions as part of the Wnt signal transduction pathway to transmit growth-promoting signals to the nucleus via its interactions with Tcf/Lef transcription factors. Previous reports have demonstrated altered beta-catenin expression in numerous tumor types; however, reports regarding beta-catenin expression in pancreatic cancer have been conflicting. METHODS: beta-Catenin expression was examined in 10 pancreatic cancer cell lines by Western and Northern analysis and by immunofluorescence. Expression was also examined by immunohistochemistry in 57 primary pancreatic cancers and 7 foci of carcinoma-in-situ. RESULTS: Reduced expression of beta-catenin was observed in 4 of 10 pancreatic cancer cell lines. Reduced membranous expression was noted in 32 pancreatic cancers (56%) and correlated with loss of tumor differentiation. Nuclear beta-catenin expression was identified in two tumors (4%). beta-Catenin expression was present in all seven foci of carcinoma-in-situ; however, nuclear expression was predominant in four of the seven cases. CONCLUSIONS: Alterations in beta-catenin expression are common in pancreatic cancer; however, signaling and adhesion functions may be perturbed at different times during tumor progression. Therefore, dysregulation of beta-catenin may contribute to the development and progression of this disease through distinct mechanisms.

Risk factors for advanced colorectal adenomas: a pooled analysis.

Although most colorectal cancers arise from adenomatous polyps, most adenomas do not progress to invasive cancer. Understanding the epidemiology of advanced adenomas, specifically those with severe dysplasia, carcinoma in situ, or intramucosal carcinoma, is crucial to uncovering why some adenomas progress and some do not. Using data from four colonoscopy-based adenoma case-control studies, we compared two case groups: subjects with advanced adenomas (those with severe dysplasia, carcinoma in situ, or intramucosal carcinoma; n = 119) and subjects with nonadvanced adenomas (those with none, mild, or moderate dysplasia; n = 441) to a polyp-free control group (n = 1866) in regard to frequently studied risk factors for colorectal neoplasia. All of the cases were newly diagnosed and had no prior history of adenomas. We used an unordered polytomous logistic model to calculate multivariate odds ratios for advanced and nonadvanced adenoma cases relative to polyp-free controls. Among women, ever use of hormone replacement therapy was more strongly associated with reduced risk of advanced adenomas relative to polyp-free controls [odds ratio (OR), 0.4; 95% confidence interval (CI), 0.2-0.9] than with reduced risk of nonadvanced adenomas (OR, 0.7; 95% CI, 0.4-1.0). Among men, increased physical activity (>or=2 h/week) was more strongly associated with reduced risk for advanced adenomas (OR, 0.4; 95% CI, 0.2-1.0) than with reduced risk for nonadvanced adenomas (OR, 0.8; 95% CI, 0.5-1.2). Apart from these differences, most other risk factors, including body size and cigarette smoking were similar in their association with advanced and nonadvanced adenomas, suggesting that many risk factors for colorectal neoplasia may be important to adenoma formation but not to dysplasia per se.

Reliability in the classification of advanced colorectal adenomas.

In conjunction with a pooled analysis of risk factors for advanced adenomas [adenomas with severe dysplasia, carcinoma in situ (CIS), and intramucosal carcinoma], we undertook a reliability study on the pathological diagnosis of advanced adenomas. We assessed intraobserver agreement (using Kappa (kappa) as the measure of agreement) across two time periods 10 years apart with a single pathologist and interobserver agreement (using Kappa) between two pathologists rating the same slides concurrently. The study pathologists were blinded to the original case classification. We used the slides of 190 colorectal adenomatous polyp cases (104 originally diagnosed as advanced adenomas, 86 adenomas without advanced lesions) from a colonoscopy-based case-control study conducted in New York City between 1986 and 1988. We also assessed conditional agreement for 71 slides of advanced adenomas from four adenoma case-control studies conducted in different geographic regions of the United States in the 1990s. Intra- and interobserver agreement was only fair to moderate on the classification of both histological type (villous, tubulovillous, and tubular: intraobserver kappa = 0.28; 95% confidence interval (CI), 0.17-0.39; interobserver kappa = 0.48; 95% CI, 0.33-0.62) and degree of dysplasia (none/mild, moderate, severe, CIS, and intramucosal: intraobserver kappa = 0.20; 95% CI, 0.12-0.28; interobserver kappa = 0.42; 95% CI, 0.29-0.55). Using broader, rather than finer, classifications for degree of dysplasia substantially improved the reliability (interobserver agreement for high-grade dysplasia (including severe dysplasia, CIS, and intramucosal carcinoma) versus low-grade dysplasia: kappa = 0.69; 95% CI, 0.55-0.83). These findings suggest that future epidemiological studies of advanced adenomas should use broad categories, such as high-grade versus low-grade dysplasia, include central review of all slides, and take measurement error into account in sample size calculations.

beta-Catenin mutation is a frequent cause of Wnt pathway activation in gastric cancer.

Studies of Wnt activation in gastric cancer have yielded conflicting results. The goals of this study were to determine the frequency of Wnt pathway activation and beta-catenin mutation in these tumors. Three hundred eleven gastric cancers were examined for beta-catenin expression by immunostaining and dissected using laser capture microscopy to obtain DNA from those tumors with nuclear beta-catenin. Exon 3 of beta-catenin was amplified using PCR and sequenced. Ninety gastric cancers (29%) displayed nuclear beta-catenin. DNAs from 73 tumors were amplified and sequenced; 19 (26%) contained mutations in exon 3 of beta-catenin, whereas no mutations were detected in 19 tumors negative for beta-catenin nuclear staining (P < 0.05). Most mutations were adjacent to or abolished known regulatory phosphorylation sites. Mutations in exon 3 of beta-catenin are common in gastric cancer that display nuclear beta-catenin. These results suggest that Wnt pathway activation contributes to carcinogenesis in a subset of gastric adenocarcinomas.

Gastric carcinoma distal to the cardia: a review of the epidemiological pathology of the precusors to a preventable cancer.

A distinctive gastritis precedes the development of cancer distal to the cardia. Helicobacter pylori infection and the use of pickled foods as substitutes for fresh fruits and vegetables constitute the most important environmental factors that generate this gastritis. This review describes the anatomical changes that characterise the step-by-step evolution of a process that begins in childhood and culminates in invasive cancer in middle and old age. Progression of the gastritis can be followed by measuring the host antibody response to the H. pylori infection and by serum assays that indicate loss of parietal cell mass. Cancer of the distal stomach will disappear if adequate, sanitary housing and year-round fresh vegetables are made available to all economic levels of society. Programmes that offer these reforms must be sustained over several generations, since the anatomical changes that precede gastric cancer are probably not reversible and begin early in life. In the absence of these reforms, death from gastric cancer may be prevented if patients with asymptomatic, early cancers are identified. High H. pylori antibody levels and serum pepsinogen assays may be used to identify persons with the extensive gastritis that favours the presence of such early cancers.