Long-term survival and prognostic indicators in small (<or=2 cm) pancreatic cancer

OBJECTIVES

In a matched analysis, we investigated clinical, histopathological, and survival characteristics of small (

METHODS

From the Mayo pathology database, we identified 41 consecutive patients with small PaC and 94 matched controls with margin-negative PaC >2 cm. Two experienced pathologists, who were blinded to survival data, independently reviewed tumor stage and differentiation. Kaplan-Meier survival analysis and Cox proportional hazards models were applied for data analyses.

RESULTS

In patients with localized disease (stages I and II), survival was similar in small and large PaC but survival was significantly better in small PaC with regional nodal metastasis (stage III) as compared to similar stage large PaC (5-year survival 44 vs. 7%, median survival 58 vs.18 months, p < 0.001). Well-differentiated small and large PaC had similar median survival (76 vs. 74 months, p = NS). In multivariate analysis, tumor differentiation, not tumor size, was the only independent factor predicting survival in PaC (risk ratio, RR, for moderate vs. well- differentiated: 2.6, 95% confidence interval, CI, 1.5-4.5, and RR for poorly differentiated vs. well-differentiated: 5.0, 95% CI 2.4-10.1).

CONCLUSION

Tumor differentiation may be a better predictor of survival in resectable PaC than tumor stage.

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Key Words

• small pancreatic cancer
• tumor stage
• tumor differentiation
• survival prediction

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MESH Headings

• Aged
• Antineoplastic Agents/therapeutic use
• Female
• Humans
• Male
• Middle Aged
• Neoplasm Staging
• Pancreatic Neoplasms/mortality
• Pancreatic Neoplasms/pathology
• Pancreatic Neoplasms/therapy
• Prognosis
• Radiotherapy, Adjuvant

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Grants

• P50 CA102701-06 NCI NIH HHS
• P50 CA102701 NCI NIH HHS
• P50 CA 10270 NCI NIH HHS
• R01 CA 100685 NCI NIH HHS
• R01 CA100685 NCI NIH HHS
• R01 CA100685-04 NCI NIH HHS

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Affiliation(s)

Supot Pongprasobchai Divisions of Gastroenterology and Hepatology, Rochester, Minn., USA
Rahul Pannala Divisions of Gastroenterology and Hepatology, Rochester, Minn., USA
Thomas C. Smyrk Anatomic Pathology, Rochester, Minn., USA
William Bamlet Biostatistics, Mayo Clinic, Rochester, Minn., USA
Suresh Pitchumoni Divisions of Gastroenterology and Hepatology, Rochester, Minn., USA
Andrei Ougolkov Anatomic Pathology, Rochester, Minn., USA
Mariza de Andrade Biostatistics, Mayo Clinic, Rochester, Minn., USA
Gloria M. Petersen Biostatistics, Mayo Clinic, Rochester, Minn., USA
Suresh T. Chari Divisions of Gastroenterology and Hepatology, Rochester, Minn., USA

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CRD-BP mediates stabilization of betaTrCP1 and c-myc mRNA in response to beta-catenin signalling

Although constitutive activation of beta-catenin/Tcf signalling is implicated in the development of human cancers, the mechanisms by which the beta-catenin/Tcf pathway promotes tumorigenesis are incompletely understood. Messenger RNA turnover has a major function in regulating gene expression and is responsive to developmental and environmental signals. mRNA decay rates are dictated by cis-acting elements within the mRNA and by trans-acting factors, such as RNA-binding proteins (reviewed in refs 2, 3). Here we show that beta-catenin stabilizes the mRNA encoding the F-box protein betaTrCP1, and identify the RNA-binding protein CRD-BP (coding region determinant-binding protein) as a previously unknown target of beta-catenin/Tcf transcription factor. CRD-BP binds to the coding region of betaTrCP1 mRNA. Overexpression of CRD-BP stabilizes betaTrCP1 mRNA and elevates betaTrCP1 levels (both in cells and in vivo), resulting in the activation of the Skp1-Cullin1-F-box protein (SCF)(betaTrCP) E3 ubiquitin ligase and in accelerated turnover of its substrates including IkappaB and beta-catenin. CRD-BP is essential for the induction of both betaTrCP1 and c-Myc by beta-catenin signalling in colorectal cancer cells. High levels of CRD-BP that are found in primary human colorectal tumours exhibiting active beta-catenin/Tcf signalling implicates CRD-BP induction in the upregulation of betaTrCP1, in the activation of dimeric transcription factor NF-kappaB and in the suppression of apoptosis in these cancers.

Deregulated GSK3beta activity in colorectal cancer: its association with tumor cell survival and proliferation

Glycogen synthase kinase 3beta (GSK3beta) reportedly has opposing roles, repressing Wnt/beta-catenin signaling on the one hand but maintaining cell survival and proliferation through the NF-kappaB pathway on the other. The present investigation was undertaken to clarify the roles of GSK3beta in human cancer. In colon cancer cell lines and colorectal cancer patients, levels of GSK3beta expression and amounts of its active form were higher in tumor cells than in their normal counterparts; these findings were independent of nuclear accumulation of beta-catenin oncoprotein in the tumor cells. Inhibition of GSK3beta activity by phosphorylation was defective in colorectal cancers but preserved in non-neoplastic cells and tissues. Strikingly, inhibition of GSK3beta activity by chemical inhibitors and its expression by RNA interference targeting GSK3beta induced apoptosis and attenuated proliferation of colon cancer cells in vitro. Our findings demonstrate an unrecognized role of GSK3beta in tumor cell survival and proliferation other than its predicted role as a tumor suppressor, and warrant proposing this kinase as a potential therapeutic target in colorectal cancer.

Associations Among -TrCP, an E3 Ubiquitin Ligase Receptor, -Catenin, and NF- B in Colorectal Cancer

BACKGROUND

The ubiquitin-proteasome pathway is important in regulating protein signaling pathways that are involved in tumorigenesis. beta-transducin repeat-containing proteins (beta-TrCP) are components of the ubiquitin ligase complex targeting beta-catenin and IkappaBalpha for proteasomal degradation and are thus a negative regulator of Wnt/beta-catenin signaling and a positive regulator of NF-kappaB signaling. We analyzed expression of beta-TrCP in colorectal cancers and its association with types of beta-catenin subcellular localization, an indirect measure of activation.

METHODS

Levels of beta-TrCP1 mRNA and protein were measured by quantitative reverse transcription-polymerase chain reaction and immunoblotting, respectively, in samples of tumor and normal tissues from 45 patients with colorectal cancer. Types of beta-catenin activation (diffuse or invasion edge) and NF-kappaB activation were examined by immunohistochemistry. Apoptosis was determined by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labeling (TUNEL) assay. All statistical tests were two-sided.

RESULTS

Compared with the beta-TrCP1 levels in normal tissues, 25 (56%) of 45 tumors had increased beta-TrCP1 mRNA and protein levels. Of the 22 (49%) tumors with beta-catenin activation, 12 had the diffuse type (i.e., nuclear accumulation throughout the tumor) and 10 had the invasion edge type (i.e., nuclear accumulation predominantly in the tumor cells that formed the invasion edge). Increased beta-TrCP1 levels were statistically significantly associated with beta-catenin activation (P =.023) and decreased apoptosis (P =.035). beta-TrCP accumulated in the nuclei of tumor cells that contained increased levels of beta-TrCP1 mRNA and the active form of NF-kappaB. Higher levels of beta-TrCP1 mRNA were detected in primary tumors of patients who had metastases (0.960 arbitrary units, 95% confidence interval = 0.878 to 1.042) than in the tumors of patients who did not (0.722 arbitrary units, 95% confidence interval = 0.600 to 0.844; P =.016).

CONCLUSION

In colorectal cancer, increased expression of beta-TrCP1 is associated with activation of both beta-catenin and NF-kappaB, suggesting that the integration of these signaling pathways by increased beta-TrCP expression may contribute to an inhibition of apoptosis and tumor metastasis.

beta-Catenin and ras oncogenes detect most human colorectal cancer

PURPOSE AND STUDY DESIGN: Recent studies have shown that beta-catenin translocated into the cell nucleus functions like an oncogene. Accumulating evidence suggests that activation of the beta-catenin oncogenic signaling cascade along with its twin, the K-ras cascade, may exert syngeneic or synergistic effects on tumor development and progression. In the study reported here, we analyzed oncogenic beta-catenin activation on the basis of its nuclear accumulation (NA) and compared the results with those of mutational activation of K-ras in 74 patients with colorectal cancer to determine whether the two oncogene-mediated signaling cascades interact.

RESULTS

We found two distinct patterns of beta-catenin activation, i.e., diffuse NA in 20 cases (27%) and selective NA at the tumor invasion front (NAinv) in 19 cases (26%). The presence of the NAinv pattern was significantly correlated with advanced Dukes' stage tumor (P = 0.0005) and the presence of distant metastases (P = 0.0064). K-ras proto-oncogene was mutated in the tumors of 31 cases (42%). Activated beta-catenin or K-ras was detected in most (78%) colorectal cancers analyzed, although a weak inverse correlation was found between the activities of the two oncogenes in the tumors. Importantly, most (7 of 8) patients with tumor showing both K-ras activation and the NAinv pattern of beta-catenin activation were in Dukes' stage C at surgery, and half of them developed distant metastases to the liver and lungs.

CONCLUSION

The results suggest that although oncogenic activation of beta-catenin and K-ras is independent in the process of clinical cancer development, combined analysis of the two major oncogenes can detect most colorectal cancers and identify a subset of patients with poorer outcomes. Consequently, activation of either or both of these oncogenes may serve as a genetic marker for molecular diagnosis.

Abnormal expression of E-cadherin, beta-catenin, and c-erbB-2 in advanced gastric cancer: its association with liver metastasis

BACKGROUND AND AIMS

We investigated expression of E-cadherin, beta-catenin, and c-erbB-2 in gastric cancer to identify molecular factor(s) relevant to development of liver metastasis, which is a frequent cause of mortality in gastric cancer patients.

PATIENTS AND METHODS

We analyzed by immunohistochemistry and compared expression patterns of E-cadherin, beta-catenin, and c-erbB-2 in the tumor between 40 cases of gastric cancer (GC) without (GC-H(-)) and 16 with concurrent liver metastasis (GC-H(+)).

RESULTS

Loss of E-cadherin expression in the primary tumor was found in 18% of GC-H(-) and in 19% of GC-H(+). Oncogenic beta-catenin activation, represented by its nuclear translocation, was detected in 13% of GC-H(-) and in 31% of GC-H(+). There was no statistical difference in incidence of alteration in these molecules between the two groups of patients. c-erbB-2 overexpression was more frequently observed in GC-H(+) (10/16, 63%) than in GC-H(-) (5/40, 13%) while the distribution of histological types of the tumors was similar in the two groups of patients. This overexpression was also detected in metastatic liver tumors and biopsy specimens in the ten of the former group of patients.

CONCLUSION

Our results strongly suggest a role of activated c-erbB-2 in the process of liver metastasis, and an importance of detection of this overexpression in biopsy specimens to identify GC patients who are at high risk of developing liver metastasis.

Altered expression of beta-catenin and c-erbB-2 in early gastric cancer

To investigate the possible relationship between altered expression (loss of membranous staining or nuclear accumulation) of beta-catenin and invasion/metastasis in early gastric cancer (EGC), beta-catenin was detected immunohistochemically in 116 cases of EGC, including 86 differentiated and 30 undifferentiated carcinomas. In parallel, immunohistochemical expression of c-erbB-2 was analyzed in all EGC cases. Regardless of histological type, altered expression of beta-catenin was found in 47% of mucosal carcinomas and 89% of carcinomas with submucosal invasion (p<0.001). Of particular interest is that beta-catenin alteration was found in almost all EGCs with lymph node metastasis, even though no significant statistical comparison could be made. These results suggest that molecular changes resulting in abnormal beta-catenin expression participate in the process of submucosal invasion and metastasis. While loss of expression was preferentially observed in undifferentiated EGCs, nuclear accumulation was found exclusively in 24% of differentiated EGCs. c-erbB-2 was overexpressed in only 16% of differentiated EGCs but there was no correlation between this overexpression and invasion or metastasis. However, it is intriguing that 12 out of 14 cases with c-erbB-2 overexpression also showed altered beta-catenin expression, suggesting that both molecules are involved in the development of a certain set of differentiated EGCs.