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Characterization of somatostatin receptor expression in human pancreatic cancer using real-time RT-PCR
ASSOCIATION FOR ACADEMIC SURGERY—ABSTRACTS tive RT-PCR. Serum levels of C-reactive protein and histopathology of colon tissue were evaluated. Results: Expression of PAP is minimal in normal colon. PAP I expression in colon was dramatically upregulated by 22.0 ⫾ 1.2-fold at seven days after induction of inflammation when compared to untreated control group. Our time course results show that PAP I mRNA levels initially decreased at day one (by 4.2 fold), peaked at day seven (22.0 fold), and declined to baseline by day fourteen when compared to untreated control (p ⬍ 0.05 for day 1 and day 7). Similar changes in PAP II gene regulation were also observed. Serum C-reactive protein levels, increased from 1.73 ⫾ 0.2 mg/dL at day one to 2.36 ⫾ 0.21 mg/dL at day seven (p ⬍ 0.05). Changes in expression of PAP I corresponded to changes in serum C-reactive protein levels. Both PAP I expression and C-reactive protein levels decreased at day one, peaked at day seven, and dropped back to baseline at day fourteen when compared to untreated control group. Histopathological evaluation showed extensive intestinal wall damage characterized by epithelial exfoliation, mucosal hemorrhage, submucosal infiltration with leukocytes and transmural edema at day 7. Conclusion: Transcriptional profiling of PAP gene expression identified that it is highly upregulated in a rat model of chronic IBD. Significant changes in PAP expression, that parallel changes of CRP levels, indicate physiological relevance of PAP to inflammatory processes in the colon. P63. Characterization of Somatostatin Receptor Expression in Human Pancreatic Cancer Using Real-Time RT-PCR. M. Li, MD, Q. Yao, C. Chen, W.E. Fisher, MD. Baylor College of Medicine. Background: Somatostatin inhibits cell proliferation and may act as a tumor suppressor by interacting with five different somatostatin receptors (SSTRs). We hypothesized that SSTR expression is down regulated in human pancreatic cancer. In the present study, we used a powerful real-time RT-PCR technique to examine the mRNA expression levels of all five SSTR subtypes in human pancreatic cancer. Methods: Total RNA was extracted from three pancreatic cancer cell lines (MIA PaCa-2, Panc-1, and HS766T), three surgical specimens of pancreatic cancer, and adjacent pancreatic tissue, and a pancreatic cancer cell line transfected with the sstr2 gene. Specific primers were designed and mRNA levels for the five SSTRs were analyzed with real-time quantitative RT-PCR using a Bio-Rad iCycler system. The presence of SSTR receptor protein was determined by a competitive binding assay. The proliferative response to somatostatin in pancreatic cancer cell lines was analyzed by incorporation of [ 3H]-thymidine. Results: The pancreatic tumor specimens had a 2.5 and 4.3 fold reduction of SSTR2 and SSTR5 mRNA levels, respectively, as compared to their adjacent pancreatic tissues. SSTR1 and SSTR3 were also detected in both the cancer specimens and adjacent tissues, but SSTR4 was absent. Human pancreatic cancer cell lines also expressed SSTR2 and SSTR5 mRNA, but not SSTR1, SSTR3, and SSTR4. SSTR receptor protein and inhibition of cell proliferation was demonstrated only in wild type MiaPaCa-2 cells. Up regulation of SSTR2 mRNA by 2.2 ⫻ 10 4 fold in Panc-1 cells resulted in receptor expression and growth inhibition. Conclusion: Expression of SSTR2 and SSTR5 could be important in the growth inhibitory effect of somatostatin in human pancreatic cancer. Down regulation of SSTR transcription or SSTR mRNA instability may result in loss of a tumor suppressive effect of SSTRs in human pancreatic cancer.
EDUCATION/CLINICAL TRIALS ORAL POSTER SESSION P64. Are Survival Rates Different for Young and Old Patients with Rectal Cancer? J.B. O’Connell, M.D., M. A. Maggard, M.D., D. A. Etzioni, M.D., J. H. Liu, M.D., C. Y. Ko, M.D., M.S.H.S., M.S. David Geffen School of Medicine at UCLA.
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Introduction: While it is generally believed that young patients with rectal cancer may have worse overall and stage-specific survival, no comprehensive analysis has been reported. Nearly all studies to date have reported the experiences of single institutions and may not be representative of the population. This study uses a national level population-based cancer registry to compare rectal cancer outcomes between the young versus older population. Methods: All patients with rectal carcinoma in the SEER cancer database from 1991–1999 were evaluated. A young group (20 – 40 y/o, n ⫽ 466) and an older group (60 – 80 y/o, n ⫽ 11,312) were compared for patient and tumor characteristics, patterns of treatment, and 5-year overall and stage-specific survival. Multivariate Cox regression analysis was performed to predict hazard ratios for death. Results: Mean ages for the groups were 34.1 and 70.0 years; 60% were male (in both groups). The young group was comprised of fewer white, more black, and more Hispanic patients as compared to the older group (p ⬍ 0.001). Young patients presented with less stage I disease (17% vs. 23.7%, p ⬍ 0.001), and more stage III (27% vs. 20%, p ⬍ 0.001) and stage IV disease (17% vs. 13%, p ⬍ 0.02). The younger group also had worse grade tumors (poorly differentiated, 31% vs. 17%, p ⬍ 0.001). While 85% of both groups received surgical treatment, a significantly higher proportion of younger patients received appropriate stagerelated radiation treatment (p ⬍ 0.001). Importantly, while the overall 5-year survival was significantly worse for the young group, no differences in stage-specific 5-year survival rates were identified between the young as compare to the older group (Table 1). Conclusions: This study demonstrates that young rectal cancer patients have poorer overall survival, but equivalent stage-for-stage survival. The observed difference in overall survival is likely due to the finding that younger patients present with more advanced stage disease. Future studies should continue to use data that is representative of the population when performing these types of epidemiologic and outcomes-related analyses. P65. The Incidence of Bone Marrow Circulating Tumour Cells in Breast Cancer Patients is Directly Related to the Size of the Primary Tumour. M. A. Kelly, N. Relihan, K. C. Redmond, N. J. Aherne, J. H. Wang, J. Kelly, D. Richardson, D. O’Hanlon, H. P. Redmond, M.B., B.A.O., B.C.H., Fr.Cs.I. Department of Academic Surgery. Introduction: Metastatic spread of tumours is the most important factor affecting cancer mortality rates. There is, as yet, little scientific research supporting the development of overt metastatic disease from subclinical micrometastatic deposits. We conducted a prospective study investigating the incidence of circulating tumour cells in patients with breast carcinoma. Methods: Pre-operatively, each patient underwent bone marrow aspiration from right rib and bilateral iliac crests. The mononuclear cell layer was isolated using the Ficoll-Paque density centrifugation technique. The cells were stained with both a membrane bound epithelial marker (HEA) and an intracellular marker (MNF116) and analysed using Flow Cytometry. IgG1 FITC (DAKO) was used as a control. Results: From July 2001 to May 2003, 60 patients undergoing definitive surgery for breast carcinoma were enrolled. Tumour size ranged from 1 cm to 4.8 cm. Bone marrow aspiration was successful in all patients. Circulating tumour cells were detected in 46 patients. Tumours less that 2.5 cm had an average of 5.9% HEA positive cells while those greater than 2.5 cm had an average of 19.9%. (p ⬍ 0.05) Conclusion: We have demonstrated that the size of the primary tumour is directly related to the incidence of circulating tumour cells found in bone marrow. We conclude that this may contribute to the poor prognosis associated with larger tumours in patients with breast carcinoma. P66. Palliation for Advanced Pancreatic Cancer: An Analysis of Cost and Clinical Outcome. M. M. Mortenson, M.D., H. S. Ho, M.D., R. J. Bold, M.D. University of California, Davis.
EDUCATION/CLINICAL TRIALS ORAL POSTER SESSION P64. Are Survival Rates Different for Young and Old Patients with Rectal Cancer? J.B. O’Connell, M.D., M. A. Maggard, M.D., D. A. Etzioni, M.D., J. H. Liu, M.D., C. Y. Ko, M.D., M.S.H.S., M.S. David Geffen School of Medicine at UCLA.
293
Introduction: While it is generally believed that young patients with rectal cancer may have worse overall and stage-specific survival, no comprehensive analysis has been reported. Nearly all studies to date have reported the experiences of single institutions and may not be representative of the population. This study uses a national level population-based cancer registry to compare rectal cancer outcomes between the young versus older population. Methods: All patients with rectal carcinoma in the SEER cancer database from 1991–1999 were evaluated. A young group (20 – 40 y/o, n ⫽ 466) and an older group (60 – 80 y/o, n ⫽ 11,312) were compared for patient and tumor characteristics, patterns of treatment, and 5-year overall and stage-specific survival. Multivariate Cox regression analysis was performed to predict hazard ratios for death. Results: Mean ages for the groups were 34.1 and 70.0 years; 60% were male (in both groups). The young group was comprised of fewer white, more black, and more Hispanic patients as compared to the older group (p ⬍ 0.001). Young patients presented with less stage I disease (17% vs. 23.7%, p ⬍ 0.001), and more stage III (27% vs. 20%, p ⬍ 0.001) and stage IV disease (17% vs. 13%, p ⬍ 0.02). The younger group also had worse grade tumors (poorly differentiated, 31% vs. 17%, p ⬍ 0.001). While 85% of both groups received surgical treatment, a significantly higher proportion of younger patients received appropriate stagerelated radiation treatment (p ⬍ 0.001). Importantly, while the overall 5-year survival was significantly worse for the young group, no differences in stage-specific 5-year survival rates were identified between the young as compare to the older group (Table 1). Conclusions: This study demonstrates that young rectal cancer patients have poorer overall survival, but equivalent stage-for-stage survival. The observed difference in overall survival is likely due to the finding that younger patients present with more advanced stage disease. Future studies should continue to use data that is representative of the population when performing these types of epidemiologic and outcomes-related analyses. P65. The Incidence of Bone Marrow Circulating Tumour Cells in Breast Cancer Patients is Directly Related to the Size of the Primary Tumour. M. A. Kelly, N. Relihan, K. C. Redmond, N. J. Aherne, J. H. Wang, J. Kelly, D. Richardson, D. O’Hanlon, H. P. Redmond, M.B., B.A.O., B.C.H., Fr.Cs.I. Department of Academic Surgery. Introduction: Metastatic spread of tumours is the most important factor affecting cancer mortality rates. There is, as yet, little scientific research supporting the development of overt metastatic disease from subclinical micrometastatic deposits. We conducted a prospective study investigating the incidence of circulating tumour cells in patients with breast carcinoma. Methods: Pre-operatively, each patient underwent bone marrow aspiration from right rib and bilateral iliac crests. The mononuclear cell layer was isolated using the Ficoll-Paque density centrifugation technique. The cells were stained with both a membrane bound epithelial marker (HEA) and an intracellular marker (MNF116) and analysed using Flow Cytometry. IgG1 FITC (DAKO) was used as a control. Results: From July 2001 to May 2003, 60 patients undergoing definitive surgery for breast carcinoma were enrolled. Tumour size ranged from 1 cm to 4.8 cm. Bone marrow aspiration was successful in all patients. Circulating tumour cells were detected in 46 patients. Tumours less that 2.5 cm had an average of 5.9% HEA positive cells while those greater than 2.5 cm had an average of 19.9%. (p ⬍ 0.05) Conclusion: We have demonstrated that the size of the primary tumour is directly related to the incidence of circulating tumour cells found in bone marrow. We conclude that this may contribute to the poor prognosis associated with larger tumours in patients with breast carcinoma. P66. Palliation for Advanced Pancreatic Cancer: An Analysis of Cost and Clinical Outcome. M. M. Mortenson, M.D., H. S. Ho, M.D., R. J. Bold, M.D. University of California, Davis.