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Peritumoral Fibroblast SPARC Expression and Patient Outcome With Resectable Pancreatic Adenocarcinoma

Jeffrey R. Infante, Hiroyuki Matsubayashi, Norihiro Sato, James Tonascia, Alison P. Klein, Taylor A. Riall, Charles Yeo, Christine Iacobuzio-Donahue, Michael Goggins

From the Departments of Pathology, Oncology, and Medicine, Surgery and Epidemiology and Biostatistics, and The Sol Goldman Pancreatic Research Center, The Johns Hopkins Medical Institutions, Baltimore, MD

Address reprint requests to Michael Goggins, MD, Departments of Pathology, Medicine, and Oncology, The Sol Goldman Pancreatic Cancer Research Center, The Johns Hopkins Medical Institutions, 1550 Orleans St, Baltimore, MD 21205; e-mail: mgoggins{at}jhmi.edu

	ABSTRACT

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PURPOSE: SPARC (secreted protein acidic and rich in cysteine) is a protein involved in cell matrix interactions, wound repair, and cell migration, and has been reported to inhibit cancer growth. SPARC undergoes epigenetic silencing in many pancreatic cancers, but stromal fibroblasts adjacent to infiltrating pancreatic adenocarcinomas frequently express SPARC. We evaluated the prognostic significance of tumor and peritumoral SPARC expression in patients with pancreatic adenocarcinoma.

PATIENTS AND METHODS: The expression patterns of SPARC were characterized by immunohistochemistry in 299 primary pancreatic ductal adenocarcinoma resection specimens from patients who underwent pancreaticoduodenectomy at Johns Hopkins Hospital (Baltimore, MD) between 1998 and 2003. Kaplan-Meier analysis and Cox proportional hazards regression modeling were used to assess the mortality risk associated with the presence or absence of tumor SPARC and peritumoral SPARC status.

RESULTS: By Kaplan-Meier analysis, patients whose pancreatic cancer stromal fibroblasts expressed SPARC (median survival, 15 months) had a significantly worse prognosis than patients whose tumor stroma did not express SPARC (median survival, 30 months; log-rank P < .001). In contrast, the expression of SPARC in pancreatic cancer cells was not associated with prognosis (log-rank P = .13). Controlling for other prognostic factors (tumor size, positive lymph nodes, margin status, tumor grade, and age), the relative hazard for patients whose stroma expressed SPARC compared with those whose stroma did not was 1.89 (95% CI, 1.31 to 2.74); the expression of SPARC in pancreatic cancer cells remained unrelated to prognosis (relative hazard, 1.02; 95% CI, 0.73 to 1.42).

CONCLUSION: The expression of SPARC by peritumoral fibroblasts portends a poorer prognosis for patients with pancreatic cancer.

	INTRODUCTION

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Pancreatic ductal adenocarcinoma is the fourth most common cause of death and remains one of the most lethal human cancers.¹ Approximately 85% of patients present with advanced unresectable disease,² and because pancreatic cancer remains extremely resistant to standard cytotoxic and targeted chemotherapies, median survival after diagnosis for these patients is only approximately 6 months. Survival is significantly better for patients with pancreatic cancers localized to the pancreas and its regional lymph nodes, for whom surgical resection at present offers the only likely chance of cure. For patients with resectable ductal adenocarcinoma of the head of the pancreas, the 5-year overall survival rate is approximately 20% to 25%.³ Clinicopathologic parameters provide some prognostic information. Tumor diameter more than 2.5 to 3.0 cm, positive lymph nodes, positive margins, and poor differentiation are all features that have been associated consistently with a worse prognosis.^3,4

Numerous genetic and epigenetic alterations occur during the development of pancreatic adenocarcinoma. As our understanding of the molecular and genetic changes that lead to pancreatic neoplasia has grown, so has our hope that markers would be identified that better predict tumor behavior and the response to rational therapies.

Several studies have investigated whether genetic changes important for pancreatic cancer development influence prognosis.⁵ Most pancreatic adenocarcinomas mutationally activate K-ras (approximately 90%), and inactivate p16 genetically or epigenetically (> 95%), suggesting that their prognostic ability, if any, would apply to few individuals. SMAD4/DPC4 is genetically inactivated in approximately 55% of pancreatic ductal adenocarcinomas. Other components of the transforming growth factor beta/SMAD4 pathway are rarely mutated in pancreatic cancers. SMAD4 protein expression reliably predicts SMAD4 genetic status and has been used to evaluate the prognostic role of SMAD4 inactivation among patients undergoing pancreatic resection for pancreatic cancer, but conflicting results have been reported.^6,7

Epigenetic changes are thought to contribute to the development and progression of pancreatic neoplasia including promoter methylation and silencing of genes such as SPARC, RELN, TFPI-2, p16 and occasionally, hMLH1, p14,^8-11 and others.^12,13 SPARC (secreted protein acidic and rich in cysteine, or osteonectin/BM40) is a calcium-binding protein that interacts with an extracellular matrix. SPARC influences cell migration,¹⁴ proliferation, angiogenesis (especially during wound healing), matrix cell adhesion, and tissue remodeling. SPARC is expressed during embryogenesis, in bone, and in platelets, and is a marker of activated fibroblasts.¹⁵ SPARC-knockout mice grow cancers faster than mice expressing SPARC,^16,17 highlighting its growth-inhibitory functions. SPARC expression is often lost in pancreatic cancer cells through aberrant DNA methylation, but juxta-tumoral fibroblasts often express SPARC.¹⁰ These findings suggest that SPARC's role in tumorigenesis may be complex. Indeed, SPARC was identified as a pancreatic cancer invasion-specific gene through serial analysis of gene expression.¹⁸ Increased SPARC expression has been described in multiple cancers, including colon, esophagus,¹⁹ pancreas,¹⁰ breast,²⁰ lung,²¹ brain, bladder,²² renal cell,²³ and melanoma. SPARC may help facilitate metastasis by increasing the migration and invasion capacity of prostate and breast cancer cells in vitro.^24,25 SPARC overexpression has been associated with poor prognosis,^{19,20,22,26,27} but these studies often did not specify whether they evaluated cancer cell or stromal SPARC expression.

In this study, we evaluated the prognostic significance of SPARC expression in pancreatic cancer cells and tumor stroma in a large cohort of patients who underwent pancreaticoduodenectomy for pancreatic ductal adenocarcinoma using a multivariate model that included the clinicopathologic parameters shown previously to influence the prognosis of patients with pancreatic ductal adenocarcinomas.

	PATIENTS AND METHODS

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Patients and Study Design
We included a cohort of 299 patients with resectable infiltrating adenocarcinoma of the pancreas who underwent pancreaticoduodenectomy at Johns Hopkins Hospital (Baltimore, MD) between January 2, 1998, and July 25, 2003. Because the natural history for variant pancreatic neoplasms differs from usual pancreatic ductal adenocarcinoma, patients with intraductal papillary mucinous neoplasms, mucinous cystic adenocarcinomas, and medullary adenocarcinomas were excluded. Patients were also excluded if gross metastatic or unresectable disease beyond the Whipple margins was found at the time of surgery.

All clinical and pathologic patient information is maintained in a regularly updated clinical database. The primary outcome of the study was overall survival as determined from date of Whipple resection to the time of death or last follow-up. Patients, their families, or their primary physicians are contacted by postcard at least annually to confirm patient status, with the last observation recorded in March 2004. This study was conducted as part of a Johns Hopkins Hospital institutional review board–approved protocol.

Immunohistochemistry
Formalin-fixed, paraffin-embedded blocks of tumor tissue from each patient were analyzed using tissue microarrays, as described previously.¹¹ Immunohistochemical analysis was performed as described previously.^6,10,28 The monoclonal anti-SPARC antibody (clone ON1-1) was from Zymed Laboratories Inc (San Francisco, CA). Sections were incubated for 60 minutes with the anti-SPARC monoclonal antibody (final concentration, 4 µg/mL). Sections were incubated for 60 minutes with the anti-SMAD4 monoclonal antibody (clone B-8; Santa Cruz Biotechnology, San Francisco, CA) after a dilution of 1:100. Labeling for both markers was carried out in accordance with the manufacturer's protocol using the Envision Plus Detection Kit (DAKO, Carpinteria, CA). Nuclei were counterstained with hematoxylin.

As in previous studies,¹⁰ immunolabeling of the markers was scored by authors blinded to the outcome (H.M., J.I, and C.I.). SPARC immunolabeling was categorized as negative when the intensity was absent to weak (+) and the extent was less than 10%. Immunolabeling was positive if the intensity was moderate (++), to strong (+++), and the extent was 10%. SPARC was categorized as positive or negative for both the carcinoma and the normal juxta-tumoral pancreas tissue: tumor negative/stroma negative, tumor positive/stroma negative, tumor negative/stroma positive, and tumor positive/stroma positive. Scoring of SMAD4/DPC4 labeling was determined by three authors (J.I., C.I., and M.G.) with agreement in all cases. As in previous studies,^6,28 neoplastic cells were positive when staining was diffuse and comparable to the surrounding normal pancreas, and negative if there was complete absence of SMAD4 labeling, a barely detectable labeling (trace positive), or when two populations of cells existed, one that labeled and one that did not (focal positive).

Statistical Analysis
Time-to-event analysis was performed measuring overall survival from the date of surgery to the time of last follow-up or death. Censoring occurred if patients were still alive at last follow-up, with a maximum follow-up of 60 months. For comparison of baseline characteristics across groups, two-sided Fisher's exact tests for row-by-column (r-by-c) tables for categoric and analysis of variance for continuous characteristics were used. P values for comparisons of Kaplan-Meier survival curves refer to log-rank tests. Cox proportional hazards regression models were used to control for the following patient features: tumor size 3 cm versus less than 3 cm, positive versus negative margins, positive versus negative nodes, poorly versus well to moderately differentiated, and positive versus negative SMAD4/DPC4 expression; age (analyzed both as a continuous variable and as three categories (younger than 60, 60 to 70, and older than 70 years); and positive adjuvant therapy (defined as any known postoperative therapy (chemotherapy alone, radiation alone, or combined chemoradiation). STATA version 8.2 (STATA Corp, College Station, TX) was used for all statistical analyses.

	RESULTS

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Patient Characteristics
The median survival of patients in this cohort was 17 months, and approximately 20% of patients were alive at 5 years, similar to previous 5-year survival figures reported for patients after Whipple resection.^3,6 Most patients in our series had cancers with adverse risk factors (Table 1).

View larger version (147K): [in this window] [in a new window] [PowerPoint Slide for Teaching]   Fig 1. Patterns of immunohistochemical expression of SPARC in pancreatic ductal adenocarcinomas. (A) Cancer SPARC expression negative, stromal expression negative; (B) cancer SPARC expression positive, stromal expression negative; (C) cancer SPARC expression negative, stromal expression positive; and (D) cancer SPARC expression positive, stromal expression positive.

View larger version (19K): [in this window] [in a new window] [PowerPoint Slide for Teaching]   Fig 2. Kaplan-Meier survival curves for patients with pancreatic ductal adenocarcinoma after pancreaticoduodenectomy stratified by their tumor and stromal SPARC status.

Immunolabeling for SMAD4 was also performed on the entire cohort in an effort to determine if the prognostic value of SPARC expression was related to SMAD4 status. A previous study found SPARC expression is repressed by SMAD4.²⁹ In addition, SMAD4 status has been reported to be associated with pancreas cancer mortality. We found loss of SMAD4 expression in 150 of 261 (55%) patients. Thirty-seven cancers were unavailable for SMAD4 analysis due to inadequate staining or insufficient tissue. SMAD4 expression was not associated with tumor size, nodal status, margin status, differentiation status, adjuvant therapy status, patient age, or the amount of intraoperative blood loss. By univariate analysis, the hazard ratio for SMAD4-expressing cancers was 1.07 (95% CI, 0.78 to 1.48) compared with cancers lacking SMAD4 expression. As measured by a two-sided Fisher's exact test, intratumor (P = .39) and stromal (P = .66) SPARC expression was not associated with SMAD4 loss. Stromal SPARC expression remained significantly associated with mortality (hazard ratio, 2.19; 95% CI, 1.51 to 3.14) after SMAD4 expression was added to the model.

In the multivariable regression model based on all 299 patients in our cohort, the adjusted Cox proportional hazards regression for patients whose cancer stroma expressed SPARC was 1.89 (95% CI, 1.31 to 2.74) compared with patients whose stroma did not express SPARC (Table 3). In the multivariable model, increased tumor size, positive lymph nodes, positive margins, increased tumor grade, and older age all independently and significantly increased mortality.

View larger version (22K): [in this window] [in a new window] [PowerPoint Slide for Teaching]   Fig 3. Kaplan-Meier survival curves for patients with pancreatic ductal adenocarcinoma after pancreaticoduodenectomy stratified by their stromal SPARC and tumor grade. RR, relative risk.

	DISCUSSION

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Although there is a possibility of bias associated with retrospective studies, our study is strengthened by the large number of patients accrued over a relatively short time span (5.5 years). The point estimates in the multivariable Cox proportional hazards models suggest that stromal SPARC expression may be as significant a marker in outcome as common clinical parameters, including positive margins, lymphatic spread, and tumor size. When comparing the baseline characteristics of the cohort, SPARC status was only associated with histologic grade; however, SPARC remained independently prognostic in the multivariable models. A Kaplan-Meier subgroup analysis examining stromal SPARC expression with histologic grade strongly suggests a differential effect of stromal SPARC on survival, depending on the histologic grade of the tumor. The only cohort with a good prognosis after a Whipple procedure (4-year survival, approximately 60%) included patients with well or moderately differentiated cancers whose stromal fibroblasts did not express SPARC. Patients with poorly differentiated cancers had a uniformly poor prognosis (regardless of SPARC expression). However, patients with well or moderately differentiated cancers whose stromal fibroblasts expressed SPARC also had a poor prognosis.

Our evaluation of SPARC applied to patients with resectable pancreatic ductal adenocarcinomas. Whether SPARC status is important in patients with unresectable disease is not known. In theory, molecular markers such as SPARC status could be used before surgical resection to inform clinical decision making, but until better therapies are available, all patients with resectable pancreatic cancer are best considered for surgical resection irrespective of molecular marker status. Furthermore, a preoperative evaluation of stromal versus tumor cell SPARC expression would require Tru-cut biopsy of the pancreatic tumor. Although preliminary studies indicate that such biopsies are technically feasible and can add diagnostic information,³⁰ larger studies are needed to evaluate their safety and utility.

The clinical benefit of adjuvant chemotherapy and radiation for patients with pancreatic adenocarcinoma remains controversial. In this study, adjuvant therapy was stratified into those who received chemotherapy alone, radiation therapy alone, or combined-modality therapy. Information on the dose and duration associated with these therapies was unavailable. In addition, 122 of the patients in our cohort were labeled as unknown with respect to whether they received adjuvant therapy. In our study, we were not able to address the question of whether adjuvant therapy improves overall survival. By comparing hazards in those who were known to have received adjuvant therapy with the entire cohort, we were able to make sure that this did not affect our relationship between SPARC and survival.

Our current results also suggest SMAD4 status is not a prognostic marker for pancreatic adenocarcinoma. Previous studies suggested that SMAD4 loss was associated with both a worse⁶ and improved prognosis.⁷ The few differences in the design of the current and previous study likely do not explain the different results in the two studies. In the original study, the point estimate describing the worse prognosis associated with SMAD4 loss was modest (1.36; 95% CI, 1.01 to 1.83),⁶ and could have occurred by chance. Our previous report used full tissue sections, and this study used tissue microarrays, but this is not likely to explain the different study results. Tissue microarray analyses have been shown to reflect analysis of full-thickness sections³¹ and the proportion of cancers with SMAD4 loss was 55% in the current study, which was similar to the previous report (58%).

Our study complements other observations suggesting that the neighboring stroma may play an important role in the phenotypic behavior of a malignancy. West et al³² confirmed that the host stromal response varies significantly among carcinomas. Using the gene expression profiles seen in solitary fibrous tumor and desmoid-type fibromatosis, they suggested that there may be distinct stromal reactions in breast cancer. Koukourakis et al³³ found a strong association between stromal SPARC expression and outcome in patients with non–small-cell lung cancer. Normal lung did not express SPARC, and intratumoral expression of SPARC was rare (4% of patients), but in approximately 72% of the cancers, peritumoral stroma expressed SPARC, mirroring our results in pancreatic cancer. Jones et al³⁴ demonstrated that SPARC expression in myoepithelial cells compared with luminal cells of breast cancers conferred a worse prognosis, although only approximately 5% of breast cancers expressed SPARC.

The mechanism by which stromal SPARC expression portends a worse prognosis is not known. We did not find a correlation between intratumoral SPARC expression and stromal SPARC expression. Although SMAD4 has been reported to influence SPARC expression, we did not find differences in SPARC expression by SMAD4 status. We believe the most likely explanation for our findings is that peritumoral fibroblast SPARC expression is a marker of activated fibroblasts. We hypothesize that activated peritumoral fibroblasts portend a significantly poor patient prognosis, by mechanisms not yet understood. Recent studies have also demonstrated that a wound-like response of fibroblasts in breast, gastric, and lung cancers is associated with a poor outcome.³⁵ Interestingly, recent studies have identified differences in the epigenetic profiles of normal stromal fibroblasts and fibroblasts associated with breast carcinomas.³⁶ A combination of both tumor-derived and host-derived factors are likely to be responsible for the activated fibroblast response to infiltrating carcinoma.

SPARC could be a potential target for antineoplastic therapy. Watkins et al³⁷ suggested that -Linolenic acid can potentially regulate SPARC expression and secretion. Tai et al³⁸ restored sensitivity to fluorouracil and irinotecan and to radiation by re-expressing SPARC in tumor xenografts of modified cell lines. ABI-007 (Abraxane; Abraxis Oncology, Los Angeles, CA) is an albumin-bound 130-nm particle form of paclitaxel, the uptake of which into cells may be dependant on SPARC expression.^39-42

The prognostic influence of stromal behavior seen in our study suggests there may be a need for therapeutic efforts that not only target tumor cells, but that also target the juxta-tumoral stroma cells that provide the supportive microenvironment. Given that cancer cells undergo clonal evolution independent of stromal cells, the therapeutic targets of stromal cells will be different from those in cancer cells. Given the success of compounds that target the tumor microenvironment such as bevacizumab and sunitinib,^43-45 it is not unreasonable to hope that agents that target the activated fibroblast component of the tumor microenvironment may improve patient outcome.

In summary, stromal SPARC expression is a marker of poor prognosis, independent of common clinical parameters including tumor size, margin status, and lymph node metastasis. The mechanisms that confer this malignant phenotype warrant additional study.

	AUTHORS' DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST

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The authors indicated no potential conflicts of interest.

	AUTHOR CONTRIBUTIONS

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Conception and design: Jeffrey R. Infante, Hiroyuki Matsubayashi, Michael Goggins

Financial support: Michael Goggins

Administrative support: Michael Goggins

Provision of study materials or patients: Taylor A. Riall, Charles Yeo, Michael Goggins

Collection and assembly of data: Jeffrey R. Infante, Hiroyuki Matsubayashi, Norihiro Sato, Taylor A. Riall, Charles Yeo, Christine Iacobuzio-Donahue, Michael Goggins

Data analysis and interpretation: Jeffrey R. Infante, Hiroyuki Matsubayashi, James Tonascia, Alison P. Klein, Christine Iacobuzio-Donahue, Michael Goggins

Manuscript writing: Jeffrey R. Infante, James Tonascia, Michael Goggins

Final approval of manuscript: Michael Goggins

	NOTES

 
Supported by Grants No. CA90709 and CA62924 from the National Cancer Institute, and the Michael Rolfe Foundation.

Authors' disclosures of potential conflicts of interest and author contributions are found at the end of this article.

	REFERENCES

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1. Jemal A, Murray T, Ward E, et al: Cancer statistics, 2005. CA Cancer J Clin 55:10-30, 2005[Abstract/Free Full Text]

2. Lowenfels AB, Maisonneuve P, DiMagno EP, et al: Hereditary pancreatitis and the risk of pancreatic cancer: International Hereditary Pancreatitis Study Group. J Natl Cancer Inst 89:442-446, 1997[Abstract/Free Full Text]

3. Sohn TA, Yeo CJ, Cameron JL, et al: Resected adenocarcinoma of the pancreas-616 patients: Results, outcomes, and prognostic indicators. J Gastrointest Surg 4:567-579, 2000[CrossRef][Medline]

4. Geer RJ, Brennan MF: Prognostic indicators for survival after resection of pancreatic adenocarcinoma. Am J Surg 165:68-73, 1993[CrossRef][Medline]

5. Hruban RH, Goggins M, Parsons J, et al: Progression model for pancreatic cancer. Clin Cancer Res 6:2969-2972, 2000[Free Full Text]

6. Tascilar M, Skinner HG, Rosty C, et al: The SMAD4 protein and prognosis of pancreatic ductal adenocarcinoma. Clin Cancer Res 7:4115-4121, 2001[Abstract/Free Full Text]

7. Biankin AV, Morey AL, Lee CS, et al: DPC4/Smad4 expression and outcome in pancreatic ductal adenocarcinoma. J Clin Oncol 20:4531-4542, 2002[Abstract/Free Full Text]

8. Ueki T, Toyota M, Sohn T, et al: Hypermethylation of multiple genes in pancreatic adenocarcinoma. Cancer Res 60:1835-1839, 2000[Abstract/Free Full Text]

9. Sato N, Parker AR, Fukushima N, et al: Epigenetic inactivation of TFPI-2 as a common mechanism associated with growth and invasion of pancreatic ductal adenocarcinoma. Oncogene 24:850, 2004

10. Sato N, Fukushima N, Maehara N, et al: SPARC/osteonectin is a frequent target for aberrant methylation in pancreatic adenocarcinoma and a mediator of tumor-stromal interactions. Oncogene 22:5021-5030, 2003[CrossRef][Medline]

11. Sato N, Fukushima N, Chang R, et al: Differential and epigenetic gene expression profiling identifies frequent disruption of the RELN pathway in pancreatic cancers. Gastroenterology 130:548-565, 2006[CrossRef]

12. Sato N, Goggins M: Epigenetic alterations in intraductal papillary mucinous neoplasms of the pancreas. J Hepatobiliary Pancreat Surg 13:280-285, 2006[CrossRef][Medline]

13. Sato N, Goggins M: The role of epigenetic alterations in pancreatic cancer. J Hepatobiliary Pancreat Surg 13:286-295, 2006[CrossRef][Medline]

14. Funk SE, Sage EH: The Ca2(+)-binding glycoprotein SPARC modulates cell cycle progression in bovine aortic endothelial cells. Proc Natl Acad Sci U S A 88:2648-2652, 1991[Abstract/Free Full Text]

15. Kalluri R, Zeisberg M: Fibroblasts in cancer. Nat Rev Cancer 6:392-401, 2006[CrossRef][Medline]

16. Puolakkainen PA, Brekken RA, Muneer S, et al: Enhanced growth of pancreatic tumors in SPARC-null mice is associated with decreased deposition of extracellular matrix and reduced tumor cell apoptosis. Mol Cancer Res 2:215-224, 2004[Abstract/Free Full Text]

17. Brekken RA, Puolakkainen P, Graves DC, et al: Enhanced growth of tumors in SPARC null mice is associated with changes in the ECM. J Clin Invest 111:487-495, 2003[CrossRef][Medline]

18. Ryu B, Jones J, Hollingsworth MA, et al: Invasion-specific genes in malignancy: Serial analysis of gene expression comparisons of primary and passaged cancers. Cancer Res 61:1833-1838, 2001[Abstract/Free Full Text]

19. Yamashita K, Upadhay S, Mimori K, et al: Clinical significance of secreted protein acidic and rich in cysteine in esophageal carcinoma and its relation to carcinoma progression. Cancer 97:2412-2419, 2003[CrossRef][Medline]

20. Watkins G, Douglas-Jones A, Bryce R, et al: Increased levels of SPARC (osteonectin) in human breast cancer tissues and its association with clinical outcomes. Prostaglandins Leukot Essent Fatty Acids 72:267-272, 2005[CrossRef][Medline]

21. Piao CQ, Liu L, Zhao YL, et al: Immortalization of human small airway epithelial cells by ectopic expression of telomerase. Carcinogenesis 26:725-731, 2005[Abstract/Free Full Text]

22. Yamanaka M, Kanda K, Li NC, et al: Analysis of the gene expression of SPARC and its prognostic value for bladder cancer. J Urol 166:2495-2499, 2001[CrossRef][Medline]

23. Uehara H, Nakaizumi A, Tatsuta M, et al: Diagnosis of pancreatic cancer by detecting telomerase activity in pancreatic juice: Comparison with K-ras mutations. Am J Gastroenterol 94:2513-2518, 1999[CrossRef][Medline]

24. Jacob K, Webber M, Benayahu D, et al: Osteonectin promotes prostate cancer cell migration and invasion: A possible mechanism for metastasis to bone. Cancer Res 59:4453-4457, 1999[Abstract/Free Full Text]

25. Briggs J, Chamboredon S, Castellazzi M, et al: Transcriptional upregulation of SPARC, in response to c-Jun overexpression, contributes to increased motility and invasion of MCF7 breast cancer cells. Oncogene 21:7077-7091, 2002[CrossRef][Medline]

26. Handrich SJ, Hough DM, Fletcher JG, et al: The natural history of the incidentally discovered small simple pancreatic cyst: Long-term follow-up and clinical implications. AJR Am J Roentgenol 184:20-23, 2005[Abstract/Free Full Text]

27. Wang CS, Lin KH, Chen SL, et al: Overexpression of SPARC gene in human gastric carcinoma and its clinic-pathologic significance. Br J Cancer 91:1924-1930, 2004[CrossRef][Medline]

28. Wilentz RE, Su GH, Dai JL, et al: Immunohistochemical labeling for dpc4 mirrors genetic status in pancreatic adenocarcinomas: A new marker of DPC4 inactivation. Am J Pathol 156:37-43, 2000[Abstract/Free Full Text]

29. Volmer MW, Radacz Y, Hahn SA, et al: Tumor suppressor Smad4 mediates downregulation of the anti-adhesive invasion-promoting matricellular protein SPARC: Landscaping activity of Smad4 as revealed by a secretome analysis. Proteomics 4:1324-1334, 2004[CrossRef][Medline]

30. Levy MJ, Smyrk TC, Reddy RP, et al: Endoscopic ultrasound-guided trucut biopsy of the cyst wall for diagnosing cystic pancreatic tumors. Clin Gastroenterol Hepatol 3:974-979, 2005[CrossRef][Medline]

31. Maitra A, Adsay NV, Argani P, et al: Multicomponent analysis of the pancreatic adenocarcinoma progression model using a pancreatic intraepithelial neoplasia tissue microarray. Mod Pathol 16:902-912, 2003[CrossRef][Medline]

32. West RB, Nuyten DS, Subramanian S, et al: Determination of stromal signatures in breast carcinoma. PLoS Biol 3:e187, 2005[CrossRef][Medline]

33. Koukourakis MI, Giatromanolaki A, Brekken RA, et al: Enhanced expression of SPARC/osteonectin in the tumor-associated stroma of non-small cell lung cancer is correlated with markers of hypoxia/acidity and with poor prognosis of patients. Cancer Res 63:5376-5380, 2003[Abstract/Free Full Text]

34. Jones C, Mackay A, Grigoriadis A, et al: Expression profiling of purified normal human luminal and myoepithelial breast cells: Identification of novel prognostic markers for breast cancer. Cancer Res 64:3037-3045, 2004[Abstract/Free Full Text]

35. Lindmark F, Zheng SL, Wiklund F, et al: H6D polymorphism in macrophage-inhibitory cytokine-1 gene associated with prostate cancer. J Natl Cancer Inst 96:1248-1254, 2004[Abstract/Free Full Text]

36. Hu M, Yao J, Cai L, et al: Distinct epigenetic changes in the stromal cells of breast cancers. Nat Genet 37:899-905, 2005[CrossRef][Medline]

37. Watkins G, Martin TA, Bryce R, et al: Gamma-Linolenic acid regulates the expression and secretion of SPARC in human cancer cells. Prostaglandins Leukot Essent Fatty Acids 72:273-278, 2005[CrossRef][Medline]

38. Tai IT, Dai M, Owen DA, et al: Genome-wide expression analysis of therapy-resistant tumors reveals SPARC as a novel target for cancer therapy. J Clin Invest 115:1492-1502, 2005[CrossRef][Medline]

39. John TA, Vogel SM, Tiruppathi C, et al: Quantitative analysis of albumin uptake and transport in the rat microvessel endothelial monolayer. Am J Physiol Lung Cell Mol Physiol 284:L187-L196, 2003[Abstract/Free Full Text]

40. Minshall RD, Sessa WC, Stan RV, et al: Caveolin regulation of endothelial function. Am J Physiol Lung Cell Mol Physiol 285:L1179-L1183, 2003[Abstract/Free Full Text]

41. Schnitzer JE, Oh P: Antibodies to SPARC inhibit albumin binding to SPARC, gp60, and microvascular endothelium. Am J Physiol Heart Circ Physiol 263:H1872-H1879, 1992[Abstract/Free Full Text]

42. Tiruppathi C, Finnegan A, Malik AB: Isolation and characterization of a cell surface albumin-binding protein from vascular endothelial cells. Proc Natl Acad Sci U S A 93:250-254, 1996[Abstract/Free Full Text]

43. Motzer RJ, Michaelson MD, Redman BG, et al: Activity of SU11248, a multitargeted inhibitor of vascular endothelial growth factor receptor and platelet-derived growth factor receptor, in patients with metastatic renal cell carcinoma. J Clin Oncol 24:16-24, 2006[Abstract/Free Full Text]

44. Hurwitz H, Fehrenbacher L, Novotny W, et al: Bevacizumab plus irinotecan, fluorouracil, and leucovorin for metastatic colorectal cancer. N Engl J Med 350:2335-2342, 2004[Abstract/Free Full Text]

45. Faivre L, Guardiola P, Lewis C, et al: Association of complementation group and mutation type with clinical outcome in fanconi anemia. European Fanconi Anemia Research Group. Blood 96:4064-4070, 2000[Abstract/Free Full Text]

Submitted June 15, 2006; accepted October 12, 2006.

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