Circulating tumour cells as a biomarker for diagnosis and staging in pancreatic cancer

BACKGROUND

Current diagnosis and staging of pancreatic ductal adenocarcinoma (PDAC) has important limitations and better biomarkers are needed to guide initial therapy. We investigated the performance of circulating tumour cells (CTCs) as an adjunctive biomarker at the time of disease presentation.

METHODS

Venous blood (VB) was collected prospectively from 100 consecutive, pre-treatment patients with PDAC. Utilising the microfluidic NanoVelcro CTC chip, samples were evaluated for the presence and number of CTCs. KRAS mutation analysis was used to compare the CTCs with primary tumour tissue. CTC enumeration data was then evaluated as a diagnostic and staging biomarker in the setting of PDAC.

RESULTS

We found 100% concordance for KRAS mutation subtype between primary tumour and CTCs in all five patients tested. Evaluation of CTCs as a diagnostic revealed the presence of CTCs in 54/72 patients with confirmed PDAC (sensitivity=75.0%, specificity=96.4%, area under the curve (AUROC)=0.867, 95% CI=0.798-0.935, and P<0.001). Furthermore, a cut-off of ⩾3 CTCs in 4 ml VB was able to discriminate between local/regional and metastatic disease (AUROC=0.885; 95% CI=0.800-0.969; and P<0.001).

CONCLUSION

CTCs appear to function well as a biomarker for diagnosis and staging in PDAC.

An engineered anti-CA19-9 cys-diabody for PET imaging of pancreas cancer and targeting of polymerized liposomal nanoparticles

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Background: Antibody-based therapeutics is a rapidly growing field. Small engineered antibody fragments, such as the cys-diabody demonstrate similar antigen affinity compared to the parental antibody but have a shorter serum half-life (4hrs) and possess the ability to be conjugated to nanoparticles. Our goal was to engineer an anti-CA19-9 cys-diabody fragment in hopes of imaging and targeting pancreatic cancer.

Methods: The anti-CA19-9 cys-diabody was created by cloning the variable region of the parental antibody, engineering a C-terminus cysteine, expressing in NS0 cells followed by protein purification utilizing HPLC. Maleimide chemistry was used to conjugate the cys-diabody to PLNs through the engineered cysteine residues. Immunofluorescence and flow cytometry were used to evaluate targeting of cys-diabody and diabody conjugated PLNs to human pancreatic cancer cell lines. The cys-diabody was evaluated in a mouse xenograft model harboring CA19-9 positive (BxPC3) and negative (MiaPaca) tumors. The cys-diabody was radiolabeled with a positron emitter (I-124) and microPET/CT were performed after tail vein injection. Percent of injected dose per gram (%ID/g) of radioactivity was measured in blood and tumor to provide objective confirmation of the microPET images.

Results: Immunofluorescence and flow cytometry showed specific binding of the anti-CA19-9 cys- diabody. Tumor xenograft imaging of the anti-CA19-9 cys-diabody demonstrated an average tumor:blood (%ID/g) ratio of 3.3 and positive:negative tumor ratio of 7.4. Successful conjugation of the cys-diabody to PLNs was indicated by immunofluorescence showing specific targeting of PLN-cys- diabody conjugate to human pancreatic cancer cells in vitro.

Conclusions: Our results show that the anti-CA19.9 cys- diabody targets pancreatic cancer providing specific molecular imaging in tumor xenograft models. Furthermore, the PLN-cys-diabody conjugate targets human pancreatic cancer cells with the potential to deliver targeted treatment. Further studies evaluating the in vivo ability of the PLN-cys-diabody conjugate to target pancreatic cancer need to be performed.

No significant financial relationships to disclose.

Quality of care in advanced ovarian cancer: How important is provider specialty?

e16519

Background: Ovarian cancer is one of the most aggressive and deadly cancers in women. While the mainstay of therapy is surgery, ovarian cancer surgical procedures are performed by surgeons with different specialty training, including gynecology, gynecologic oncology, general surgery, and others. We examine the degree to which surgeon specialty impacts survival and other quality of life-related outcomes in advanced ovarian cancer patients. Methods: Analyses of Stage 3c/4 ovarian cancer patients were performed from 4 states (California, Washington, New York, Florida). Four databases were linked for each state: cancer registry, inpatient-hospital discharge, AMA masterfile, and 2000 U.S. Census SF4 File. Multivariate modeling was performed to identify predictors of survival as well as proxy quality of life-related outcomes, as measured by creation of a fecal ostomy. Hospital case volume was defined as low volume (LV) [0–4 cases], middle volume (MV) [5–9], high volume (HV) [10–19], and very high volume (VHV) [20+]. Results: 60,405 ovarian cancer patients were identified; 53% were Stage 3c/4. Mean age was 64 years. Patients had lower hazard of death when treated in higher volume hospitals as compared to LV [HV (Hazard Ratio) HR = 0.89, p < 0.0001; VHV HR = 0.79, p < 0.001]. Patients treated by gynecologists/gynecologic-oncologists had lower hazard of death (HR = 0.61, p < 0.0001) as compared to other surgeons (non-gynecologist), controlling for hospital type, case volume, comorbidity, and demographics. Also, patients treated by a trained gynecologist had the lowest chance of having an ostomy performed as compared to those of other specialties (HR = 0.22, p < 0.0001). Factors associated with receiving treatment from a non-gynecologist included low volume, rural patient residence, poverty, and high comorbidity. Conclusions: Stage 3c/4 ovarian cancer patients have better survival when treated by gynecology-trained surgeons. Our data suggest that gynecology-trained specialists optimize quality of life-related outcomes, specifically minimizing the creation of a fecal ostomy. Surgeon specialty was more important than procedure volume for these outcomes. Referral to gynecology-trained surgeons would improve survival and quality of life outcomes in advanced ovarian cancer patients.

No significant financial relationships to disclose.

Polypectomy or surgery for malignant colonic polyps: Do we need to change the NCCN guidelines?

4031

Background: Colonoscopic screening and appreciation of the adenoma-carcinoma sequence have led to increased detection and removal of colonic polyps. The National Comprehensive Cancer Network (NCCN) considers polypectomy alone to be adequate therapy for low-grade invasive T1 polyps that are limited to the head/stalk region and can be excised with negative margins. We examined the implications of this guideline for the general population. Methods: The National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) database (1988–2003) was queried to identify patients with invasive T1 colonic polyps. Patients treated with a polypectomy (PP) were compared with those who received a surgical resection (SR). Results: Of 9,162 patients with invasive T1 colonic polyps, 61.6% (11,812) underwent SR and 38.4% (7,350) underwent PP. The percentage of polyps removed increased from 4.2% (812) in 1988 to 9% (1739) in 2003. Patients undergoing SR vs. PP had larger polyps (median size 1.3 vs. 1.0 cm, p <0.001) and higher grade tumors (8.6% vs. 4.7%, p <0.001). The percentage of node positivity was 7% after SR, or 8.9% if at least 12 nodes were resected. The percentage of node positivity reached a surprising 6% in 1,478 patients who underwent SR for low-grade polyps limited to the head/stalk, and nodal status significantly affected the 3-year disease-specific survival of this subgroup: 83% with nodal metastases vs. 96% without nodal metastases (p < 0.003). Conclusions: Malignant colonic polyps with favorable histological features have a 6% risk of lymph node metastases even when removed with negative margins, bringing into question the NCCN recommendation that PP alone is adequate therapy.

No significant financial relationships to disclose.

Effect of blood transfusion on outcome after pancreaticoduodenectomy for exocrine tumour of the pancreas

BACKGROUND

Blood transfusion is thought to have an immunosuppressive effect. The aims of this study were to examine survival in patients with pancreatic cancer receiving blood transfusion in association with pancreaticoduodenectomy, and to define preoperative risk factors for subsequent transfusion.

METHODS

A retrospective review was performed of a prospective database of patients with exocrine tumours of the head of the pancreas who had undergone pancreaticoduodenectomy between 1998 and 2003. Clinical data, transfusion records and preoperative laboratory values were recorded.

RESULTS

A total of 294 patients underwent pancreaticoduodenectomy for exocrine tumours in the pancreatic head. Of these, 140 (47.6 per cent) received a blood transfusion. Their median survival was 18 months, compared with 24 months for those who did not have a transfusion (P = 0.036). Postoperative transfusion, margin status and node stage were independent predictors of survival. Age and preoperative total bilirubin and haemoglobin levels were the only preoperative factors that correlated with transfusion.

CONCLUSION

In patients with exocrine tumours of the pancreas, blood transfusion should be avoided when possible. Preoperative risk factors can identify patients who are likely to require transfusion and would therefore benefit most from blood conservation methods.

An intact overexpressed E-cadherin/alpha,beta-catenin axis characterizes the lymphovascular emboli of inflammatory breast carcinoma

The step of intravasation (lymphovascular invasion), a rate-limiting step in metastasis, is greatly exaggerated in inflammatory breast carcinoma (IBC). Because nearly all human breast carcinoma cell lines grow as solitary nodules in nude/severe combined immunodeficient mice without manifesting lymphovascular invasion, this step has been difficult to study. We captured the essence of the IBC phenotype by establishing a unique human transplantable IBC xenograft, MARY-X, which manifests florid lymphovascular emboli in severe combined immunodeficient/nude mice. Comparing MARY-X with common non-IBC cell lines/xenografts, we discovered an overexpressed and overfunctioning E-cadherin/alpha,beta-catenin axis. In MARY-X, the E-cadherin and catenins were part of a structurally and functionally intact adhesion axis involving the actin cytoskeleton. In vitro, MARY-X grew as round compact spheroids with a cell density 5-10-fold higher than that of other lines. The spheroids of MARY-X completely disadhered when placed in media containing absent Ca(2+) or anti-E-cadherin antibodies or when retrovirally transfected with a dominant-negative E-cadherin mutant (H-2K(d)-E-cad). Anti-E-cadherin antibodies injected i.v. immunolocalized to the pulmonary lymphovascular emboli of MARY-X and caused their dissolution. H-2K(d)-E-cad-transfected MARY-X spheroids were only weakly tumorigenic and did not form lymphovascular emboli. A total of 90% of human IBCs showed increased membrane E-cadherin/alpha,beta-catenin immunoreactivity. These findings indicate that it is the gain and not the loss of the E-cadherin axis that contributes to the IBC phenotype.

The human myoepithelial cell displays a multifaceted anti-angiogenic phenotype

Human myoepithelial cells which surround ducts and acini of certain organs such as the breast form a natural border separating epithelial cells from stromal angiogenesis. Myoepithelial cell lines (HMS-1-6), derived from diverse benign myoepithelial tumors, all constitutively express high levels of active angiogenic inhibitors which include TIMP-1, thrombospondin-1 and soluble bFGF receptors but very low levels of angiogenic factors. These myoepithelial cell lines inhibit endothelial cell chemotaxis and proliferation. These myoepithelial cell lines sense hypoxia, respond to low O2 tension by increased HIF-1 alpha but with only a minimal increase in VEGF and iNOS steady state mRNA levels. Their corresponding xenografts (HMS-X-6X) grow very slowly compared to their non-myoepithelial carcinomatous counterparts and accumulate an abundant extracellular matrix devoid of angiogenesis but containing bound angiogenic inhibitors. These myoepithelial xenografts exhibit only minimal hypoxia but extensive necrosis in comparison to their non-myoepithelial xenograft counterparts. These former xenografts inhibit local and systemic tumor-induced angiogenesis and metastasis presumably from their matrix-bound and released circulating angiogenic inhibitors. These observations collectively support the hypothesis that the human myoepithelial cell (even when transformed) is a natural suppressor of angiogenesis. Oncogene (2000) 19, 3449 - 3459

A novel human xenograft model of inflammatory breast cancer

The step of intravasation or lymphovascular invasion can be a rate-limiting step in the metastatic process. Inflammatory breast carcinoma manifests an exaggerated degree of lymphovascular invasion in situ; hence, a study of its molecular basis might shed light on the general mechanism of lymphovascular invasion exhibited by all metastasizing cancers. To this end, we have established the first human transplantable inflammatory breast carcinoma xenograft (MARY-X) in scid/nude mice. Whereas all other human xenografts grew as isolated s.c. nodules, MARY-X grew exclusively within murine lymphatics and blood vessels, and these latter elements and their supporting stroma comprised, by murine Cot-1 DNA analysis, 30% of the tumor. MARY-X, like its human counterpart, exhibited striking erythema of the overlying skin. MARY-X was estrogen receptor, progesterone receptor, Her-2/neu negative and p53, epidermal growth factor receptor positive. The primary tumor of origin of MARY-X exhibited identical markers, except that about 50% of its cells exhibited Her-2/neu amplification. Comparative studies of MARY-X with noninflammatory xenografts indicated 10-20-fold overexpression of E-cadherin and MUC1, findings that were reflected in actual cases of human inflammatory breast cancer. MARY-X should allow us to further dissect out both the upstream regulatory machinery and the downstream effector molecules responsible for the inflammatory carcinoma phenotype.

Pleural-based mesothelioma in immune competent rats: a model to study adenoviral gene transfer

BACKGROUND

Despite multimodality approaches, pleural-based malignant mesothelioma remains a disease with a very poor prognosis. Novel therapeutic strategies such as gene therapy clearly are needed to improve the survival of patients with this neoplasm. To aid in the evaluation of new treatment strategies, animal models that closely mimic human disease are required. This article describes the establishment of a pleural-based model of malignant mesothelioma in immune-competent Fischer rats.

METHODS

Via a modified left anterior lateral thorocotomy, a syngeneic malignant mesothelioma cell line, called II-45, was placed into the pleural cavity of Fischer rats.

RESULTS

Placement of II-45 cells into the pleural cavity of Fischer rats results in a model of pleural mesothelioma that closely resembles the disease seen in patients and is highly reproducible, with animals dying within 1 month. We also demonstrate the feasibility of adenoviral-mediated gene transfer to normal mesothelial cells lining the pleural cavity, as well as to malignant cells deep within the substance of pleural-based malignant mesothelioma.

CONCLUSIONS

The model described here offers the opportunity to study a variety of new treatment modalities, especially somatic gene transfer, against pleural-based malignant mesothelioma in an immune competent setting.