Purpose: The purpose of this study was to determine the accuracy, precision, and linearity of the CellSearch system and evaluate the number of circulating tumor cells (CTCs) per 7.5 mL of blood in healthy subjects, patients with nonmalignant diseases, and patients with a variety of metastatic carcinomas.Experimental Design: The CellSearch system was used to enumerate CTCs in 7.5 mL of blood. Blood samples spiked with cells from tumor cell lines were used to establish analytical accuracy, reproducibility, and linearity. Prevalence of CTCs was determined in blood from 199 patients with nonmalignant diseases, 964 patients with metastatic carcinomas, and 145 healthy donors.Results Conclusions:The CellSearch system can be standardized across multiple laboratories and may be used to determine the clinical utility of CTCs. CTCs are extremely rare in healthy subjects and patients with nonmalignant diseases but present in various metastatic carcinomas with a wide range of frequencies.

A highly sensitive assay combining immunomagnetic enrichment with multiparameter f low cytometric and immunocytochemical analysis has been developed to detect, enumerate, and characterize carcinoma cells in the blood. The assay can detect one epithelial cell or less in 1 ml of blood. Peripheral blood (10-20 ml) from 30 patients with carcinoma of the breast, from 3 patients with prostate cancer, and from 13 controls was examined by f low cytometry for the presence of circulating epithelial cells defined as nucleic acid ؉ , CD45 ؊ , and cytokeratin ؉ . Highly significant differences in the number of circulating epithelial cells were found between normal controls and patients with cancer including 17 with organ-confined disease. To determine whether the circulating epithelial cells in the cancer patients were neoplastic cells, cytospin preparations were made after immunomagnetic enrichment and were analyzed. Epithelial cells from patients with breast cancer generally stained with mAbs against cytokeratin and 3 of 5 for mucin-1. In contrast, no cells that stained for these antigens were observed in the blood from normal controls. The morphology of the stained cells was consistent with that of neoplastic cells. Of 8 patients with breast cancer followed for 1-10 months, there was a good correlation between changes in the level of tumor cells in the blood with both treatment with chemotherapy and clinical status. The present assay may be helpful in early detection, in monitoring disease, and in prognostication.Evidence is accumulating that primary cancers begin shedding neoplastic cells into the circulation at an early stage (1-4); however, the natural history of these cells, their ability to establish metastases, and their bearing on future relapses are unclear. For instance, circulating tumor cells have been detected by PCR in a variety of patients with a good prognosis who are unlikely to develop metastatic disease (5-8). In addition, immunocytochemistry has detected cancer cells in the bone marrow in a proportion of patients with clinically localized disease (9-11). If tumor cell shedding is, in fact, an early event in tumorigenesis, it may be possible to detect cancer cells in the bloodstream before the primary tumor is large enough to be detected by standard screening examinations.To explore this possibility, we have developed a cellular assay that is more sensitive than PCR and that allows precise enumeration and characterization of circulating carcinoma cells. In model studies, the sensitivity of the technique is below 1 epithelial cell͞ml of blood regardless of the number of leukocytes present and the recovery is between 75 and 100%. The assay was used to study the blood of 30 patients with breast cancer, 3 with prostate cancer, and 13 control individuals. An excess of circulating epithelial cells was found in virtually all of the cancer patients unless they were being treated with chemotherapy. In addition, 8 patients with breast cancer undergoing chemotherapy were followed for 1-10 months to determin...

Pancreatic cancer is an exceptionally aggressive disease in great need of more effective therapeutic options. Epithelial-mesenchymal transition (EMT) plays a key role in cancer invasion and metastasis and there is a gain of stem cell properties during EMT. Here we report increased expression of the putative pancreatic stem cell marker DCAMKL-1 in an established KRAS transgenic mouse model of pancreatic cancer and in human pancreatic adenocarcinoma. Co-localization of DCAMKL-1 with vimentin, a marker of mesenchymal lineage, along with 14-3-3 σ was observed within pre-malignant PanIN lesions that arise in the mouse model. siRNA-mediated knockdown of DCAMKL-1 in human pancreatic cancer cells induced microRNA miR-200a, an EMT inhibitor, along with down-regulation of EMT-associated transcription factors ZEB1, ZEB2, Snail, Slug and Twist. Furthermore, DCAMKL-1 knockdown resulted in downregulation of c-Myc and KRAS through a let-7a microRNA-dependent mechanism, and downregulation of Notch-1 through a miR-144 microRNA-dependent mechanism. These findings illustrate direct regulatory links between DCAMKL-1, microRNAs and EMT in pancreatic cancer. Moreover, they demonstrate a functional role for DCAMKL-1 in pancreatic cancer. Together, our results rationalize DCAMKL-1 as a therapeutic target for eradicating pancreatic cancers.