Circulating tumor cell enumeration for improved screening and disease detection of patients with colorectal cancer.

BACKGROUND: The immunochemical fecal occult blood test (iFOBT) for colorectal cancer (CRC) screening and the serum carcinoembryonic antigen (CEA) assay for disease detection of CRC is associated with a high false-positive rate and a low detection sensitivity, respectively. There is an unmet need to define additional modalities to complement these assays. Different subsets of circulating tumor cells (CTCs) are present in the peripheral blood of cancer patients. Whether or not CTCs testing supplements these clinical assays and is valuable for patients with CRC was investigated. METHODS: CTCs were enriched from pre-operative patients with CRC (n = 109) and the non-cancerous controls (n = 65). CTCs expressing either epithelial cell adhesion molecule (EpCAM) or podoplanin (PDPN, the marker associated with poor cancer prognosis) were defined by immunofluorescence staining and were analyzed alone or in combination with iFOBT or serum CEA. RESULTS: Patients with early or advanced stage of CRC can be clearly identified and differentiated from the non-cancerous controls (p < 0.001) by EpCAM+-CTC or PDPN+-CTC count. The sensitivity and specificity of EpCAM+-CTCs was 85.3% and 78.5%, respectively, when the cutoff value was 23 EpCAM+-CTCs/mL of blood; and the sensitivity and specificity of PDPN+-CTCs was 78.0% and 75.4%, respectively, when the cutoff value was 7 PDPN+-CTCs/mL of blood. Combined analysis of iFOBT with the EpCAM+-CTC and PDPN+-CTC count reduced the false-positive rate of iFOBT from 56.3% to 18.8% and 23.4%, respectively. Combined analysis of serum CEA with the EpCAM+-CTC and PDPN+-CTC count increased the disease detection rate from 30.3% to 89.9% and 86.2%, respectively. CONCLUSION: CTC testing could supplement iFOBT to improve CRC screening and supplement serum CEA assay for better disease detection of patients with CRC.

Sequential Circulating Tumor Cell Counts in Patients with Locally Advanced or Metastatic Hepatocellular Carcinoma: Monitoring the Treatment Response.

Hepatocellular carcinoma (HCC) is among the most common causes of cancer death in men. Whether or not a longitudinal follow-up of circulating tumor cells (CTCs) before and at different time points during systemic/targeted therapy is useful for monitoring the treatment response of patients with locally advanced or metastatic HCC has been evaluated in this study. Blood samples (n = 104) were obtained from patients with locally advanced or metastatic HCC (n = 30) for the enrichment of CTCs by a negative selection method. Analysis of the blood samples from patients with defined disease status (n = 81) revealed that those with progressive disease (PD, n = 37) had significantly higher CTC counts compared to those with a partial response (PR) or stable disease (SD; n = 44 for PR + SD, p = 0.0002). The median CTC count for patients with PD and for patients with PR and SD was 50 (interquartile range 21-139) and 15 (interquartile range 4-41) cells/mL of blood, respectively. A longitudinal analysis of patients (n = 17) after a series of blood collections demonstrated that a change in the CTC count correlated with the patient treatment response in most of the cases and was particularly useful for monitoring patients without elevated serum alpha-fetoprotein (AFP) levels. Sequential CTC enumeration during treatment can supplement standard medical tests and benefit the management of patients with locally advanced or metastatic HCC, in particular for the AFP-low cases.

Circulating Epithelial Cell Characterization and Correlation with Remission and Survival in Patients with Thyroid Cancer.

BACKGROUND: Thyroid cancer is the most common endocrine tumor and generally has relatively good clinical outcomes. However, 15-20% of patients ultimately develop recurrence or disease-related death. The appropriate prognostic factors for thyroid cancer are still elusive. This study evaluated whether the number of circulating tumor cells/circulating epithelial cells (CECs) expressing either epithelial cell adhesion molecule (EpCAM), podoplanin (PDPN), or thyrotropin receptor (TSHR) is related to remission and disease-specific mortality (DSM) of patients with thyroid cancer. METHODS: Blood samples were collected from patients (n = 128) after thyroidectomy or radioactive iodide therapy. CECs were enriched by lysis of red blood cells and depletion of leukocytes. Subtyping and quantification of the enriched cells were performed with immunofluorescence staining using antibodies against EpCAM, TSHR, and PDPN, respectively. Whether the number of a specific subtype of CECs is related to remission and DSM of patients was determined by univariate and multivariate analyses. RESULTS: The EpCAM+-CECs, TSHR+-CECs, and PDPN+-CECs counts for patients in the non-remission group (n = 43) were significantly higher when compared to the remission group (n = 85; p < 0.001). Receiver operating characteristic analysis showed that the number of EpCAM+-CECs, TSHR+-CECs, and PDPN+-CECs was able to distinguish the status of remission from non-remission. The cutoff point for EpCAM+-CECs, TSHR+-CECs, and PDPN+-CECs was 40, 47, and 14 (cells/mL), with the accuracy of the assay equivalent to 80.4%, 76.6%, and 77.3%, respectively. On the other hand, the number of EpCAM+-CECs (p < 0.001), PDPN+-CECs (p = 0.013), and TSHR+-CECs (p < 0.001) for patients in the DSM group (n = 17) was significantly higher when compared to the patients who survived (n = 111). Receiver operating characteristic analysis showed that EpCAM+-CECs, TSHR+-CECs, and PDPN+-CECs counts were able to distinguish mortality from survival status. The cutoff point for EpCAM+-CECs, TSHR+-CECs, and PDPN+-CECs was 27, 25, and 9 (cells/mL), with the accuracy of the assay equivalent to 69.5%, 67.2%, and 68.5%, respectively. CONCLUSIONS: CEC testing is a useful tool for analysis of overall survival and remission status of patients with thyroid cancer. Implementation of CEC testing into routine clinical test may be worthy to consider for patient clinical care.

Circulating epithelial cells as potential biomarkers for detection of recurrence in patients of papillary thyroid carcinoma with positive serum anti-thyroglobulin antibody.

BACKGROUND: Serum thyroglobulin (Tg) is not a reliable tumor marker for monitoring disease status after treatment in patients with papillary thyroid carcinoma (PTC) with positive anti-thyroglobulin antibody (TgAb). The aim of this study was to evaluate the clinical role of circulating epithelial cells (CECs) in PTC patients with positive serum TgAb and undetectable serum Tg. METHODS: A pilot study was performed to evaluate CECs in 25 PTC patients with positive serum TgAb and undetectable serum Tg. CECs were isolated and enriched from peripheral blood with a negative selection system PowerMag. Immunofluorescence staining with anti-epithelial cell adhesion molecule (anti-EpCAM) and anti-thyroid stimulating hormone receptor (anti-TSHR) antibodies were used to define EpCAM+-CECs and TSHR+-CECs. After CECs testing, 25 patients were classified into two groups: recurrence group (n=7) and remission group (n=18) based on biopsy or imaging studies. The diagnostic accuracy and cutoff points of EpCAM+-CECs and TSHR+-CECs were evaluated using receiver operating characteristic (ROC) curves. The optimal cut-off values of CECs were determined by the Youden index (sensitivity+specificity-1). RESULTS: The median numbers of EpCAM+-CECs (72.5 vs. 10.75) and TSHR+-CECs (54 vs. 5.25) were significantly increased in recurrence group compared to remission group. The area under the curve (AUC) showed good performance of EpCAM+-CECs (0.937) and TSHR+-CECs (0.825) to discriminate between recurrence and remission. The cut-off value for EpCAM+-CECs and TSHR+-CECs were set at 48cells/ml and 10cells/ml, respectively and showed a sensitivity (EpCAM+-CECs: 85.7%; TSHR+-CECs: 85.7%) and a specificity (EpCAM+-CECs: 100%; TSHR+-CECs: 77.8%) in predicting the recurrence. CONCLUSIONS: Our study suggests CECs testing could be a potential biomarker to identify recurrence in PTC patients with positive serum TgAb and undetectable serum Tg.

Circulating epithelial cell counts for monitoring the therapeutic outcome of patients with papillary thyroid carcinoma.

Loco-regional recurrence or distant metastasis usually leads to the death of patients with papillary thyroid carcinoma (PTC). Whether or not circulating epithelial cells (CECs) count is a valuable marker in monitoring the therapeutic outcome of PTC was investigated. Patients with PTC (n=129) were treated in our medical center and were categorized into 4 groups with excellent (n=45), biochemical incomplete (n=15), indeterminate (n=37), and structural incomplete (n=32) responses. CECs were enriched from the peripheral blood by the PowerMag negative selection system. Three subtypes of CECs expressing epithelial cell adhesion molecule (EpCAM), thyroid-stimulating hormone receptor (TSHR, a marker for thyroid cells), and podoplanin (PDPN, a marker related to poor prognosis in patients with PTC) were defined by immunofluorescence staining, respectively. The median number of CECs (cells/mL of blood) expressing EpCAM, TSHR, and PDPN was 23 (interquartile range 10-61), 19 (interquartile range 8-50), and 8 (interquartile range 3-22), respectively, for patients enrolled in this study. The number of EpCAM+-CECs, TSHR+-CECs, and PDPN+-CECs was statistically different among patients in different treatment response groups without interference from anti-thyroglobulin antibody (P<0.0001). Patients with structural incomplete response had higher counts for all three CECs subtypes when compared to other patients. EpCAM+-CECs was better in distinguishing patients with excellent response from structural incomplete response among the three subtypes of CECs. The sensitivity and specificity of the assay was 84.4% and 95.6%, respectively, when the cut off value was 39 EpCAM+-CECs/mL. CECs testing can supplement the current standard methods for monitoring the therapeutic outcome of PTC.

Disabled-2 is a negative regulator of integrin alpha(IIb)beta(3)-mediated fibrinogen adhesion and cell signaling.

Disabled-2 (DAB2) is an adapter protein that is up-reg-ulated during megakaryocytic differentiation of hematopoietic cells and is abundantly expressed in platelets. In this study, the role of DAB2 in integrin alpha(IIb)beta(3)-mediated matrix protein fibrinogen adhesion and cell signaling was investigated. In K562 cells differentiating to the megakaryocytic lineage, down-regulation of DAB2 by DAB2 small interfering RNA augmented integrin alpha(IIb)beta(3) activation and resulted in an increase in cell adhesion to fibrinogen. Ectopic expression of DAB2 reversed the DAB2 small interfering RNA effect or, by itself, decreased fibrinogen adhesion of K562 cells. Mutational analysis revealed that a DAB2 Ser(24) phosphorylation mutant (S24A) abrogated the inhibitory function of DAB2. The spatial and temporal association/interaction of DAB2 and platelet integrin alpha(IIb)beta(3) (CD61) in both megakaryocytic cells and platelets led us to examine the effect of Ser(24) phosphorylation on the interaction between DAB2 and integrin beta(3). Through cellular localization and co-immunoprecipitation analysis, we demonstrate for the first time that Ser(24) phosphorylation promotes membrane translocation of DAB2 and its subsequent interaction with integrin beta(3), thereby defining a mechanism for DAB2 in regulating integrin alpha(IIb)beta(3) activation and inside-out signaling. Consistent with the effect on fibrinogen adhesion, Ser(24) phosphorylation of DAB2 was also involved in the negative regulation of alpha(IIb)beta(3)-induced T cell factor transcriptional activity. In contrast, the S24A mutant acted like wild-type DAB2 and inhibited both beta-catenin- and plakoglobin-mediated T cell factor transactivation. Hence, DAB2 elicits distinct regulatory mechanisms in alpha(IIb)beta(3) and beta-catenin/plakoglobin signaling in a Ser(24) phosphorylation-dependent and -independent manner, respectively. These findings indicate Ser(24) phosphorylation as a molecular basis for DAB2 acting as a negative regulator in alpha(IIb)beta(3) inside-out signaling and contribute to our understanding of DAB2 in megakaryocytic differentiation and platelet function.