A Direct Comparison between the Lateral Magnetophoretic Microseparator and AdnaTest for Isolating Prostate Circulating Tumor Cells
MICROMACHINES
Authors: Cho, Hyungseok; Chung, Jae-Seung; Han, Ki-Ho
Abstract
Circulating tumor cells (CTCs) are important biomarkers for the diagnosis, prognosis, and treatment of cancer. However, because of their extreme rarity, a more precise technique for isolating CTCs is required to gain deeper insight into the characteristics of cancer. This study compares the performance of a lateral magnetophoretic microseparator ("CTC-mu Chip"), as a representative microfluidic device, and AdnaTest ProstateCancer (Qiagen), as a commercially available specialized method, for isolating CTCs from the blood of patients with prostate cancer. The enumeration and genetic analysis results of CTCs isolated via the two methods were compared under identical conditions. In the CTC enumeration experiment, the number of CTCs isolated by the CTC-mu Chip averaged 17.67 CTCs/mL, compared to 1.56 CTCs/mL by the AdnaTest. The number of contaminating white blood cells (WBCs) and the CTC purity with the CTC-mu Chip averaged 772.22 WBCs/mL and 3.91%, respectively, whereas those with the AdnaTest averaged 67.34 WBCs/mL and 1.98%, respectively. Through genetic analysis, using a cancer-specific gene panel (AR (androgen receptor), AR-V7 (A\androgen receptor variant-7), PSMA (prostate specific membrane antigen), KRT19 (cytokeratin-19), CD45 (PTPRC, Protein tyrosine phosphatase, receptor type, C)) with reverse transcription droplet digital PCR, three genes (AR, AR-V7, and PSMA) were more highly expressed in cells isolated by the CTC-mu Chip, while KRT19 and CD45 were similarly detected using both methods. Consequently, this study showed that the CTC-mu Chip can be used to isolate CTCs more reliably than AdnaTest ProstateCancer, as a specialized method for gene analysis of prostate CTCs, as well as more sensitively obtain cancer-associated gene expressions.
Tumour-infiltrating T-cell subsets, molecular changes in colorectal cancer, and prognosis: cohort study and literature review
JOURNAL OF PATHOLOGY
Authors: Nosho, Katsuhiko; Baba, Yoshifumi; Tanaka, Noriko; Shima, Kaori; Hayashi, Marika; Meyerhardt, Jeffrey A.; Giovannucci, Edward; Dranoff, Glenn; Fuchs, Charles S.; Ogino, Shuji
Abstract
The abundance of tumour-infiltrating T-cells has been associated with microsatellite instability (MSI) and a favourable prognosis in colorectal cancer. However, numerous molecular alterations have been associated with clinical outcome, and potentially confounding the biological and prognostic significance of tumour-infiltrating T-cells. We utilized a database of clinically and molecularly-annotated colon and rectal carcinoma cases (N = 768; stage I-IV) in two prospective cohort studies (the Nurses' Health Study and the Health Professionals Follow-up Study) and quantified the densities of CD3(+), CD8(+), CD45RO(+) (PTPRC), and FOXP3(+) cells within neoplastic epithelial areas using an Ariol image analysis system and tissue microarray. We used Cox proportional hazard models to compute the mortality hazard ratio, adjusting for clinical and molecular features including KRAS, BRAF, and PIK3CA mutations, MSI, CIMP, and LINE-1 hypomethylation. The densities of CD8(+), CD45RO(+), and FOXP3(+) cells were significantly associated with patient survival in univariate analyses (p(trend) < 0.007). In the multivariate model, tumour-infiltrating CD45RO(+)-cell density, but not CD3(+), CD8(+) or FOXP3(+)-cell density, was significantly associated with survival (p = 0.0032). In multivariate linear regression analysis, MSI-high (p < 0.0001) and high-level tumour LINE-1 methylation (p = 0.0013) were independently associated with higher CD45RO(+)-cell density. The survival benefit associated with CD45RO(+) cells was independent of MSI and LINE-1 status. In conclusion, tumour-infiltrating CD45RO(+)-cell density is a prognostic biomarker associated with longer survival of colorectal cancer patients, independent of clinical, pathological, and molecular features. In addition, MSI-high and tumour LINE-1 methylation level are independent predictors of CD45RO(+)-cell density. Our data offer a possible mechanism by which MSI confers an improved clinical outcome and support efforts to augment the host immune response in the tumour microenvironment as a strategy of targeted immunotherapy. Copyright (C) 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.