Circulating tumor cells in melanoma patients.

Circulating tumor cells (CTCs) are of recognized importance for diagnosis and prognosis of cancer patients. With melanoma, most studies do not show any clear relationship between CTC levels and stage of disease. Here, CTCs were enriched (∼400X) from blood of melanoma patients using a simple centrifugation device (OncoQuick), and 4 melanocyte target RNAs (TYR, MLANA, MITF, and MIF) were quantified using QPCR. Approximately one-third of melanoma patients had elevated MIF and MLANA transcripts (p<0.0001 and p<0.001, respectively) compared with healthy controls. In contrast, healthy controls had uniformly higher levels of TYR and MITF than melanoma patients (p<0.0001). There was a marked shift of leukocytes into the CTC-enriched fractions (a 430% increase in RNA recovery, p<0.001), and no relationship between CTC levels and stage of disease was found. CTCs were captured on microfabricated filters and cultured. Captured melanoma CTCs were large cells, and consisted of 2 subpopulations, based on immunoreactivity. One subpopulation (∼50%) stained for both pan-cytokeratin (KRT) markers and the common leukocyte marker CD-45, whereas the second subpopulation stained for only KRT. Since similar cells are described in many cancers, we also examined blood from colorectal and pancreatic cancer patients. We observed analogous results, with most captured CTCs staining for both CD-45/KRT markers (and for the monocyte differentiation marker CD-14). Our results suggest that immature melanocyte-related cells (expressing TYR and MITF RNA) may circulate in healthy controls, although they are not readily detectable without considerable enrichment. Further, as early-stage melanomas develop, immature melanocyte migration into the blood is somehow curtailed, whereas a significant proportion of patients develop elevated CTC levels (based on MIF and MLANA RNAs). The nature of the captured CTCs is consistent with literature describing leukocyte/macrophage-tumor cell fusion hybrids, and their role in metastatic progression

Heterogeneity of Human Breast Stem and Progenitor Cells as Revealed by Transcriptional Profiling

Summary: During development, the mammary gland undergoes extensive remodeling driven by stem cells. Breast cancers are also hierarchically organized and driven by cancer stem cells characterized by CD44+CD24low/− or aldehyde dehydrogenase (ALDH) expression. These markers identify mesenchymal and epithelial populations both capable of tumor initiation. Less is known about these populations in non-cancerous mammary glands. From RNA sequencing, ALDH+ and ALDH−CD44+CD24− human mammary cells have epithelial-like and mesenchymal-like characteristics, respectively, with some co-expressing ALDH+ and CD44+CD24− by flow cytometry. At the single-cell level, these cells have the greatest mammosphere-forming capacity and express high levels of stemness and epithelial-to-mesenchymal transition-associated genes including ID1, SOX2, TWIST1, and ZEB2. We further identify single ALDH+ cells with a hybrid epithelial/mesenchymal phenotype that express genes associated with aggressive triple-negative breast cancers. These results highlight single-cell analyses to characterize tissue heterogeneity, even in marker-enriched populations, and identify genes and pathways that define this heterogeneity. : In this article, Colacino and colleagues use flow-cytometry-sorted populations and single-cell analyses to investigate human mammary stem cells. They discover unexpected phenotypic and functional heterogeneity at the single-cell level, including a subpopulation of ALDH+ stem cells with a hybrid epithelial/mesenchymal phenotype and triple-negative breast cancer-like gene expression pattern. Keywords: breast stem cell, single-cell RNA, epithelial, mesenchymal, hybrid, RNA-se

Marker RNA levels for TYR and MITF in melanoma patients vs. healthy controls.

<p>Blood was fractionated as described using OncoQuick columns, RNA was purified from the enriched CTC fractions, and TYR and MITF RNA levels were quantified by QPCR. Panel A shows results with blood drawn on the same day as excision of melanomas, or the corresponding healthy controls. Panel B shows results with blood drawn one week after excision. Staging information for melanoma patients is given in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041052#pone-0041052-t002" target="_blank">Table 2</a>. The Y-axis depicts RNA copy numbers per ml of blood. Shown to the far right of Panel A are calculated transcript numbers for 2 patients with squamous cell carcinoma of skin and for a patient with neurofibromatosis (left to right, respectively).</p

Receiver Operating Characteristic Analysis for MIF.

<p>ROC analysis was performed using the R Package software version 1.0-4 as described <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041052#pone.0041052-Team1" target="_blank">[53]</a>.</p