Improving the CellSearch® system.

INTRODUCTION: The CellSearch® CTC test enumerates tumor cells present in 7.5 ml blood of cancer patients. improvements, extensions and different utilities of the cellsearch system are discussed in this paper. Areas covered: This paper describes work performed with the CellSearch system, which go beyond the normal scope of the test. All results from searches with the search term 'CellSearch' from Web of Science and PubMed were categorized and discussed. Expert commentary: The CellSearch Circulating Tumor Cell test captures and identifies tumor cells in blood that are associated with poor clinical outcome. How to best use CTC in clinical practice is being explored in many clinical trials. The ability to extract information from the CTC to guide therapy will expand the potential clinical utility of CTC.

Circulating tumour cells during laparoscopic and open surgery for primary colonic cancer in portal and peripheral blood.

BACKGROUND: The objective of this study was to detect and quantify circulating tumour cells (CTC) in peripheral and portal blood of patients who had open or laparoscopic surgery for primary colonic cancer. METHODS: Patients in the laparoscopic-group were operated on in a medial to lateral approach ("vessels first"), in the open-group a lateral to medial approach was applied. The enumeration of CTC was performed with the CellSearch System. Intra-operative samples were taken paired-wise (from peripheral and portal circulation) directly after entering the abdominal cavity (T1), after mobilisation of the tumour baring segment (T2), and after tumour resection (T3). Ploidy of both the CTC and tissue of the primary tumour was determined for chromosome 1, 7, 8 and 17. RESULTS: Thirty-one patients were included; 18 patients had open surgery, 13 patients were operated on laparoscopically. The percentage of samples with CTC at T1 was 7% in peripheral blood and 54% in portal blood (p=0.002). At T2, 4% and 31% respectively (p=0.031). And at T3, 4% and 26% respectively (p=0.125). The cumulative percentage of samples with CTC was significantly higher during open surgery as compared to the laparoscopic approach. Both the CTC and tissue of the primary tumour were diploid for chromosome 1, 7, 8 and 17. CONCLUSION: The detection rate and quantity of CTC is significantly increased intra-operatively and is significantly higher in portal blood compared to peripheral blood. Significantly less CTC were detected during laparoscopic surgery probably as result of the medial to lateral approach.

Growth hormone induces tyrosyl phosphorylation of the transcription factors Stat5a and Stat5b in CMT-U335 canine mammary tumor cells.

It has now been well documented that the normal and tumorous canine mammary glands can be extra-pituitary sites of substantial growth hormone (GH) synthesis. Until now, attempts to reproduce the GH synthesis in-vitro using canine mammary explants or mammary tumor cells have not been successful. Therefore, the response of CMT-U335 canine mammary tumor cells to administered porcine GH (pGH) was investigated as an in-vitro model to study the possible effects of GH synthesis on this site. CMT-U335 cells spontaneously express the growth hormone receptor (GHR) as well as the prolactin receptor (PRLR). Twenty five minutes after administration, GH induced, in a dose-dependent manner, phosphorylation of the transcription factors Stat5a and Stat5b. Clear phosphorylation was induced by 10(-7) M and 10(-8) M pGH, with virtually no phosphorylation at 10(-9) M pGH. A similar dose-dependent phosphorylation of Stat5a by ovine prolactin was found in these cells. Although at high concentrations binding of pGH to the canine PRLR can occur (albeit with a low pKa), the similar dose-dependent effect of oPRL on Stat5a phosphorylation indicated that pGH signaled through the GHR. Remarkably, pGH induced a moderately decreased proliferation of CMT-U335 tumor cells, which may indicate that GH induces differentiation in these tumor cells. The GH-induced activation of Stat5a and Stat5b in these cells, as part of the JAK/Stat signal transduction pathway, is consistent with mammary GH playing a role in autocrine and/or paracrine stimulation of (tumorous) mammary cells.

Expression and molecular characterization of the growth hormone receptor in canine mammary tissue and mammary tumors.

GH synthesis has been documented in canine mammary tissue and mammary tumors. In the present report, the characteristics of the GH receptor (GHR) are studied in these tissues. First, using immunohistochemistry, GHR was found to be present throughout normal and tumorous mammary tissues, being localized in epithelial and myoepithelial/spindle cell components and in the activated fibroblasts of desmoplastic tumor stroma. GHR expression seemed to be down-regulated only in terminally differentiated alveoli in normal tissue. GHR immunoreactivity in particular mammary (adeno)carcinomas was heterogenous. Second, the canine GHR was characterized at the molecular level. Northern blot analysis revealed a major GHR transcript of approximately 4.2 kb. The coding sequence of the canine GHR shows extensive homology with the GHR of several species. Seminested RT-PCR (using primers annealing in exons 4-5, exon 6, and exon 9) generated, next to the primary product, four different products in mammary tissues and the canine mammary tumor cell line CMT-U335, which seemed to be alternative GHR transcripts. These alternative GHR transcripts were characterized by exon 8 skipping, exon 7 skipping, and use of alternative splice donor and acceptor sites. Especially, the transcript that is missing exon 8 may encode a GH binding protein. In most malignant mammary samples, only the primary transcript was present; and alternative transcripts could not be detected. The absence of alternative GHR transcripts in mammary carcinomas, and thus putative inhibitors of GH-induced signal transduction, may contribute to enhanced sensitivity of malignant tumors to GH.