Circulating Tumor Cells in Desmoid Tumors: New Perspectives

Introduction

Desmoid tumor (DT) is a rare neoplasm with high local recurrence rates, composed of fibroblastic cells that are characterized by the expression of key molecules, including the intermediate filament vimentin, cyclooxygenase-2 (COX-2), and nuclear β-catenin, and lack of epithelial markers. Circulating tumor cells (CTCs) isolated from the peripheral blood of patients with sarcomas and other neoplasms can be used as early biomarkers of tumor invasion and dissemination. Moreover, CTCs can also re-colonize their tumors of origin through a process of "tumor self-seeding."

Objectives

We aimed to identify CTCs in the peripheral blood of patients with DT and evaluate their expression of β-catenin, transforming growth factor receptor I (TGF-βRI), COX-2, and vimentin proteins.

Material and Methods

We conducted a prospective study of patients with initial diagnosis or relapsed DT with measurable disease. Blood samples from each patient were processed and filtered by ISET^® (Rarecells, France) for CTC isolation and quantification. The CTC expression of β-catenin, COX-2, TGF-βRI, and vimentin was analyzed by immunocytochemistry (ICC).

Results

A total of 18 patients were included, and all had detectable CTCs. We found a concordance of β-catenin expression in both CTCs and primary tumors in 42.8% (6/14) of cases by using ICC and immunohistochemistry, respectively.

Conclusions

Our study identified a high prevalence of CTCs in DT patients. Concordance of β-catenin expression between primary tumor and CTCs brings new perspectives to assess the dynamics of CTCs in the blood compartment, opening new avenues for studying the biology and behavior of DT. In addition, these results open the possibility of using CTCs to predict DT dynamics at the time of disease progression and treatment. Further studies with larger sample sizes are needed to validate our findings.

Genomics and epidemiology for gastric adenocarcinomas (GE4GAC): a Brazilian initiative to study gastric cancer

Gastric cancer (GC) is the fifth most common type of cancer worldwide with high incidences in Asia, Central, and South American countries. This patchy distribution means that GC studies are neglected by large research centers from developed countries. The need for further understanding of this complex disease, including the local importance of epidemiological factors and the rich ancestral admixture found in Brazil, stimulated the implementation of the GE4GAC project. GE4GAC aims to embrace epidemiological, clinical, molecular and microbiological data from Brazilian controls and patients with malignant and pre-malignant gastric disease. In this letter, we summarize the main goals of the project, including subject and sample accrual and current findings.

The Potential Clinical Implications of Circulating Tumor Cells and Circulating Tumor Microemboli in Gastric Cancer

BACKGROUND

Gastric adenocarcinoma (GAC) is the third deadliest malignant neoplasm worldwide, mostly because of late disease diagnosis, low chemotherapy response rates, and an overall lack of tumor biology understanding. Therefore, tools for prognosis and prediction of treatment response are needed. Quantification of circulating tumor cells (CTCs) and circulating tumor microemboli (CTM) and their expression of biomarkers has potential clinical relevance. Our aim was to evaluate CTCs and CTM and their expression of HER2 and plakoglobin in patients with nonmetastatic GAC, correlating the findings to clinicopathological data.

MATERIALS AND METHODS

CTC enrichment was performed with isolation by size of epithelial tumor cells, and the analysis was performed with immunocytochemistry and microscopy. Two collections were made: one at diagnosis (55 samples before neoadjuvant treatment) and one after surgery and before adjuvant therapy (33 samples).

RESULTS

A high detection rate of CTCs (90%) was observed at baseline. We evaluated HER2 expression in 45/55 biopsy samples and in 42/55 CTC samples, with an overlap of 36 subjects. Besides the good agreement observed for HER2 expression in primary tumors and paired CTCs for 36 cases (69.4%; κ = 0.272), the analysis of HER2 in CTCs showed higher positivity (43%) compared with primary tumors (11%); 3/5 patients with disease progression had HER2-negative primary tumors but HER2-positive CTCs. A significant CTC count drop in follow-up was seen for CTC-HER2-positive cases (4.45 to 1.0 CTCs per mL) compared with CTC-HER2-negative cases (2.6 to 1.0 CTCs per mL). The same was observed for CTC-plakoglobin-positive cases (2.9 to 1.25 CTCs per mL).

CONCLUSION

CTC analysis, including their levels, plakoglobin, and HER2 expression, appears to be a promising tool in the understanding the biology and prognosis of GAC.

IMPLICATIONS FOR PRACTICE

The analysis of circulating tumor cell levels from the blood of patients with gastric adenocarcinoma, before and after neoadjuvant treatment, is useful to better understand the behavior of the disease as well as the patients more likely to respond to treatment.

Abstract B07: CTC and CTM detection in sarcoma patients

Background: Sarcomas represent 1% of all cancers in adults, 8% in adolescents and young people, and 10% in children. Even though it is a rare cancer, it contributes to a significant loss of years of life in comparison with other types of cancer (Amankwah et al., 2013). The presence of isolated circulating tumor cells (CTCs) or circulating tumor microemboli (CTM) in the blood of patients with sarcoma may be early markers of tumor invasion, because it is known that these cells circulate in the blood for months or years before the development of metastases (Paterlini-Brechot and Benali, 2007; Klain, 2009; Rhim et al., 2012).

Objective: To isolate and quantify CTCs and CTM from sarcoma patients, evaluating their presence and correlation with progression-free survival (PFS).

Methods: Blood (approximately 8 mL) was prospectively collected from patients with different types of high-degree sarcoma. Blood was collected before the beginning of chemotherapy. The samples were processed and filtered on ISET (Isolation by Size of Epithelial Tumor Cells, Rarecells, France) system for the isolation and quantification of CTCs and CTMs. Immunocytochemistry (ICC) was later performed with anti-CD45 antibody and counterstained with hematoxylin-eosyn for leucocytes population exclusion. The cutoff was estimated using the maximum of the standardized log-rank statistic proposed by Lausen and Schumacher (1992).

Results: We analyzed 11 high-degree sarcoma patients after metastasis diagnosis, before the beginning of treatment. The median age was 53 years (18-77) and 54.5% were male. The median CTCs number was 2.0 CTCs/mL (1.0-11.0) at baseline. By Kaplan-Meier test, we observed that patients with CTC number below the established cutoff (4.5 CTCs/mL) had better PFS compared to those above the cutoff (7.4 vs. 1.0 months, respectively; P= 0.006). Moreover, patients without CTM had also better PFS compared to those patients with the presence of CTM (7.6 vs. 2.7 months, respectively; P= 0.13).

Conclusion: This is the first study to demonstrate, besides the CTC and CTM presence in sarcoma patients, its real prognostic value, even in a limited sample. Our next step is to characterize these cells to better understand its capability to promote tumor progression.

Citation Format: Alexcia C. Braun, Celso A L Mello, Marcelo P. Corassa, Alves S. Vanessa, Emne A. Abdallah, Nicolau R. Ulisses, Mônica T. M. Díaz, Bianca T. C. P. Flores, Marcelo F. Fanelli, Patrizia Paterlini-Brechót, Ludmilla T. D. Chinen. CTC and CTM detection in sarcoma patients [abstract]. In: Proceedings of the AACR International Conference held in cooperation with the Latin American Cooperative Oncology Group (LACOG) on Translational Cancer Medicine; May 4-6, 2017; São Paulo, Brazil. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(1_Suppl):Abstract nr B07.

Abstract 1728: CTCs and CTM as prognostic factors in sarcoma patients

Background: Sarcomas represent 1% of all cancers in adults, 8% in adolescents and young people, and 10% in children. Even though it is a rare cancer, it contributes to a significant loss of years of life in comparison with other types of cancer (Amankwah, et al., 2013). The presence of isolated Circulating Tumor Cells (CTCs) or Circulating Tumor Microemboli (CTM) in the blood of patients with sarcoma may be early markers of tumor invasion, because it is known that these cells circulate in the blood for months or years before the development of metastases (Paterlini-Brechot and Benali, 2007; Klain, 2009; Rhim et al., 2012).

Objective: To isolate and quantify CTCs and CTM from sarcoma patients, evaluating their presence and correlation with progression free survival (PFS).

Methods: The blood (approximately 8mL) was prospectively collected from patients with different types of high degree sarcoma. Blood was collected before the beginning of chemotherapy. The samples were processed and filtered on ISET (Isolation by Size of Epithelial Tumor Cells, Rarecells, France) system for the isolation and quantification of CTCs and CTMs. Later, was performed immunocytochemistry (ICC) with anti-CD45 antibody and counterstained with hematoxylin-eosyn for leucocytes population exclusion. The cutoff was estimated using the maximum of the standardized log-rank statistic proposed by Lausen & Schumacher (1992).

Results: we analyzed 11 high degree sarcoma patients before the beginning of treatment (any treatment line). The median age was 53 years-old (18-77) and 54,5% were male. The median CTCs number was 2.0 CTCs/mL (1.0-11.0) at baseline. By Kaplan-Meier test, we observed that patients with CTC number below the established cutoff (4.5 CTCs/mL) had better PFS compared to those above the cutoff (7.4 vs. 1.0 months respectively; P= 0.006). Moreover, patients without CTM had also better PFS compared to those patients with the presence of CTM (7.6 vs. 2.7 months respectively; P= 0.13).

Conclusion: this is the first study to demonstrate, besides the CTC and CTM presence in sarcoma patients, its real prognostic value, even in a limited sample. Our next step is to characterize these cells to better understand its capability to promote tumor progression.

Citation Format: Alexcia C. Braun, Celso A. Mello, Marcelo P. Corassa, Vanessa S. Alves, Emne A. Abdallah, Ulisses R. Nicolau, Mônica Taiane de Macedo Díaz, Bianca de Cássia Troncarelli de Campos Parra Flores, Marcelo F. Fanelli, Patrizia Paternili-Brechót, Ludmilla T. Chinen. CTCs and CTM as prognostic factors in sarcoma patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1728. doi:10.1158/1538-7445.AM2017-1728

Early detection of poor outcome in patients with metastatic colorectal cancer: tumor kinetics evaluated by circulating tumor cells

BACKGROUND

Colorectal cancer (CRC) is the third most prevalent cancer worldwide. New prognostic markers are needed to identify patients with poorer prognosis, and circulating tumor cells (CTCs) seem to be promising to accomplish this.

PATIENTS AND METHODS

A prospective study was conducted by blood collection from patients with metastatic CRC (mCRC), three times, every 2 months in conjunction with image examinations for evaluation of therapeutic response. CTC isolation and counting were performed by Isolation by Size of Epithelial Tumor Cells (ISET).

RESULTS

A total of 54 patients with mCRC with a mean age of 57.3 years (31-82 years) were included. Among all patients, 60% (n=32) were carriers of wild-type KRAS (WT KRAS) tumors and 90% of them (n=29) were exposed to monoclonal antibodies along with systemic treatment. Evaluating CTC kinetics, when we compared the baseline (pretreatment) CTC level (CTC1) with the level at first follow-up (CTC2), we observed that CTC1-positive patients (CTCs above the median), who became negative (CTCs below the median) had a favorable evolution (n=14), with a median progression-free survival (PFS) of 14.7 months. This was higher than that for patients with an unfavorable evolution (CTC1- that became CTC2+; n=13, 6.9 months; P=0.06). Patients with WT KRAS with favorable kinetics had higher PFS (14.7 months) in comparison to those with WT KRAS with unfavorable kinetics (9.4 months; P=0.02). Moreover, patients whose imaging studies showed radiological progression had an increased quantification of CTCs at CTC2 compared to those without progression (P=0.04).

CONCLUSION

This study made possible the presentation of ISET as a feasible tool for evaluating CTC kinetics in patients with mCRC, which can be promising in their clinical evaluation.

Detection of KRAS mutations in circulating tumor cells from patients with metastatic colorectal cancer

BACKGROUND

Quantification of Circulating Tumor Cells (CTCs) as a prognostic marker in metastatic colorectal cancer (mCRC) has already been validated and approved for routine use. However, more than quantification, qualification or characterization of CTCs is gaining importance, since the genetic characterization of CTCs may reflect, in a real time fashion, genetic profile of the disease.

OBJECTIVE

To characterize KRAS mutations (codon 12 and 13) in CTCs from patients with mCRC and to compare with matched primary tumor. Additionally, correlate these mutations with clinical and pathological features of patients.

METHODS

Blood samples were collected from 26 patients with mCRC from the AC Camargo Cancer Center (São Paulo-Brazil). CTCs were isolated by ISET technology (Isolation by Size of Epithelial Tumors; Rarecells Diagnostics, France) and mutations analyzes were performed by pyrosequencing (QIAGEN).

RESULTS

KRAS mutation was detected in 7 of the 21 cases (33%) of samples from CTCs. In matched primary tumors, 9 of the 24 cases (37.5%) were found KRAS mutated. We observed that 5 of the 9 samples with KRAS mutation in their primary tumor had also KRAS mutation in CTCs, meaning a concordance of 71% of matched cases (P = 0.017). KRAS mutation neither on primary tumor nor in CTCs was associated with clinical-pathological parameters analyzed.

CONCLUSION

Faced with a polyclonal disease like colorectal cancer, which is often treated with alternating and successive lines of chemotherapy, real time genetic characterization of CTCs, in a fast and feasible fashion, can provide important information to clinical management of metastatic patients. Although our cohort was limited, it was possible to show a high grade of concordance between primary tumor and CTCs, which suggests that CTCs can be used as surrogate of primary tumors in clinical practice, when the knowledge of mutation profile is necessary and the primary tumor is not available.

Abstract 5188: Immunostaining of MRP-1 protein in circulating tumor cells predicts shorter progression free survival in metastatic colorectal cancer patients

Background: colorectal cancer (CRC) is the third leading cause of cancer death in both men and women in the United States (Siegel et al., 2014). So, it is important to look for novel biomarkers to identify and define the best treatment for patients with this disease. Circulating Tumor Cells (CTCs) have been appointed for many researchers as a manner to follow up patients at current status. MRP-1 protein acts as an ATP-dependent efflux pump, naturally protecting cells from both toxic and therapeutic compounds. It works as a drug resistant protein, generally with irinotecan-based chemotherapy (Cole, 2014; Gazzaniga et al., 2010). Objective: to study the presence of MRP-1 protein in CTCs and its predictable value in treatment resistance, evaluating the time of progression free survival (PFS). Methods: This present cohort (n = 18) belongs to a larger cohort of patients (n = 54) treated with many chemotherapeutic agents combined with 5-FU. The results of 5-FU resistance were presented previously in AACR annual meeting 2014. The blood was collected prospectively from patients with metastatic CRC. Blood was collected before the beginning of chemotherapy. The sample was filtered on ISET (Isolation by Size of Epithelial Tumor Cells, Rarecells, France) according to manufacture procedure. CTCs fixed on spots from ISET membranes were stained by immunocytochemistry with anti- MRP-1 antibody (1/100) and counterstained with hematoxylin-eosyn. Leucocytes were identified by anti-CD45 antibody. CTCs were analyzed by light microscope and quantified by 1 mL of blood. Results: here we analyzed blood samples of 18 mCRC patients who underwent irinotecan-based chemotherapy, with or without 5-FU. The median age was 54 years-old (32 - 80) and 77.7% were male. All the patients included were clinical stage IV with tumors classified as adenocarcinoma. The median CTC number detected was 1.5 CTC/ml (0 - 13.75) at baseline. Immunostaining of MRP-1 in CTCs was performed in all samples and 4 (21%) were found positive. By Kaplan-Meier test we observed that patients with CTC MRP-1 positive had shorter PFS than patients CTC MRP-1 negative (2.1 vs. 9.8 months respectively; P = 0.003). Interestingly, patients irinotecan resistant do not belong to the same group of patients 5-FU resistant (CTC TYMS positive, link: http://www.abstractsonline.com/Plan/ViewAbstract.aspx?mID = 3404&sKey = f39b6e91-7d91-4e03-a37e-3bc3724bade3&cKey = 1fa1e08e-af70-461a-9275-d8cdc2dd7b14&mKey = 6ffe1446-a164-476a-92e7-c26446874d93). Conclusion: the necessity of novel tools to follow up and to predict treatment response has been increasing. Here, we proposed a potential protein found in CTCs, MRP-1, which might represent a powerful tool to manage and triage patients candidate to receive treatment with irinotecan. Furthermore, we are the first group to demonstrate the role of MRP-1 in CTCs as a predictive factor for patients with metastatic CRC.

Citation Format: Emne A. Abdallah, Ludmilla T. D. Chinen, Virgílio S. Silva, Natalia B. Mingues, Marcelo C. Machado Netto, José Luiz Gasparini Júnior, Bruna M. M. Rocha, Juliana V. Romero, Marcilei E. C. Buim, Mitzi Brentani, Marcello F. Fanelli. Immunostaining of MRP-1 protein in circulating tumor cells predicts shorter progression free survival in metastatic colorectal cancer patients. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5188. doi:10.1158/1538-7445.AM2015-5188

Differential effects of paraoxon on the M3 muscarinic receptor and its effector system in rat submaxillary gland cells

The effects of the organophosphorus anticholinesterase paraoxon on the binding of radioactive ligands to the M3 subtype of the muscarinic receptor and receptor-coupled synthesis of second messengers in intact rat submaxillary gland (SMG) cells were investigated. The binding of [3H]quinuclidinyl benzilate ([3H]QNB) was most sensitive to atropine and the M3-specific antagonist 4-DAMP followed by pirenzepine and least sensitive to the cardioselective M2 antagonist AFDX116. This, and the binding characteristics of [3H]4-DAMP, confirmed that the muscarinic receptors in this preparation are of the M3 subtype. Activation of these muscarinic receptors by carbamylcholine (CBC) produced both stimulation of phosphoinositide (PI) hydrolysis and inhibition of cAMP synthesis, suggesting that this receptor subtype couples to both effector systems. Paraoxon (100 microM) reduced Bmax of [3H]4-DAMP binding from 27 +/- 4 to 13 +/- 3 fmol/mg protein with nonsignificant change in affinity, suggesting noncompetitive inhibition of binding by paraoxon. Like the agonist CBC, paraoxon inhibited the forskolin-induced cAMP formation in SMG cells with an EC50 of 200 nM, but paraoxon was greater than 500 fold more potent than CBC. However, while the inhibition by CBC was counteracted by 2 microM atropine, that by paraoxon was unaffected by up to 100 microM atropine. It suggested that this effect of paraoxon was not via binding to the muscarinic receptor. Paraoxon did not affect beta-adrenoreceptor function in the preparation, since it did not affect the 10 microM isoproterenol-induced cAMP synthesis, which was inhibited totally by 10 microM propranolol and partially by CBC. Paraoxon had a small but significant effect on CBC-stimulated PI metabolism in the SMG cells.(ABSTRACT TRUNCATED AT 250 WORDS)

The presence of an M4 subtype muscarinic receptor in the bovine adrenal medulla revealed by mRNA and receptor binding analyses

The muscarinic receptor subtype present in the bovine adrenal medulla was characterized. Hybridization of RNA to highly specific m1-m5 muscarinic receptor cDNA probes detected the presence of only m4 subtype mRNA in this tissue. Muscarinic receptor binding studies using the non-selective ligand [3H]N-methyl-scopolamine showed a single class of binding sites with a maximum density of 19.8 fmol/mg protein and a dissociation constant (KD) of 220 pM in the adrenal medulla, while the M1 selective ligand [3H]telenzepine did not bind detectably. Competition of specific antagonists with [3H]N-methyl-scopolamine for binding to the membranes produced a rank order of potencies with a profile that fitted either the cloned m3 or m4 receptor. In further comparative studies, the adrenal gland of the rat showed the presence of m4 subtype mRNA in addition to the m3 subtype.

DFP-induced regulation of cardiac muscarinic receptor mRNA in vivo measured by DNA-excess solution hybridization

Relationship between in vivo down-regulation of cardiac muscarinic receptors and changes in their encoding mRNA was investigated. Rats were treated either once or for ten days with an irreversible inhibitor of acetylcholinesterase, followed by measurements of cardiac acetylcholinesterase, the density and affinity of muscarinic receptors, and the concentration of mRNA coding for these receptors. mRNA was quantitated using the sensitive method of DNA-excess solution hybridization. Our data indicate that while short-term treatment resulted in a marked decrease in the density of cardiac muscarinic receptors by 34%, there was no accompanying significant change in the concentration of their mRNA. In contrast, long-term inhibition of acetylcholinesterase significantly decreased the concentration of both receptors and mRNA by 40% and 29%, respectively. These results are indicative of multiple mechanisms of down-regulation of cardiac muscarinic receptors, some of which might involve alterations at the transcriptional level.

Lack of desensitization of muscarinic receptor-mediated second messenger signals in rat brain upon acute and chronic inhibition of acetylcholinesterase

We studied the effects of acute and chronic in vivo inhibition of acetylcholinesterase on both the density and function of brain muscarinic cholinergic receptors. Adult male rats were treated either once or multiple times over a period of 10 days with the irreversible acetylcholinesterase inhibitor diisopropylfluorophosphate (DFP). The concentration and affinity of muscarinic receptors in various brain regions were determined using radioligand binding techniques. Acute DFP treatment resulted in a significant reduction in receptor number only in the brain stem, while chronic treatment caused receptor down-regulation in the brain stem, cerebral cortex, and striatum. There was no change in ligand affinity in any of the brain regions. In sharp contrast, muscarinic receptor function was fully preserved, in terms of coupling of the receptors to increased phosphoinositide hydrolysis in the cerebral cortex, hippocampus, and striatum, or inhibition of cyclic AMP formation in the cerebral cortex or striatum. Therefore, there is a marked lack or correlation between DFP-induced muscarinic receptor down-regulation and receptor desensitization.

Aging does not alter muscarinic receptor-mediated inhibition of cyclic AMP formation in the striatum and hippocampus

The effects of aging on the inhibition of forskolin-stimulated cyclic AMP formation by muscarinic receptors were investigated. There were no detectable changes in the magnitude of maximal inhibition by carbamylcholine or the potency of the agonist in inducing this response in either the striatum or hippocampus obtained from young or old Fisher 344 rats.

Relationship between the partial inhibition of muscarinic receptor-mediated phosphoinositide hydrolysis by phorbol esters and tetrodotoxin in rat cerebral cortex

Our results demonstrate that phorbol esters and tetrodotoxin (TTX) partially inhibit muscarinic receptor-mediated increase in phosphoinositide (PI) hydrolysis in rat cerebral cortex cell aggregates; this inhibition was observed using several muscarinic agonists. While these effects were not accompanied by major changes in the total muscarinic receptor population, phorbol esters, but not TTX, reduced the relative concentration of the high affinity binding sites of the M1-selective ligands pirenzepine and telenzepine. In contrast, the binding of a muscarinic agonist to multiple receptor conformations was not influenced by either phorbol esters or TTX. Our data also show that the partial inhibition of the PI response by these agents is not due to a selective effect on the response mediated by a certain muscarinic receptor subtype or a receptor population which is more sensitive to agonist-induced desensitization. Evidence is provided that the effects of both phorbol esters and TTX might be mediated largely, although not entirely, by a common mechanism.

Aging does not alter brain muscarinic receptor-mediated phosphoinositide hydrolysis and its inhibition by phorbol esters, tetrodotoxin and receptor desensitization

The effects of aging on muscarinic receptor-mediated phosphoinositide (PI) hydrolysis in the brain were investigated in Fischer-344 rats. Oxotremorine-M stimulated this response to the same magnitude in young and old rats in the cerebral cortex, striatum, hippocampus, thalamus, hypothalamus and cerebellum, although maximal stimulation varied among brain regions within each age group. The PI response was also equally potentiated by elevated K+ or suppressed by tetrodotoxin in both age groups. In addition, a phorbol ester attenuated muscarinic receptor-mediated PI hydrolysis in the cerebral cortex to the same extent in young and aged rats. Moreover, preincubation with oxotremorine-M resulted in a similar down-regulation of cell-surface receptors and desensitization of receptor function regardless of age. Therefore, under our experimental conditions, PI hydrolysis in response to activation of brain muscarinic receptors does not appear to be sensitive to aging-related alterations.