Resistance to BRAF inhibition explored through single circulating tumour cell molecular profiling in BRAF-mutant non-small-cell lung cancer.

BACKGROUND: Resistance mechanisms to combination therapy with dabrafenib plus trametinib remain poorly understood in patients with BRAFV600E-mutant advanced non-small-cell lung cancer (NSCLC). We examined resistance to BRAF inhibition by single CTC sequencing in BRAFV600E-mutant NSCLC. METHODS: CTCs and cfDNA were examined in seven BRAFV600E-mutant NSCLC patients at failure to treatment. Matched tumour tissue was available for four patients. Single CTCs were isolated by fluorescence-activated cell sorting following enrichment and immunofluorescence (Hoechst 33342/CD45/pan-cytokeratins) and sequenced for mutation and copy number-alteration (CNA) analyses. RESULTS: BRAFV600E was found in 4/4 tumour biopsies and 5/7 cfDNA samples. CTC mutations were mostly found in MAPK-independent pathways and only 1/26 CTCs were BRAFV600E mutated. CTC profiles encompassed the majority of matched tumour biopsy CNAs but 72.5% to 84.5% of CTC CNAs were exclusive to CTCs. Extensive diversity, involving MAPK, MAPK-related, cell cycle, DNA repair and immune response pathways, was observed in CTCs and missed by analyses on tumour biopsies and cfDNA. Driver alterations in clinically relevant genes were recurrent in CTCs. CONCLUSIONS: Resistance was not driven by BRAFV600E-mutant CTCs. Extensive tumour genomic heterogeneity was found in CTCs compared to tumour biopsies and cfDNA at failure to BRAF inhibition, in BRAFV600E-mutant NSCLC, including relevant alterations that may represent potential treatment opportunities.

Proficiency Testing to Assess Technical Performance for CTC-Processing and Detection Methods in CANCER-ID.

BACKGROUND: Multiple technologies are available for detection of circulating tumor cells (CTCs), but standards to evaluate their technical performance are still lacking. This limits the applicability of CTC analysis in clinic routine. Therefore, in the context of the CANCER-ID consortium, we established a platform to assess technical validity of CTC detection methods in a European multi-center setting using non-small cell lung cancer (NSCLC) as a model. METHODS: We characterized multiple NSCLC cell lines to define cellular models distinct in their phenotype and molecular characteristics. Standardized tumor-cell-bearing blood samples were prepared at a central laboratory and sent to multiple European laboratories for processing according to standard operating procedures. The data were submitted via an online tool and centrally evaluated. Five CTC-enrichment technologies were tested. RESULTS: We could identify 2 cytokeratin expressing cell lines with distinct levels of EpCAM expression: NCI-H441 (EpCAMhigh, CKpos) and NCI-H1563 (EpCAMlow, CKpos). Both spiked tumor cell lines were detected by all technologies except for the CellSearch system that failed to enrich EpCAMlow NCI-H1563 cells. Mean recovery rates ranged between 49% and 75% for NCI-H411 and 32% and 76% for NCI-H1563 and significant differences were observed between the tested methods. CONCLUSIONS: This multi-national proficiency testing of CTC-enrichment technologies has importance in the establishment of guidelines for clinically applicable (pre)analytical workflows and the definition of minimal performance qualification requirements prior to clinical validation of technologies. It will remain in operation beyond the funding period of CANCER-ID in the context of the European Liquid Biopsy Society (ELBS).

Toward a real liquid biopsy in metastatic breast and prostate cancer: Diagnostic LeukApheresis increases CTC yields in a European prospective multicenter study (CTCTrap).

Frequently, the number of circulating tumor cells (CTC) isolated in 7.5 mL of blood is too small to reliably determine tumor heterogeneity and to be representative as a "liquid biopsy". In the EU FP7 program CTCTrap, we aimed to validate and optimize the recently introduced Diagnostic LeukApheresis (DLA) to screen liters of blood. Here we present the results obtained from 34 metastatic cancer patients subjected to DLA in the participating institutions. About 7.5 mL blood processed with CellSearch® was used as "gold standard" reference. DLAs were obtained from 22 metastatic prostate and 12 metastatic breast cancer patients at four different institutions without any noticeable side effects. DLA samples were prepared and processed with different analysis techniques. Processing DLA using CellSearch resulted in a 0-32 fold increase in CTC yield compared to processing 7.5 mL blood. Filtration of DLA through 5 µm pores microsieves was accompanied by large CTC losses. Leukocyte depletion of 18 mL followed by CellSearch yielded an increase of the number of CTC but a relative decrease in yield (37%) versus CellSearch DLA. In four out of seven patients with 0 CTC detected in 7.5 mL of blood, CTC were detected in DLA (range 1-4 CTC). The CTC obtained through DLA enables molecular characterization of the tumor. CTC enrichment technologies however still need to be improved to isolate all the CTC present in the DLA.

First-in-human phase 1 of YS110, a monoclonal antibody directed against CD26 in advanced CD26-expressing cancers.

BACKGROUND: YS110 is a humanised IgG1 monoclonal antibody with high affinity to the CD26 antigen. YS110 demonstrated preclinical anti-tumour effects without significant side effects. METHODS: This FIH study was designed to determine the maximal tolerated dose (MTD) and recommended phase 2 dose (RP2D) to assess the tolerance, pharmacokinetics (PK) and pharmacodynamics profiles of YS110 and preliminary efficacy. YS110 were initially administered intravenously once every 2 weeks (Q2W) for three doses and then, based on PK data, once every week (Q1W) for five doses in patients with CD26-expressing solid tumours. RESULTS: Thirty-three patients (22 mesothelioma) received a median of 3 (range 1-30) YS110 infusions across six dose levels (0.1-6 mg kg-1). MTD was not reached and two dose-limiting toxicities (infusion hypersensitivity reactions) led to the institution of a systemic premedication. Low-grade asthenia (30.3%), hypersensitivity (27.3%), nausea (15.2%), flushing (15.2%), chills (12.1%) and pyrexia (12.1%) were reported as ADRs. Pharmacokinetic parameters (AUC and Cmax) increased in proportion with the dose. sCD26/DPPIV assays indicated CD26 modulation. Prolonged stable diseases were observed in 13 out of 26 evaluable patients. CONCLUSIONS: YS110 is well tolerated up to 6 mg kg-1 Q1W, which has been defined as the RP2D, with encouraging prolonged disease stabilisations observed in a number of patients with advanced/refractory mesothelioma.

Detection of Gene Rearrangements in Circulating Tumor Cells: Examples of ALK-, ROS1-, RET-Rearrangements in Non-Small-Cell Lung Cancer and ERG-Rearrangements in Prostate Cancer.

Circulating tumor cells (CTCs) hold promise as biomarkers to aid in patient treatment stratification and disease monitoring. Because the number of cells is a critical parameter for exploiting CTCs for predictive biomarker's detection, we developed a FISH (fluorescent in situ hybridization) method for CTCs enriched on filters (filter-adapted FISH [FA-FISH]) that was optimized for high cell recovery. To increase the feasibility and reliability of the analyses, we combined fluorescent staining and FA-FISH and developed a semi-automated microscopy method for optimal FISH signal identification in filtration-enriched CTCs . Here we present these methods and their use for the detection and characterization of ALK-, ROS1-, RET-rearrangement in CTCs from non-small-cell lung cancer and ERG-rearrangements in CTCs from prostate cancer patients.

Method for semi-automated microscopy of filtration-enriched circulating tumor cells.

BACKGROUND: Circulating tumor cell (CTC)-filtration methods capture high numbers of CTCs in non-small-cell lung cancer (NSCLC) and metastatic prostate cancer (mPCa) patients, and hold promise as a non-invasive technique for treatment selection and disease monitoring. However filters have drawbacks that make the automation of microscopy challenging. We report the semi-automated microscopy method we developed to analyze filtration-enriched CTCs from NSCLC and mPCa patients. METHODS: Spiked cell lines in normal blood and CTCs were enriched by ISET (isolation by size of epithelial tumor cells). Fluorescent staining was carried out using epithelial (pan-cytokeratins, EpCAM), mesenchymal (vimentin, N-cadherin), leukocyte (CD45) markers and DAPI. Cytomorphological staining was carried out with Mayer-Hemalun or Diff-Quik. ALK-, ROS1-, ERG-rearrangement were detected by filter-adapted-FISH (FA-FISH). Microscopy was carried out using an Ariol scanner. RESULTS: Two combined assays were developed. The first assay sequentially combined four-color fluorescent staining, scanning, automated selection of CD45(-) cells, cytomorphological staining, then scanning and analysis of CD45(-) cell phenotypical and cytomorphological characteristics. CD45(-) cell selection was based on DAPI and CD45 intensity, and a nuclear area >55 µm(2). The second assay sequentially combined fluorescent staining, automated selection of CD45(-) cells, FISH scanning on CD45(-) cells, then analysis of CD45(-) cell FISH signals. Specific scanning parameters were developed to deal with the uneven surface of filters and CTC characteristics. Thirty z-stacks spaced 0.6 µm apart were defined as the optimal setting, scanning 82 %, 91 %, and 95 % of CTCs in ALK-, ROS1-, and ERG-rearranged patients respectively. A multi-exposure protocol consisting of three separate exposure times for green and red fluorochromes was optimized to analyze the intensity, size and thickness of FISH signals. CONCLUSIONS: The semi-automated microscopy method reported here increases the feasibility and reliability of filtration-enriched CTC assays and can help progress towards their validation and translation to the clinic.

Phase I study of afatinib combined with nintedanib in patients with advanced solid tumours.

BACKGROUND: This Phase I study evaluated continuous- and intermittent-dosing (every other week) of afatinib plus nintedanib in patients with advanced solid tumours. METHODS: In the dose-escalation phase (n=45), maximum tolerated doses (MTDs) were determined for continuous/intermittent afatinib 10, 20, 30 or 40 mg once daily plus continuous nintedanib 150 or 200 mg twice daily. Secondary objectives included safety and efficacy. Clinical activity of continuous afatinib plus nintedanib at the MTD was further evaluated in an expansion phase (n=25). RESULTS: The most frequent dose-limiting toxicities were diarrhoea (11%) and transaminase elevations (7%). Maximum tolerated doses were afatinib 30 mg continuously plus nintedanib 150 mg, and afatinib 40 mg intermittently plus nintedanib 150 mg. Treatment-related adverse events (mostly Grade⩽3) included diarrhoea (98%), asthenia (64%), nausea (62%) and vomiting (60%). In the dose-escalation phase, two patients had partial responses (PRs) and 27 (60%) had stable disease (SD). In the expansion phase, one complete response and three PRs were observed (all non-small cell lung cancer), with SD in 13 (52%) patients. No pharmacokinetic interactions were observed. CONCLUSIONS: MTDs of continuous or intermittent afatinib plus nintedanib demonstrated a manageable safety profile with proactive management of diarrhoea. Antitumour activity was observed in patients with solid tumours.

Microfluidic sorting and multimodal typing of cancer cells in self-assembled magnetic arrays.

We propose a unique method for cell sorting, "Ephesia," using columns of biofunctionalized superparamagnetic beads self-assembled in a microfluidic channel onto an array of magnetic traps prepared by microcontact printing. It combines the advantages of microfluidic cell sorting, notably the application of a well controlled, flow-activated interaction between cells and beads, and those of immunomagnetic sorting, notably the use of batch-prepared, well characterized antibody-bearing beads. On cell lines mixtures, we demonstrated a capture yield better than 94%, and the possibility to cultivate in situ the captured cells. A second series of experiments involved clinical samples--blood, pleural effusion, and fine needle aspirates--issued from healthy donors and patients with B-cell hematological malignant tumors (leukemia and lymphoma). The immunophenotype and morphology of B-lymphocytes were analyzed directly in the microfluidic chamber, and compared with conventional flow cytometry and visual cytology data, in a blind test. Immunophenotyping results using Ephesia were fully consistent with those obtained by flow cytometry. We obtained in situ high resolution confocal three-dimensional images of the cell nuclei, showing intranuclear details consistent with conventional cytological staining. Ephesia thus provides a powerful approach to cell capture and typing allowing fully automated high resolution and quantitative immunophenotyping and morphological analysis. It requires at least 10 times smaller sample volume and cell numbers than cytometry, potentially increasing the range of indications and the success rate of microbiopsy-based diagnosis, and reducing analysis time and cost.

Hyperthermic pelvic perfusion with tumor necrosis factor-α for locally advanced cancers: encouraging results of a phase II study.

PURPOSE: To assess the efficacy of isolated pelvic perfusion (IPP) with tumor necrosis factor (TNF)-α and melphalan in patients with locally advanced cancers in the pelvic and groin area requiring mutilating surgery. METHODS: A total of 27 patients were enrolled (carcinoma, n = 17; sarcoma/melanoma, n = 4; and endocrine tumor, n = 6). They were candidates for exarticulation (n = 3) or exenteration (n = 11) or were judged unresectable (n = 13). In installing IPP, tourniquets were positioned around both thighs, and an inflated pressure suit was placed at a subthoracic position. Tumor necrosis factor-α (300 µg) was injected in the perfusate, followed 5 minutes later by melphalan at 1.5 mg/kg. After 30 minutes, the remaining drugs were washed out. Leakage was assessed with technetium Tc 99m radiolabeled human serum albumin, and a pharmacokinetic study was performed. Efficacy was based on the complete response rate observed on magnetic resonance imaging. RESULTS: Pelvic/systemic ratios of melphalan/TNF/technetium Tc 99m were 14.2/7/3.6. Responses on magnetic resonance imaging were as follows: 30% complete, 30% partial, 19% no change, and 15% progression. Two patients were not evaluable because they did not receive the treatment. Pre-IPP/post-IPP median percentage of necrosis on magnetic resonance imaging was 10%/70%. Median follow-up was 43 months. Median overall survival was 17 months. Twelve-month survival rate, disease-free survival, and local and metastatic recurrence rates were 67%, 30%, 57%, and 26%, respectively. CONCLUSIONS: Isolated pelvic perfusion with TNF-α compares favorably with historical data, as it was observed in limb perfusion and could provide a chance to translate its successful combination with chemotherapy into treatment of locally advanced pelvic cancers.

Efficacy, safety, and biomarkers of single-agent bevacizumab therapy in patients with advanced hepatocellular carcinoma.

OBJECTIVE: Hepatocellular carcinoma (HCC) is a highly vascularized tumor in which neoangiogenesis contributes to growth and metastasis. We assessed the safety, efficacy, and potential biomarkers of activity of bevacizumab in patients with advanced HCC. METHODS: In this phase II trial, eligible patients received bevacizumab, 5 mg/kg or 10 mg/kg every 2 weeks. The disease-control rate at 16 weeks (16W-DCR) was the primary endpoint. Circulating endothelial cells (CECs) and plasma cytokines and angiogenic factors (CAFs) were measured at baseline and throughout treatment. RESULTS: The 16W-DCR was 42% (95% confidence interval, 27%-57%). Six of the 43 patients who received bevacizumab achieved a partial response (objective response rate [ORR], 14%). Grade 3-4 asthenia, hemorrhage, and aminotransferase elevation occurred in five (12%), three (7%), and three (7%) patients, respectively. During treatment, placental growth factor markedly increased, whereas vascular endothelial growth factor (VEGF)-A dramatically decreased (p < .0001); soluble VEGF receptor-2 (p < .0001) and CECs (p = .03) transiently increased on day 3. High and increased CEC counts at day 15 were associated with the ORR (p = .04) and the 16W-DCR (p = .02), respectively. Lower interleukin (IL)-8 levels at baseline (p = .01) and throughout treatment (p ≤ .04) were associated with the 16W-DCR. High baseline IL-8 and IL-6 levels predicted shorter progression-free and overall survival times (p ≤ .04). CONCLUSION: Bevacizumab is active and well tolerated in patients with advanced HCC. The clinical value of CECs, IL-6, and IL-8 warrants further investigation.

Circulating tumor cells in lung cancer.

Circulating tumor cells (CTCs) have emerged as potential biomarkers in several cancers such as colon, prostate, and breast carcinomas, with a correlation between CTC number and patient prognosis being established by independent research groups. The detection and enumeration of CTCs, however, is still a developing field, with no universal method of detection suitable for all types of cancer. CTC detection in lung cancer in particular has proven difficult to perform, as CTCs in this type of cancer often present with nonepithelial characteristics. Moreover, as many detection methods rely on the use of epithelial markers to identify CTCs, the loss of these markers during epithelial-to-mesenchymal transition in certain metastatic cancers can render these methods ineffective. The development of personalized medicine has led to an increase in the advancement of molecular characterization of CTCs. The application of techniques such as FISH and RT-PCR to detect EGFR, HER2, and KRAS abnormalities in lung, breast, and colon cancer, for example, could be used to characterize CTCs in real time. The use of CTCs as a 'liquid biopsy' is therefore an exciting possibility providing information on patient prognosis and treatment efficacy. This review summarizes the state of CTC detection today, with particular emphasis on lung cancer, and discusses the future applications of CTCs in helping the clinician to develop new strategies in patient treatment.

Targeting genome integrity dysfunctions impedes metastatic potency in non-small cell lung cancer circulating tumor cell-derived explants.

DNA damage and genomic instability contribute to non-small cell lung cancer (NSCLC) etiology and progression. However, their therapeutic exploitation is disappointing. CTC-derived explants (CDX) offer systems for mechanistic investigation of CTC metastatic potency and may provide rationale for biology-driven therapeutics. Four CDX models and 3 CDX-derived cell lines were established from NSCLC CTCs and recapitulated patient tumor histology and response to platinum-based chemotherapy. CDX (GR-CDXL1, GR-CDXL2, GR-CDXL3, GR-CDXL4) demonstrated considerable mutational landscape similarity with patient tumor biopsy and/or single CTCs. Truncal alterations in key DNA damage response (DDR) and genome integrity-related genes were prevalent across models and assessed as therapeutic targets in vitro, in ovo, and in vivo. GR-CDXL1 presented homologous recombination deficiency linked to biallelic BRCA2 mutation and FANCA deletion, unrepaired DNA lesions after mitosis, and olaparib sensitivity, despite resistance to chemotherapy. SLFN11 overexpression in GR-CDXL4 led to olaparib sensitivity and was in coherence with neuroendocrine marker expression in patient tumor biopsy, suggesting a predictive value of SLFN11 in NSCLC histological transformation into small cell lung cancer (SCLC). Centrosome clustering promoted targetable chromosomal instability in GR-CDXL3 cells. These CDX unravel DDR and genome integrity-related defects as a central mechanism underpinning metastatic potency of CTCs and provide rationale for their therapeutic targeting in metastatic NSCLC.

The selective VEGFR1-3 inhibitor axitinib (AG-013736) shows antitumor activity in human neuroblastoma xenografts.

Tumor angiogenesis in childhood neuroblastoma is an important prognostic factor suggesting a potential role for antiangiogenic agents in the treatment of high-risk disease. Within the KidsCancerKinome project, we evaluated the new oral selective pan-VEGFR tyrosine kinase inhibitor axitinib (AG-013736) against neuroblastoma cell lines and the subcutaneous and orthotopic xenograft model IGR-N91 derived from a primary bone marrow metastasis. Axitinib reduced cell proliferation in a dose-dependent manner with IC(50) doses between 274 and >10,000 nmol/l. Oral treatment with 30 mg/kg BID for 2 weeks in advanced tumors yielded significant tumor growth delay, with a median time to reach five times initial tumor volume of 11.4 days compared to controls (p = 0.0006) and resulted in significant reduction in bioluminescence. Simultaneous inhibition of VEGFR downstream effector mTOR using rapamycin 20 mg/kg q2d×5 did not statistically enhance tumor growth delay compared to single agent activities. Axitinib downregulated VEGFR-2 phosphorylation resulting in significantly decreased microvessel density (MVD) and overall surface fraction of tumor vessels (OSFV) in all xenografts as measured by CD34 immunohistochemical staining (mean MVD ± SD and OSFV at 14 days 21.27 ± 10.03 in treated tumors vs. 48.79 ± 17.27 in controls and 0.56% vs. 1.29%; p = 0.0006, respectively). We further explored the effects of axitinib on circulating mature endothelial cells (CECs) and endothelial progenitor cells (CEPs) measured by flow cytometry. While only transient modification was observed for CECs, CEP counts were significantly reduced during and up to 14 days after end of treatment. Axitinib has potent antiangiogenic properties that may warrant further evaluation in neuroblastoma.

Tumor Evolution and Therapeutic Choice Seen through a Prism of Circulating Tumor Cell Genomic Instability.

Circulating tumor cells (CTCs) provide an accessible tool for investigating tumor heterogeneity and cell populations with metastatic potential. Although an in-depth molecular investigation is limited by the extremely low CTC count in circulation, significant progress has been made recently in single-cell analytical processes. Indeed, CTC monitoring through molecular and functional characterization may provide an understanding of genomic instability (GI) molecular mechanisms, which contribute to tumor evolution and emergence of resistant clones. In this review, we discuss the sources and consequences of GI seen through single-cell analysis of CTCs in different types of tumors. We present a detailed overview of chromosomal instability (CIN) in CTCs assessed by fluorescence in situ hybridization (FISH), and we reveal utility of CTC single-cell sequencing in identifying copy number alterations (CNA) oncogenic drivers. We highlight the role of CIN in CTC-driven metastatic progression and acquired resistance, and we comment on the technical obstacles and challenges encountered during single CTC analysis. We focus on the DNA damage response and depict DNA-repair-related dynamic biomarkers reported to date in CTCs and their role in predicting response to genotoxic treatment. In summary, the suggested relationship between genomic aberrations in CTCs and prognosis strongly supports the potential utility of GI monitoring in CTCs in clinical risk assessment and therapeutic choice.

Circulating tumor cell copy-number heterogeneity in ALK-rearranged non-small-cell lung cancer resistant to ALK inhibitors.

Gatekeeper mutations are identified in only 50% of the cases at resistance to Anaplastic Lymphoma Kinase (ALK)-tyrosine kinase inhibitors (TKIs). Circulating tumor cells (CTCs) are relevant tools to identify additional resistance mechanisms and can be sequenced at the single-cell level. Here, we provide in-depth investigation of copy number alteration (CNA) heterogeneity in phenotypically characterized CTCs at resistance to ALK-TKIs in ALK-positive non-small cell lung cancer. Single CTC isolation and phenotyping were performed by DEPArray or fluorescence-activated cell sorting following enrichment and immunofluorescence staining (ALK/cytokeratins/CD45/Hoechst). CNA heterogeneity was evaluated in six ALK-rearranged patients harboring ≥ 10 CTCs/20 mL blood at resistance to 1st and 3rd ALK-TKIs and one presented gatekeeper mutations. Out of 82 CTCs isolated by FACS, 30 (37%) were ALK+/cytokeratins-, 46 (56%) ALK-/cytokeratins+ and 4 (5%) ALK+/cytokeratins+. Sequencing of 43 CTCs showed highly altered CNA profiles and high levels of chromosomal instability (CIN). Half of CTCs displayed a ploidy >2n and 32% experienced whole-genome doubling. Hierarchical clustering showed significant intra-patient and wide inter-patient CTC diversity. Classification of 121 oncogenic drivers revealed the predominant activation of cell cycle and DNA repair pathways and of RTK/RAS and PI3K to a lower frequency. CTCs showed wide CNA heterogeneity and elevated CIN at resistance to ALK-TKIs. The emergence of epithelial ALK-negative CTCs may drive resistance through activation of bypass signaling pathways, while ALK-rearranged CTCs showed epithelial-to-mesenchymal transition characteristics potentially contributing to ALK-TKI resistance. Comprehensive analysis of CTCs could be of great help to clinicians for precision medicine and resistance to ALK-targeted therapies.

EPAC-lung: European pooled analysis of the prognostic value of circulating tumour cells in small cell lung cancer.

BACKGROUND: Circulating tumour cell (CTC) number is an independent prognostic factor in patients with small cell lung cancer (SCLC) but there is no consensus on the CTC threshold for prognostic significance. We undertook a pooled analysis of individual patient data to clinically validate CTC enumeration and threshold for prognostication. METHODS: Four European cancer centres, experienced in CellSearch CTC enumeration for SCLC provided pseudo anonymised data for patients who had undergone pre-treatment CTC count. Data was collated, and Cox regression models, stratified by centre, explored the relationship between CTC count and survival. The added value of incorporating CTCs into clinico-pathological models was investigated using likelihood ratio tests. RESULTS: A total of 367 patient records were evaluated. A one-unit increase in log-transformed CTC counts corresponded to an estimated hazard ratio (HR) of 1.24 (95% CI: 1.19-1.29, P<0.0001) for progression free survival (PFS) and 1.23 (95% CI: 1.18-1.28, P<0.0001) for overall survival (OS). CTC count of ≥15 or ≥50 was significantly associated with an increased risk of progression (CTC ≥15: HR 3.20, 95% CI: 2.50-4.09, P<0.001; CTC ≥50: HR 2.56, 95% CI: 2.01-3.25, P<0.001) and an increased risk of death (CTC ≥15: HR 2.90, 95% CI: 2.28-3.70, P<0.001; CTC ≥50: HR 2.47, 95% CI: 1.95-3.13, P<0.001). There was no significant inter-centre heterogeneity observed. Addition of CTC count to clinico-pathological models as a continuous log-transformed variable, offers further prognostic value (both likelihood ratio P<0.001 for OS and PFS). CONCLUSIONS: Higher pre-treatment CTC counts are a negative independent prognostic factor in SCLC when considered as a continuous variable or dichotomised counts of ≥15 or ≥50. Incorporating CTC counts, as a continuous variable, improves clinic-pathological prognostic models.

SFCE-RAPIRI Phase I Study of Rapamycin Plus Irinotecan: A New Way to Target Intra-Tumor Hypoxia in Pediatric Refractory Cancers.

Hypoxic environment is a prognostic factor linked in pediatric cancers to a worse outcome, favoring tumor progression and resistance to treatments. The activation of mechanistic Target Of Rapamycin (mTor)/hypoxia inducible factor (HIF)-1 pathway can be targeted by rapamycin and irinotecan, respectively. Therefore, we designed a phase I trial associating both drugs in pediatric refractory/relapsing solid tumors. Patients were enrolled according to a 3 + 3 escalation design with ten levels, aiming to determine the MTD (maximum tolerated dose) of rapamycin plus irinotecan. Rapamycin was administered orally once daily in a 28-day cycle (1 to 2.5 mg/m2/day), associating biweekly intravenous irinotecan (125 to 240 mg/m2/dose). Toxicities, pharmacokinetics, efficacy analyses, and pharmacodynamics were evaluated. Forty-two patients, aged from 2 to 18 years, were included. No MTD was reached. Adverse events were mild to moderate. Only rapamycin doses of 1.5 mg/m2/day reached over time clinically active plasma concentrations. Tumor responses and prolonged stable disease were associated with a mean irinotecan area under the curve of more than 400 min.mg/L. Fourteen out of 31 (45.1%) patients had a non-progressive disease at 8 weeks. Most of them were sarcomas and brain tumors. For the phase II trial, we can then propose biweekly 125 mg/m2 irinotecan dose with a pharmacokinetic (PK) follow-up and a rapamycin dose of 1.5 mg/m2/day, reaching a blood concentration above 10 g/L.

Genetic characterization of a unique neuroendocrine transdifferentiation prostate circulating tumor cell-derived eXplant model.

Transformation of castration-resistant prostate cancer (CRPC) into an aggressive neuroendocrine disease (CRPC-NE) represents a major clinical challenge and experimental models are lacking. A CTC-derived eXplant (CDX) and a CDX-derived cell line are established using circulating tumor cells (CTCs) obtained by diagnostic leukapheresis from a CRPC patient resistant to enzalutamide. The CDX and the derived-cell line conserve 16% of primary tumor (PT) and 56% of CTC mutations, as well as 83% of PT copy-number aberrations including clonal TMPRSS2-ERG fusion and NKX3.1 loss. Both harbor an androgen receptor-null neuroendocrine phenotype, TP53, PTEN and RB1 loss. While PTEN and RB1 loss are acquired in CTCs, evolutionary analysis suggest that a PT subclone harboring TP53 loss is the driver of the metastatic event leading to the CDX. This CDX model provides insights on the sequential acquisition of key drivers of neuroendocrine transdifferentiation and offers a unique tool for effective drug screening in CRPC-NE management.

An Accessible and Unique Insight into Metastasis Mutational Content Through Whole-exome Sequencing of Circulating Tumor Cells in Metastatic Prostate Cancer.

BACKGROUND: Genomic analysis of circulating tumor cells (CTCs) could provide a unique and accessible representation of tumor diversity but remains hindered by technical challenges associated with CTC rarity and heterogeneity. OBJECTIVE: To evaluate CTCs as surrogate samples for genomic analyses in metastatic castration-resistant prostate cancer (mCRPC). DESIGN, SETTING, AND PARTICIPANTS: Three isolation strategies (filter laser-capture microdissection, self-seeding microwell chips, and fluorescence-activated cell sorting) were developed to capture CTCs with various epithelial and mesenchymal phenotypes and isolate them at the single-cell level. Whole-genome amplification (WGA) and WGA quality control were performed on 179 CTC samples, matched metastasis biopsies, and negative controls from 11 patients. All patients but one were pretreated with enzalutamide or abiraterone. Whole-exome sequencing (WES) of 34 CTC samples, metastasis biopsies, and negative controls were performed for seven patients. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: WES of CTCs was rigorously qualified in terms of percentage coverage at 10× depth, allelic dropout, and uncovered regions. Shared somatic mutations between CTCs and matched metastasis biopsies were identified. A customized approach based on determination of mutation rates for CTC samples was developed for identification of CTC-exclusive mutations. RESULTS AND LIMITATIONS: Shared mutations were mostly detected in epithelial CTCs and were recurrent. For two patients for whom a deeper analysis was performed, a few CTCs were sufficient to represent half to one-third of the mutations in the matched metastasis biopsy. CTC-exclusive mutations were identified in both epithelial and nonepithelial CTCs and affected cytoskeleton, invasion, DNA repair, and cancer-driver genes. Some 41% of CTC-exclusive mutations had a predicted deleterious impact on protein function. Phylogenic relationships between CTCs with distinct phenotypes were evidenced. CONCLUSIONS: CTCs can provide unique insight into metastasis mutational diversity and reveal undiagnosed genomic aberrations in matched metastasis biopsies. PATIENT SUMMARY: Our results demonstrate the clinical potential of circulating tumor cells to provide insight into metastatic events that could be critical to target using precision medicine.

Circulating tumor cells (CTCs) for the noninvasive monitoring and personalization of non-small cell lung cancer (NSCLC) therapies.

Growing evidences for tumor heterogeneity confirm that single-tumor biopsies frequently fail to reveal the widespread mutagenic profile of tumor. Repeated biopsies are in most cases unfeasible, especially in advanced cancers. We describe here how circulating tumor cells (CTCs) isolated from minimally invasive blood sample might inform us about intratumor heterogeneity, tumor evolution and treatment resistance. We also discuss the advances of CTCs research, most notably in molecularly selected non-small cell lung cancer (NSCLC) patients, highlighting challenges and opportunities related to personalized therapy.