ObjectiveAlthough counting of circulating tumour cells (CTC) has attracted a broad interest as potential markers of tumour progression and treatment response, the lack of functional characterisation of these cells had become a bottleneck in taking these observations to the clinic. Our objective was to culture these cells in order to understand them and exploit their therapeutic potential to the full.DesignHere, hypothesising that some CTC potentially have cancer stem cell (CSC) phenotype, we generated several CTC lines from the blood of patients with advanced metastatic colorectal cancer (CRC) based on their self-renewal abilities. Multiple standard tests were then employed to characterise these cells.ResultsOur CTC lines self-renew, express CSC markers and have multilineage differentiation ability, both in vitro and in vivo. Patient-derived CTC lines are tumorigenic in subcutaneous xenografts and are also able to colonise the liver after intrasplenic injection. RNA sequencing analyses strikingly demonstrate that drug metabolising pathways represent the most upregulated feature among CTC lines in comparison with primary CRC cells grown under similar conditions. This result is corroborated by the high resistance of the CTC lines to conventional cytotoxic compounds.ConclusionsTaken together, our results directly demonstrate the existence of patient-derived colorectal CTCs that bear all the functional attributes of CSCs. The CTC culture model described here is simple and takes <1 month from blood collection to drug testing, therefore, routine clinical application could facilitate access to personalised medicine.Clinical Trial RegistrationClinicalTrial.gov NCT01577511.

Since January 2021, the diffusion of the most propagated SARS-CoV-2 variants in France (UK variant 20I/501Y.V1 (lineage B.1.1.7), 20H/H501Y.V2 (lineage B.1.351) and 20J/H501Y.V3 (lineage P.1)) were urgently screened, needing a surveillance with an RT-PCR screening assay. In this study, we evaluated one RT-PCR kit for this screening (ID SARS-CoV-2/UK/SA Variant Triplex®, ID Solutions, Grabels, France) on 2207 nasopharyngeal samples that were positive for SARS-CoV-2. Using ID Solutions kit, 4.1% (92/2207) of samples were suspected to belonged to B.1.351 or P.1 variants. Next-generation sequencing that was performed on 67.4% (62/92) of these samples confirmed the presence of a B.1.351 variant in only 75.8% of the samples (47/62). Thirteen samples belonged to the UK variant (B.1.1.7), and two to A.27 with N501Y mutation. The thirteen with the UK variant presented one mutation in the S-gene, near the ΔH69/ΔV70 deletion (S71F or A67S), which impacted the detection of ΔH69/ΔV70 deletion. Using another screening kit (PKampVariantDetect SARS-CoV-2 RT-PCR combination 1 and 3® PerkinElmer, Waltham, MA, USA) on the misidentified samples, we observed that the two mutations, S71F or A67S, did not impact the detection of the UK variant. In conclusion, this study highlights the limitations of the screening strategy based on the detection of few mutations/deletions as well as it not being able to follow the virus evolution.

To support the global restart of elective surgery, data from an international prospective cohort study of 8492 patients (69 countries) was analysed using artificial intelligence (machine learning techniques) to develop a predictive score for mortality in surgical patients with SARS-CoV-2. We found that patient rather than operation factors were the best predictors and used these to create the COVIDsurg Mortality Score (https://covidsurgrisk.app). Our data demonstrates that it is safe to restart a wide range of surgical services for selected patients.

Chronic myeloid leukemia (CML) patients treated with imatinib develop frequent resistance generally due to a point mutation. Recently, large rearrangements of abl sequence have also been described. In this study, we focused on the complete deletion of exon 7. We screened for bcr-abl delexon7 in 63 resistant patients by high-resolution melting (HRM) analysis and direct sequencing. Moreover, we analyzed expression of abl delexon7 and bcr-abl delexon7 in 17 CML patients at diagnosis, 32 patients at resistance, and 20 negative controls by quantitative PCR or fragment length analysis. bcr-abl delexon7 was detected on 34 (54%) among 63 resistant patients by HRM, showing an increase in the sensitivity of screening, because only 3.2% could be detected by direct sequencing. This deletion was not associated with a point mutation (P = 0.3362). In addition, abl delexon7 was found in all tested samples with the same pattern of expression, suggesting an alternative splicing mechanism. In the bcr-abl component, there was no statistical difference between CML patients at diagnosis and resistant patients (P = 0.2815) as regarding bcr-abl delexon7 proportion, thus arguing against involvement of deletion in resistance. Moreover, among two patients harboring bcr-abl delexon7 at diagnosis, one experienced a complete disappearance of this transcript, and the other decreased >75% at resistance. In conclusion, bcr-abl delexon7 is frequently observed in CML patients when using sensitive techniques. It seems to be the result of an alternative splicing mechanism and to be independent from the occurrence of resistance. Mol Cancer Ther; 9(11); 3083-9. ©2010 AACR.