Could palliative sedation be seen as unnamed euthanasia?: a survey among healthcare professionals in oncology

BACKGROUND

In 2016 a French law created a new right for end-of-life patients: deep and continuous sedation maintained until death, with discontinuation of all treatments sustaining life such as artificial nutrition and hydration. It was totally unprecedented that nutrition and hydration were explicitly defined in France as sustaining life treatments, and remains a specificity of this law. End- of-life practices raise ethical and practical issues, especially in Europe actually. We aimed to know how oncology professionals deal with the law, their opinion and experience and their perception.

METHODS

Online mono-centric survey with closed-ended and open-ended questions in a Cancer Comprehensive Centre was elaborated. It was built during workshops of the ethics committee of the Institute, whose president is an oncologist with a doctoral degree in medical ethics. 58 oncologists and 121 nurses-all professionals of oncological departments -, received it, three times, as mail, with an information letter.

RESULTS

63/ 179 professionals answered the questionnaire (35%). Conducting end-of-life discussions and advanced care planning were reported by 46/63 professionals. In the last three months, 18 doctors and 7 nurses faced a request for a deep and continuous sedation maintained until death, in response to physical or existential refractory suffering. Artificial nutrition and even more hydration were not uniformly considered as treatment. Evaluation of the prognosis, crucial to decide a deep and continuous sedation maintained until death, appears to be very difficult and various, between hours and few weeks. Half of respondents were concerned that this practice could lead to or hide euthanasia practices, whereas for the other half, this new law formalised practices necessary for the quality of palliative care at the end-of-life.

CONCLUSION

Most respondents support the implementation of deep and continuous sedation maintained until death in routine end-of-life care. Nevertheless, difficulty to stop hydration, confusion with euthanasia practices, ethical debates it provokes and the risk of misunderstanding within teams and with families are significant. This is certainly shared by other teams. This could lead to a multi-centric survey and if confirmed might be reported to the legislator.

Accelerated subsequent lung cancer after post-operative radiotherapy for breast cancer

BACKGROUND

Post-operative whole breast radiotherapy for breast cancer (BC) may increase the risk of subsequent lung cancer (LC). The impact of radiotherapy intensification (boost) has not been specifically explored in this context. We investigated the role of radiation modalities on the development of subsequent LC among our patients treated by radiotherapy for localized BC.

METHODS

All patients with a diagnosis of LC between 2000 and 2020 with a history of prior localized BC treated by surgery and post-operative radiotherapy were retrospectively reviewed. Primary endpoint was time to first diagnosis of LC after BC treatment with radiotherapy (RT).

RESULTS

From 98 patients who developed subsequent LC after primary BC treated with post-operative RT, 38% of patients (n = 37) received an additional RT boost, and 46% (n = 45) received hormonal treatment post radiation. A total of 61% (n = 60) were smokers. With regards to LC characteristics, adenocarcinoma was the most frequent histology (68%, n = 66); 36% (n = 35) harbored at least 1 molecular alteration, 57% (n = 20) of them being amenable to targeted therapy. Median time to first diagnosis of LC was 6 years [1.7-28.4 yrs] in the whole cohort. In the subgroup of patients treated with boost this time was reduced to 4 years [1.8-20.8 years] compared to 8 years for patients without boost [1.7-28.4 yrs] (p = 0.007). Boost, smoking usage, endocrine therapy, and age <50 yrs old at BC radiation remained independent factors associated with shorter time to first diagnosis of LC after BC treatment.

DISCUSSION

We report for the first time the potential impact of boost -part of BC radiation treatment- for BC on the risk of subsequent LC. The impact of low dose radiation on lung parenchyma could explain this phenomenon, but the underlying physiopathology is still under investigation. This work highlights the need for clinicians to identify patients at risk of developing faster subsequent thoracic malignancy after BC radiation, for implementing personalized surveillance.

Federated learning for predicting histological response to neoadjuvant chemotherapy in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a rare cancer, characterized by high metastatic potential and poor prognosis, and has limited treatment options. The current standard of care in nonmetastatic settings is neoadjuvant chemotherapy (NACT), but treatment efficacy varies substantially across patients. This heterogeneity is still poorly understood, partly due to the paucity of curated TNBC data. Here we investigate the use of machine learning (ML) leveraging whole-slide images and clinical information to predict, at diagnosis, the histological response to NACT for early TNBC women patients. To overcome the biases of small-scale studies while respecting data privacy, we conducted a multicentric TNBC study using federated learning, in which patient data remain secured behind hospitals' firewalls. We show that local ML models relying on whole-slide images can predict response to NACT but that collaborative training of ML models further improves performance, on par with the best current approaches in which ML models are trained using time-consuming expert annotations. Our ML model is interpretable and is sensitive to specific histological patterns. This proof of concept study, in which federated learning is applied to real-world datasets, paves the way for future biomarker discovery using unprecedentedly large datasets.

Psychometric properties of the French Hot Flash Related Daily Interference Scale (HFRDIS)

OBJECTIVE

Hot flashes are one of the major symptoms of climacteric syndrome. Despite the high prevalence of these symptoms, few questionnaires assessing the impact of hot flashes on quality of life have been validated. The aim of this study was to validate a French version of the Hot Flash Related Daily Interference Scale (HFRDIS) in a sample of French women.

METHODS

In this prospective study, data were obtained from two groups of women aged between 40 and 60 years from both women without breast cancer and women under hormone therapy for breast cancer between March 2021 and February 2022. Translation was made by an official English-French translator using the forward-backward method.

RESULTS

One hundred and sixty-seven women completed the HFRDIS questionnaire. The scree plots confirmed unidimensional structure. Cronbach's α coefficient was 0.92 [0.90-0.94] similar to the original version. The intra-class correlation coefficients of each item ranged between 0.58 and 0.71 Concordance of the scores of each item with those obtained during the validation of the original version of the HFRDIS was confirmed.

CONCLUSION

The validation results show that the French version of the HFRDIS questionnaire is a valid tool to evaluate the impact of hot flashes on the daily life activities of patients.

Collaborative federated learning behind hospitals’ firewalls for predicting histological complete response to neoadjuvant chemotherapy in triple-negative breast cancer

590

Background: Triple-Negative Breast Cancer (TNBC) is characterized by high metastatic potential and poor prognosis with limited treatment options. Neoadjuvant chemotherapy (NACT) is the standard of care in non-metastastic setting due to the ability to assess pathologic responses providing important prognostic information and guidance in adjuvant therapy decisions. However, the histological response heterogeneity is still poorly understood. We investigate the use of Machine Learning (ML) to predict from diagnosis Whole-Slide Images (WSI) of early TNBC the positive histological Complete Response (pCR) to NACT on surgical specimens. To overcome the known biases of small scale studies while respecting data privacy, we conduct a study in a multi-centric fashion behind hospitals’ firewalls using collaborative Federated Learning (FL). Thereby allowing access to enough TNBC data to sustain a complete response heterogeneity investigation. Methods: We collected in both comprehensive cancer centers: Centre Léon Bérard (A)(n=99) and Institut Curie (B) (n=420), WSI of biopsies performed at diagnosis and relevant clinical variables. We use traditional Multiple Instance Learning pipelines by tiling the matter on each WSI with a pre-trained Neural Network (NN). We train a second NN to predict the NACT pCR using the mean feature of each WSI. ML trainings are performed using either one cohort in isolation (NN Local) or both cohorts using FL. We compare the performance of this federated WSI based model to the best clinical model (Clin.) simulating clinical practice (using grade and Tumor-Infiltrating Lymphocytes (TILs) percentage) on both centers. Results: Performance of models to predict NACT pCR (AUC). All results are evaluated in 5 repeated 4-folds cross validations. Conclusions: The final ML model, that was trained in a privacy preserving fashion on both hospitals, provides better prediction of NACT pCR than current clinical standards. This study shows that 1. Not all relevant information is routinely extracted from WSI and 2. Non simulated FL is possible in Healthcare and gives better results than siloed studies on open medical questions. Additional interpretability results of the model show that it has re-discovered known biomarkers such as TILs and apocrine tumor cells without any tile-level annotation, and hints at potential new biomarkers. [Table: see text]

Digital phenotyping in young breast cancer patients treated with neoadjuvant chemotherapy (the NeoFit Trial): protocol for a national, multicenter single-arm trial

Background

Breast cancer (BC) has particular characteristics in young women, with diagnosis at more advanced stages, a poorer prognosis and highly aggressive tumors. In NeoFit, we will use an activity tracker to identify and describe various digital profiles (heart rate, physical activity, and sleep patterns) in women below the age of 45 years on neoadjuvant chemotherapy for BC.

Methods

NeoFit is a prospective, national, multicenter, single-arm open-label study. It will include 300 women below the age of 45 years treated with neoadjuvant chemotherapy for BC. Participants will be asked to wear a Withing Steel HR activity tracker round the clock for 12 months. The principal assessments will be performed at baseline, at the end of neoadjuvant chemotherapy and at 12 months. We will evaluate clinical parameters, such as toxicity and the efficacy of chemotherapy, together with quality of life, fatigue, and parameters relating to lifestyle and physical activity. The women will complete REDCap form questionnaires via a secure internet link.

Discussion

In this study, the use of an activity tracker will enable us to visualize changes in the lifestyle of young women on neoadjuvant chemotherapy for BC, over the course of a one-year period. This exploratory study will provide crucial insight into the digital phenotypes of young BC patients on neoadjuvant chemotherapy and the relationship between these phenotypes and the toxicity and efficacy of treatment. This trial will pave the way for interventional studies involving sleep and physical activity interventions.

Trial registration

Clinicaltrials.gov identifier: NCT05011721. Registration date: 18/08/2021.

Different Pigmentation Risk Loci for High-Risk Monosomy 3 and Low-Risk Disomy 3 Uveal Melanomas

BACKGROUND

Uveal melanoma (UM), a rare malignant tumor of the eye, is predominantly observed in populations of European ancestry. UMs carrying a monosomy 3 (M3) frequently relapse mainly in the liver, whereas UMs with disomy 3 (D3) are associated with more favorable outcome. Here, we explored the UM genetic predisposition factors in a large genome-wide association study (GWAS) of 1142 European UM patients and 882 healthy controls .

METHODS

We combined 2 independent datasets (Global Screening Array) with the dataset described in a previously published GWAS in UM (Omni5 array), which were imputed separately and subsequently merged. Patients were stratified according to their chromosome 3 status, and identified UM risk loci were tested for differential association with M3 or D3 subgroups. All statistical tests were 2-sided.

RESULTS

We recapitulated the previously identified risk locus on chromosome 5 on CLPTM1L (rs421284: odds ratio [OR] =1.58, 95% confidence interval [CI] = 1.35 to 1.86; P = 1.98 × 10-8) and identified 2 additional risk loci involved in eye pigmentation: IRF4 locus on chromosome 6 (rs12203592: OR = 1.76, 95% CI = 1.44 to 2.16; P = 3.55 × 10-8) and HERC2 locus on chromosome 15 (rs12913832: OR= 0.57, 95% CI = 0.48 to 0.67; P = 1.88 × 10-11). The IRF4 rs12203592 single-nucleotide polymorphism was found to be exclusively associated with risk for the D3 UM subtype (ORD3 = 2.73, 95% CI = 1.87 to 3.97; P = 1.78 × 10-7), and the HERC2 rs12913832 single-nucleotide polymorphism was exclusively associated with risk for the M3 UM subtype (ORM3 = 2.43, 95% CI = 1.79 to 3.29; P = 1.13 × 10-8). However, the CLPTM1L risk locus was equally statistically significant in both subgroups.

CONCLUSIONS

This work identified 2 additional UM risk loci known for their role in pigmentation. Importantly, we demonstrate that UM tumor biology and metastatic potential are influenced by patients' genetic backgrounds.

Les deux faces du confinement. Préoccupations et satisfactions des personnes atteintes de cancer pendant le confinement

Objectif et méthode : Quelle a été l’expérience du confinement (16 mars 2020–11 mai 2020) en France, chez les patients atteints de cancer ? Au travers de questions ouvertes envoyées par messagerie électronique pendant les deux dernières semaines du confinement (27 avril–11 mai 2020), l’enquête BaroCov a étudié, auprès de patients suivis à l’institut Curie, les motifs de préoccupation et de satisfaction. À partir des réponses libres, 12 thématiques de préoccupation et 8 thématiques de satisfaction ont été extraites de manière inductive, à partir desquelles les réponses ont été codées puis analysées statistiquement.

Résultats : Deux mille quatre cent soixante-dix-huit patients ont répondu, dont 90 % ont plus de 40 ans et 58,9 % entre 40 et 65 ans. Quatre-vingt-trois pour cent sont des femmes. Cinquante et un pour cent vivent à Paris et en proche banlieue. 61,4 % déclarent être en cours de traitement.

Préoccupations : Les préoccupations concernaient la santé chez deux tiers des répondants (63,6 %). Elles avaient rapport avec le cancer chez la moitié (45,5 %), dont 9,8 % sur la poursuite du traitement et 5,7%sur les effets secondaires. La Covid-19 préoccupait un cinquième (18,1 %) des personnes. Un quart des répondants citaient comme thématique soit la vie quotidienne (16,6 %) [ne pas vivre comme d’habitude, l’activité professionnelle, l’argent, le logement, le climat social], soit les proches (12,8 %) [la séparation, leur santé, leur avenir].

Appréciations : Un tiers des répondants (33,7 %) citaient les relations avec les proches et un autre tiers (32 %) les conditions de vie (avec la qualité de vie chez 14,6 %, prendre son temps chez 10 % et la nature chez 7,4 %). Plus de 10 % des personnes (13,5 %) citaient spontanément une thématique liée à la maladie (chez 7,3 %, l’état de santé et chez 6,2 % les soins). La thématique du travail n’apparaissait quasiment pas (2,8 %).

Conclusion : Le thème principal cité pendant le confinement n’était pas la Covid-19, mais plutôt les polarités existentielles de la vie face au cancer avec d’un côté la peur et les préoccupations liées à la maladie et de l’autre l’importance de l’entourage et la réévaluation positive de la vie quotidienne.

[Experience of care and daily life during national sanitary confinement in patients followed and treated in Cancer Control Centers: The BaroCov Inquiry]

Le confinement dans le cadre de la CoVid 19 a nécessité des organisations en centre de lutte contre le cancer avec notamment le report de certains soins. Nous avons interrogé 6 080 patients qui avaient un rendez-vous programmé durant cette période. Deux mille quatre cent soixante-dix-huit patients ont donné leur avis concernant l’accès et l’organisation des soins, la téléconsultation, leurs préoccupations et leurs motifs de satisfaction. S’ils se disent pour 83 % d’entre eux, satisfaits de l’organisation des soins, 25 % des répondants déclarent un renoncement à des soins qu’ils qualifient d’indispensables dans un tiers des cas. La préoccupation en lien avec le suivi de la maladie cancéreuse passe avant celle d’attraper le virus Sars-cov-2, contrairement à la population générale, et les relations avec leurs proches sont spontanément citées comme motif de satisfaction. Cette méthode permet de saisir l’expérience des patients, malgré certaines limites. Une telle approche pourrait servir à la mise en place en période normale d’un dispositif spécifique.

Tumor invasion in draining lymph nodes is associated with Treg accumulation in breast cancer patients

Tumor-draining lymph node (TDLN) invasion by metastatic cells in breast cancer correlates with poor prognosis and is associated with local immunosuppression, which can be partly mediated by regulatory T cells (Tregs). Here, we study Tregs from matched tumor-invaded and non-invaded TDLNs, and breast tumors. We observe that Treg frequencies increase with nodal invasion, and that Tregs express higher levels of co-inhibitory/stimulatory receptors than effector cells. Also, while Tregs show conserved suppressive function in TDLN and tumor, conventional T cells (Tconvs) in TDLNs proliferate and produce Th1-inflammatory cytokines, but are dysfunctional in the tumor. We describe a common transcriptomic signature shared by Tregs from tumors and nodes, including CD80, which is significantly associated with poor patient survival. TCR RNA-sequencing analysis indicates trafficking between TDLNs and tumors and ongoing Tconv/Treg conversion. Overall, TDLN Tregs are functional and express a distinct pattern of druggable co-receptors, highlighting their potential as targets for cancer immunotherapy.

Multiple Hotspot Mutations Scanning by Single Droplet Digital PCR

BACKGROUND

Progress in the liquid biopsy field, combined with the development of droplet digital PCR (ddPCR), has enabled noninvasive monitoring of mutations with high detection accuracy. However, current assays detect a restricted number of mutations per reaction. ddPCR is a recognized method for detecting alterations previously characterized in tumor tissues, but its use as a discovery tool when the mutation is unknown a priori remains limited.

METHODS

We established 2 ddPCR assays detecting all genomic alterations within KRAS exon 2 and EGFR exon 19 mutation hotspots, which are of clinical importance in colorectal and lung cancer, with use of a unique pair of TaqMan® oligoprobes. The KRAS assay scanned for the 7 most common mutations in codons 12/13 but also all other mutations found in that region. The EGFR assay screened for all in-frame deletions of exon 19, which are frequent EGFR-activating events.

RESULTS

The KRAS and EGFR assays were highly specific and both reached a limit of detection of &lt;0.1% in mutant allele frequency. We further validated their performance on multiple plasma and formalin-fixed and paraffin-embedded tumor samples harboring a panel of different KRAS or EGFR mutations.

CONCLUSIONS

This method presents the advantage of detecting a higher number of mutations with single-reaction ddPCRs while consuming a minimum of patient sample. This is particularly useful in the context of liquid biopsy because the amount of circulating tumor DNA is often low. This method should be useful as a discovery tool when the tumor tissue is unavailable or to monitor disease during therapy.

A GWAS in uveal melanoma identifies risk polymorphisms in the CLPTM1L locus

Uveal melanoma, a rare malignant tumor of the eye, is predominantly observed in populations of European ancestry. A genome-wide association study of 259 uveal melanoma patients compared to 401 controls all of European ancestry revealed a candidate locus at chromosome 5p15.33 (region rs421284: OR = 1.7, CI 1.43-2.05). This locus was replicated in an independent set of 276 cases and 184 controls. In addition, risk variants from this region were positively associated with higher expression of CLPTM1L. In conclusion, the CLPTM1L region contains risk alleles for uveal melanoma susceptibility, suggesting that CLPTM1L could play a role in uveal melanoma oncogenesis.

Patient-Specific Circulating Tumor DNA Detection during Neoadjuvant Chemotherapy in Triple-Negative Breast Cancer

BACKGROUND

In nonmetastatic triple-negative breast cancer (TNBC) patients, we investigated whether circulating tumor DNA (ctDNA) detection can reflect the tumor response to neoadjuvant chemotherapy (NCT) and detect minimal residual disease after surgery.

METHODS

Ten milliliters of plasma were collected at 4 time points: before NCT; after 1 cycle; before surgery; after surgery. Customized droplet digital PCR (ddPCR) assays were used to track tumor protein p53 (TP53) mutations previously characterized in tumor tissue by massively parallel sequencing (MPS).

RESULTS

Forty-six patients with nonmetastatic TNBC were enrolled. TP53 mutations were identified in 40 of them. Customized ddPCR probes were validated for 38 patients, with excellent correlation with MPS (r = 0.99), specificity (≥2 droplets/assay), and sensitivity (at least 0.1%). At baseline, ctDNA was detected in 27/36 patients (75%). Its detection was associated with mitotic index (P = 0.003), tumor grade (P = 0.003), and stage (P = 0.03). During treatment, we observed a drop of ctDNA levels in all patients but 1. No patient had detectable ctDNA after surgery. The patient with rising ctDNA levels experienced tumor progression during NCT. Pathological complete response (16/38 patients) was not correlated with ctDNA detection at any time point. ctDNA positivity after 1 cycle of NCT was correlated with shorter disease-free (P &lt; 0.001) and overall (P = 0.006) survival.

CONCLUSIONS

Customized ctDNA detection by ddPCR achieved a 75% detection rate at baseline. During NCT, ctDNA levels decreased quickly and minimal residual disease was not detected after surgery. However, a slow decrease of ctDNA level during NCT was strongly associated with shorter survival.

Abstract 410: Exhaustive scanning of mutation hotspot regions using a new tool: The MHS-ddPCR

Background: Recent progress in the ‘liquid biopsy’ field in combination with the development of the droplet digital PCR (ddPCR) technology now enables non-invasive monitoring of cancer-related genomic alterations with high detection accuracy. Current ddPCR techniques represent the gold standard for the detection of point mutations that have been previously characterized on tumor tissues. However, ddPCR screen for only one mutation (or a few mutations, with multicolor ddPCR) per reaction. This is a clear limitation to use it as a discovery tool, to detect resistance-associated mutations that may appear during therapy (e.g. ESR1 activating mutations in breast cancer) or when tumor tissue is not available (e.g. EGFR activating mutations in lung cancers).

Methods:

We developed the Multiple Hotspot mutations detection by Single droplet digital PCR (MHS-ddPCR) method, a variant of the conventional ddPCR technique, which detects all genomic alterations within a hotspot region, using a unique couple of Taqman oligo-probes. We first established two specific assays covering KRAS and EGFR mutation hotspot regions, which are of clinical importance in the context of colorectal cancer. The assay for KRAS scans for the 7 most common mutations in codons 12 and 13 of the gene as well as all other mutations with lower frequency (&lt;1%). The EGFR assay screens for all in-frame deletions of exon 19, which are frequent activating events in EGFR.

Results:

Sensitivity and specificity of MHS-ddPCR were assessed on decreasing fractions of tumor DNA mutated for KRAS. The KRAS assay reaches a sensitivity of 0.02% and was validated on plasma and tumor samples harboring a panel of different KRAS mutations. Similarly, the EGFR assay can detect numerous exon 19 deletions from patient samples and with limited amounts of tumor DNA.

Conclusions:

The MHS-ddPCR is extremely sensitive, works for numerous hotspot regions with different types of alterations (SNV, deletion) and is cost-effective as it combines multiple assays in one reaction.

Citation Format: Charles Decraene, Francois-Clement Bidard, Samia Belaabi, Etienne Rouleau, Adrien Saliou, Alexandre Houy, Maud Milder, Olivier Lantz, Marc Ychou, Jean-Yves Pierga, Marc-Henri Stern, Charlotte Proudhon. Exhaustive scanning of mutation hotspot regions using a new tool: The MHS-ddPCR. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 410.

Circulating tumor DNA and circulating tumor cells in metastatic triple negative breast cancer patients

Circulating tumor DNA (ctDNA) is a new circulating tumor biomarker which might be used as a prognostic biomarker in a way similar to circulating tumor cells (CTCs). Here, we used the high prevalence of TP53 mutations in triple negative breast cancer (TNBC) to compare ctDNA and CTC detection rates and prognostic value in metastatic TNBC patients. Forty patients were enrolled before starting a new line of treatment. TP53 mutations were characterized in archived tumor tissues and in plasma DNA using two next generation sequencing (NGS) platforms in parallel. Archived tumor tissue was sequenced successfully for 31/40 patients. TP53 mutations were found in 26/31 (84%) of tumor samples. The same mutation was detected in the matched plasma of 21/26 (81%) patients with an additional mutation found only in the plasma for one patient. Mutated allele fractions ranged from 2 to 70% (median 5%). The observed correlation between the two NGS approaches (R(2) = 0.903) suggested that ctDNA levels data were quantitative. Among the 27 patients with TP53 mutations, CTC count was ≥1 in 19 patients (70%) and ≥5 in 14 patients (52%). ctDNA levels had no prognostic impact on time to progression (TTP) or overall survival (OS), whereas CTC numbers were correlated with OS (p = 0.04) and marginally with TTP (p = 0.06). Performance status and elevated LDH also had significant prognostic impact. Here, absence of prognostic impact of baseline ctDNA level suggests that mechanisms of ctDNA release in metastatic TNBC may involve, beyond tumor burden, biological features that do not dramatically affect patient outcome.

High numbers of differentiated effector CD4 T cells are found in patients with cancer and correlate with clinical response after neoadjuvant therapy of breast cancer

CD4(+) T cells influence tumor immunity in complex ways that are not fully understood. In this study, we characterized a population of human differentiated effector CD4(+) T cells that is defined by low levels of the interleukin (IL)-2 and IL-7 receptors (CD25(-)CD127(-)). We found that this cell population expands in patients with various types of cancer, including breast cancer, to represent 2% to 20% of total CD4(+) blood T lymphocytes as compared with only 0.2% to 2% in healthy individuals. Notably, these CD25(-)CD127(-)CD4 T cells expressed effector markers such as CD244 and CD11b with low levels of CD27, contrasting with the memory phenotype dominating this population in healthy individuals. These cells did not cycle in patients, nor did they secrete IL-10 or IL-17, but instead displayed cytotoxic features. Moreover, they encompassed oligoclonal expansions paralleling an expansion of effector CD8(+) T cells that included tumor antigen-specific T cells. During neoadjuvant chemotherapy in patients with breast cancer, we found that the increase in CD25(-)CD127(-) CD4(+) T cells correlated with tumor regression. This observation suggested that CD4(+) T cells included tumor antigen-specific cells, which may be generated by or participate in tumor regressions during chemotherapy. In summary, our results lend support to the hypothesis that CD4(+) T cells are involved in human antitumor responses.

Specific MAIT cell behaviour among innate-like T lymphocytes in critically ill patients with severe infections

PURPOSE

In between innate and adaptive immunity, the recently identified innate-like mucosal-associated invariant T (MAIT) lymphocytes display specific reactivity to non-streptococcal bacteria. Whether they are involved in bacterial sepsis has not been investigated. We aimed to assess the number and the time course of circulating innate-like T lymphocytes (MAIT, NKT and γδ T cells) in critically ill septic and non-septic patients and to establish correlations with the further development of intensive care unit (ICU)-acquired infections.

METHODS

We prospectively enrolled consecutive patients with severe sepsis and septic shock. Controls were critically ill patients with non-septic shock and age-matched healthy subjects. Circulating innate-like lymphocytes were enumerated using a flow cytometry assay at day 1, 4 and 7.

RESULTS

One hundred and fifty six patients (113 severe bacterial infections, 36 non-infected patients and 7 patients with severe viral infections) and 26 healthy subjects were enrolled into the study. Patients with severe bacterial infections displayed an early decrease in MAIT cell count [median 1.3/mm(3); interquartile range (0.4-3.2)] as compared to control healthy subjects [31.1/mm(3) (12.1-45.2)], but also to non-infected critically ill patients [4.3/mm(3) (1.4-13.2)] (P < 0.0001 for all comparisons). In contrast NKT and γδ T cell counts did not differ between patients groups. The multivariate analysis identified non-streptococcal bacterial infection as an independent determinant of decrease in MAIT cell count. Furthermore, the incidence of ICU-acquired infections was higher in patients with persistent MAIT cell depletion.

CONCLUSIONS

This large human study provides valuable information about MAIT cells in severe bacterial infections. The persistent depletion of MAIT cells is associated with the further development of ICU-acquired infections.

Detection rate and prognostic value of circulating tumor cells and circulating tumor DNA in metastatic uveal melanoma

Circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) have been recently investigated in several cancer types, but their respective clinical significance remains to be determined. In our prospective study, we compared the detection rate and the prognostic value of these two circulating biomarkers in patients with metastatic uveal melanoma. GNAQ/GNA11 mutations were characterized in archived tumor tissue. Using a highly sensitive and mutation-specific bidirectional pyrophosphorolysis-activated polymerization (bi-PAP) technique, GNAQ c.626A>T, GNAQ c.626A>C and GNA11 c.626A>T copy numbers were quantified in plasma from 12 mL of blood. CTCs were detected at the same time in 7.5 mL of blood by the CellSearch technique. Patient characteristics and outcome were prospectively collected. CTCs (≥1) were detected in 12 of the 40 included patients (30%, range 1-20). Among the 26 patients with known detectable mutations, ctDNA was detected and quantified in 22 (84%, range 4-11,421 copies/mL). CTC count and ctDNA levels were associated with the presence of miliary hepatic metastasis (p = 0.004 and 0.03, respectively), with metastasis volume (p = 0.005 and 0.004) and with each other (p < 0.0001). CTC count and ctDNA levels were both strongly associated with progression-free survival (p = 0.003 and 0.001) and overall survival (p = 0.0009 and <0.0001). In multivariate analyses, ctDNA appeared to be a better prognostic marker than CTC. In conclusion, ctDNA and CTC are correlated and both have poor prognostic significance. CTC detection can be performed in every patient but, in patients with detectable mutations, ctDNA was more frequently detected than CTC and has possibly more prognostic value.

Abstract C48: Detection of GNAQ/GNA11 mutations in circulating cell-free DNA as a biomarker of uveal melanoma

Background: Circulating tumor-derived DNA (ctDNA) can be detected in the plasma of cancer patients. Recently, ctDNA was proposed as a biomarker to follow tumor burden and monitor treatment efficacy (1). However, ctDNA represents a tiny fraction of the normal cell-free circulating DNA, and its assessment is challenging due to specificity, sensitivity and quantitative issues.

Patients and methods: We developed a real-time PCR based on the pyrophosphorolysis-activated polymerization (bi-PAP) for the quantification of ctDNA in plasma of patients with uveal melanoma (UM). Bi-PAP can detect known point mutations independently of large excess of normal DNA (2). Our assay targets the activating mutation of codon 626 of GNAQ or GNA11 which are present in most UM (3, 4).

Results: Bi-PAP primer pairs specific for GNAQ 626A&gt;T, GNAQ 626A&gt;C and GNA11 626A&gt;T have been chosen. Their sensitivity and specificity were assessed on serial dilutions of tumor DNA in normal DNA. Each assay could detect a single mutated molecule per reaction, while 104 copies of normal DNA were not detected. In plasma of mice bearing UM xenografts, ctDNA were proportional to the amount of circulating human DNA and to the size of the xenograft. Furthermore, in a retrospective analysis of 19 UM patient sera, 8 were found positive.

Conclusion: Bi-PAP represents a promising tool for the quantification of ctDNA in the blood of UM patients. A prospective study is on going to confirm the clinical value of ctDNA level in metastatic UM patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C48.