Stability of gut microbiome after COVID-19 vaccination in healthy and immuno-compromised individuals.

Bidirectional interactions between the immune system and the gut microbiota are key contributors to various physiological functions. Immune-associated diseases such as cancer and autoimmunity, and efficacy of immunomodulatory therapies, have been linked to microbiome variation. Although COVID-19 infection has been shown to cause microbial dysbiosis, it remains understudied whether the inflammatory response associated with vaccination also impacts the microbiota. Here, we investigate the temporal impact of COVID-19 vaccination on the gut microbiome in healthy and immuno-compromised individuals; the latter included patients with primary immunodeficiency and cancer patients on immunomodulating therapies. We find that the gut microbiome remained remarkably stable post-vaccination irrespective of diverse immune status, vaccine response, and microbial composition spanned by the cohort. The stability is evident at all evaluated levels including diversity, phylum, species, and functional capacity. Our results indicate the resilience of the gut microbiome to host immune changes triggered by COVID-19 vaccination and suggest minimal, if any, impact on microbiome-mediated processes. These findings encourage vaccine acceptance, particularly when contrasted with the significant microbiome shifts observed during COVID-19 infection.

Olaparib plus Durvalumab, with or without Bevacizumab, as Treatment in PARP Inhibitor-Naïve Platinum-Sensitive Relapsed Ovarian Cancer: A Phase II Multi-Cohort Study.

PURPOSE: Early results from the phase II MEDIOLA study (NCT02734004) in germline BRCA1- and/or BRCA2-mutated (gBRCAm) platinum-sensitive relapsed ovarian cancer (PSROC) showed promising efficacy and safety with olaparib plus durvalumab. We report efficacy and safety of olaparib plus durvalumab in an expansion cohort of women with gBRCAm PSROC (gBRCAm expansion doublet cohort) and two cohorts with non-gBRCAm PSROC, one of which also received bevacizumab (non-gBRCAm doublet and triplet cohorts). PATIENTS AND METHODS: In this open-label, multicenter study, PARP inhibitor-naïve patients received olaparib plus durvalumab treatment until disease progression; the non-gBRCAm triplet cohort also received bevacizumab. Primary endpoints were objective response rate (ORR; gBRCAm expansion doublet cohort), disease control rate (DCR) at 24 weeks (non-gBRCAm cohorts), and safety (all cohorts). RESULTS: The full analysis and safety analysis sets comprised 51, 32, and 31 patients in the gBRCAm expansion doublet, non-gBRCAm doublet, and non-gBRCAm triplet cohorts, respectively. ORR was 92.2% [95% confidence interval (CI), 81.1-97.8] in the gBRCAm expansion doublet cohort (primary endpoint); DCR at 24 weeks was 28.1% (90% CI, 15.5-43.9) in the non-gBRCAm doublet cohort (primary endpoint) and 74.2% (90% CI, 58.2-86.5) in the non-gBRCAm triplet cohort (primary endpoint). Grade ≥ 3 adverse events were reported in 47.1%, 65.6%, and 61.3% of patients in the gBRCAm expansion doublet, non-gBRCAm doublet, and non-gBRCAm triplet cohorts, respectively, most commonly anemia. CONCLUSIONS: Olaparib plus durvalumab continued to show notable clinical activity in women with gBRCAm PSROC. Olaparib plus durvalumab with bevacizumab demonstrated encouraging clinical activity in women with non-gBRCAm PSROC. No new safety signals were identified.

Age-associated B cells predict impaired humoral immunity after COVID-19 vaccination in patients receiving immune checkpoint blockade.

Age-associated B cells (ABC) accumulate with age and in individuals with different immunological disorders, including cancer patients treated with immune checkpoint blockade and those with inborn errors of immunity. Here, we investigate whether ABCs from different conditions are similar and how they impact the longitudinal level of the COVID-19 vaccine response. Single-cell RNA sequencing indicates that ABCs with distinct aetiologies have common transcriptional profiles and can be categorised according to their expression of immune genes, such as the autoimmune regulator (AIRE). Furthermore, higher baseline ABC frequency correlates with decreased levels of antigen-specific memory B cells and reduced neutralising capacity against SARS-CoV-2. ABCs express high levels of the inhibitory FcγRIIB receptor and are distinctive in their ability to bind immune complexes, which could contribute to diminish vaccine responses either directly, or indirectly via enhanced clearance of immune complexed-antigen. Expansion of ABCs may, therefore, serve as a biomarker identifying individuals at risk of suboptimal responses to vaccination.

The different faces of metastatic melanoma in the gastrointestinal tract.

Melanoma is the most aggressive form of skin cancer, with tendency to spread to any organ of the human body, including the gastrointestinal tract (GIT). The diagnosis of metastases to the GIT can be difficult, as they may be clinically silent for somewhile and may occur years after the initial melanoma diagnosis. CT imaging remains the standard modality for staging and surveillance of melanoma patients, and in most cases, it will be the first imaging modality to identify GIT lesions. However, interpretation of CT studies in patients with melanoma can be challenging as lesions may be subtle and random in distribution, as well as sometimes mimicking other conditions. Even so, early diagnosis of GIT metastases is critical to avoid emergency hospitalisations, whilst surgical intervention can be curative in some cases. In this review, we illustrate the various imaging presentations of melanoma metastases within the GIT, discuss the clinical aspects and offer advice on investigation and management. We offer tips intended to aid radiologists in their diagnostic skills and interpretation of melanoma imaging scans.

Magnetization transfer imaging of ovarian cancer: initial experiences of correlation with tissue cellularity and changes following neoadjuvant chemotherapy.

Objectives: To investigate the relationship between magnetization transfer (MT) imaging and tissue macromolecules in high-grade serous ovarian cancer (HGSOC) and whether MT ratio (MTR) changes following neoadjuvant chemotherapy (NACT). Methods: This was a prospective observational study. 12 HGSOC patients were imaged before treatment. MTR was compared to quantified tissue histology and immunohistochemistry. For a subset of patients (n = 5), MT imaging was repeated after NACT. The Shapiro-Wilk test was used to assess for normality of data and Spearman's rank-order or Pearson's correlation tests were then used to compare MTR with tissue quantifications. The Wilcoxon signed-rank test was used to assess for changes in MTR after treatment. Results: Treatment-naïve tumour MTR was 21.9 ± 3.1% (mean ± S.D.). MTR had a positive correlation with cellularity, rho = 0.56 (p < 0.05) and a negative correlation with tumour volume, ρ = -0.72 (p = 0.01). MTR did not correlate with the extracellular proteins, collagen IV or laminin (p = 0.40 and p = 0.90). For those patients imaged before and after NACT, an increase in MTR was observed in each case with mean MTR 20.6 ± 3.1% (median 21.1) pre-treatment and 25.6 ± 3.4% (median 26.5) post-treatment (p = 0.06). Conclusion: In treatment-naïve HGSOC, MTR is associated with cellularity, possibly reflecting intracellular macromolecular concentration. MT may also detect the HGSOC response to NACT, however larger studies are required to validate this finding. Advances in knowledge: MTR in HGSOC is influenced by cellularity. This may be applied to assess for cell changes following treatment.

Weekly dose-dense chemotherapy in first-line epithelial ovarian, fallopian tube, or primary peritoneal cancer treatment (ICON8): overall survival results from an open-label, randomised, controlled, phase 3 trial.

BACKGROUND: Standard-of-care first-line chemotherapy for epithelial ovarian cancer is carboplatin and paclitaxel administered once every 3 weeks. The JGOG 3016 trial reported significant improvement in progression-free and overall survival with dose-dense weekly paclitaxel and 3-weekly (ie, once every 3 weeks) carboplatin. However, this benefit was not observed in the previously reported progression-free survival results of ICON8. Here, we present the final coprimary outcomes of overall survival and updated progression-free survival analyses of ICON8. METHODS: In this open-label, randomised, controlled, phase 3 trial (ICON8), women aged 18 years or older with newly diagnosed stage IC-IV epithelial ovarian, primary peritoneal, or fallopian tube carcinoma (here collectively termed ovarian cancer, as defined by International Federation of Gynecology and Obstetrics [FIGO] 1988 criteria) and an Eastern Cooperative Oncology Group performance status of 0-2 were recruited from 117 hospitals with oncology departments in the UK, Australia and New Zealand, Mexico, South Korea, and Ireland. Patients could enter the trial after immediate primary surgery (IPS) or with planned delayed primary surgery (DPS) during chemotherapy, or could have no planned surgery. Participants were randomly assigned (1:1:1), using the Medical Research Council Clinical Trials Unit at University College London randomisation line with stratification by Gynecologic Cancer Intergroup group, FIGO disease stage, and outcome and timing of surgery, to either 3-weekly carboplatin area under the curve (AUC)5 or AUC6 and 3-weekly paclitaxel 175 mg/m2 (control; group 1), 3-weekly carboplatin AUC5 or AUC6 and weekly paclitaxel 80 mg/m2 (group 2), or weekly carboplatin AUC2 and weekly paclitaxel 80 mg/m2 (group 3), all administered via intravenous infusion for a total of six 21-day cycles. Coprimary outcomes were progression-free survival and overall survival, with comparisons done between group 2 and group 1, and group 3 and group 1, in the intention-to-treat population. Safety was assessed in all patients who started at least one chemotherapy cycle. The trial is registered on ClinicalTrials.gov, NCT01654146, and ISRCTN registry, ISRCTN10356387, and is closed to accrual. FINDINGS: Between June 6, 2011, and Nov 28, 2014, 1566 patients were randomly assigned to group 1 (n=522), group 2 (n=523), or group 3 (n=521). The median age was 62 years (IQR 54-68), 1073 (69%) of 1566 patients had high-grade serous carcinoma, 1119 (71%) had stage IIIC-IV disease, and 745 (48%) had IPS. As of data cutoff (March 31, 2020), with a median follow-up of 69 months (IQR 61-75), no significant difference in overall survival was observed in either comparison: median overall survival of 47·4 months (95% CI 43·1-54·8) in group 1, 54·8 months (46·6-61·6) in group 2, and 53·4 months (49·2-59·6) in group 3 (group 2 vs group 1: hazard ratio 0·87 [97·5% CI 0·73-1·05]; group 3 vs group 1: 0·91 [0·76-1·09]). No significant difference was observed for progression-free survival in either comparison and evidence of non-proportional hazards was seen (p=0·037), with restricted mean survival time of 23·9 months (97·5% CI 22·1-25·6) in group 1, 25·3 months (23·6-27·1) in group 2, and 24·8 months (23·0-26·5) in group 3. The most common grade 3-4 adverse events were reduced neutrophil count (78 [15%] of 511 patients in group 1, 183 [36%] of 514 in group 2, and 154 [30%] of 513 in group 3), reduced white blood cell count (22 [4%] in group 1, 80 [16%] in group 2, and 71 [14%] in group 3), and anaemia (26 [5%] in group 1, 66 [13%] in group 2, and 24 [5%] in group 3). No new serious adverse events were reported. Seven treatment-related deaths were reported (two in group 1, four in group 2, and one in group 3). INTERPRETATION: In our cohort of predominantly European women with epithelial ovarian cancer, we found that first-line weekly dose-dense chemotherapy did not improve overall or progression-free survival compared with standard 3-weekly chemotherapy and should not be used as part of standard multimodality front-line therapy in this patient group. FUNDING: Cancer Research UK, Medical Research Council, Health Research Board in Ireland, Irish Cancer Society, and Cancer Australia.

A Randomized, Phase III Trial to Evaluate Rucaparib Monotherapy as Maintenance Treatment in Patients With Newly Diagnosed Ovarian Cancer (ATHENA-MONO/GOG-3020/ENGOT-ov45).

PURPOSE: ATHENA (ClinicalTrials.gov identifier: NCT03522246) was designed to evaluate rucaparib first-line maintenance treatment in a broad patient population, including those without BRCA1 or BRCA2 (BRCA) mutations or other evidence of homologous recombination deficiency (HRD), or high-risk clinical characteristics such as residual disease. We report the results from the ATHENA-MONO comparison of rucaparib versus placebo. METHODS: Patients with stage III-IV high-grade ovarian cancer undergoing surgical cytoreduction (R0/complete resection permitted) and responding to first-line platinum-doublet chemotherapy were randomly assigned 4:1 to oral rucaparib 600 mg twice a day or placebo. Stratification factors were HRD test status, residual disease after chemotherapy, and timing of surgery. The primary end point of investigator-assessed progression-free survival was assessed in a step-down procedure, first in the HRD population (BRCA-mutant or BRCA wild-type/loss of heterozygosity high tumor), and then in the intent-to-treat population. RESULTS: As of March 23, 2022 (data cutoff), 427 and 111 patients were randomly assigned to rucaparib or placebo, respectively (HRD population: 185 v 49). Median progression-free survival (95% CI) was 28.7 months (23.0 to not reached) with rucaparib versus 11.3 months (9.1 to 22.1) with placebo in the HRD population (log-rank P = .0004; hazard ratio [HR], 0.47; 95% CI, 0.31 to 0.72); 20.2 months (15.2 to 24.7) versus 9.2 months (8.3 to 12.2) in the intent-to-treat population (log-rank P < .0001; HR, 0.52; 95% CI, 0.40 to 0.68); and 12.1 months (11.1 to 17.7) versus 9.1 months (4.0 to 12.2) in the HRD-negative population (HR, 0.65; 95% CI, 0.45 to 0.95). The most common grade ≥ 3 treatment-emergent adverse events were anemia (rucaparib, 28.7% v placebo, 0%) and neutropenia (14.6% v 0.9%). CONCLUSION: Rucaparib monotherapy is effective as first-line maintenance, conferring significant benefit versus placebo in patients with advanced ovarian cancer with and without HRD.

The forgotten appearance of metastatic melanoma in the small bowel.

BACKGROUND: Melanoma is the most aggressive form of skin cancer, with a tendency to metastasise to any organ of the human body. While the most common body organs affected include liver, lungs, brain and soft tissues, spread to the gastrointestinal tract is not uncommon. In the bowel, it can present with a multitude of imaging appearances, more rarely as an aneurysmal dilatation. This appearance is classically associated with lymphoma, but it has more rarely been associated with other forms of malignancy. CASE PRESENTATION: We report a case series of three patients with aneurysmal dilatation in the small bowel (SB) confirmed to be due to metastatic melanoma (MM). All patients had non-specific symptoms; most times being attributed initially to causes other than melanoma. On CT the identified aneurysmal SB dilatations were diagnosed as presumed lymphoma in all cases. In two cases, the aneurysmal dilatation was the first presentation of metastatic disease and in two of the cases more than one site of the gastrointestinal tract was concomitantly involved. All patients underwent surgical resection with histological confirmation of MM. CONCLUSIONS: Recognition of unusual SB presentation of MM, such as aneurysmal SB dilatation, is important to expedite diagnosis, provide appropriate treatment, and consequently improve quality of life and likely survival of these patients. As the most common cancer to metastasise to the SB and as a known imaging mimicker, MM should remain in any radiologist's differential diagnosis for SB lesions with aneurysmal dilatation.

Tumour gene expression signature in primary melanoma predicts long-term outcomes.

Adjuvant systemic therapies are now routinely used following resection of stage III melanoma, however accurate prognostic information is needed to better stratify patients. We use differential expression analyses of primary tumours from 204 RNA-sequenced melanomas within a large adjuvant trial, identifying a 121 metastasis-associated gene signature. This signature strongly associated with progression-free (HR = 1.63, p = 5.24 × 10-5) and overall survival (HR = 1.61, p = 1.67 × 10-4), was validated in 175 regional lymph nodes metastasis as well as two externally ascertained datasets. The machine learning classification models trained using the signature genes performed significantly better in predicting metastases than models trained with clinical covariates (pAUROC = 7.03 × 10-4), or published prognostic signatures (pAUROC < 0.05). The signature score negatively correlated with measures of immune cell infiltration (ρ = -0.75, p < 2.2 × 10-16), with a higher score representing reduced lymphocyte infiltration and a higher 5-year risk of death in stage II melanoma. Our expression signature identifies melanoma patients at higher risk of metastases and warrants further evaluation in adjuvant clinical trials.

The mutational landscape of melanoma brain metastases presenting as the first visceral site of recurrence.

Brain metastases are a major cause of melanoma-related mortality and morbidity. We undertook whole-exome sequencing of 50 tumours from patients undergoing surgical resection of brain metastases presenting as the first site of visceral disease spread and validated our findings in an independent dataset of 18 patients. Brain metastases had a similar driver mutational landscape to cutaneous melanomas in TCGA. However, KRAS was the most significantly enriched driver gene, with 4/50 (8%) of brain metastases harbouring non-synonymous mutations. Hotspot KRAS mutations were mutually exclusive from BRAFV600, NRAS and HRAS mutations and were associated with a reduced overall survival from the resection of brain metastases (HR 10.01, p = 0.001). Mutations in KRAS were clonal and concordant with extracranial disease, suggesting that these mutations are likely present within the primary. Our analyses suggest that KRAS mutations could help identify patients with primary melanoma at higher risk of brain metastases who may benefit from more intensive, protracted surveillance.

Objective responses to first-line neoadjuvant carboplatin-paclitaxel regimens for ovarian, fallopian tube, or primary peritoneal carcinoma (ICON8): post-hoc exploratory analysis of a randomised, phase 3 trial.

BACKGROUND: Platinum-based neoadjuvant chemotherapy followed by delayed primary surgery (DPS) is an established strategy for women with newly diagnosed, advanced-stage epithelial ovarian cancer. Although this therapeutic approach has been validated in randomised, phase 3 trials, evaluation of response to neoadjuvant chemotherapy using Response Evaluation Criteria in Solid Tumors, version 1.1 (RECIST), and cancer antigen 125 (CA125) has not been reported. We describe RECIST and Gynecologic Cancer InterGroup (GCIG) CA125 responses in patients receiving platinum-based neoadjuvant chemotherapy followed by DPS in the ICON8 trial. METHODS: ICON8 was an international, multicentre, randomised, phase 3 trial done across 117 hospitals in the UK, Australia, New Zealand, Mexico, South Korea, and Ireland. The trial included women aged 18 years or older with an Eastern Cooperative Oncology Group performance status of 0-2, life expectancy of more than 12 weeks, and newly diagnosed International Federation of Gynecology and Obstetrics (FIGO; 1988) stage IC-IIA high-grade serous, clear cell, or any poorly differentiated or grade 3 histological subtype, or any FIGO (1988) stage IIB-IV epithelial cancer of the ovary, fallopian tube, or primary peritoneum. Patients were randomly assigned (1:1:1) to receive intravenous carboplatin (area under the curve [AUC]5 or AUC6) and intravenous paclitaxel (175 mg/m2 by body surface area) on day 1 of every 21-day cycle (control group; group 1); intravenous carboplatin (AUC5 or AUC6) on day 1 and intravenous dose-fractionated paclitaxel (80 mg/m2 by body surface area) on days 1, 8, and 15 of every 21-day cycle (group 2); or intravenous dose-fractionated carboplatin (AUC2) and intravenous dose-fractionated paclitaxel (80 mg/m2 by body surface area) on days 1, 8, and 15 of every 21-day cycle (group 3). The maximum number of cycles of chemotherapy permitted was six. Randomisation was done with a minimisation method, and patients were stratified according to GCIG group, disease stage, and timing and outcome of cytoreductive surgery. Patients and clinicians were not masked to group allocation. The scheduling of surgery and use of neoadjuvant chemotherapy were determined by local multidisciplinary case review. In this post-hoc exploratory analysis of ICON8, progression-free survival was analysed using the landmark method and defined as the time interval between the date of pre-surgical planning radiological tumour assessment to the date of investigator-assessed clinical or radiological progression or death, whichever occurred first. This definition is different from the intention-to-treat primary progression-free survival analysis of ICON8, which defined progression-free survival as the time from randomisation to the date of first clinical or radiological progression or death, whichever occurred first. We also compared the extent of surgical cytoreduction with RECIST and GCIG CA125 responses. This post-hoc exploratory analysis includes only women recruited to ICON8 who were planned for neoadjuvant chemotherapy followed by DPS and had RECIST and/or GCIG CA125-evaluable disease. ICON8 is closed for enrolment and follow-up, and registered with ClinicalTrials.gov, NCT01654146. FINDINGS: Between June 6, 2011, and Nov 28, 2014, 1566 women were enrolled in ICON8, of whom 779 (50%) were planned for neoadjuvant chemotherapy followed by DPS. Median follow-up was 29·5 months (IQR 15·6-54·3) for the neoadjuvant chemotherapy followed by DPS population. Of 564 women who had RECIST-evaluable disease at trial entry, 348 (62%) had a complete or partial response. Of 727 women who were evaluable by GCIG CA125 criteria at the time of diagnosis, 610 (84%) had a CA125 response. Median progression-free survival was 14·4 months (95% CI 9·2-28·0; 297 events) for patients with a RECIST complete or partial response and 13·3 months (8·1-20·1; 171 events) for those with RECIST stable disease. Median progression-free survival for women with a GCIG CA125 response was 13·8 months (95% CI 8·8-23·4; 544 events) and 9·7 months (5·8-14·5; 111 events) for those without a GCIG CA125 response. Complete cytoreduction (R0) was achieved in 187 (56%) of 335 women with a RECIST complete or partial response and 73 (42%) of 172 women with RECIST stable disease. Complete cytoreduction was achieved in 290 (50%) of 576 women with a GCIG CA125 response and 30 (30%) of 101 women without a GCIG CA125 response. INTERPRETATION: The RECIST-defined radiological response rate was lower than that frequently quoted to patients in the clinic. RECIST and GCIG CA125 responses to neoadjuvant chemotherapy for epithelial ovarian cancer should not be used as individual predictive markers to stratify patients who are likely to benefit from DPS, but instead used in conjunction with the patient's clinical capacity to undergo cytoreductive surgery. A patient should not be denied surgery based solely on the lack of a RECIST or GCIG CA125 response. FUNDING: Cancer Research UK, UK Medical Research Council, Health Research Board in Ireland, Irish Cancer Society, and Cancer Australia.

Multi-site clonality analysis uncovers pervasive heterogeneity across melanoma metastases.

Metastatic melanoma carries a poor prognosis despite modern systemic therapies. Understanding the evolution of the disease could help inform patient management. Through whole-genome sequencing of 13 melanoma metastases sampled at autopsy from a treatment naïve patient and by leveraging the analytical power of multi-sample analyses, we reveal evidence of diversification among metastatic lineages. UV-induced mutations dominate the trunk, whereas APOBEC-associated mutations are found in the branches of the evolutionary tree. Multi-sample analyses from a further seven patients confirmed that lineage diversification was pervasive, representing an important mode of melanoma dissemination. Our analyses demonstrate that joint analysis of cancer cell fraction estimates across multiple metastases can uncover previously unrecognised levels of tumour heterogeneity and highlight the limitations of inferring heterogeneity from a single biopsy.

ctDNA monitoring using patient-specific sequencing and integration of variant reads.

Circulating tumor-derived DNA (ctDNA) can be used to monitor cancer dynamics noninvasively. Detection of ctDNA can be challenging in patients with low-volume or residual disease, where plasma contains very few tumor-derived DNA fragments. We show that sensitivity for ctDNA detection in plasma can be improved by analyzing hundreds to thousands of mutations that are first identified by tumor genotyping. We describe the INtegration of VAriant Reads (INVAR) pipeline, which combines custom error-suppression methods and signal-enrichment approaches based on biological features of ctDNA. With this approach, the detection limit in each sample can be estimated independently based on the number of informative reads sequenced across multiple patient-specific loci. We applied INVAR to custom hybrid-capture sequencing data from 176 plasma samples from 105 patients with melanoma, lung, renal, glioma, and breast cancer across both early and advanced disease. By integrating signal across a median of >105 informative reads, ctDNA was routinely quantified to 1 mutant molecule per 100,000, and in some cases with high tumor mutation burden and/or plasma input material, to parts per million. This resulted in median area under the curve (AUC) values of 0.98 in advanced cancers and 0.80 in early-stage and challenging settings for ctDNA detection. We generalized this method to whole-exome and whole-genome sequencing, showing that INVAR may be applied without requiring personalized sequencing panels so long as a tumor mutation list is available. As tumor sequencing becomes increasingly performed, such methods for personalized cancer monitoring may enhance the sensitivity of cancer liquid biopsies.

Diffusion kurtosis MRI as a predictive biomarker of response to neoadjuvant chemotherapy in high grade serous ovarian cancer.

This study assessed the feasibility of using diffusion kurtosis imaging (DKI) as a measure of tissue heterogeneity and proliferation to predict the response of high grade serous ovarian cancer (HGSOC) to neoadjuvant chemotherapy (NACT). Seventeen patients with HGSOC were imaged at 3 T and had biopsy samples taken prior to any treatment. The patients were divided into two groups: responders and non-responders based on Response Evaluation Criteria In Solid Tumours (RECIST) criteria. The following imaging metrics were calculated: apparent diffusion coefficient (ADC), apparent diffusion (Dapp) and apparent kurtosis (Kapp). Tumour cellularity and proliferation were quantified using histology and Ki-67 immunohistochemistry. Mean Kapp before therapy was higher in responders compared to non-responders: 0.69 ± 0.13 versus 0.51 ± 0.11 respectively, P = 0.02. Tumour cellularity correlated positively with Kapp (rho = 0.50, P = 0.04) and negatively with both ADC (rho = -0.72, P = 0.001) and Dapp (rho = -0.80, P < 0.001). Ki-67 expression correlated with Kapp (rho = 0.53, P = 0.03) but not with ADC or Dapp. In conclusion, Kapp was found to be a potential predictive biomarker of NACT response in HGSOC, which suggests that DKI is a promising clinical tool for use oncology and radiology that should be evaluated further in future larger studies.

Sodium MRI with 3D-cones as a measure of tumour cellularity in high grade serous ovarian cancer.

The aim of this study was to assess the feasibility of rapid sodium MRI (23Na-MRI) for the imaging of peritoneal cancer deposits in high grade serous ovarian cancer (HGSOC) and to evaluate the relationship of 23Na-MRI with tumour cellularity. 23Na-MRI was performed at 3 T on twelve HGSOC patients using a 3D-cones acquisition technique. Tumour biopsies specimens were collected after imaging and cellularity was measured from histology. Total 23Na-MRI scan time for each patient was approximately 11 min. At an isotropic resolution of 5.6 mm, signal-to-noise ratios (SNRs) of 82.2 ± 15.3 and 15.1 ± 7.1 (mean ± standard deviation) were achieved for imaging of tumour tissue sodium concentration (TSC) and intracellular weighted sodium concentration (IWS) respectively. Tumour TSC and IWS concentrations were: 56.8 ± 19.1 mM and 30.8 ± 9.2 mM respectively and skeletal muscle TSC and IWS concentrations were 33.2 ± 16.3 mM and 20.5 ± 9.9 mM respectively. There were significant sodium concentration differences between cancer and skeletal muscle, Wilcoxon signed-rank test, P < 0.001 for TSC and P = 0.01 for IWS imaging. Tumour cellularity displayed a strong negative correlation with TSC, Spearman's rho = -0.92, P < 0.001, but did not correlate with IWS. This study demonstrates that 23Na-MRI using 3D-cones can rapidly assess sodium concentration in peritoneal deposits of HGSOC and that TSC may serve as a biomarker of tumour cellularity.

Enhanced detection of circulating tumor DNA by fragment size analysis.

Existing methods to improve detection of circulating tumor DNA (ctDNA) have focused on genomic alterations but have rarely considered the biological properties of plasma cell-free DNA (cfDNA). We hypothesized that differences in fragment lengths of circulating DNA could be exploited to enhance sensitivity for detecting the presence of ctDNA and for noninvasive genomic analysis of cancer. We surveyed ctDNA fragment sizes in 344 plasma samples from 200 patients with cancer using low-pass whole-genome sequencing (0.4×). To establish the size distribution of mutant ctDNA, tumor-guided personalized deep sequencing was performed in 19 patients. We detected enrichment of ctDNA in fragment sizes between 90 and 150 bp and developed methods for in vitro and in silico size selection of these fragments. Selecting fragments between 90 and 150 bp improved detection of tumor DNA, with more than twofold median enrichment in >95% of cases and more than fourfold enrichment in >10% of cases. Analysis of size-selected cfDNA identified clinically actionable mutations and copy number alterations that were otherwise not detected. Identification of plasma samples from patients with advanced cancer was improved by predictive models integrating fragment length and copy number analysis of cfDNA, with area under the curve (AUC) >0.99 compared to AUC <0.80 without fragmentation features. Increased identification of cfDNA from patients with glioma, renal, and pancreatic cancer was achieved with AUC > 0.91 compared to AUC < 0.5 without fragmentation features. Fragment size analysis and selective sequencing of specific fragment sizes can boost ctDNA detection and could complement or provide an alternative to deeper sequencing of cfDNA.

Effects of Collection and Processing Procedures on Plasma Circulating Cell-Free DNA from Cancer Patients.

Circulating tumor DNA (ctDNA) offers new opportunities for noninvasive cancer management. Detecting ctDNA in plasma is challenging because it constitutes only a minor fraction of the total cell-free DNA (cfDNA). Pre-analytical factors affect cfDNA levels contributed from leukocyte lysis, hence the ability to detect low-frequency mutant alleles. This study investigates the effects of the delay in processing, storage temperatures, different blood collection tubes, centrifugation protocols, and sample shipment on cfDNA levels. Peripheral blood (n = 231) from cancer patients (n = 62) were collected into K3EDTA or Cell-free DNA BCT tubes and analyzed by digital PCR, targeted amplicon, or shallow whole-genome sequencing. To assess pre-analytic effects, plasma was processed under different conditions after 0, 6, 24, 48, 96 hours, and 1 week at room temperature or 4°C, or using different centrifugation protocols. Digital PCR showed that cfDNA levels increased gradually with time in K3EDTA tubes, but were stable in BCT tubes. K3EDTA samples stored at 4°C showed less variation than room temperature storage, but levels were elevated compared with BCT. A second centrifugation at 3000 × g gave similar cfDNA yields compared with higher-speed centrifugation. Next-generation sequencing showed negligible differences in background error or copy number changes between K3EDTA and BCT, or following shipment in BCT. This study provides insights into the effects of sample processing on ctDNA analysis.

Severe steroid-resistant anti-PD1 T-cell checkpoint inhibitor-induced hepatotoxicity driven by biliary injury.

INTRODUCTION: Hepatotoxicity from T-cell checkpoint blockade is an increasingly common immune-related adverse event, but remains poorly characterised and can be challenging to manage. Such toxicity is generally considered to resemble autoimmune hepatitis, although this assumption is extrapolated from limited clinicopathological reports of anti-cytotoxic T-lymphocyte-associated protein 4-induced hepatotoxicity. METHODS: Here we report, with full clinicopathological correlation, three cases of T-cell checkpoint inhibitor-induced hepatotoxicity associated with anti-programmed cell death protein 1 agents. RESULTS: We find that a major feature of these cases is biliary injury, including a unique case of vanishing bile duct syndrome, and that such toxicity was poorly responsive to long-term immunosuppression (corticosteroids and mycophenolate mofetil). Any potential benefits of long-term immunosuppression in these cases were outweighed by therapy-related complications. DISCUSSION: We discuss potential aetiologies and risk factors for immune-mediated biliary toxicity in the context of the limited literature in this field, and provide guidance for the investigation and supportive management of affected patients.

Exploratory Analysis of TP53 Mutations in Circulating Tumour DNA as Biomarkers of Treatment Response for Patients with Relapsed High-Grade Serous Ovarian Carcinoma: A Retrospective Study.

BACKGROUND: Circulating tumour DNA (ctDNA) carrying tumour-specific sequence alterations may provide a minimally invasive means to dynamically assess tumour burden and response to treatment in cancer patients. Somatic TP53 mutations are a defining feature of high-grade serous ovarian carcinoma (HGSOC). We tested whether these mutations could be used as personalised markers to monitor tumour burden and early changes as a predictor of response and time to progression (TTP). METHODS AND FINDINGS: We performed a retrospective analysis of serial plasma samples collected during routine clinical visits from 40 patients with HGSOC undergoing heterogeneous standard of care treatment. Patient-specific TP53 assays were developed for 31 unique mutations identified in formalin-fixed paraffin-embedded tumour DNA from these patients. These assays were used to quantify ctDNA in 318 plasma samples using microfluidic digital PCR. The TP53 mutant allele fraction (TP53MAF) was compared to serum CA-125, the current gold-standard response marker for HGSOC in blood, as well as to disease volume on computed tomography scans by volumetric analysis. Changes after one cycle of treatment were compared with TTP. The median TP53MAF prior to treatment in 51 relapsed treatment courses was 8% (interquartile range [IQR] 1.2%-22%) compared to 0.7% (IQR 0.3%-2.0%) for seven untreated newly diagnosed stage IIIC/IV patients. TP53MAF correlated with volumetric measurements (Pearson r = 0.59, p < 0.001), and this correlation improved when patients with ascites were excluded (r = 0.82). The ratio of TP53MAF to volume of disease was higher in relapsed patients (0.04% per cm3) than in untreated patients (0.0008% per cm3, p = 0.004). In nearly all relapsed patients with disease volume > 32 cm3, ctDNA was detected at ≥20 amplifiable copies per millilitre of plasma. In 49 treatment courses for relapsed disease, pre-treatment TP53MAF concentration, but not CA-125, was associated with TTP. Response to chemotherapy was seen earlier with ctDNA, with a median time to nadir of 37 d (IQR 28-54) compared with a median time to nadir of 84 d (IQR 42-116) for CA-125. In 32 relapsed treatment courses evaluable for response after one cycle of chemotherapy, a decrease in TP53MAF of >60% was an independent predictor of TTP in multivariable analysis (hazard ratio 0.22, 95% CI 0.07-0.67, p = 0.008). Conversely, a decrease in TP53MAF of ≤60% was associated with poor response and identified cases with TTP < 6 mo with 71% sensitivity (95% CI 42%-92%) and 88% specificity (95% CI 64%-99%). Specificity was improved when patients with recent drainage of ascites were excluded. Ascites drainage led to a reduction of TP53MAF concentration. The limitations of this study include retrospective design, small sample size, and heterogeneity of treatment within the cohort. CONCLUSIONS: In this retrospective study, we demonstrated that ctDNA is correlated with volume of disease at the start of treatment in women with HGSOC and that a decrease of ≤60% in TP53MAF after one cycle of chemotherapy was associated with shorter TTP. These results provide evidence that ctDNA has the potential to be a highly specific early molecular response marker in HGSOC and warrants further investigation in larger cohorts receiving uniform treatment.