Changepoint detection on a graph of time series

When analysing multiple time series that may be subject to changepoints, it is sometimes possible to specify a priori, by means of a graph G, which pairs of time series are likely to be impacted by simultaneous changepoints. This article proposes a novel Bayesian changepoint model for multiple time series that borrows strength across clusters of connected time series in G to detect weak signals for synchronous changepoints. The graphical changepoint model is further extended to allow dependence between nearby but not necessarily synchronous changepoints across neighbour time series in G. A novel reversible jump MCMC algorithm making use of auxiliary variables is proposed to sample from the graphical changepoint model. The merit of the proposed model is demonstrated via a changepoint analysis of real network authentication data from Los Alamos National Laboratory (LANL), with some success at detecting weak signals for network intrusions across users that are linked by network connectivity, whilst limiting the number of false alerts.Comment: 31 pages, 13 figure

Subsequent female breast cancer risk associated with anthracycline chemotherapy for childhood cancer.

Anthracycline-based chemotherapy is associated with increased subsequent breast cancer (SBC) risk in female childhood cancer survivors, but the current evidence is insufficient to support early breast cancer screening recommendations for survivors treated with anthracyclines. In this study, we pooled individual patient data of 17,903 survivors from six well-established studies, of whom 782 (4.4%) developed a SBC, and analyzed dose-dependent effects of individual anthracycline agents on developing SBC and interactions with chest radiotherapy. A dose-dependent increased SBC risk was seen for doxorubicin (hazard ratio (HR) per 100 mg m-2: 1.24, 95% confidence interval (CI): 1.18-1.31), with more than twofold increased risk for survivors treated with ≥200 mg m-2 cumulative doxorubicin dose versus no doxorubicin (HR: 2.50 for 200-299 mg m-2, HR: 2.33 for 300-399 mg m-2 and HR: 2.78 for ≥400 mg m-2). For daunorubicin, the associations were not statistically significant. Epirubicin was associated with increased SBC risk (yes/no, HR: 3.25, 95% CI: 1.59-6.63). For patients treated with or without chest irradiation, HRs per 100 mg m-2 of doxorubicin were 1.11 (95% CI: 1.02-1.21) and 1.26 (95% CI: 1.17-1.36), respectively. Our findings support that early initiation of SBC surveillance may be reasonable for survivors who received ≥200 mg m-2 cumulative doxorubicin dose and should be considered in SBC surveillance guidelines for survivors and future treatment protocols

Cohort profile: Risk and risk factors for female breast cancer after treatment for childhood and adolescent cancer: an internationally pooled cohort.

PURPOSE The International Consortium for Pooled Studies on Subsequent Malignancies after Childhood and Adolescent Cancer was established in 2018 to address gaps in knowledge of risk and risk factors for breast cancer subsequent to childhood/adolescent cancer by pooling individual patient data from seven cohorts. Initially, the pooled cohort will focus on three clinically relevant questions regarding treatment-related subsequent breast cancer risk in female survivors, which are the risk related to low-dose radiotherapy exposure to the chest, specific chemotherapy agents and attained age. PARTICIPANTS The consortium database includes pooled data on 21 892 female survivors from seven cohorts in North America and Europe with a primary cancer diagnosis at <21 years of age, and survival ≥5 years from diagnosis. FINDINGS TO DATE This is a newly established pooled study. The cohort profile summarised the data collected from each included cohort, including childhood cancer diagnosis information and treatment details (ie, radiotherapy fields and cumulative doses, and chemotherapy agents and cumulative doses for each agent). Included cohorts' follow-up started 1951-1981 and ended 2013-2021, respectively, for a median follow-up duration of 24.3 (IQR 18.0-32.8) years since primary cancer diagnosis. The median age at primary cancer diagnosis was 5.4 (IQR 2.5-11.9) years. And the median attained age at last follow-up was 32.2 (IQR 24.0-40.4) years. In all, 4240 (19.4%) survivors were treated with radiotherapy to the chest and 9308 (42.5%) with anthracyclines. At the end of the follow-up, 835 females developed a first subsequent breast cancer, including 635 invasive breast cancer only, 184 carcinomas in situ only (172 ductal carcinomas in situ and 12 lobular carcinomas in situ), and 16 with both an invasive and in situ diagnosis at the same moment. The cumulative incidences of subsequent breast cancer (both invasive and in situ) 25 and 35 years after primary cancer diagnosis were 2.2% and 6.2%, respectively. FUTURE PLANS The consortium is intended to serve as a model and robust source of childhood/adolescent cancer survivor data for elucidating other knowledge gaps on subsequent breast cancer risk, and risk of other subsequent malignancies (including data on males) in the future

Automated Design of Tailored Link Prediction Heuristics for Applications in Enterprise Network Security

The link prediction problem, which involves determining the likelihood of a relationship between objects, has numerous applications in the areas of recommendation systems, social networking, anomaly detection, and others. A variety of link prediction techniques have been developed to improve predictive performance for different application domains. Selection of the appropriate link prediction heuristic is critical which demonstrates the need for tailored solutions. This work explores the use of hyper-heuristics to automate the selection and generation of customized link prediction algorithms. A genetic programming approach is used to evolve novel solutions from functionality present in existing techniques that exploit characteristics of a specific application to improve performance. Applications of this approach are tested using data from a real-world enterprise computer network to differentiate normal activity from randomly generated anomalous events. Results are presented that demonstrate the potential for the automated design of custom link prediction heuristics that improve upon the predictive capabilities of conventional methods

Genetic variation in POT1 and risk of thyroid subsequent malignant neoplasm: A report from the Childhood Cancer Survivor Study.

BackgroundTelomere length is associated with risk for thyroid subsequent malignant neoplasm in survivors of childhood cancer. Here, we investigated associations between thyroid subsequent malignant neoplasm and inherited variation in telomere maintenance genes.MethodsWe used RegulomeDB to annotate the functional impact of variants mapping to 14 telomere maintenance genes among 5,066 five-or-more year survivors who participate in the Childhood Cancer Survivor Study (CCSS) and who are longitudinally followed for incidence of subsequent cancers. Hazard ratios for thyroid subsequent malignant neoplasm were calculated for 60 putatively functional variants with minor allele frequency ≥1% in or near telomere maintenance genes. Functional impact was further assessed by measuring telomere length in leukocyte subsets.ResultsThe minor allele at Protection of Telomeres-1 (POT1) rs58722976 was associated with increased risk for thyroid subsequent malignant neoplasm (adjusted HR = 6.1, 95% CI: 2.4, 15.5, P = 0.0001; Fisher's exact P = 0.001). This imputed SNP was present in three out of 110 survivors who developed thyroid cancer vs. 14 out of 4,956 survivors who did not develop thyroid cancer. In a subset of 83 survivors with leukocyte telomere length data available, this variant was associated with longer telomeres in B lymphocytes (P = 0.004).ConclusionsUsing a functional variant approach, we identified and confirmed an association between a low frequency intronic regulatory POT1 variant and thyroid subsequent malignant neoplasm in survivors of childhood cancer. These results suggest that intronic variation in POT1 may affect key protein binding interactions that impact telomere maintenance and genomic integrity

Lifestyle and Subsequent Malignant Neoplasms in Childhood Cancer Survivors: A Report from the St. Jude Lifetime Cohort Study

Introduction: This study aimed to assess longitudinal associations between lifestyle and subsequent malignant neoplasms (SMNs) in young adult childhood cancer survivors. Methods: Members of the St. Jude Lifetime Cohort (SJLIFE) aged ≥18 years and surviving ≥5 years after childhood cancer diagnosis were queried and evaluated for physical activity, cardiorespiratory fitness (CRF), muscle strength, body mass index (BMI), smoking, risky drinking, and a combined lifestyle score. Time to first SMN, excluding nonmalignant neoplasms and nonmelanoma skin cancer, was the outcome of longitudinal analysis. Results: Survivors (n = 4072, 47% female, 29% smokers, 37% risky drinkers, 34% obese, and 48% physically inactive) had a mean (SD) time between baseline evaluation and follow-up of 7.0 (3.3) years, an age of 8.7 (5.7) years at diagnosis, and an age of 30 (8.4) years at baseline lifestyle assessment. Neither individual lifestyle factors nor a healthy lifestyle score (RR 0.8, 0.4–1.3, p = 0.36) were associated with the risk of developing an SMN. Conclusions: We did not identify any association between lifestyle factors and the risk of SMN in young adult childhood cancer survivors

Cohort profile: Risk and risk factors for female breast cancer after treatment for childhood and adolescent cancer: an internationally pooled cohort

Purpose The International Consortium for Pooled Studies on Subsequent Malignancies after Childhood and Adolescent Cancer was established in 2018 to address gaps in knowledge of risk and risk factors for breast cancer subsequent to childhood/adolescent cancer by pooling individual patient data from seven cohorts. Initially, the pooled cohort will focus on three clinically relevant questions regarding treatment-related subsequent breast cancer risk in female survivors, which are the risk related to low-dose radiotherapy exposure to the chest, specific chemotherapy agents and attained age. Participants The consortium database includes pooled data on 21 892 female survivors from seven cohorts in North America and Europe with a primary cancer diagnosis at <21 years of age, and survival ≥5 years from diagnosis. Findings to date This is a newly established pooled study. The cohort profile summarised the data collected from each included cohort, including childhood cancer diagnosis information and treatment details (ie, radiotherapy fields and cumulative doses, and chemotherapy agents and cumulative doses for each agent). Included cohorts' follow-up started 1951-1981 and ended 2013-2021, respectively, for a median follow-up duration of 24.3 (IQR 18.0-32.8) years since primary cancer diagnosis. The median age at primary cancer diagnosis was 5.4 (IQR 2.5-11.9) years. And the median attained age at last follow-up was 32.2 (IQR 24.0-40.4) years. In all, 4240 (19.4%) survivors were treated with radiotherapy to the chest and 9308 (42.5%) with anthracyclines. At the end of the follow-up, 835 females developed a first subsequent breast cancer, including 635 invasive breast cancer only, 184 carcinomas in situ only (172 ductal carcinomas in situ and 12 lobular carcinomas in situ), and 16 with both an invasive and in situ diagnosis at the same moment. The cumulative incidences of subsequent breast cancer (both invasive and in situ) 25 and 35 years after primary cancer diagnosis were 2.2% and 6.2%, respectively. Future plans The consortium is intended to serve as a model and robust source of childhood/adolescent cancer survivor data for elucidating other knowledge gaps on subsequent breast cancer risk, and risk of other subsequent malignancies (including data on males) in the future