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This study assessed the psychological predictors of preferences for return of comprehensive tumor genomic profiling (CTGP) results in patients with advanced cancers, enrolled in the Molecular Screening and Therapeutics Program. Patients completed a questionnaire prior to undergoing CTGP. Of the 1434 who completed a questionnaire, 96% would like to receive results that can guide treatment for their cancer, and preference for receiving this type of result was associated with lower tolerance of uncertainty. Sixty-four percent would like to receive results that cannot guide treatment, and lower tolerance of uncertainty, self-efficacy, and perceived importance were associated with this preference. Fifty-nine percent would like to receive variants of unknown significance, which was associated with lower tolerance of uncertainty, higher self-efficacy, and perceived importance. Eighty-six percent wanted to receive germline results that could inform family risk. This was associated with higher self-efficacy, perceived importance, and perceived susceptibility. Although most patients wanted to receive all types of results, given the differing patient preferences regarding the return of results depending on the utility of the different types of results, it appears critical to safeguard patient understanding of result utility to achieve informed patient choices. This should be accompanied by appropriate consent processes.

Fear of cancer recurrence/occurrence (FCR/O) is prevalent and associated with poorer psychological outcomes but can also motivate individuals to pursue genomic information about cancer risk. Guided by Protection Motivation Theory, this study investigated FCR/O prevalence and associated factors among probands previously diagnosed with a cancer of likely heritable origin, and their relatives, who had agreed to have germline genome sequencing. Three hundred and forty-eight probands and 167 relatives completed the Concerns about Recurrence Questionnaire (adapted for occurrence for some relatives) within 1 month of agreeing to undertake genome sequencing. Linear regressions investigated demographic, disease, attitude and behavioral associations with FCR/O. Probands demonstrated greater FCR compared to relatives. In probands, greater FCR was associated with being female, non-English speaking at home, less time since diagnosis, greater intention to change behavior if gene variant found, lower perceived ability to cope with results, higher perceived susceptibility to having a recurrence, and more negative attitudes towards uncertainty. For relatives with cancer, greater FCR was associated with being male, greater intention to change behavior if a gene variant found, and higher perceived susceptibility to recurrence. In relatives without cancer, greater FCO was associated with not having had genetic testing prior to this study, lower perceived ability to cope with results, and higher perceived susceptibility to developing cancer. Current findings on FCR/O prevalence and associated demographic and attitudinal variables in those who pursue genomic risk information might be used to target interventions that can prevent adverse psychological outcomes in vulnerable patients.

Purpose The introduction of comprehensive tumour genomic profiling (CGP) into clinical oncology allows the identification of molecular therapeutic targets. However, the potential complexity of genomic results and their implications may cause confusion and distress for patients undergoing CGP. We investigated the experience of advanced cancer patients receiving CGP results in a research setting. Methods Semi-structured interviews with 37 advanced cancer patients were conducted within two weeks of patients receiving CGP results. Interviewees were purposively sampled based on CGP result, cancer type, age and gender to ensure diversity. Themes were derived from interview transcripts using a framework analysis approach. Results We identified six themes: (1) hoping against the odds; (2) managing expectations; (3) understanding is cursory; (4) communication of results is cursory; (5) genomics and incurable cancer; and (6) decisions about treatment. Conclusion Despite enthusiasm regarding CGP about the hope it provides for new treatments, participants experienced challenges in understanding results, and acceptance of identified treatments was not automatic. Support is needed for patients undergoing CGP to understand the implications of testing and cope with non-actionable results.

Comprehensive tumor genomic profiling (CGP) offers hope for personalized treatment for cancer patients when other treatment options have been exhausted. However, receipt of nonactionable or ambiguous results could be an ongoing source of distress. We investigated patterns of hope, anxiety, depression, and CGP-specific anxiety in advanced cancer patients after receiving CGP results and 2-3 months later.Participants were enrolled in a longitudinal psychosocial substudy, embedded in the Molecular Screening and Therapeutics Program, and had advanced solid cancers of any histological type with sufficient and accessible tissue for CGP. At T0 (before receiving CGP results), 1,431 participants completed sociodemographic, disease and psychosocial measures. At T1 (1-4 weeks after receiving CGP results) and T2 (2-3 months post-T1), 374 participants completed psychological outcome measures. Predictors of outcomes at T2 were identified using multinomial logistic regression.Approximately 75% of participants did not experience significant hopelessness or distress at T1 and T2. Hope decreased by T2, yet general anxiety and CGP-specific anxiety also decreased. Receiving actionable results did not impact psychological outcomes at T2. At T2, lower hope, and higher anxiety, depression and CGP-specific anxiety were associated with lower self-efficacy. Psychological and demographic factors (age, socioeconomic status, language, medical occupation, urban living, family history of cancer) independently predicted one or more psychological trajectories. Worse health status and perceived susceptibility to cancer progression predicted hope and anxiety trajectories.Further research on interventions to best support patients undergoing CGP with high anxiety, hopelessness, fear of cancer progression, and poorer health is urgently needed. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

It is important to understand how individuals perceive uncertainties and the consequent impact on their psychological well-being and health behavior. The Perceptions of Uncertainties in Genome Sequencing (PUGS) scale measures clinical, affective, and evaluative uncertainties about information from sequencing. The PUGS scale has been shown to be valid and reliable among individuals receiving results about their genomes. This study assessed whether its validity generalized to patients with cancer undergoing tumor sequencing. Exploratory factor analysis (EFA) was conducted on data from the Molecular Screening and Therapeutics Program (n = 310) to identify a measurement model. Confirmatory factor analysis (CFA) was used to determine the adequacy of the resulting fit. EFA identified the same three-factor structure reported previously. CFA confirmed that the measurement model yielded a good fit (χ

OBJECTIVE This study aimed to discern preferences for receiving somatic molecular profiling (MP) results in cancer patients who have given consent to undergo testing. METHODS We conducted a mixed-methods study to explore patients' views on which MP results they would like to receive and why. Advanced cancer patients (n = 1299) completed questionnaires after giving consent to participate in a parent genomics study and undergoing MP. A subset of patients (n = 20) participated in qualitative interviews. RESULTS Almost all (96%) participants were interested in receiving results which would direct cancer treatment (ie, were actionable). A smaller majority wanted to access results which were not actionable (64%) or were variants of unknown significance (60%). Most (86%) were interested in finding out about germline findings, though not as a priority. Themes identified in interview data were: (a) Cancer is the focus; (b) Trust in clinicians; and (c) Respect for a right not to know. CONCLUSIONS The majority of advanced cancer patients undergoing MP prioritised results which would lead to treatment options. They trusted their oncologists to help them navigate the results return process. While there was interest in knowing about other results, this was a lesser priority. Nevertheless, given high levels of interest in receiving all results, ethical aspects of not providing uninformative results requires further research, including a consideration of patient rationales for desiring this information and what health professionals can and should do to support patients in the absence of meaningful information being available.

While genomics provides new clinical opportunities, its complexity generates uncertainties. This systematic review aimed to summarize what is currently known about the experience of uncertainty for adult patients undergoing cancer genomic testing. A search of five databases (2001 to 2018) yielded 6508 records. After removing duplicates, abstract/title screening, and assessment of full articles, ten studies were included for quality appraisal and data extraction. Qualitative studies were subjected to thematic analysis, and quantitative data were summarized using descriptive statistics. Cancer genomic results reduced uncertainty for patients regarding treatment decisions but did not reduce uncertainty in the risk context. Qualitative and quantitative data synthesis revealed four themes: (1) coexisting uncertainties, (2) factors influencing uncertainty, (3) outcomes of uncertainty, and (4) coping with uncertainty. Uncertainty can motivate, or be a barrier to, pursuing cancer genomic testing. Appraisal of uncertainty influences the patient experience of uncertainty, the outcome of uncertainty for patients, as well as the coping strategies utilized. While this systematic review found that appraisal of uncertainty is important to the patients' experience of uncertainty in the cancer genomic context, more mixed methods longitudinal research is needed to address the complexities that contribute to patient uncertainty across the process.

Telomerase is a ribonucleoprotein complex that maintains the length and integrity of telomeres, and thereby enables cellular proliferation. Understanding the regulation of telomerase in hematopoietic cells is relevant to the pathogenesis of leukemia, in which telomerase is constitutively activated, as well as bone marrow failure syndromes that feature telomerase insufficiency. Past studies showing high levels of telomerase in human erythroblasts and a prevalence of anemia in disorders of telomerase insufficiency provide the rationale for investigating telomerase regulation in erythroid cells. Here it is shown for the first time that the telomerase RNA-binding protein dyskerin (encoded by DKC1) is dramatically upregulated as human hematopoietic stem and progenitor cells commit to the erythroid lineage, driving an increase in telomerase activity in the presence of limiting amounts of TERT mRNA. It is also shown that upregulation of DKC1 was necessary for expansion of glycophorin A+ erythroblasts and sufficient to extend telomeres in erythroleukemia cells. Chromatin immunoprecipitation and reporter assays implicated GATA1-mediated transcriptional regulation of DKC1 in the modulation of telomerase in erythroid lineage cells. Together these results describe a novel mechanism of telomerase regulation in erythroid cells which contrasts with mechanisms centered on transcriptional regulation of TERT that are known to operate in other cell types. This is the first study to reveal a biological context in which telomerase is upregulated by DKC1 and to implicate GATA1 in telomerase regulation. The results from this study are relevant to hematopoietic disorders involving DKC1 mutations, GATA1 deregulation and/or telomerase insufficiency.

Purpose: Comprehensive genomic profiling (CGP) is increasingly used to guide cancer therapy. This study aimed to characterise oncologists’ experiences and needs when utilising genomic results. Materials and Methods: An electronic survey distributed nation-wide to practising medical oncologists in Australia explored oncologists’ experiences with consenting, interpreting and communicating CGP results to patients. Results: The survey was completed by 108 of 333 oncologists (32%) and most respondents (n = 97, 90%) had referred patients for CGP. Using a 100-point visual analogue scale score [VAS], where higher values indicate greater confidence, most oncologists were confident consenting patients for referral [median 75 (Interquartile range, IQR: 53–85), discussing CGP results (median VAS: 70, IQR: 51–80), but significantly less confident discussing secondary germline findings (median VAS: 56, IQR 30–70, p < 0.001). Confidence with pursuing therapies based on CGP results increased with clinical experience (mean VAS increases by 4.8 per 5 years of experience, p < 0.001). Most oncologists (N = 68, 63%) reported wanting assistance with interpretation of CGP and patient-centric resources to aid communication with patients. Conclusions: Oncologists are integrating genomics into clinical care, but only display moderate confidence in communication and changing management accordingly. The development of patient- and clinician- targeted resources may assist with routine utilisation of CGP results in cancer care.

Introduction: Fear of cancer progression (FCP) impacts quality of life and is a prevalent unmet need in patients diagnosed with advanced cancer, particularly as treatment options are reduced. We aimed to identify longitudinal patterns in FCP over 6 months in patients with advanced cancer receiving comprehensive tumour genomic profiling (CTGP) results, and their correlates. Methods: Patients with pathologically confirmed metastatic disease (∼70% rare cancers) receiving or post their last line of standard therapy completed questionnaires at T0 (prior to CTGP), T1 (immediately post CTGP results) and T2 (2 months later). Results: High stable (N = 52; 7.3%) and low/moderate stable (N = 56; 7.8%) FCP patterns over time typified the largest participant groups (N = 721). Those with an immediately actionable variant versus a non-actionable variant (p = 0.045), with higher FCP (p

Genomic Sequencing (GS) to identify high cancer risk will soon enter clinical practice at significant cost to the health system. This study aimed to quantify perceived value of GS to Australian cancer patients and their first-degree relatives participating in a genomic sequencing study, and factors associated with value. Participants were recruited upon consent to the genomics study. Eligible participants (with cancer of likely genetic etiology, or a first-degree relative) completed a questionnaire prior to GS. Willingness to pay was assessed via hypothetical trade-off scenarios of actionable result return rates of 1%, 10%, 20%, 30%, 40% or 50%. Of 348 probands and 213 relatives (92% and 93% response rate), 81% would consistently have GS for as little as a 1% actionable return rate. Participants would pay a median of $1,000 for return rates of at least 20% (probands) or 30% (relatives), and $300 for lower return rates. Probands with common cancers and negative attitudes to uncertainty were more likely to have GS; those with higher education were more willing to pay $1,000 and $3,000 for lower return rates. This study found high interest in, but lower willingness to pay for GS in cancer patients and their first-degree relatives, possibly due to inability to pay. Further research is needed to improve our understanding of how individuals in different risk circumstances, trade-off the risks, harms, and benefits of GS.

This study assessed the psychological predictors of attitudes toward the return of germline genomic sequencing results in cancer patients and their biological relatives with a likely genetic basis for their cancer diagnosis, who completed a questionnaire prior to undergoing genomic sequencing. Of 602 probands and relatives, 94% of probands and 89% of relatives thought people would like to be informed about single-gene conditions for which there is prevention or treatment. Amongst relatives, this view was associated with higher perceived susceptibility and self-efficacy. Probands (66%) and relatives (59%) thought people would be interested in learning about single-gene conditions for which there is no prevention or treatment. Amongst probands, this view was associated with lower tolerance of uncertainty and amongst relatives with higher self-efficacy. Probands (92%) and relatives (90%) thought people would like to be informed about polygenic conditions that can have a major impact on health. Amongst probands this view was associated with lower perceived susceptibility of cancer recurrence, and amongst relatives, with higher perceived susceptibility and self-efficacy. Probands (86%) and relatives (86%) thought that people would like to be informed about polygenic conditions that can have a lower impact on health, and this view was associated with a lower perceived susceptibility of recurrence amongst probands. In conclusion, these findings show that individuals' attitudes about the return of results depend on the perceived utility of different types of tests. Therefore, individuals need to gain a clear understanding of test utility, and appropriate consent processes are required to achieve informed choices.

There is limited knowledge about cancer patients' experiences of uncertainty while waiting for genome sequencing results, and whether prolonged uncertainty contributes to psychological factors in this context. To investigate uncertainty in patients with a cancer of likely hereditary origin while waiting for genome sequencing results, we collected questionnaire and interview data at baseline, and at three and 12 months follow up (prior to receiving results). Participants (N = 353) had negative attitudes towards uncertainty (M = 4.03, SD 0.68) at baseline, and low levels of uncertainty at three (M = 8.23, SD 7.37) and 12 months (M = 7.95, SD 7.64). Uncertainty about genome sequencing did not change significantly over time [t(210) = 0.660, p = 0.510]. Greater perceived susceptibility for cancer [r(348) = 0.14, p < 0.01], fear of cancer recurrence [r(348) = 0.19, p < 0.01], perceived importance of genome sequencing [r(350) = 0.24, p < 0.01], intention to change behavior if a gene variant indicating risk is found [r(349) = 0.29, p < 0.01], perceived ability to cope with results [r(349) = 0.36, p < 0.01], and satisfaction with decision to have genome sequencing [r(350) = 0.52, p < 0.01] were significantly correlated with negative attitudes towards uncertainty at baseline. Multiple primary cancer diagnoses [B = −2.364 [−4.238, −0.491], p = 0.014], lower perceived ability to cope with results [B = −0.1.881 [−3.403, −0.359], p = 0.016] at baseline, greater anxiety about genome sequencing (avoidance) [B = 0.347 [0.148, 0.546], p = 0.0012] at 3 months, and greater perceived uncertainty about genome sequencing [B = 0.494 [0.267, 0.721] p = 0.000] at 3 months significantly predicted greater perceived uncertainty about genome sequencing at 12 months. Greater perceived uncertainty about genome sequencing at 3 months significantly predicted greater anxiety (avoidance) about genome sequencing at 12 months [B = 0.291 [0.072, 0.509], p = 0.009]. Semi-structured interviews revealed that while participants were motivated to pursue genome sequencing as a strategy to reduce their illness and risk uncertainty, genome sequencing generated additional practical, scientific and personal uncertainties. Some uncertainties were consistently discussed over the 12 months, while others emerged over time. Similarly, some uncertainty coping strategies were consistent over time, while others emerged while patients waited for their genome sequencing results. This study demonstrates the complexity of uncertainty generated by genome sequencing for cancer patients and provides further support for the inter-relationship between uncertainty and anxiety. Helping patients manage their uncertainty may ameliorate psychological morbidity.

Fear of cancer recurrence/occurrence (FCR/O) is prevalent and associated with poorer psychological outcomes but can also motivate individuals to pursue genomic information about cancer risk. Guided by Protection Motivation Theory, this study investigated FCR/O prevalence and associated factors among probands previously diagnosed with a cancer of likely heritable origin, and their relatives, who had agreed to have germline genome sequencing.Three hundred and forty-eight probands and 167 relatives completed the Concerns about Recurrence Questionnaire (adapted for occurrence for some relatives) within 1 month of agreeing to undertake genome sequencing. Linear regressions investigated demographic, disease, attitude and behavioral associations with FCR/O.Probands demonstrated greater FCR compared to relatives. In probands, greater FCR was associated with being female, non-English speaking at home, less time since diagnosis, greater intention to change behavior if gene variant found, lower perceived ability to cope with results, higher perceived susceptibility to having a recurrence, and more negative attitudes towards uncertainty. For relatives with cancer, greater FCR was associated with being male, greater intention to change behavior if a gene variant found, and higher perceived susceptibility to recurrence. In relatives without cancer, greater FCO was associated with not having had genetic testing prior to this study, lower perceived ability to cope with results, and higher perceived susceptibility to developing cancer.Current findings on FCR/O prevalence and associated demographic and attitudinal variables in those who pursue genomic risk information might be used to target interventions that can prevent adverse psychological outcomes in vulnerable patients.

Germline genome sequencing (GS) holds great promise for cancer prevention by identifying cancer risk and guiding prevention strategies, however research evidence is mixed regarding patient preferences for receiving GS results. The aim of this study was to discern preferences for return of results by cancer patients who have actually undergone GS. We conducted a mixed methods study with a cohort of cancer probands (n = 335) and their genetic relatives (n = 199) undergoing GS in a research setting. Both groups completed surveys when giving consent. A subset of participants (n = 40) completed semi-structured interviews. A significantly higher percentage of probands thought people would like to be informed about genetic conditions for which there is prevention or treatment that can change cancer risk compared to conditions for which there is no prevention or treatment (93% [311] versus 65% [216]; p p

OBJECTIVES: Germline genome sequencing (GS) is becoming mainstream in cancer diagnosis and risk management. Identifying knowledge gaps and determinants of health behavior change intentions will enable effective targeting of educational and management strategies to translate genomic findings into improved cancer outcomes. METHODS: Probands diagnosed with cancer of likely genetic origin that consented to but not yet undergone GS, and their biological relatives, completed a cross-sectional questionnaire assessing GS knowledge and hypothetical intention to change behaviors. RESULTS: Probands (n = 348; 57% university educated) and relatives (n = 213; 38% university educated) had moderate GS knowledge levels, with greater knowledge associated with higher education. Both populations reported high behavioral change intentions, significantly associated with being female (p = 0.01) and greater perceived importance of GS (p

Objective This study explored family communication about undertaking genomic sequencing, and intentions to communicate pertinent heritable results to family members. Methods Semi-structured interviews were conducted with cancer patients (n = 53) and their relatives (n = 20) who underwent germline genome sequencing or molecular tumor testing. Interviews were audio-recorded, transcribed and analyzed using thematic analysis. Results Key themes relevant to family communication about undertaking sequencing included: perceiving family member interest, delaying discussion until results were received, having shared capacity to understand and cope, and having open communication in the family. Intended communication subsequent to receiving results was affected by: disease severity, risk management options, degree of closeness in the family, sense of responsibility, and potential adverse impacts on family. Resource and support needs varied based on the complexity of test results, health professionals’ availability, and disease severity. Unique subthemes were identified for specific subgroups. Conclusion Current findings support the need to assess the impact and resource needs specific to each clinical application of genomic sequencing. Practice implications Increasingly sophisticated and complex clinical genomic sequencing warrants development of family-centered interventions and resources to facilitate preference-sensitive communication about genomic sequencing, including disseminating relevant information to family members.

The replicative immortality of human cancer cells is achieved by activation of a telomere maintenance mechanism (TMM). To achieve this, cancer cells utilise either the enzyme telomerase, or the Alternative Lengthening of Telomeres (ALT) pathway. These distinct molecular pathways are incompletely understood with respect to activation and propagation, as well as their associations with clinical outcomes. We have identified significant differences in the telomere repeat composition of tumours that use ALT compared to tumours that do not. We then employed a machine learning approach to stratify tumours according to telomere repeat content with an accuracy of 91.6%. Importantly, this classification approach is applicable across all tumour types. Analysis of pathway mutations that were under-represented in ALT tumours, across 1,075 tumour samples, revealed that the autophagy, cell cycle control of chromosomal replication, and transcriptional regulatory network in embryonic stem cells pathways are involved in the survival of ALT tumours. Overall, our approach demonstrates that telomere sequence content can be used to stratify ALT activity in cancers, and begin to define the molecular pathways involved in ALT activation.

Cancers that utilize the alternative lengthening of telomeres (ALT) mechanism for telomere maintenance are often difficult to treat and have a poor prognosis. They are also commonly deficient for expression of ATRX protein, a repressor of ALT activity, and a component of promyelocytic leukemia nuclear bodies (PML NBs) that are required for intrinsic immunity to various viruses. Here, we asked whether ATRX deficiency creates a vulnerability in ALT cancer cells that could be exploited for therapeutic purposes. We showed in a range of cell types that a mutant herpes simplex virus type 1 (HSV-1) lacking ICP0, a protein that degrades PML NB components including ATRX, was ten- to one thousand-fold more effective in infecting ATRX-deficient cells than wild-type ATRX-expressing cells. Infection of co-cultured primary and ATRX-deficient cancer cells revealed that mutant HSV-1 selectively killed ATRX-deficient cells. Sensitivity to mutant HSV-1 infection also correlated inversely with PML protein levels, and we showed that ATRX upregulates PML expression at both the transcriptional and post-transcriptional levels. These data provide a basis for predicting, based on ATRX or PML levels, which tumors will respond to a selective oncolytic herpesvirus., Summary: ATRX deficiency in cancer cells induces downregulation of PML, rendering the cells highly sensitive to lysis with ICP0-null mutant herpes simplex virus-1, with potential therapeutic applications.

1541 Background: Somatic tumor mutation profiling (STMP) is entering clinical practice. We aimed to investigate psychological impacts of receiving results. Methods: Eligible participants had: advanced solid cancers of any histological type; accessible tissue for STMP; and enrolled in the Molecular Screening and Therapeutics (MoST) Program. 1074 participants (91%) completed a baseline assessment prior to STMP (T0), of whom 570 (47%) received results and completed a post-result assessment (T1) of impact of genetic results (MICRA), anxiety and depression (HADS), cancer-specific anxiety (IES), and satisfaction with decision to have STMP. Linear regression models controlling for age, gender, parental status, cultural diversity, education and ECOG status explored associations between result received and psychological outcomes. Results: 360 participants received an actionable result and were recommended personalised treatment: 152 via a MoST sub-study (G1) and 208 via their treating oncologist (G2). 210 received a non-actionable result (G3). At T1, G3 were significantly more distressed and less positive about their result (MICRA subscales) and less satisfied with their decision to have STMP than both G1 and G2; G2 was less positive than G1. IES and HADs were not impacted by type of result. Interactions between gender and age, and result were non-significant for all psychological outcomes. Perceived self-efficacy in coping with results (p=0.015) and knowledge (p=0.04) at T0 was significantly correlated with satisfaction with decision at T1; self efficacy (T0) was also correlated with MICRA total (T1) (p=0.006). Conclusions: Pathway to treatment receipt is less important to advanced cancer patients than actionability. Patients’ self-efficacy to cope with results prior to testing can identify patients vulnerable to distress post-receipt of STMP results who should be offered psychological counseling. Ensuring good knowledge of STMP at consent may avoid decisional regret. [Table: see text]

Key Points Question What value do patients with advanced cancer place on tumor variation profiling? Findings In this survey study of 777 patients with advanced cancer, 689 individuals (89%) indicated that they would have tumor molecular profiling for as little as a 1% actionable return rate, but fewer were willing to pay for it. Country of birth, medical- or science-related occupation, attitude toward uncertainty, and perceived importance of tumor molecular profiling were associated with willingness to pay. Meaning Ability to pay may limit access to tumor molecular profiling; ongoing societal debate is required to establish the value of tumor molecular profiling and whether subsidization is necessary to ensure equity of access., Importance Use of tumor molecular profiling (MP) is entering routine clinical practice; however, little is known about how much and why patients value MP. Objective To examine the perceived value of MP to patients with advanced cancer and factors associated with perceived value. Design, Setting, and Participants A cross-sectional survey that included willingness-to-pay trade-off scenarios was administered to participants after consent and before MP. A total of 777 participants (94% response rate) were recruited from the Molecular Screening and Therapeutics Program. Eligible patients had advanced solid cancers of any histologic type, were receiving or had completed their last line of effective therapy, had an Eastern Cooperative Oncology Group Performance Status 0 to 3, and had sufficient accessible tissue for MP. The participants were recruited between October 24, 2017, and March 12, 2019, and data analysis was conducted from March 13 to April 14, 2019. Main Outcomes and Measures Willingness to pay for MP was assessed via hypothetical trade-off scenarios varying in the actionable return rate (1%, 20%, or 40%) and cost (A$0, A$300 [US$210], A$1000 [US $700], A$3000 [US $2100], or A$10 000 [US $7000]). Ordinal regressions were used to explore factors associated with willingness to have and pay for MP. Results Of 777 participants (405 women [52%]; mean [SD] age, 55.47 [14.26] years), 689 patients (89%) would have MP for as little as a 1% actionable return rate. Fifty-six patients (7%) would require at least a 20% return rate and 11 patients (1%) would require at least a 40% return rate. Fifteen patients (2%) consistently chose not to have the test; 6 participants (0.8%) had missing values on this item. Participants were willing to pay a median of A$1000 if the actionable return rate was 1% and A$3000 for an actionable return rate of 20% to 40%. Of 762 individuals who agreed to testing, 482 patients (64%) were consistently unwilling to pay A$10 000, regardless of the actionable return rate. Patients born in Australia or New Zealand were more likely to want MP (eg, participants born in South Asia had an ordered odds for the tipping point of 7.74 [95% CI, 1.67-36.05; P = .009] times higher than Australian- and/or New Zealand–born participants). Patients born in Australia or New Zealand were also more willing to pay A$1000 or A$3000 (eg, participants born in Western Europe had an ordered odds for the tipping point for paying A$1000 of 1.74 [95% CI, 1.01-3.00; P = .048] times higher than Australian- and/or New Zealand–born participants). People with a medical- or science-related occupation and with more negative attitudes toward uncertainty were more likely to pay A$10 000 (eg, A$10 000 tipping point–ordered odds of participants with a medical- or science-related occupation was 0.49 [95% CI, 0.7-0.87; P = .02] times that of participants without a medical- or science-related occupation). Conclusions and Relevance This study found apparent high interest in but lower willingness to pay for MP among patients with advanced cancer. Ability to pay may limit access to MP. Ongoing societal debate is required to establish the value of MP and whether subsidization is needed to ensure equity of access., This survey study examines the acceptance of and willingness to pay for molecular profiling of tumors by patients with advanced cancer.

The unlimited proliferation of cancer cells requires a mechanism to prevent telomere shortening. Alternative Lengthening of Telomeres (ALT) is an homologous recombination-mediated mechanism of telomere elongation used in tumors, including osteosarcomas, soft tissue sarcoma subtypes, and glial brain tumors. Mutations in the ATRX/DAXX chromatin remodeling complex have been reported in tumors and cell lines that use the ALT mechanism, suggesting that ATRX may be an ALT repressor. We show here that knockout or knockdown of ATRX in mortal cells or immortal telomerase-positive cells is insufficient to activate ALT. Notably, however, in SV40-transformed mortal fibroblasts ATRX loss results in either a significant increase in the proportion of cell lines activating ALT (instead of telomerase) or in a significant decrease in the time prior to ALT activation. These data indicate that loss of ATRX function cooperates with one or more as-yet unidentified genetic or epigenetic alterations to activate ALT. Moreover, transient ATRX expression in ALT-positive/ATRX-negative cells represses ALT activity. These data provide the first direct, functional evidence that ATRX represses ALT.

Protein colocalisation is often studied using pixel intensity-based coefficients such as Pearson, Manders, Li or Costes. However, these methods cannot be used to study object-based colocalisations in biological systems. Therefore, a novel method is required to automatically identify regions of fluorescent signal in two channels, identify the co-located parts of these regions, and calculate the statistical significance of the colocalisation. We have developed MatCol to address these needs. MatCol can be used to visualise protein and/or DNA colocalisations and fine tune user-defined parameters for the colocalisation analysis, including the application of median or Wiener filtering to improve the signal to noise ratio. Command-line execution allows batch processing of multiple images. Users can also calculate the statistical significance of the observed object colocalisations compared to overlap by random chance using Student’s t-test. We validated MatCol in a biological setting. The colocalisations of telomeric DNA and TRF2 protein or TRF2 and PML proteins in >350 nuclei derived from three different cell lines revealed a highly significant correlation between manual and MatCol identification of colocalisations (linear regression R2 = 0.81, P

Summary: Acquisition of replicative immortality is currently regarded as essential for malignant transformation. This is achieved by activating a telomere lengthening mechanism (TLM), either telomerase or alternative lengthening of telomeres, to counter normal telomere attrition. However, a substantial proportion of some cancer types, including glioblastomas, liposarcomas, retinoblastomas, and osteosarcomas, are reportedly TLM-negative. As serial samples of human tumors cannot usually be obtained to monitor telomere length changes, it has previously been impossible to determine whether tumors are truly TLM-deficient, there is a previously unrecognized TLM, or the assay results are false-negative. Here, we show that a subset of high-risk neuroblastomas (with ∼50% 5-year mortality) lacked significant TLM activity. Cancer cells derived from these highly aggressive tumors initially had long telomeres and proliferated for >200 population doublings with ever-shorter telomeres. This indicates that prevention of telomere shortening is not always required for oncogenesis, which has implications for inhibiting TLMs for cancer therapy. : Dagg et al. find that a subset of highly malignant neuroblastomas (survival ∼50% despite intensive treatment) lack an effective telomere length maintenance mechanism. Their cells undergo continuous telomere shortening throughout >200 population doublings, challenging the concept that activation of a mechanism to prevent telomere shortening is essential for oncogenesis. Keywords: telomeres, ever-shorter telomeres, telomerase, alternative lengthening of telomeres, neuroblastoma

10521 Background: Molecular tumor profiling (MTP) to guide therapy is increasingly being applied in the clinic, although how medical oncologists (MOs) manage this in clinical practice is not fully understood. Methods: An online survey explored MOs’ experience with MTP interpretation, treatment (tx) decisions, identifying resources, and communicating results to patients with cancer. MOs were identified based on their participation in the Australian Molecular Screening and Therapeutics Program. Results: 108 MOs (57% male, median years of practice, 5-9 years, 83% urban-based practice and median age range, 40-49 years) participated from June 2018 – Jan 2019. Most MOs had experience with MTP (90%), and felt it was their role to discuss results. MOs felt confident discussing the process of MTP, the probability of a ‘therapeutically actionable finding’, and results (score 70-75, range 0 least confident - 100 completely confident). However, almost two-thirds of MOs needed/wanted assistance with interpretation of results, favouring a Family Cancer Clinic (FCC) helpline, patient information sheets on MTP, and decision aids. In particular, MOs were less confident discussing germline results and their implications (median score 56) but were comfortable (median score 96) to refer to an FCC. Most MOs felt there was sufficient information on the MTP report to understand results. Some preferred to receive ‘all cancer gene variants’ (36%), others only those with clinical actionability (45%), and some only those with therapeutic actionability (19%). Most MOs (85%) wanted to know the full list of genes assayed, tx recommendations, and/or a list of relevant trials. Interestingly, MOs indicated little confidence that MTP would guide useful tx decisions (median score 51) and most reserved it for the tx-refractory setting. A minimal level of evidence supporting treatment was required by 83% of MOs prior to recommending biomarker-guided tx. Conclusions: MOs are increasingly integrating MTP into clinical practice, despite uncertainty about result validity and clinical translation, particularly regarding germline results. Understanding these potential barriers is the first step in developing clinician supports to facilitate clinical translation.

Telomeres are regions of repetitive DNA at the ends of human chromosomes that function to maintain the integrity of the genome. Telomere attrition is associated with cellular ageing, whilst telomere maintenance is a prerequisite for malignant transformation. Whole genome sequencing (WGS) captures sequence information from the entire genome, including the telomeres, and is increasingly being applied in research and in the clinic. Several bioinformatics tools have been designed to determine telomere content and length from WGS data, and include Motif_counter, TelSeq, Computel, qMotif, and Telomerecat. These tools utilise different approaches to identify, quantify and normalise telomeric reads; however, it is not known how they compare to one another. Here we describe the details and utility of each tool, and directly compare WGS telomere length output with laboratory-based telomere length measurements. In addition, we evaluate the accessibility, practicality, speed, and additional features of each tool. Each tool was tested using a range of telomere read extraction criteria, to determine the optimal parameters for the specific WGS read length. The aim of this article is to improve the accessibility of WGS telomere length measurement tools, which have the potential to be applied to WGS cohorts for clinical as well as research benefit.

Study question What factors regulate elongated telomere length in the human placenta? Summary answer Hypomethylation of TERRA promoters in the human placenta is associated with high TERRA expression, however, no clear mechanistic link between these phenomena and elongated telomere length in the human placenta was found. What is known already Human placenta tissue and trophoblasts show longer telomere lengths compared to gestational age-matched somatic cells. However, telomerase (hTERT) expression and activity in the placenta is low, suggesting a role for an alternative lengthening of telomeres (ALT). While ALT is observed in 10-15% of human cancers and in some mouse stem cells, ALT has never been reported in non-cancerous human tissues. Study design, samples/materials, methods Human term placental tissue and matched cord blood mononuclear cells (CBMCs) were collected as part of the Peri/Postnatal Epigenetic Twins study (PETS). In addition, first trimester placental villi, purified cytotrophoblasts, choriocarcinoma cell lines and a panel of ALT-positive cancer cell lines were tested. Telomere length was determined using the Terminal Restriction Fragment (TRF) assay and a relative quantitative PCR method. DNA methylation levels at several CpG rich subtelomeric TERRA promoters were determined using bisulfite conversion and the SEQUENOM EpiTYPER platform. Expression of TERRA and hTERT was determined using quantitative RT-PCR. ALT was assessed using the C-circle assay (CCA). Main results and the role of chance The human placenta tissue and purified first trimester trophoblasts showed low subtelomeric (TERRA) DNA methylation compared to matched CBMCs and other somatic cells. Interestingly placental TERRA methylation was lower than ALT-cancer cell lines, previously reported to be hypomethylated at these loci. Low TERRA methylation was associated with higher expression of TERRA RNA in placenta compared to matched CBMCs. Detectable levels of C-circles were observed in first trimester placental villi, but not term placenta, suggesting that the ALT mechanism may be active in specific placental cells in early gestation. C-circle analysis of purified first trimester trophoblasts and ALT-associated PML bodies (APB) staining of first trimester villi cross-sections failed to identify this specific cell type population. Limitations, reasons for caution While first trimester villi showed detectable levels of C-circles, these levels were very low compared with those observed in ALT-positive tumours and cell lines. This is consistent with a small sub-population of ALT-positive cells but this requires further investigation. Finally, no mechanistic link was established between TERRA DNA methylation, the presence of C-circles and longer telomere length. Wider implications of the findings Given the previously described role of TERRA ncRNA as a negative regulator of telomerase, the finding of elevated TERRA and long telomeres is counterintutive. ALT as a mechanism for telomere length maintenance has only been reported in certain human cancers, and recently in mouse embryonic stem cells and embryos. As with many aspects of cancer, it appears that ALT activity in tumours may be the inappropriate activation of a pathway found in very specific cell types in human development. Our data are the first supportive evidence for ALT in a non-cancerous human tissue, a result that requires further investigation and replication. The level of TERRA methylation in the human placenta is significantly lower than found in ALT cancer cell lines and somatic cells, raising the possibility of a novel mechanism in maintaining low methylation at subtelomeric regions. Large scale data Not applicable. Study funding and competing interests This study was supported by NHMRC early career fellowship (B.N.), NHMRC Senior Research Fellowship (R.S.) and the Victoria Government Infrastructure Grant. R.R. holds a patent for the C-circle assay. No other conflicts declared.

Reactivation of telomerase in endothelial cells (ECs) may be an effective approach to the treatment of vascular disorders associated with telomere attrition and EC senescence. However, overexpression of human telomerase reverse transcriptase (hTERT) does not prevent net telomere loss in ECs grown in standard culture medium with exposure to atmospheric oxygen (21% O2). Since these culture conditions are hyperoxic relative to normal tissue in vivo, where oxygen tension is estimated to be 1%–6%, we examined the effects of reduced exposure to oxidative stress (OS) on telomere length maintenance in hTERT-transduced bone marrow endothelial (BMhTERT) cells. Propagation of BMhTERT cells in the free radical scavenger, tert-butylhydroxylamine (tBN), and/or in 5% O2 increased telomerase enzyme activity and facilitated telomere length maintenance. The enhancement of telomerase activity correlated with higher levels of the telomerase RNA component (hTR). We also investigated the role of the telomere binding protein, TRF1, in telomere length regulation under alternate OS conditions. Inhibition of TRF1 function had no effect on telomere length in BMhTERT cells grown under standard culture conditions. However, alleviation of OS by growth in tBN plus 5% O2, elevated hTR levels, enhanced telomerase enzyme activity, and enabled progressive telomere lengthening. The direct impact of hTR levels on telomerase-mediated telomere lengthening was demonstrated by overexpression of hTR. BMhTERT cells transduced with hTR exhibited very high telomerase enzyme activity and underwent dramatic telomere lengthening under standard culture conditions. Overall, these results demonstrate that hTR levels are reduced by mild hyperoxia and limit telomerase-mediated telomere lengthening in hTERT-transduced ECs.

Over the past two decades, it has become increasingly apparent that telomerase-mediated telomere maintenance plays a crucial role in hematopoiesis. Supporting evidence is underscored by recent findings of mutations in genes involved in telomerase-mediated telomere maintenance that contribute to the pathogenesis of bone marrow failure syndromes. More recently described telomere-independent functions of telomerase are also likely to contribute to both normal hematopoiesis and hematologic diseases. The high levels of telomerase detected in aggressive leukemias have fueled fervent investigation into diverse approaches to targeting telomerase in hematologic malignancies. Successful preclinical investigations that employed genetic strategies, oligonucleotides, small-molecule inhibitors and immunotherapy have resulted in a rapid translation to clinical trials. Further investigation of telomere-independent functions of telomerase and detailed preclinical studies of telomerase inhibition in both normal and malignant hematopoiesis will be invaluable for refining treatments to effectively and safely exploit telomerase as a therapeutic target in hematologic malignancies.

Telomere dysfunction is typically studied under conditions in which a component of the six-subunit shelterin complex that protects chromosome ends is disrupted. The nature of spontaneous telomere dysfunction is less well understood. Here we report that immortalized human cell lines lacking wild-type p53 function spontaneously show many telomeres with a DNA damage response (DDR), commonly affecting only one sister chromatid and not associated with increased chromosome end-joining. DDR(+) telomeres represent an intermediate configuration between the fully capped and uncapped (fusogenic) states. In telomerase activity-positive (TA(+)) cells, DDR is associated with low TA and short telomeres. In cells using the alternative lengthening of telomeres mechanism (ALT(+)), DDR is partly independent of telomere length, mostly affects leading strand-replicated telomeres, and can be partly suppressed by TRF2 overexpression. In ALT(+) (but not TA(+)) cells, DDR(+) telomeres preferentially associate with large foci of extrachromosomal telomeric DNA and recombination proteins. DDR(+) telomeres therefore arise through different mechanisms in TA(+) and ALT(+) cells and have different consequences.

In human somatic cells, telomeres shorten every cell division due to the end replication problem. Once reaching a critically short length, the cells will undergo permanent cell cycle arrest and become senescent. Cancer cells acquire unlimited proliferation ability by activation of a telomere maintenance mechanism, either the enzyme telomerase or the homologous recombination-based mechanism Alternative Lengthening of Telomeres (ALT). Cancers that utilize the ALT mechanism commonly are deficient for ATRX protein expression, are difficult to treat, and have a poor prognosis. We discovered that ICP0-null herpes simplex virus type 1 (HSV-1) was ten to one thousand-fold more effective in killing cancer cell lines that are ATRX-deficient. Sensitivity to mutant HSV-1 infection resulted from ATRX-dependent regulation of PML expression at both the transcriptional and post-transcriptional levels. Reduction of PML protein resulted in a concomitant reduction in PML nuclear bodies, which weakened the innate cellular immunity to viral infection. Infection of co-cultured primary and ATRX-null cancer cells revealed that mutant ICP0-null HSV-1 treatment preferentially killed ATRX-null cells. Our results suggest that mutant ICP0-null HSV-1 may have therapeutic benefit against ATRX-null cells. Moreover, these data provide an applicable approach for predicting, based on tumor ATRX or PML protein status, which tumors will respond to an oncolytic herpes virus. Citation Format: Mingqi Han, Christine E. Napier, Sonja Frölich, Roger D. Everett, Anthony J. Cesare, Roger R. Reddel. Synthetic lethality of cytolytic HSV-1 in cancer cells with ATRX and PML deficiency [abstract]. In: Proceedings of the AACR Precision Medicine Series: Opportunities and Challenges of Exploiting Synthetic Lethality in Cancer; Jan 4-7, 2017; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2017;16(10 Suppl):Abstract nr A22.

Here we describe a method for growing fibroblasts from human skin explants that increases the number of cells obtained by up to two orders of magnitude, thus increasing the amount of material available for research and diagnostic purposes and potentially for cell-based therapies. Explants can be transferred sequentially up to 80 times, if required, at which point the explants appear to be completely depleted of fibroblasts. Utilizing skin samples obtained from 16 donors, aged 18-66 years old, the first 20 transfers produced cultures with lifespan and growth characteristics that were all very similar to each other, but the cultures derived from later transfers had a decreasing replicative capacity. Final cumulative population doublings did not correlate with donor age, but correlated positively with the telomere length at early passage. We also demonstrated that explants can be transduced directly by lentiviral infection, and that cryopreserved tissue can be explanted successfully using this procedure.

Alternative Lengthening of Telomeres (ALT) is a non-telomerase mechanism of telomere lengthening that occurs in about 10% of cancers overall and is particularly common in astrocytic brain tumors and specific types of sarcomas. Somatic cell hybridization analyses have previously shown that normal telomerase-negative fibroblasts and telomerase-positive immortalized cell lines contain repressors of ALT activity, indicating that activation of ALT results from loss of one or more unidentified repressors. More recently, ATRX or DAXX was shown to be mutated both in tumors with telomere lengths suggestive of ALT activity and in ALT cell lines. Here, an ALT cell line was separately fused to each of four telomerase-positive cell lines, and four or five independent hybrid lines from each fusion were examined for expression of ATRX and DAXX and for telomere lengthening mechanism. The hybrid lines expressed either telomerase or ALT, with the other mechanism being repressed. DAXX was expressed normally in all parental cell lines and in all of the hybrids. ATRX was expressed normally in each of the four telomerase-positive parental cell lines and in every telomerase-positive hybrid line, and was abnormal in the ALT parental cells and in all but one of the ALT hybrids. This correlation between ALT activity and loss of ATRX expression is consistent with ATRX being a repressor of ALT.

Abstract 980 Telomerase is a ribonuclear protein complex that functions to maintain the integrity of chromosomal-end structures (telomeres), and thereby enables continued cell replication. The active telomerase holoenzyme includes telomerase reverse transcriptase (hTERT) as its catalytic core, an RNA component (hTR) that functions as a template for synthesis of telomere repeats and an RNA-modifying protein dyskerin, which stabilizes TERC within the telomerase holoenzyme. While telomerase activity is high in acute myeloid leukemia cells, low levels of telomerase enzyme activity are detected in human CD34+ progenitor cells (HPCs). Telomerase activity is increased by cytokine stimulation of HPCs, then downregulated during myelomonocytic cell differentiation. Data accumulated to date suggest that telomerase enzyme levels are principally determined by Myc-mediated transcriptional regulation of the gene encoding hTERT, although the dyskerin gene (DKC1) is also a known Myc target. Our studies of the regulation and function of telomerase in human myeloid cells utilize cord blood-derived HPCs subject to ex vivo expansion and differentiation along specific myeloid lineages. Our past results revealed for the first time, that in contrast to the repression of telomerase activity observed during granulocytic, monocytic and megakaryocytic differentiation, telomerase activity was upregulated during erythroid differentiation, to reach levels comparable to tumor cell lines in CD34-/Glycophorin A+ erythroid precursor cells (Schuller et al., Leukemia 21: 983–991. 2007). Here we show that the upregulation of telomerase during erythroid differentiation is accompanied by a parallel increase in dyskerin mRNA and protein expression. In contrast to dyskerin expression, but consistent with the pattern of hTERT expression in other myeloid lineages, TERT gene expression was downregulated to a minimally detectable level in erythroid precursor cells. Chromatin-immunoprecipitation revealed that while Myc-binding at the DKC1 promoter decreased, binding of the erythroid-specific transcription factor GATA-1 increased during erythroid differentiation. Overexpression of DKC1 in HPCs confirmed that the upregulation of dyskerin was sufficient to hyperactivate telomerase, while shRNA-mediated depletion of dyskerin from erythroid precursors cells suppressed telomerase activity and decreased expansion of erythroid precursor cells. These data are the first to demonstrate a cellular context in which the upregulation of dyskerin drives telomerase enzyme activity. Further, the results implicate GATA-1 in the regulation of DKC1 transcription and show that high levels of dyskerin are required to sustain proliferation of Glycophorin A+ erythroid precursors. These results have important implications in relation to the pathogenesis of the inherited syndrome dyskeratosis congenita in which the DKC1 gene is mutated, and illustrate a novel mechanism by which telomerase may be reactivated in myeloid leukemia. Disclosures: No relevant conflicts of interest to declare.