Germline mutations and developmental mosaicism underlying EGFR-mutant lung cancer

While the development of multiple primary tumors in smokers with lung cancer can be attributed to carcinogen-induced field cancerization, the occurrence of multiple primary tumors in individuals with EGFR-mutant lung cancer who lack known environmental exposures remains unexplained. We identified ten patients with early-stage, resectable non-small cell lung cancer who presented with multiple anatomically distinct EGFR-mutant tumors. We analyzed the phylogenetic relationships among multiple tumors from each patient using whole exome sequencing (WES) and hypermutable poly-guanine (poly-G) repeat genotyping, as orthogonal methods for lineage tracing. In two patients, we identified germline EGFR variants, which confer moderately enhanced signaling when modeled in vitro. In four other patients, developmental mosaicism is supported by the poly-G lineage tracing and WES, indicating a common non-germline cell-of-origin. Thus, developmental mosaicism and germline variants define two distinct mechanisms of genetic predisposition to multiple EGFR-mutant primary tumors, with implications for understanding their etiology and clinical management.

TP53 Gain-of-Function and Non-Gain-of-Function Mutations Are Associated With Differential Prognosis in Advanced Pancreatic Ductal Adenocarcinoma

PURPOSE

To examine the impact of TP53 gain-of-function (GOF) and non-GOF mutations on prognosis of advanced pancreatic ductal adenocarcinoma (PDAC) among patients with KRAS, CDKN2A, and SMAD4 comutations.

METHODS

This cohort included patients with locally advanced, recurrent, and de novo metastatic PDAC with next-generation sequencing performed from November 2017 to May 2022. We defined R175H, R248W, R248Q, R249S, R273H, R273L, and R282W as GOF and all other p53 mutations (mutp53) as non-GOF. We used Cox regression modeling to examine the association between GOF and non-GOF mutp53 and overall survival (OS), adjusting for demographics, performance status, Charlson comorbidity index, receipt of chemotherapy, and KRAS, CDKN2A, and SMAD4 comutations.

RESULTS

Of 893 total eligible patients, 68.5% had tumors with mutp53, 90.1% had KRAS mutations (mutKRAS), 44.7% had CDKN2A mutations (mutCDKN2A), and 17.0% had SMAD4 mutations. Among patients with mutp53, 121 had GOF and 491 had non-GOF. GOF mutp53 was associated with worse OS than non-GOF mutp53 (hazard ratio [HR], 1.27; 95% CI, 1.02 to 1.59) and wild-type p53 (wtp53; HR, 1.24; 95% CI, 0.98 to 1.57), whereas non-GOF was not associated with worse OS than wtp53 (HR, 0.95; 95% CI, 0.80 to 1.13). In addition, mutKRAS was associated with worse OS than wild-type KRAS in patients with mutCDKN2A (HR, 1.57; 95% CI, 0.88 to 2.80) but not in patients with wild-type CDKN2A (HR, 1.03; 95% CI, 0.76 to 1.39).

CONCLUSION

GOF and non-GOF mutp53 were associated with differential prognosis in advanced PDAC. The adverse effect of mutKRAS on OS appeared to be primarily driven by patients with mutCDKN2A. Our results provide new insight that could be helpful for prognostic stratification in clinical practice and for aiding future clinical trial designs.

Abstract 771: Mechanisms of genetic predisposition to multifocal lung cancer

Detection of multiple primary lung cancers is increasing in frequency, with up to 15% of all non-small cell lung cancer (NSCLC) patients presenting with two or more anatomically separate tumor nodules on CT scans. Increased detection is in part due to expanded lung cancer screening criteria in an aging population. Distinguishing multiple primary tumors from intrapulmonary metastases can be challenging, yet is critical for determining clinical management. Current models predict development of multiple primary tumors out of a cancerized field, such as occurs due to smoking. The occurrence of multiple primary tumors is unexplained in patients with EGFR-mutant lung cancer (~15% of all NSCLC), lacking environmental exposures. We identified patients with non-small cell lung cancer (NSCLC) who presented with multiple primary EGFR-mutant tumors, in the absence of family history of lung cancer or heavy smoking. We subjected the macrodissected tumors and surrounding normal tissues to whole exome sequencing as well as to analysis of hypermutable poly-guanine (poly-G) repeats, which are two orthogonal methods of lineage tracing. An additional familial case with a germline EGFR-T790M mutation was used to establish parameters for timing of somatic mutations, and functional properties of novel germline variants were modeled in vitro. Of eleven non-familial NSCLC cases with two or more geographically distinct EGFR-mutant lung cancers, two patients harbored a germline EGFR variant allele, which confers moderately enhanced signaling in vitro, followed by a somatically acquired EGFR mutation. In an additional four cases, both whole exome sequencing and poly-G repeat analyses indicate a distant shared somatic cell-of-origin, consistent with embryonic mosaicism. Three cases revealed clinically unappreciated metastasis and two cases remain unexplained. Together, our data suggest that multiple primary lung cancers with somatic EGFR driver mutations may result from genetic susceptibility, attributable either to attenuated EGFR germline variants or to embryonic mosaicism resulting in geographically disparate patches of predisposed lung tissue. Such predisposed cases should be surveilled for early detection of future tumors, and surgical resection in these cases should consider the life-long risk of additional cancers.

Citation Format: Risa Burr, Ignaty Leshchiner, Christina L. Costantino, Martin Blohmer, Tilak Sundaresan, Justin Cha, Karsen Seeger, Sara Guay, Brian P. Danysh, Ira Gore, Raquel A. Jacobs, Kara Slowik, Filippo Utro, Kahn Rhrissorrakrai, Chaya Levovitz, Jaimie L. Barth, Taronish Dubash, Brian Chirn, Laxmi Parida, Lecia V. Sequist, Mari Mino-Kenudson, Kamila Naxerova, Shyamala Maheswaran, Gad Getz, Daniel A. Haber. Mechanisms of genetic predisposition to multifocal lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 771.

Future of Teleoncology: Trends and Disparities in Telehealth and Secure Message Utilization in the COVID-19 Era

PURPOSE

The COVID-19 pandemic created an imperative to re-examine the role of telehealth in oncology. We studied trends and disparities in utilization of telehealth (video and telephone visits) and secure messaging (SM; ie, e-mail via portal/app), before and during the pandemic.

METHODS

Retrospective cohort study of hematology/oncology patient visits (telephone/video/office) and SM between January 1, 2019, and September 30, 2020, at Kaiser Permanente Northern California.

RESULTS

Among 334,666 visits and 1,161,239 SM, monthly average office visits decreased from 10,562 prepandemic to 1,769 during pandemic, telephone visits increased from 5,114 to 8,663, and video visits increased from 40 to 4,666. Monthly average SM increased from 50,788 to 64,315 since the pandemic began. Video visits were a significantly higher fraction of all visits (P < .01) in (1) younger patients (Generation Z 48%, Millennials 46%; Generation X 40%; Baby Boomers 34.4%; Silent Generation 24.5%); (2) patients with commercial insurance (39%) compared with Medicaid (32.7%) or Medicare (28.1%); (3) English speakers (33.7%) compared with those requiring an interpreter (24.5%); (4) patients who are Asian (35%) and non-Hispanic White (33.7%) compared with Black (30.1%) and Hispanic White (27.5%); (5) married/domestic partner patients (35%) compared with single/divorced/widowed (29.9%); (6) Charlson comorbidity index ≤ 3 (36.2%) compared with > 3 (31.3%); and (7) males (34.6%) compared with females (32.3%). Similar statistically significant SM utilization patterns were also seen.

CONCLUSION

In the pandemic era, hematology/oncology telehealth and SM use rapidly increased in a manner that is feasible and sustained. Possible disparities existed in video visit and SM use by age, insurance plan, language, race, ethnicity, marital status, comorbidities, and sex.

TP53 Gain-of-Function and Non-Gain-of-Function Mutations Are Differentially Associated With Sidedness-Dependent Prognosis in Metastatic Colorectal Cancer

PURPOSE

To examine the association of gain-of-function (GOF) and non-gain-of-function (non-GOF) TP53 mutations with prognosis of metastatic right-sided (RCC) versus left-sided colorectal cancer (LCC).

METHODS

This cohort study included patients with metastatic colorectal cancer (CRC) who had next-generation sequencing performed from November 2017 to January 2021. We defined R175H, R248W, R248Q, R249S, R273H, R273L, and R282W as GOF and all other mutp53 as non-GOF. We used Cox regression modeling to examine the association between GOF and non-GOF mutp53 and overall survival (OS), adjusting for age, sex, ethnicity, performance status, Charlson comorbidity index and receipt of chemotherapy.

RESULTS

Of total 1,043 patients, 735 had tumors with mutp53 and 308 had wild-type p53 (wtp53). GOF was associated with worse OS than non-GOF mutp53 only in LCC (hazard ratio [HR] = 1.66 [95% CI, 1.20 to 2.29]), but not in RCC (HR = 0.79 [95% CI, 0.49 to 1.26]). Importantly, RCC was associated with worse OS than LCC only in the subset of patients whose CRC carried non-GOF (HR = 1.76 [95% CI, 1.30 to 2.39]), but not GOF mutp53 (HR = 0.92 [95% CI, 0.55 to 1.53]) or wtp53 (HR = 0.88 [95% CI, 0.60 to 1.28]). These associations were largely unchanged after also adjusting for RAS, BRAF, and PIK3CA mutations, and microsatellite instability-high.

CONCLUSION

Poorer survival of patients with metastatic RCC versus LCC appeared to be restricted to the subset with non-GOF mutp53, whereas GOF versus non-GOF mutp53 was associated with poorer survival only among patients with LCC. This approach of collectively classifying mutp53 into GOF and non-GOF provides new insight for prognostic stratification and for understanding the mechanism of sidedness-dependent prognosis. If confirmed, future CRC clinical trials may benefit from incorporating this approach.

Attitudes and Perceptions of Multidisciplinary Cancer Care Clinicians Toward Telehealth and Secure Messages

Importance

Telehealth use including secure messages has rapidly expanded since the COVID-19 pandemic, including for multidisciplinary aspects of cancer care. Recent reports described rapid uptake and various benefits for patients and clinicians, suggesting that telehealth may be in standard use after the pandemic.

Objective

To examine attitudes and perceptions of multidisciplinary cancer care clinicians toward telehealth and secure messages.

Design, Setting, and Participants

Cross-sectional specialty-specific survey (ie, some questions appear only for relevant specialties) among multidisciplinary cancer care clinicians, collected from April 29, 2020, to June 5, 2020. Participants were all 285 clinicians in the fields of medical oncology, radiation oncology, surgical oncology, survivorship, and oncology navigation from all 21 community cancer centers of Kaiser Permanente Northern California.

Main Outcomes and Measures

Clinician satisfaction, perceived benefits and challenges of telehealth, perceived quality of telehealth and secure messaging, preferred visit and communication types for different clinical activities, and preferences regarding postpandemic telehealth use.

Results

A total of 202 clinicians (71%) responded (104 of 128 medical oncologists, 34 of 37 radiation oncologists, 16 of 62 breast surgeons, 18 of 28 navigators, and 30 of 30 survivorship experts; 57% (116 of 202) were women; 73% [147 of 202] between ages 36-55 years). Seventy-six percent (n = 154) were satisfied with telehealth without statistically significant variations based on clinician characteristics. In-person visits were thought to promote a strong patient-clinician connection by 99% (n = 137) of respondents compared with 77% (n = 106) for video visits, 43% (n = 59) for telephone, and 14% (n = 19) for secure messages. The most commonly cited benefits of telehealth to clinicians included reduced commute (79%; n = 160), working from home (74%; n = 149), and staying on time (65%; n = 132); the most commonly cited negative factors included internet connection (84%; n = 170) or equipment problems (72%; n = 146), or physical examination needed (64%; n = 131). Most respondents (59%; n = 120) thought that video is adequate to manage the greater part of patient care in general; and most deemed various telehealth modalities suitable for any of the queried types of patient-clinician activities. For some specific activities, less than half of respondents thought that only an in-person visit is acceptable (eg, 49%; n = 66 for end-of-life discussion, 35%; n = 58 for new diagnosis). Most clinicians (82%; n = 166) preferred to maintain or increase use of telehealth after the pandemic.

Conclusions and Relevance

In this survey of multidisciplinary cancer care clinicians in the COVID-19 era, telehealth was well received and often preferred by most cancer care clinicians, who deemed it appropriate to manage most aspects of cancer care. As telehealth use becomes routine in some cancer care settings, video and telephone visits and use of asynchronous secure messaging with patients in cancer care has clear potential to extend beyond the pandemic period.

Abstract S06-03: Cancer care telehealth utilization rates and provider attitudes in the wake of the novel coronavirus pandemic: The Kaiser Permanente Northern California experience

Background: In response to the SARS-CoV-2 pandemic, the multidisciplinary care of cancer patients has rapidly evolved. This study aims to determine utilization trends of in-person, telephone, and video visits, before and after the California shelter-in-place (SIP) orders on 3/19/20, and assess perspectives of cancer care providers on telehealth.

Methods: This study was conducted in 22 medical centers of a large integrated health care system. Utilization of different visit types in medical oncology (excluding infusion visits) was collected between 12/1/2019–5/24/2020, for a total of 104,588 visits. Chi-square with Yates correction was used for p-values. Voluntary, anonymous electronic surveys were sent to 276 cancer care providers measuring attitudes and experiences with telehealth. Overall, 68.8% responded: 101/128 medical oncologists (MedOnc), 34/37 radiation oncologists (RadOnc), 16/62 breast surgeons (Brst Surg), 18/28 breast oncology nurse navigators (OncNav), and 21/21 cancer survivorship advanced practitioners (SurvOnc).

Results: Comparing visit types prior to and after SIP, in-person visits went from 55.3% to 3.3%, telephone visits went from 44.2% to 79%, and video visits went from 0.5% to 17.8% (p&lt;.0001). Between 12/2019 and 05/2020, video visits increased from 0.42% to 31.3%. Telephone visits increased from 39.3 to a peak of 86.6% in 04/2020 and then decreased to 63.7%. In-person visits dropped from 60.3% to 2.3% in 04/2020 and then increased to 5.0% (p&lt;.0001). Satisfaction with telehealth was high: 87.1% of MedOnc, 91.2% of RadOnc, 68.6% of BrstSurg, 72.2% of OncNav, and 90.4% SurvOnc providers were very or somewhat satisfied. Most providers preferred to increase or maintain telehealth utilization after the pandemic: 84% of MedOnc, 85% of RadOnc, 81% of BrstSurg, 51% of OncNav, and 90% of SurvOnc. Among most providers, highest cited benefits of telehealth included work from home, reduced commute, staying on time, flexible hours, and shorter visits. Commonly cited challenges included connection/equipment problems, need for physical exam, difficulty evaluating performance status, and in-person visit required anyway. Of MedOnc, 11.8% responded that a patient suffered an adverse effect that could have been prevented with in-person visit. In-person visits were thought to promote the strongest provider-patient connection, followed by video, telephone visits, and emails. MedOnc providers deemed in-person visits were needed for end-of-life discussion (49%), discussing a new diagnosis (47.1%), palliative care discussion (34.3%), and clinical trial enrollment (34.3%). Activities for which email or phone visits were most accepted included check-in pretreatment, survivorship planning/follow-up, and patient navigation.

Conclusion: Overall, telehealth utilization has rapidly increased and is well accepted by various cancer care providers. Addressing technical issues and tailoring visit type to specific activities may further promote telehealth adoption and satisfaction.

Citation Format: Elad Neeman, Tatjana Kolevska, Mary Reed, Tilak Sundaresan, Amit Arora, Yan Li, Samantha Seaward, Gillian Kuehner, Sharon Likely, Julia Trossman, Christine Weldon, Raymond Liu. Cancer care telehealth utilization rates and provider attitudes in the wake of the novel coronavirus pandemic: The Kaiser Permanente Northern California experience [abstract]. In: Proceedings of the AACR Virtual Meeting: COVID-19 and Cancer; 2020 Jul 20-22. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(18_Suppl):Abstract nr S06-03.

A Digital RNA Signature of Circulating Tumor Cells Predicting Early Therapeutic Response in Localized and Metastatic Breast Cancer

The multiplicity of new therapies for breast cancer presents a challenge for treatment selection. We describe a 17-gene digital signature of breast circulating tumor cell (CTC)-derived transcripts enriched from blood, enabling high-sensitivity early monitoring of response. In a prospective cohort of localized breast cancer, an elevated CTC score after three cycles of neoadjuvant therapy is associated with residual disease at surgery (P = 0.047). In a second prospective cohort with metastatic breast cancer, baseline CTC score correlates with overall survival (P = 0.02), as does persistent CTC signal after 4 weeks of treatment (P = 0.01). In the subset with estrogen receptor (ER)-positive disease, failure to suppress ER signaling within CTCs after 3 weeks of endocrine therapy predicts early progression (P = 0.008). Drug-refractory ER signaling within CTCs overlaps partially with presence of ESR1 mutations, pointing to diverse mechanisms of acquired endocrine drug resistance. Thus, CTC-derived digital RNA signatures enable noninvasive pharmacodynamic measurements to inform therapy in breast cancer.Significance: Digital analysis of RNA from CTCs interrogates treatment responses of both localized and metastatic breast cancer. Quantifying CTC-derived ER signaling during treatment identifies patients failing to respond to ER suppression despite having functional ESR1. Thus, noninvasive scoring of CTC-RNA signatures may help guide therapeutic choices in localized and advanced breast cancer. Cancer Discov; 8(10); 1286-99. ©2018 AACR. This article is highlighted in the In This Issue feature, p. 1195.

Abstract 2972: Co-clinical trial of olaparib and temozolomide in SCLC PDX models uncovers new biomarkers of sensitivity

Introduction: Small cell lung cancer (SCLC) is a common and rapidly fatal malignancy for which no biomarker-targeted therapies have been developed. Despite a critical need, progress suffers from (1) scarcity of cutting-edge laboratory models and (2) absence of promising targets. Patient-derived xenografts (PDX) may faithfully model the clinical disease, but because SCLC is rarely biopsied or resected, specimens for PDX generation are scarce. PARP inhibition has recently emerged as a compelling strategy for SCLC, and an ongoing phase 1/2 trial of combination olaparib tablets and temozolomide (O/T) has shown promising activity in patients. However, biomarkers for patient selection remain elusive.

Methods: We generated SCLC PDX models from circulating tumor cells (CTCs), biopsies and malignant effusions. CTCs were enriched with an automated microfluidic device, the CTC-iChip. To assess the genomic fidelity of the models, we performed comparative whole exome sequencing (WES) and RNA-seq on 6 sets of corresponding patient biopsies, founder (P0) PDX tumors, and early-passage PDXs. We then assessed the activity of combination O/T in a panel of PDX models, and compared PDX responses with molecular profiles to identify candidate biomarkers.

Results: 44 PDXs were generated from 32 patients, including 6 sets of serial models and 4 synchronous CTC- and biopsy-derived models. PDXs were derived with high efficiency from both CTCs (35% per blood draw) and biopsies/effusions (82% per implant). WES demonstrated that somatic alterations in tumor biopsies were stably maintained in both CTC and biopsy-derived models, without significant accumulation of new mutations, and transcriptional profiles remained consistent through early passages. Six models were derived from O/T trial patients, including two sets of serial models before and after durable responses. The serial models faithfully recapitulated patient responses to O/T: pre-trial models were highly sensitive and post-relapse were highly resistant. The co-clinical trial was expanded to 30 models, using the models derived from trial patients to delineate the margins of clinical sensitivity (6 models), intermediate sensitivity (6 models) and resistance (18 models). Among the molecular features evaluated, basal protein PARylation best distinguished the O/T-sensitive category from both intermediate (p &lt; 0.001) and resistant models (p &lt; 0.0001). In addition, PARylation decreased after relapse in serial models from O/T trial patients.

Conclusions: Both biopsy- and CTC-derived SCLC PDX models faithfully recapitulate the genomic and functional features of the donor patient tumor. O/T sensitivity in this panel correlated with basal PARylation. The value of the co-clinical trial is the potential to refine the clinical application of O/T in real time, to optimize follow-on clinical trials and to develop biomarker-directed therapy for SCLC.

Citation Format: Benjamin J. Drapkin, Julie George, Marcello Stanzione, Beow Y. Yeap, Mari Mino-Kenudson, Camilla L. Christensen, Ruben Dries, Sarah Phat, Jun Zhong, David T. Myers, Joseph A. Licausi, Tilak Sundaresan, Marina Kem, Nima Abedpour, Leica V. Sequist, Alice T. Shaw, Aaron N. Hata, Mehmet Toner, Shyamala Maheswaran, Daniel A. Haber, Martin Peifer, Roman K. Thomas, Anna F. Farago, Nicholas J. Dyson. Co-clinical trial of olaparib and temozolomide in SCLC PDX models uncovers new biomarkers of sensitivity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2972.

Genomic and Functional Fidelity of Small Cell Lung Cancer Patient-Derived Xenografts

Small cell lung cancer (SCLC) patient-derived xenografts (PDX) can be generated from biopsies or circulating tumor cells (CTC), though scarcity of tissue and low efficiency of tumor growth have previously limited these approaches. Applying an established clinical-translational pipeline for tissue collection and an automated microfluidic platform for CTC enrichment, we generated 17 biopsy-derived PDXs and 17 CTC-derived PDXs in a 2-year timeframe, at 89% and 38% efficiency, respectively. Whole-exome sequencing showed that somatic alterations are stably maintained between patient tumors and PDXs. Early-passage PDXs maintain the genomic and transcriptional profiles of the founder PDX. In vivo treatment with etoposide and platinum (EP) in 30 PDX models demonstrated greater sensitivity in PDXs from EP-naïve patients, and resistance to EP corresponded to increased expression of a MYC gene signature. Finally, serial CTC-derived PDXs generated from an individual patient at multiple time points accurately recapitulated the evolving drug sensitivities of that patient's disease. Collectively, this work highlights the translational potential of this strategy.Significance: Effective translational research utilizing SCLC PDX models requires both efficient generation of models from patients and fidelity of those models in representing patient tumor characteristics. We present approaches for efficient generation of PDXs from both biopsies and CTCs, and demonstrate that these models capture the mutational landscape and functional features of the donor tumors. Cancer Discov; 8(5); 600-15. ©2018 AACR.This article is highlighted in the In This Issue feature, p. 517.

Abstract 1736: A novel RNA-based assay for the detection and monitoring of circulating tumor cell signatures in breast cancer

Examination of circulating tumor cells (CTCs) holds the potential of offering a real-time non-invasive window into tumor biology. Information gleaned from CTC detection and characterization can be used for early cancer detection, choice of therapy decisions and long-term monitoring for disease recurrence and the emergence of drug resistance mechanisms. However, technical difficulties with CTC isolation and the inherent limitations of imaging-based analysis have hindered the broad clinical use of CTCs as biomarkers. To overcome these concerns, we have combined our unbiased microfluidic CTC enrichment technology, the iChip, with a highly sensitive and specific multi-gene RNA-based biomarker panel to develop an assay that detects CTC signatures in patient blood samples in a high throughput and quantitative fashion.

This assay was applied to a cohort of breast cancer patients, including women with both localized and metastatic disease. It successfully identified CTC signal in 50-70% of metastatic and 20-40% of localized pretreatment patient samples. Patient CTC scores, assigned based on a multi-marker prediction algorithm, correlated with cancer stage and grade, but not with hormone receptor status, suggesting the applicability of the assay to a wide range of breast cancer subtypes. To determine if CTC scoring was useful for disease monitoring, we performed monthly blood collection from metastatic patients starting a new line of treatment. CTC score as early as one month after initiation of therapy, but not at pretreatment, was predictive of progression-free survival and treatment outcome, suggesting that real-time kinetic changes in CTC signatures are more clinically informative that one-time static evaluation of their presence in a given sample. In addition, a subset of high-risk genes showed expression patterns over the course of treatment that highly correlated with disease recurrence. This observation indicates that a multi-marker panel can parse out dynamic changes in cancer gene expression programs and provide a molecular insight into treatment responses that are not achievable by assays built around one or few markers.

In conclusion, our novel RNA-based method of identifying CTC signatures in liquid biopsies provides a sensitive platform for breast cancer detection and monitoring that goes beyond CTC enumeration. It offers a non-invasive quantitative molecular characterization of tumor gene expression that can be used to guide informed clinical decisions in both standard course of care and clinical trial settings.

Citation Format: Tanya T. Kwan, Aditya Bardia, Tilak Sundaresan, Laura Spring, Mark Kalinich, David Miyamoto, Xin Hong, Joseph LiCausi, Uyen Ho, Sarah Javaid, Erin Silva, Lecia Sequist, Shyamala Maheswaran, Daniel Haber. A novel RNA-based assay for the detection and monitoring of circulating tumor cell signatures in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1736. doi:10.1158/1538-7445.AM2017-1736

Genomic Instability Is Induced by Persistent Proliferation of Cells Undergoing Epithelial-to-Mesenchymal Transition

TGF-β secreted by tumor stroma induces epithelial-to-mesenchymal transition (EMT) in cancer cells, a reversible phenotype linked to cancer progression and drug resistance. However, exposure to stromal signals may also lead to heritable changes in cancer cells, which are poorly understood. We show that epithelial cells failing to undergo proliferation arrest during TGF-β-induced EMT sustain mitotic abnormalities due to failed cytokinesis, resulting in aneuploidy. This genomic instability is associated with the suppression of multiple nuclear envelope proteins implicated in mitotic regulation and is phenocopied by modulating the expression of LaminB1. While TGF-β-induced mitotic defects in proliferating cells are reversible upon its withdrawal, the acquired genomic abnormalities persist, leading to increased tumorigenic phenotypes. In metastatic breast cancer patients, increased mesenchymal marker expression within single circulating tumor cells is correlated with genomic instability. These observations identify a mechanism whereby microenvironment-derived signals trigger heritable genetic changes within cancer cells, contributing to tumor evolution.

Metastatic Breast Cancer With ESR1 Mutation: Clinical Management Considerations From the Molecular and Precision Medicine (MAP) Tumor Board at Massachusetts General Hospital

: The last decade in oncology has witnessed impressive response rates with targeted therapies, largely because of collaborative efforts at understanding tumor biology and careful patient selection based on molecular fingerprinting of the tumor. Consequently, there has been a push toward routine molecular genotyping of tumors, and large precision medicine-based clinical trials have been launched to match therapy to the molecular alteration seen in a tumor. However, selecting the "right drug" for an individual patient in clinic is a complex decision-making process, including analytical interpretation of the report, consideration of the importance of the molecular alteration in driving growth of the tumor, tumor heterogeneity, the availability of a matched targeted therapy, efficacy and toxicity considerations of the targeted therapy (compared with standard therapy), and reimbursement issues. In this article, we review the key considerations involved in clinical decision making while reviewing a molecular genotyping report. We present the case of a 67-year-old postmenopausal female with metastatic estrogen receptor-positive (ER+) breast cancer, whose tumor progressed on multiple endocrine therapies. Molecular genotyping of the metastatic lesion revealed the presence of an ESR1 mutation (encoding p.Tyr537Asn), which was absent in the primary tumor. The same ESR1 mutation was also detected in circulating tumor DNA (ctDNA) extracted from her blood. The general approach for interpretation of genotyping results, the clinical significance of the specific mutation in the particular cancer, potential strategies to target the pathway, and implications for clinical practice are reviewed in this article.

KEY POINTS

ER+ breast tumors are known to undergo genomic evolution during treatment with the acquisition of new mutations that confer resistance to treatment.ESR1 mutations in the ligand-binding domain of ER can lead to a ligand-independent, constitutively active form of ER and mediate resistance to aromatase inhibitors.ESR1 mutations may be detected by genomic sequencing of tissue biopsies of the metastatic tumor or by sequencing the circulating tumor cells or tumor DNA (ctDNA).Sequencing results may lead to a therapeutic "match" with an existing FDA-approved drug or match with an experimental agent that fits the clinical setting.

Expression of Notch-1 and its ligands, Delta-like-1 and Jagged-1, is critical for glioma cell survival and proliferation

The Notch family of proteins plays an integral role in determining cell fates, such as proliferation, differentiation, and apoptosis. We show that Notch-1 and its ligands, Delta-like-1 and Jagged-1, are overexpressed in many glioma cell lines and primary human gliomas. Immunohistochemistry of a primary human glioma tissue array shows the presence in the nucleus of the Notch-1 intracellular domain, indicating Notch-1 activation in situ. Down-regulation of Notch-1, Delta-like-1, or Jagged-1 by RNA interference induces apoptosis and inhibits proliferation in multiple glioma cell lines. In addition, pretreatment of glioma cells with Notch-1 or Delta-like-1 small interfering RNA significantly prolongs survival in a murine orthotopic brain tumor model. These results show, for the first time, the dependence of cancer cells on a single Notch ligand; they also suggest a potential Notch juxtacrine/autocrine loop in gliomas. Notch-1 and its ligands may present novel therapeutic targets in the treatment of glioma.

BCG vaccination of children against leprosy: fourteen-year findings of the trial in Burma

The value of BCG vaccination in preventing leprosy among children was studied in an area of high leprosy endemicity in Burma through a controlled trial; one group of 13 066 children received BCG and another group of 13 176 served as controls. The overall protective effect of BCG, which was only about 20% over the 14-year period, was found to vary with the batch of vaccine, as well as age, sex, and contact status of the children. BCG protection was found to be independent of the initial tuberculin status of the children. The protective effect of BCG against the lepromatous type of leprosy could not be measured because of the low incidence. Protection was observed throughout the fourteen years of the study except for the first year. The results are compared with those of three other major BCG trials in leprosy. The trial has shown that BCG provides only a very modest level of protection and that BCG vaccination is not likely to be an important solution for leprosy control.

Epidemiological information on leprosy in the Singu area of Upper Burma

In the course of a WHO trial designed to evaluate the possible protective action of BCG vaccine against leprosy, a longitudinal epidemiological study of the whole population was carried out in an area of very high endemicity in Burma from 1964 to 1976. Two mass surveys of the whole population with an interval of 4 years and annual re-examination of the 28 000 children (0-14 years) in the BCG trial were carried out. The data collected yielded important information about general prevalence and yearly incidence of the disease as well as on sex, age, and classification of cases. The general prevalence rate declined from 32.6 per 1000 in the first survey to 25.2 per 1000 in the second. The number of cases among males was significantly higher than among females. Incidence rate among contacts of already known cases was 9.8 per 1000 person-years. The estimated yearly incidence among non-contacts was 5.9 per 1000. Prevalence rates reached a peak in the 20-39-year age group. The prevalence rate of multibacillary patients also reached a peak in the same age bracket. It is stressed that a further period of epidemiological surveillance will be essential in order to have a correct estimate of the expected number of new infections, especially multibacillary cases, in the 20-39-year group. The value of this information is considered unique for planning and programming of future control activities.

BCG vaccination of children against leprosy: nine-year findings of the controlled WHO trial in Burma

The leprosy incidence rates so far in the vaccinated and unvaccinated children aged 5-9 and 10-14 years are similar. The BCG-vaccinated children aged 0-4 years at intake had an incidence rate lower than that of children in the control group. BCG vaccination did not protect household contacts or children aged 5-14 years not exposed in the household, and did not influence the distribution of the forms of leprosy in the cases detected. The lepromin reaction in relation to the age at intake was consistently stronger in the vaccinated children than in those of the control group; the younger the age group the more pronounced was the difference, which was only slight in the age group 10-14 years at intake. If the results of the late lepromin reaction are related to the age at onset (when the children are older than at intake), the differences between the BCG and the control groups tend to decrease. It does not seem that the BCG-vaccinated children suffer from a less serious form of leprosy than the nonvaccinated children (most of them nonreactors to tuberculin).

BCG vaccination of children against leprosy: seven-year findings of the controlled WHO trial in Burma

A controlled study of the efficacy of BCG vaccination for the prevention of leprosy began in Burma at the end of August 1964. This paper presents the findings after 7 years-i.e., the results of 6 annual follow-up examinations up to the end of June 1971. The incidence rate in BCG-vaccinated children 0-4 years of age at intake was lower than that in children in the control group. The protection conferred by BCG was relatively low (44%) and applied only to early cases of leprosy, the great majority tuberculoid cases. BCG vaccination did not protect household contacts or children 5-14 years of age who were not exposed in the household. This reduction must be interpreted in the light of several factors: form of leprosy, bacterial status, lepromin reactivity, evolution of cases, and level of endemicity. Consequently it does not seem probable that the reduction in incidence would substantially affect the pattern or trend of the disease in an area similar to that where the study is being carried out; the probability would be much lower if not nil in regions of relatively low endemicity (1-2 per 1 000 or less).

Some epidemiological data on leprosy collected in a mass survey in Burma

In the WHO Leprosy BCG Trial in Burma a mass survey was undertaken to determine whether children had been exposed to patients with leprosy and, if so, the form of the index case. This paper presents the most important epidemiological data collected in this survey. The prevalence rate was 31.6 per 1 000. It seems that even if the prevalence rate is very high the L rate does not increase accordingly. The high T rates in areas of high endemicity seem to be related mainly to the degree of spreading of leprosy, even to persons who react to lepromin. Comparison of the results with data available for the area before the survey was made shows that 87% of the L cases had already been detected and that 54% of the T cases had not. There was a tendency for high L rates to be associated with high prevalence rates. The results do not suggest that any particular age group has greater susceptibility or resistance; the prevalence rates seemed to be related mainly to the age when exposure occurred. A higher prevalence of leprosy in males started to appear in the 10-14-year age group, and after the age of 15 the difference became impressive. Biological, socio-economic, and environmental factors seem to be responsible for the level of endemicity, which does not seem to be essentially or primarily related to ethnic origin.

Proposed method for estimating leprosy prevalence based on rates in children

The authors suggest that, where leprosy prevalence data for the entire population are lacking, the prevalence in schoolchildren may be a valuable index for estimating the magnitude of the problem in areas where leprosy is endemic.

The household pattern of trachoma in Taiwan

A trachoma prevalence survey was conducted in 1960-61 in Taiwan prior to the introduction of a large-scale treatment campaign. During the survey information was collected by household and by individual. In the present report an attempt is made to depict the disease pattern in the household.The study indicates that the risk of infection is not related to household size but to the over-all endemicity in the community. The higher the endemicity the less is the chance of a household escaping infection. The study also demonstrates the interaction between the socio-economic development of the household and trachoma infection among its members.The remarkable feature, however, is the unexpectedly high proportion of households that have only one active trachoma case; the introduction of a case into the household does not necessarily mean an increase in the risk of infection to the other members.It would seem from the study that the average number of trachoma cases per household is the most efficient manner of expressing the household experience with trachoma.

WHO co-ordinated short-term double-blind trial with thalidomide in the treatment of acute lepra reactions in male lepromatous patients

The treatment of lepra reactions constitutes one of the most serious problems in leprosy. For this reason, the first reports in 1965 of the favourable results obtained with thalidomide aroused considerable interest and led WHO, in 1967, to carry out a trial with the co-operation of four centres. A short-term double-blind trial was designed to study the effect of thalidomide, in comparison with acetylsalicylic acid, in the treatment of acute lepra reactions in male lepromatous patients. Acetylsalicylic acid was used instead of a placebo because of its antipyretic and analgesic activity. Because of the severe adverse reactions that may be caused by thalidomide, mainly the teratogenic effects, only males were included in the trial.The results of this short-term study seem to confirm previous reports of the efficacy of thalidomide and indicate that acetylsalicylic acid also seems to be helpful in the management of certain symptoms of lepra reactions.

BCG vaccination of children against leprosy. Preliminary findings of the WHO-controlled trial in Burma

The use of BCG vaccine in the prevention of leprosy has been one of the most important subjects of investigation in the field of leprology in the last 25 years. The action of the vaccine was for many years investigated by determining its effect on the lepromin reaction. Field studies were later considered essential to determine whether BCG vaccination would be useful to leprosy contacts, to the child population probably exposed to infection, or to persons persistently lepromin-negative.The interest of the World Health Organization in this matter began in 1952 and, following the recommendations of certain advisory committees, it was decided to institute a field trial in Singu township in Burma. The main purpose of the investigation was to observe, in a highly endemic area, the protective effect, if any, of BCG vaccine against leprosy in the child population not exposed to Mycobacterium leprae at home but possibly exposed to the infection elsewhere.Field operations began at the end of August 1964 and the preliminary findings obtained up to the end of June 1968 relate to 3 annual re-examinations. So far, from the material studied, it appears that, under the conditions prevailing in Singu township, no significant effect of BCG vaccine can be seen within a period of 3 years. When children in both trial groups are followed-up for much longer periods, mainly children aged 0-4 years at intake, it is possible that a significant difference may emerge. However, to be operationally desirable, a merely significant difference is not enough; the protective effect of BCG should be substantial to warrant its large-scale use as an immunization procedure against leprosy.

Use of local variations in trachoma endemicity in depicting interplay between socio-economic conditions and disease

A trachoma prevalence survey was conducted in 1960-61 in Taiwan prior to the introduction of a large-scale treatment campaign. Marked local differences in endemicity of trachoma were encountered in neighbouring administrative areas (lin). Use is made of these local variations in depicting the interactions between socio-economical factors and endemicity of the disease.The study demonstrates the interaction between the socio-economic development of the household, on the one hand, and of the community of which the household forms a part, on the other. In a community of low trachoma endemicity, persons who do not share in the general socio-economic level of development nevertheless benefit from a low risk of infection, while in a community of high endemicity those in the upper socio-economic groups suffer from an enhanced risk of infection, though to an appreciably lesser extent than the general average for the community.The study indicates a possibility of an absence of association between various bio-physical environmental factors; for example, in a small community, better housing does not necessarily mean a better water supply. However, if any of the factors are considered, whether there is an implied pattern in the other factors or not, the most striking index of relative prevalence appears to be provided by the number of persons per unit (i.e., ping; about 3.3 m(2)) of sleeping area.

Use of local variations in trachoma endemicity in Taiwan to elucidate some of the clinical and epidemiological aspects of the disease

A trachoma prevalence survey was conducted in 1960-61 in Taiwan prior to the introduction of large-scale treatment operations and marked local differences in trachoma endemicity were encountered among adjoining neighbourhoods. Use is made of these local variations in depicting differences in the salient clinical and epidemiological features of trachoma under various degrees of endemicity.The study suggests that a reduction in the risk of infection is first reflected in a lowering of the intensity of clinical signs and in an increase in the spontaneous cure rate and is followed later by a reduction in the incidence and hence, in the long run, in the prevalence of the disease.A scoring system applied to all cases (active and healed) reflects spontaneous cure and gives a more accurate index of endemicity than either of its 2 components relating to intensity or gravity.

Report of 4 years' follow-up of a trachoma clinical trial in Taiwan

Few widespread diseases show such marked local differences in community patterns as does trachoma; these differences occur not only in over-all prevalence but also in the mean age at onset, the age distribution of the evolutive stages and the role of associated infections. These are among the factors which determine the relative frequency of infections, reinfections and superinfections, and influence the long-term effects of a collective-treatment programme, especially when treatment is restricted to a circumscribed segment of the community.A therapeutic trial, carried out on first-grade primary-school children in Taiwan, gave immediate results in terms of rate of cure which were closely similar to those of an earlier trial on children in the same age-group in Morocco. However, 1 year after the withdrawal of treatment, the net reactivation rate was more than 25% in the Taiwan group compared with less than 2% in the Morocco group. Therapeutic trials in new territories should therefore be followed up for a sufficient length of time to assess the long-term therapeutic and prophylactic value of the treatment regimen in the population group concerned. The application of a clinical scoring system to the data from the Taiwan study provided an effective means for measuring changes in a pleomorphic disease picture which are not apparent from simple rates of cure.

WHO-supported comparative studies of attenuated live measles virus vaccines

UNDER THE AUSPICES OF WHO A COMPARATIVE STUDY OF ATTENUATED LIVE MEASLES VACCINES WAS MADE BY TEAMS IN FIVE COUNTRIES: Canada, Czechoslovakia, Nigeria, Switzerland and Yugoslavia. The reactions and antibody responses to Enders' Edmonston B vaccine with or without gamma-globulin and to the Schwarz, Beckenham and Milovanović vaccine were measured. In each trial Enders' Edmonston B vaccine with gamma-globulin was used as a "standard" vaccine, and in each trial there was also an unvaccinated control group. There were altogether 1685 children in the study-1317 vaccinated and 368 controls.Each team placed the vaccines in a similar order as to the percentages of children with rash and pyrexia after vaccination. The percentages of children with rash and pyrexia after injection of the same vaccine were, however, found to vary greatly between trials. It was therefore impossible to give accurate figures for the percentage of children who would develop pyrexia after any one vaccine, but in general terms the proportion of children with fever of 39.4 degrees C (103 degrees F) or more may be expected to vary from 10% to 30% depending on the vaccine used. Six of the vaccinated children (0.5%) had convulsions 6-9 days after vaccination, but no other serious reactions and no permanent sequelae were recorded. No convulsions occurred in the unvaccinated control groups. The antibody responses were measured by the haemagglutination-inhibition test; nearly all children gave an antibody response but this varied with the vaccine employed. Children given vaccines causing the most reaction had the highest antibody levels.