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ImportanceCancer therapy–related cardiac dysfunction (CTRCD) is a potentially serious cardiotoxicity of treatments for ERBB2-positive breast cancer (formerly HER2). Identifying early biomarkers of cardiotoxicity could facilitate an individualized approach to cardiac surveillance and early pharmacologic intervention. Circulating cell-free DNA (cfDNA) of cardiomyocyte origin is present during acute cardiac injury but has not been established as a biomarker of CTRCD.ObjectiveTo determine whether circulating cardiomyocyte cfDNA is associated with CTRCD in patients with ERBB2-positive breast cancer treated with anthracyclines and ERBB2-targeted therapy.Design, Setting, and ParticipantsA prospective cohort of 80 patients with ERBB2-positive breast cancer enrolled at an academic cancer center between July 2014 and April 2016 underwent echocardiography and blood collection at baseline, after receiving anthracyclines, and at 3 months and 6 months of ERBB2-targeted therapy. Participants were treated with doxorubicin-based chemotherapy followed by trastuzumab (+/− pertuzumab). The current biomarker study includes participants with sufficient biospecimen available for analysis after anthracycline therapy. Circulating cardiomyocyte-specific cfDNA was quantified by a methylation-specific droplet digital polymerase chain reaction assay. Data for this biomarker study were collected and analyzed from June 2021 through April 2022.Main Outcomes and MeasuresThe outcome of interest was 1-year CTRCD, defined by symptomatic heart failure or an asymptomatic decline in left ventricular ejection fraction (≥10% from baseline to less than lower limit of normal or ≥16%). Values for cardiomyocyte cfDNA and high-sensitivity cardiac troponin I (hs-cTnI) measured after patients completed treatment with anthracyclines were compared between patients who later developed CTRCD vs patients who did not using the Wilcoxon rank sum test, and the association of post-anthracycline cardiomyocyte cfDNA level with CTRCD was estimated using logistic regression.ResultsOf 71 patients included in this study, median (IQR) age was 50 (44-58) years, all were treated with dose-dense doxorubicin, and 48 patients underwent breast radiotherapy. Ten of 71 patients (14%) in this analysis developed CTRCD. The level of cardiomyocyte cfDNA at the post-anthracycline time point was higher in patients who subsequently developed CTRCD (median, 30.5 copies/mL; IQR, 24-46) than those who did not (median, 7 copies/mL; IQR, 2-22; P = .004). Higher cardiomyocyte cfDNA level after completion of anthracycline chemotherapy was associated with risk of CTRCD (hazard ratio, 1.02 per 1-copy/mL increase; 95% CI, 1.00-1.03; P = .046).Conclusions and RelevanceThis study found that higher cardiomyocyte cfDNA level after completion of anthracycline chemotherapy was associated with risk of CTRCD. Cardiomyocyte cfDNA quantification shows promise as a predictive biomarker to refine risk stratification for CTRCD among patients with breast cancer receiving cardiotoxic cancer therapy, and its use warrants further validation.Trial RegistrationClinicalTrials.gov Identifier: NCT02177175

Long noncoding RNAs (lncRNAs) play essential roles in the development and progression of many cancers. However, the contributions of lncRNAs to medulloblastoma (MB) remain poorly understood. Here, we identify Miat as an lncRNA enriched in the sonic hedgehog group of MB that is required for maintenance of a treatment-resistant stem-like phenotype in the disease. Loss of Miat results in the differentiation of tumor-initiating, stem-like MB cells and enforces the differentiation of tumorigenic stem-like MB cells into a nontumorigenic state. Miat expression in stem-like MB cells also facilitates treatment resistance by down-regulating p53 signaling and impairing radiation-induced cell death, which can be reversed by therapeutic inhibition of Miat using antisense oligonucleotides. Mechanistically, the RNA binding protein Metadherin (Mtdh), previously linked to resistance to cytotoxic therapy in cancer, binds to Miat in stem-like MB cells. Like the loss of Miat , the loss of Mtdh reduces tumorigenicity and increases sensitivity to radiation-induced death in stem-like MB cells. Moreover, Miat and Mtdh function to regulate the biogenesis of several microRNAs and facilitate tumorigenesis and treatment resistance. Taken together, these data reveal an essential role for the lncRNA Miat in sustaining a treatment-resistant pool of tumorigenic stem-like MB cells.

Highlights • Contemporary trends in radiation technique and fractionation for bone metastases at a large academic center with a specialized metastatic program. • Stereotactic body radiation therapy (SBRT) is replacing long-course conventional RT for bone metastases. • Complexity of RT is increasing, particularly in the community-based regional clinic setting. • Single-fraction conventional RT is preferentially employed at the end of life, but prognostic algorithms are needed to further optimize use., Background Bone metastases cause significant morbidity in patients with cancer, and radiation therapy (RT) is an effective treatment approach. Indications for more complex ablative techniques are emerging. We sought to evaluate RT trends at a large multi-site tertiary cancer center. Methods Patients who received RT for bone metastases at a single institution (including regional outpatient clinics) from 2016 to 2018 were identified. Patients were grouped by RT regimen: single-fraction conventional RT (8 Gy × 1), 30 Gy in 10 fractions, SBRT, and “other”. Multinomial logistic regression was performed to assess trends in regimens over time. Binary logistic regression was performed to evaluate factors associated with receipt of SBRT. Results Between 2016 and 2018, 5,952 RT episodes were received by 2,969 patients with bone metastases. Overall, 76% of episodes were ≤ 5 fractions. The median number of fractions planned for SBRT and non-SBRT episodes was 3 (IQR 3–3) and 5 (IQR 5–10), respectively. Use of SBRT increased from 2016 to 2018 (39% to 53%, p

Background Over the last 2 decades, advances in systemic therapy have increased the expected overall survival for patients with cancer. It is unclear whether the same survival benefit has been conferred to patients requiring surgery for metastatic spinal disease. Objective To examine trends in postoperative survival over a 20-yr period for patients surgically treated for spinal metastatic disease. Methods Data were obtained for 1515 patients who underwent surgery for metastatic epidural spinal cord compression or tumor-related mechanical instability. Postoperative overall survival was calculated for all included patients using Kaplan-Meier methodology from date of surgery until death or last follow-up for those who were censored. Trends were analyzed using Cox proportional hazards modeling. Results Patients with renal, breast, lung, and colon cancers experienced a statistically significant improvement in survival over time based on the year of surgery (40%-100% improvement over the study period), whereas the overall survival trend for the entire cohort did not reach statistical significance (P = .12, median survival 0.71 yr, 95% CI 0.63-0.78). Patients presenting with synchronous metastatic disease had better survival compared to those presenting with metachronous disease (median overall survival: 0.94 vs 0.63 yr, respectively; log-rank P-value = .00001). Conclusion The postoperative survival among patients with spinal metastases has improved over the past 20 yr, particularly in patients with kidney, breast, lung, and colon tumors metastatic to the spine. The observed survival improvement emphasizes the need for long-term outcome consideration in treatment decisions for patients undergoing surgery for spinal metastatic tumors.

OBJECTIVEThe current treatment of chordomas is associated with significant morbidity, high rates of local recurrence, and the potential for metastases. Stereotactic radiosurgery (SRS) as a primary treatment could reduce the need for en bloc resection to achieve wide or marginal margins. Spinal SRS outcomes support the exploration of SRS’s role in the durable control of these conventionally radioresistant tumors. The goal of the study was to evaluate outcomes of patients with primary chordomas treated with spinal SRS alone or in combination with surgery.METHODSClinical records were reviewed for outcomes of patients with primary chordomas of the mobile spine and sacrum who underwent single-fraction SRS between 2006 and 2017. Radiographic local recurrence-free survival (LRFS), overall survival (OS), symptom response, and toxicity were assessed in relation to the extent of surgery.RESULTSIn total, 35 patients with de novo chordomas of the mobile spine (n = 17) and sacrum (n = 18) received SRS and had a median post-SRS follow-up duration of 38.8 months (range 2.0–122.9 months). The median planning target volume dose was a 24-Gy single fraction (range 18–24 Gy). Overall, 12 patients (34%) underwent definitive SRS and 23 patients (66%) underwent surgery and either neoadjuvant or postoperative adjuvant SRS. Definitive SRS was selectively used to treat both sacral (n = 7) and mobile spine (n = 5) chordomas. Surgical strategies for the mobile spine were either intralesional, gross-total resection (n = 5) or separation surgery (n = 7) and for the sacrum en bloc sacrectomy (n = 11). The 3- and 5-year LRFS rates were 86.2% and 80.5%, respectively. Among 32 patients (91%) receiving 24-Gy radiation doses, the 3- and 5-year LRFS rates were 96.3% and 89.9%, respectively. The 3- and 5-year OS rates were 90.0% and 84.3%, respectively. The symptom response rate to treatment was 88% for pain and radiculopathy. The extent or type of surgery was not associated with LRFS, OS, or symptom response rates (p > 0.05), but en bloc resection was associated with higher surgical toxicity, as measured using the Common Terminology Criteria for Adverse Events (version 5.0) classification tool, than epidural decompression and curettage/intralesional resection (p = 0.03). The long-term rate of toxicity ≥ grade 2 was 31%, including 20% grade 3 tissue necrosis, recurrent laryngeal nerve palsy, myelopathy, fracture, and secondary malignancy.CONCLUSIONSHigh-dose spinal SRS offers the chance for durable radiological control and effective symptom relief with acceptable toxicity in patients with primary chordomas as either a definitive or adjuvant therapy.

Late cardiac toxicity is a potentially lethal complication of cancer therapy, yet the pathogenic mechanism remains largely unknown, and few treatment options exist. Here we report DNA damaging agents such as radiation and anthracycline chemotherapies induce delayed cardiac inflammation following therapy due to activation of cGAS and STING-dependent type I interferon signaling. Genetic ablation of cGAS-STING-signaling in mice inhibits DNA damage induced cardiac inflammation, rescues late cardiac functional decline, and prevents death from cardiac events. Treatment with a STING antagonist suppresses cardiac interferon signaling following DNA damaging therapies and effectively mitigates cardiotoxicity. These results identify a therapeutically targetable, pathogenic mechanism for one of the most vexing treatment-related toxicities in cancer survivors.

Medulloblastoma is a pediatric brain tumor arising from the cerebellum and brainstem that is curable with surgery and aggressive cytotoxic therapy including craniospinal irradiation and chemotherapy. Preclinical models indicate that a small pool of de-differentiated, stem cell-like medulloblastoma cells are resistant to cytotoxic treatment and contribute to medulloblastoma relapse after aggressive therapy. Here, we identify Miat as a Shh and Myc regulated long noncoding RNA (lncRNA) that is required for maintenance of a treatment-resistant medulloblastoma stem-like phenotype. Loss of Miat delays medulloblastoma formation in genetically defined mouse models of Shh medulloblastoma and enforces differentiation of tumorigenic stem-like medulloblastoma cells into a non-tumorigenic cell state. Miat facilitates treatment resistance in part by downregulating p53 signaling and impairing radiation induced cell death in stem-like MB cells, which can be reversed by therapeutic inhibition of Miat with antisense oligonucleotides. The RNA binding protein Metadhedrin (Mtdh), which is associated with resistance to cytotoxic therapy in numerous types of cancer, co-localizes with Miat in stem-like medulloblastoma cells. Further, loss of Mtdh activates p53 signaling and reduces tumorigenicity in stem-like medulloblastoma cells. Taken together, these data reveal a critical role for the lncRNA Miat in sustaining a treatment resistant pool of tumorigenic stem-like medulloblastoma cells.

OBJECTIVE: Dedifferentiated chordomas (DC) are genetically and clinically distinct from conventional chordomas (CC), exhibiting frequent SMARCB1 alterations and a more aggressive clinical course. We compared treatment and outcomes of DC and CC patients in a retrospective cohort study from a single, large-volume cancer center. METHODS: Overall, 11 DC patients were identified from 1994 to 2017 along with a cohort of 68 historical control patients with CC treated during the same time frame. Clinical variables and outcomes were collected from the medical record and Wilcoxon rank sum or Fisher exact tests were used to make comparisons between the two groups. Kaplan–Meier survival analysis and log-rank tests were used to compare DC and CC overall survival. RESULTS: DC demonstrated a bimodal age distribution at presentation (36% age 0–24; 64% age > 50). DC patients more commonly presented with metastatic disease than CC patients (36% vs. 3% p = 0.000). DC patients had significantly shorter time to local treatment failure after radiation therapy (11.1 months vs. 34.1 months, p = 0.000). The rate of distant metastasis following treatment was significantly higher in DC compared to CC (57% vs. 5%, p = 0.000). The median overall survival after diagnosis for DC was 20 months (95% CI 0–48 months) compared to 155 months (95% CI 94–216 months) for CC (p = 0.007). CONCLUSION: DC patients exhibit significantly higher rates of both synchronous and metachronous metastases, as well as shorter overall survival rates compared to conventional chordoma. The relatively poor survival outcomes with conventional therapies indicate the need to study targeted therapies for the treatment of DC.

Myositis of the paraspinal muscles can be a clinically significant side effect of spinal radiation surgery. This report describes the typical clinical scenario, relevant radiologic findings, treatment, and management with the best available evidence.

Benign spinal tumors are rare clinical conditions, including meningiomas, schwannomas, and neurofibromas. Although these tumors are usually treated with open surgical resection, spinal stereotactic radiosurgery may be a safe and effective alternative to surgery in selected patients.

OBJECTIVETo characterize the clinical outcomes when stereotactic body radiation therapy (SBRT) alone is used to treat high-grade epidural disease without prior surgical decompression, the authors conducted a retrospective cohort study of patients treated at the Memorial Sloan Kettering Cancer Center between 2014 and 2018. The authors report locoregional failure (LRF) for a cohort of 31 cases treated with hypofractionated SBRT alone for grade 2 epidural spinal cord compression (ESCC) with radioresistant primary cancer histology.METHODSHigh-grade epidural disease was defined as grade 2 ESCC, which is notable for radiographic deformation of the spinal cord by metastatic disease. Kaplan-Meier survival curves and cumulative incidence functions were generated to examine the survival and incidence experiences of the sample level with respect to overall survival, LRF, and subsequent requirement of vertebral same-level surgery (SLS) due to tumor progression or fracture. Associations with dosimetric analysis were also examined.RESULTSTwenty-nine patients undergoing 31 episodes of hypofractionated SBRT alone for grade 2 ESCC between 2014 and 2018 were identified. The 1-year and 2-year cumulative incidences of LRF were 10.4% (95% CI 0–21.9) and 22.0% (95% CI 5.5–38.4), respectively. The median survival was 9.81 months (95% CI 8.12–18.54). The 1-year cumulative incidence of SLS was 6.8% (95% CI 0–16.0) and the 2-year incidence of SLS was 14.5% (95% CI 0.6–28.4). All patients who progressed to requiring surgery had index lesions at the thoracic apex (T5–7).CONCLUSIONSIn carefully selected patients, treatment of grade 2 ESCC disease with hypofractionated SBRT alone offers a 1-year cumulative incidence of LRF similar to that in low-grade ESCC and postseparation surgery adjuvant hypofractionated SBRT. Use of SBRT alone has a favorable safety profile and a low cumulative incidence of progressive disease requiring open surgical intervention (14.5%).

Many long noncoding RNA (lncRNA) genes are located near cancer-associated loci, suggesting potential roles in cancer development. However, conclusive evidence connecting the function of lncRNAs to the mechanism by which these genetic alterations impact cancer are largely lacking. Here we report that DINO, the long noncoding RNA transcribed from the cancer-associated DINO/CDKN1A locus, suppresses tumor formation in a phenotype that does not require the protein encoded at the locus, p21. In rigorous, genetically-defined mouse models, Dino is a haplo-insufficient tumor suppressor of B cell lymphoma in which p21 does not suppress tumorigenesis. In human cancers, a discrete region of the DINO/CDKN1A locus is recurrently hypermethylated in human cancers, silencing DINO but not CDKN1A, the gene encoding p21. Hypermethylation silences DINO to impair the p53 signaling pathway in trans and is mutually exclusive with TP53 alterations, indicating that DINO and TP53 comprise a common tumor suppressor module. Therefore, DINO encodes a long noncoding RNA essential for tumor suppression that is recurrently silenced in human cancers as a mechanism to escape p53-dependent tumor suppression.

OBJECTIVESpinal stereotactic body radiation therapy (SBRT) has emerged as an attractive method to deliver high doses of radiation to oligometastatic spinal tumors with radioresistant histology. Because SBRT is a palliative therapy, attention to potential radiation toxicities is paramount when counseling patients. The objective of this study was to report radiation-induced myositis after SBRT, a previously undescribed complication.METHODSA total of 667 patients received 891 spine SBRT treatments (either 24 Gy in 1 fraction or 27 Gy in 3 fractions) from 2011 to 2016 and underwent retrospective review. Eleven patients were identified as having radiographic evidence of myositis following SBRT. Clinical and pathologic results were collected, including receipt of anti–vascular endothelial growth factor (VEGF) therapy, radiation dose, equivalent dose in 2-Gy fractions (EQD2), biologically effective dose (BED), and volume of muscle treated. Treatment toxicities were classified according to the Common Terminology Criteria for Adverse Events (CTCAE; version 4.03). Univariate statistical analyses were performed to evaluate the relationships between radiation fractionation schedule and myositis and between anti-VEGF therapy and myositis.RESULTSThe cumulative incidence of myositis was 1.9% at 1 year. The median of the mean dose administered to muscle with myositis was 17.5 Gy. The median EQD2 was 55.1 Gy, and the median BED was 82.7 Gy. The median time to the development of clinical symptoms was 1.4 months, while the median time to imaging evidence was 4.7 months. Two patients (18.2%) had CTCAE grade 3 complications. Single-fraction spine SBRT (HR 4.5, 95% CI 1.2–16.9; p = 0.027) was associated with increased risk of developing myositis whereas receipt of anti-VEGF therapy was not (HR 2.2, 95% CI 0.6–7.1; p = 0.2).CONCLUSIONSRadiation myositis following spinal radiosurgery is a rare but important complication. Single-fraction treatment schedules may be associated with increased risk of myositis but should be validated in a larger series.

SUMMARY Many long noncoding RNA (lncRNA) genes exist near cancer-associated loci, yet evidence connecting lncRNA functions to recurrent genetic alterations in cancer are lacking. Here, we report that DINO, the lncRNA transcribed from the cancer-associated DINO/CDKN1A locus, suppresses tumor formation independent of p21, the protein encoded at the locus. Loss of one or two alleles of Dino impairs p53 signaling and apoptosis, resulting in a haplo-insufficient tumor suppressor phenotype in genetically defined mouse models of tumorigenesis. A discrete region of the DINO/CDKN1A locus is recurrently hypermethylated in human cancers, silencing DINO but not CDKN1A, the gene encoding p21. Hypermethylation silences DINO, impairs p53 signaling pathway in trans, and is mutually exclusive with TP53 alterations, indicating that DINO and TP53 comprise a common tumor suppressor module. Therefore, DINO encodes a lncRNA essential for tumor suppression that is recurrently silenced in human cancers as a mechanism to escape p53-dependent tumor suppression., Graphical Abstract, In brief Tumorigenesis requires escape from the p53 tumor suppressor protein. How 50% of cancers develop despite an intact p53 pathway remains largely unknown. Marney et al. report here that loss of the lncRNA DINO provides a route to tumorigenesis in p53-intact cells, and DINO is recurrently silenced in human cancers.

Long noncoding RNAs (lncRNAs) are prevalent genes with frequently precise regulation but mostly unknown functions. Here we demonstrate that lncRNAs guide the organismal DNA damage response. DNA damage activated transcription of the DINO (Damage Induced Noncoding) lncRNA via p53. DINO was required for p53-dependent gene expression, cell cycle arrest and apoptosis in response to DNA damage, and DINO expression was sufficient to activate damage signaling and cell cycle arrest in the absence of DNA damage. DINO bound to p53 protein and promoted its stabilization, mediating a p53 auto-amplification loop. Dino knockout or promoter inactivation in mice dampened p53 signaling and ameliorated acute radiation syndrome in vivo. Thus, inducible lncRNA can create a feedback loop with its cognate transcription factor to amplify cellular signaling networks.

Genome-wide cancer mutation analyses are revealing an extensive landscape of functional mutations within the noncoding genome, with profound effects on the expression of long noncoding RNAs (lncRNAs). While the exquisite regulation of lncRNA transcription can provide signals of malignant transformation, we now understand that lncRNAs drive many important cancer phenotypes through their interactions with other cellular macromolecules including DNA, protein, and RNA. Recent advancements in surveying lncRNA molecular mechanisms are now providing the tools to functionally annotate these cancer-associated transcripts, making these molecules attractive targets for therapeutic intervention in the fight against cancer.

PURPOSE/OBJECTIVES The spine is a common site of metastasis from non-small cell lung cancer (NSCLC), a disease hallmarked by heterogeneity in molecular alterations. Traditional spine radiation treatment (RT) with conventionally fractionated external beam radiation therapy (cEBRT) is associated with high local failure (LF) rates in patients surviving more than 12 months. Treatment with advanced techniques including stereotactic body radiation therapy (SBRT) significantly reduces LF. We hypothesized that specific genomic mutations in NSCLC metastases impart increased risk of LF, and that treatment with SBRT would prevent LF in metastases harboring such alterations. STUDY DESIGN/SETTING Retrospective review, single institution. PATIENT SAMPLE NSCLC patients with tumor molecular profiling data who underwent spine RT with follow-up at a single institution. OUTCOME MEASURES Local control of irradiated lesions (radiographic), overall survival. METHODS Under an IRB-approved retrospective research protocol, we examined the records of 189 pathologically-confirmed lung adenocarcinoma patients who had undergone radiation therapy for spine metastases at our institution and had tumor molecular profiling via the FDA-authorized MSK-IMPACT tumor-profiling multiplex panel platform. Mutation profiles, radiation treatment details and patient follow-up were recorded. Local control was defined radiographically using spine MRI when available and CT or PET-CT in a minority of cases. cEBRT was defined as a biologically effective dose (BED) 45Gy. Cumulative incidence of LF was calculated using a competing risk analysis with R Statistical Software and examined for significance using Gray's test, stratified by alteration in canonical NSCLC driver genes. Survival after RT was calculated by the Kaplan-Meier method using GraphPad Prism software and examined for significant differences using the Log-rank (Mantel-Cox) test. Finally, radiation sensitivity was tested by clonogenic survival assay in isogenic NSCLC cell lines with CRISPR-mediated disruption of candidate genes. RESULTS We identified 189 NSCLC patients with spine metastases who underwent RT (cEBRT = 81, SBRT = 108), had available tumor profiling by MSK-IMPACT, and had at least one follow-up imaging study. There was an overall 12-month LF rate of 13.9% for all patients. When stratified by RT type, LF at 12 months after cEBRT was 24.4% vs 5.7% after SBRT (p 5%. Mutations in NF1 were associated with increased LF after RT (HR 3.63; 95% CI 1.58-8.33; p=0.002), and mutations in KEAP1 trended toward correlation with LF (HR 1.94; 95% CI 0.92-4.10; p=0.08). When stratified by RT type, mutations in NF1 and KEAP1 were significantly associated with LF after cEBRT (NF1: HR 3.72, 95% CI 1.58-8.73, p=0.003; KEAP1: HR 2.29, 95% CI 1.00-5.26, p=0.05), but not after SBRT (NF1: HR 2.52, 95% CI 0.31-20.7, p=0.39; KEAP1: HR 1.31, 95% CI 0.26-6.56, p=0.74). CRISPR-mediated disruption of NF1 with two independent guide sequences resulted in reduced radiation sensitivity in two NSCLC cell lines (H661 and H1299), as assayed by clonogenic survival assay. CONCLUSIONS LF after RT for spine metastases from lung adenocarcinoma is common, with 12-month incidence of LF=13.9% in this cohort. Progression at 12 months is more common after cEBRT as compared to SBRT (24.4% vs 5.7%), suggesting that a large subset of patients may benefit from upfront SBRT. Alterations in NF1 and KEAP1 are associated with increased risk of local progression after cEBRT, while failure after SBRT remains low even in tumors harboring these mutations. Importantly, these findings are supported by our novel preclinical data that NF1 loss of function reduces radiation sensitivity in NSCLC cells. Furthermore, it confirms preclinical results from independent laboratories showing a role for KEAP1 in radiation sensitivity. We propose that upfront SBRT for NSCLC patients harboring mutations in NF1 and KEAP1 is appropriate for prospective study. Finally, we suggest that future radiation dose escalation trials contain pre-specified stratification on molecular alteration patterns. FDA DEVICE/DRUG STATUS OF ALL MEDICAL DEVICES/MEDICATIONS DISCUSSED MSK-IMPACT Tumor-Profiling Multiplex Panel. FDA-authorized.

Patients with cancer are frequently affected by spinal metastases. Treatment is palliative, with the principle goals of pain relief, preservation of neurologic function, and improvement in quality of life. In the past decade, we have witnessed a dramatic change in the treatment paradigms due to the development of improved surgical strategies and systemic and radiation therapy. The most important change to these paradigms has been the integration of spinal stereotactic radiosurgery (SSRS), allowing delivery of tumoricidal radiation doses with sparing of nearby organs at risk. High-dose SSRS provides durable tumor control when used either as definitive therapy or as a postoperative adjuvant therapy. Integration of SSRS has fundamentally changed the indications for and type of surgery performed for metastatic spine tumors. Although the role for surgical intervention is well established, a clear trend toward less-aggressive, often minimally invasive techniques has been observed. Targeted therapies are also rapidly changing the way cancer is being treated and have demonstrated improved survival for a number of malignancies. As these treatment decisions become more complex, a multidisciplinary approach including medical oncologists, radiation oncologists, surgeons, interventionalists, and pain specialists is required. In this article, the current evidence affecting the treatment of spinal metastases is integrated into a decision framework that considers four principal assessments of a patient’s spine disease: NOMS (neurologic, oncologic, mechanical instability, and systemic disease).

OBJECTIVE An analysis of factors contributing to durable radiographic control of spinal metastases was undertaken, drawing from a large single-institution database in an attempt to elucidate indications and dose requirements for successful treatment. METHODS All patients treated at a single institution with stereotactic radiosurgery (SRS) of the spine as first-line therapy were assessed for local progression of the treated site, defined as radiographic enlargement of the treated tumor and/or biopsy-proven evidence of active tumor cells. All patients were followed with CT, PET, or MR imaging every 3–6 months until death. Treatment decisions were made by a multidisciplinary team of radiation oncologists, neurosurgeons, and neuroradiologists. Target volumes were defined according to the international consensus guidelines and were reviewed in a multidisciplinary conference. Image-guided techniques and intensity modulation were used for every case. The tumor's histological type, gross tumor volume (GTV), dose that covers 95% of the GTV (GTV D95), percentage of GTV covered by 95% of the prescribed dose (GTV V95), planning target volume (PTV), dose that covers 95% of the PTV (PTV D95), and percentage of PTV covered by 95% of the prescribed dose (PTV V95) were analyzed for significance in relation to local control, based on time to local progression. RESULTS A total of 811 lesions were treated in 657 patients between 2003 and 2015 at a single institution. The mean follow-up and overall survival for the entire cohort was 26.9 months (range 2–141 months). A total of 28 lesions progressed and the mean time to failure was 26 months (range 9.7–57 months). The median prescribed dose was 2400 cGy (range 1600–2600 cGy). Both GTV D95 and PTV D95 were highly significantly associated with local failure in univariate analysis, but GTV and PTV and histological type did not reach statistical significance. The median GTV D95 for the cohort equal to or above the GTV D95 1830 cGy cut point (high dose) was 2356 cGy, and it was 1709 cGy for the cohort of patients who received less than 1830 cGy (low dose). In terms of PTV D95, the median dose for those equal to or above the cut point of 1740 cGy (high dose) was 2233 cGy, versus 1644 cGy for those lesions below the PTV D95 cut point of 1740 cGy (low dose). CONCLUSIONS High-dose single-session SRS provides durable long-term control, regardless of the histological findings or tumor size. In this analysis, the only significant factors predictive of local control were related to the actual dose of radiation given. Although the target volumes were well treated with the intended dose, those lesions irradiated to higher doses (median GTV D95 2356 cGy, minimum 1830 cGy) had a significantly higher probability of durable local control than those treated with lower doses (median PTV D95 2232 cGy, minimum of 1740 cGy) (p < 0.001). Patients in the high-dose cohort had a 2% cumulative rate of local failure. Histological findings were not associated with local failure, suggesting that radioresistant histological types benefit in particular from radiosurgery. For patients with a favorable prognosis, a higher dose of SRS is important for long-term outcomes.

NF-κB proteins play a central and subunit-specific role in the response to DNA damage. Previous work identified p50/NF-κB1 as being necessary for cytotoxicity in response to DNA alkylation damage. Given the importance of damage-induced cell death for the maintenance of genomic stability, we examined whether Nfkb1 acts as a tumor suppressor in the setting of alkylation damage. Hprt mutation analysis demonstrates that Nfkb1(-/-) cells accumulate more alkylator-induced, but not ionizing radiation (IR)-induced, mutations than similarly treated wild-type cells. Subsequent in vivo tumor induction studies reveal that following alkylator treatment, but not IR, Nfkb1(-/-) mice develop more lymphomas than similarly treated Nfkb1(+/+) animals. Heterozygous mice develop lymphomas at an intermediate rate and retain functional p50 in their tumors, indicating that Nfkb1 acts in a haploinsufficient manner. Analysis of human cancers, including therapy-related myeloid neoplasms, demonstrates that NFKB1 mRNA expression is downregulated compared with control samples in multiple hematological malignancies. These data indicate that Nfkb1 is a haploinsufficient, pathway-specific tumor suppressor that prevents the development of hematologic malignancy in the setting of alkylation damage.

Background: Vertebral body compression fracture (VCF) is a complication following spinal stereotactic radiosurgery (SRS). However, the incidence of VCF in vertebrae adjacent to the level of SRS is unknown. This study aimed to determine the incidence of adjacent level VCF (adjVCF) following spinal SRS. Methods: A retrospective review of 239 lesions treated with single-fraction SRS from 2011–2014 was performed. Clinical and pathologic factors were collected including evaluation of VCFs in adjacent levels to SRS site. In patients with adjVCFs, dose-volume histograms for adjacent-level endplates were calculated. Cox regression analysis was performed to determine any association among clinical factors and adjVCF occurrence. Results: Median follow-up was 14.7 months. Twenty-six adjVCFs occurred (10.8%). Of the adjVCFs, 19 had metastases following SRS, and seven did not (2.9% of total treatments). Median time to fracture post-SRS was 13.5 months. In adjVCFs, median of the mean dose to adjacent level fractured endplate was 23.3 Gy, and median of the mean dose of sixteen non-fractured endplates immediately adjacent to the SRS site was 19.1 Gy. Age, gender, and histology were not associated with adjVCF. Conclusions: AdjVCF after spinal SRS occurs at a rate of 2.9%, when excluding metastatic sites of disease. Adjacent level endplates should be investigated as an organ at risk during SRS planning.

Phosphorylation of the NF-κB subunit, p50, is necessary for cytotoxicity in response to DNA methylation damage. Here, we demonstrate that serine 329 phosphorylation regulates the interaction of p50 with specific NF-κB binding elements based on the identity of a single κB-site nucleotide. Specifically, S329 phosphorylation reduces the affinity of p50 for κB-sites that have a cytosine (C) at the −1 position without affecting binding to sequences with a −1 adenine. The differential interaction between phospho-p50 and the −1 base regulates the downstream transcriptional response and underlies the inhibition of anti-apoptotic gene expression following DNA damage. In genes with multiple κB-sites, the presence of a single −1C κB-site enables inhibition of NF-κB-dependent activity. The data suggest that interaction between phospho-p50 and the −1 κB nucleotide facilitates cytotoxicity in response to DNA damage. Moreover, although conservation of the entire κB-site sequence is not seen across species, the identity of the −1 nt in critical anti-apoptotic genes is conserved such that the overall response to DNA damage is maintained.

Although only 2% of the genome encodes protein, RNA is transcribed from the majority of the genetic sequence, suggesting a massive degree of cellular functionality is programmed in the noncoding genome. The mammalian genome contains tens of thousands of long noncoding RNAs (lncRNAs), many of which occur at disease-associated loci or are specifically expressed in cancer. Although the vast majority of lncRNAs have no known function, recurring molecular mechanisms for lncRNAs are now being observed in chromatin regulation and cancer pathways and emerging technologies are now providing tools to interrogate lncRNA molecular interactions and determine function of these abundant cellular macromolecules.

OBJECTIVE Chordoma is a rare malignant tumor for which en bloc resection with wide margins is advocated as primary treatment. Unfortunately, due to anatomical constraints, en bloc resection to achieve wide or marginal margins is not feasible for many patients as the resulting morbidity would be prohibitive. The objective of this study was to evaluate the efficacy of intralesional curettage and separation surgery followed by spinal stereotactic body radiation therapy (SBRT) in patients with chordomas in the mobile spine. METHODS The authors performed a retrospective chart review of all patients with chordoma in the mobile spine treated from 2004 to 2016. Patients were identified from a prospectively collected database. Initially 22 patients were identified with mobile spine chordomas. With inclusion criteria of cytoreductive separation surgery followed closely by SBRT and a minimum of 6 months of follow-up imaging, 12 patients were included. Clinical and pathological characteristics of each patient were collected and data were analyzed. Patients were divided into two cohorts—those undergoing intralesional resection followed by SBRT as initial chordoma treatment at Memorial Sloan Kettering Cancer Center (MSKCC) (Cohort 1) and those undergoing salvage treatment following recurrence (Cohort 2). Treatment toxicities were classified according to the Common Terminology Criteria for Adverse Events version 4.03. Overall survival was analyzed using Kaplan-Meier analysis. RESULTS The 12 patients had a median post-SBRT follow-up time of 26 months. Cohort 1 had 5 patients with median post-SBRT follow-up time of 65.9 months and local control rate of 80% at last follow-up. Only one patient had disease progression, at 48.2 months following surgery and SBRT. Cohort 2 had 7 patients who had been treated at other institutions prior to undergoing both surgery and SBRT (salvage therapy) at MSKCC. The local control rate was 57.1% and the median follow-up duration was 10.7 months. One patient required repeat irradiation. Major surgery- and radiation-related complications occurred in 18% and 27% of patients, respectively. Epidural spinal cord compression scores were collected for each patient pre- and postoperatively. CONCLUSIONS The combination of surgery and SBRT provides excellent local control following intralesional curettage and separation surgery for chordomas in the mobile spine. Patients who underwent intralesional curettage and spinal SBRT as initial treatment had better disease control than those undergoing salvage therapy. High-dose radiotherapy may offer several biological benefits for tumor control.

The functional significance of the signaling pathway induced by O(6)-methylguanine (O(6)-MeG) lesions is poorly understood. Here, we identify the p50 subunit of NF-κB as a central target in the response to O(6)-MeG and demonstrate that p50 is required for S(N)1-methylator-induced cytotoxicity. In response to S(N)1-methylation, p50 facilitates the inhibition of NF-κB-regulated antiapoptotic gene expression. Inhibition of NF-κB activity is noted to be an S phase-specific phenomenon that requires the formation of O(6)-MeG:T mismatches. Chk1 associates with p50 following S(N)1-methylation, and phosphorylation of p50 by Chk1 results in the inhibition of NF-κB DNA binding. Expression of an unphosphorylatable p50 mutant blocks inhibition of NF-κB-regulated antiapoptotic gene expression and attenuates S(N)1-methylator-induced cytotoxicity. While O(6)-MeG:T-induced, p50-dependent signaling is not sufficient to induce cell death, this pathway sensitizes cells to the cytotoxic effects of DNA breaks.

NF-κB proteins play a complex role in modulating carcinogenesis following DNA damage. Previous work identified p50/NF-κB1 as a necessary factor in the cytotoxic response to alkylation damage. Recently, these findings were extended to demonstrate that in the setting of alkylation damage, this NF-κB subunit acts as a haploinsufficient tumor suppressor that prevents hematologic malignancy formation.

Computational modelling has suggested that at least two counteracting forces are required for establishing topographic maps. Ephrin-family proteins are required for both anterior-posterior and medial-lateral topographic mapping, but the opposing forces have not been well characterized. Wnt-family proteins are recently discovered axon guidance cues. We find that Wnt3 is expressed in a medial-lateral decreasing gradient in chick optic tectum and mouse superior colliculus. Retinal ganglion cell (RGC) axons from different dorsal-ventral positions showed graded and biphasic response to Wnt3 in a concentration-dependent manner. Wnt3 repulsion is mediated by Ryk, expressed in a ventral-to-dorsal decreasing gradient, whereas attraction of dorsal axons at lower Wnt3 concentrations is mediated by Frizzled(s). Overexpression of Wnt3 in the lateral tectum repelled the termination zones of dorsal RGC axons in vivo. Expression of a dominant-negative Ryk in dorsal RGC axons caused a medial shift of the termination zones, promoting medially directed interstitial branches and eliminating laterally directed branches. Therefore, a classical morphogen, Wnt3, acting as an axon guidance molecule, plays a role in retinotectal mapping along the medial-lateral axis, counterbalancing the medial-directed EphrinB1-EphB activity.

The discovery of long non-coding RNAs that control the liaisons between a transcription factor with a key role in prostate cancer and its target genes sheds light on how RNAs dictate information flow in the cell nucleus. See Letter p.598 Several long non-coding RNAs (lncRNAs) are known to be overexpressed in prostate cancer. Michael Rosenfeld and colleagues have investigated the mechanistic and biological roles of two of these, known as PRNCR1 and PCGEM1. Both are found to interact with the androgen receptor (AR) dependent on specific post-translational modifications, and to enhance the looping of AR-bound enhancers to target gene promoters, leading to enhanced gene expression. They also enhance AR-mediated proliferation in prostate cancer cells and are required for tumour growth in a prostate cancer xenograft mouse model. PRNCR1 and PCGEM1 are upregulated in castration-resistant prostate cancer cell lines. The regulatory roles of lncRNAs in prostate cancer uncovered in this manuscript may open the way to new therapeutic approaches.

Background: O6-methylguanine (O6-MeG) is the primary cytotoxic lesion formed by SN1-methylating agents such as temozolomide. Cytotoxicity is induced following the mispairing of O6-MeG with deoxythymidine (T) residues and the subsequent activation of a mismatch repair (MMR)-mediated process. While it is generally recognized that MMR-induced DNA double strand breaks (DSBs) are central to O6-MeG-induced cell death, our previous work demonstrates that signaling via the p50 subunit of nuclear factor-κB (NF-κB) is also necessary for efficient SN1-methylation-induced cytotoxicity. In the current study, we isolated O6-MeG:T mismatches using a series of oligonucleotide duplexes and examined the hypothesis that O6-MeG:T mismatches induce a p50-dependent signaling pathway that sensitizes cells to DNA strand break-mediated cell death. Methods: A series of 40bp oligonucleotide duplex substrates bearing a unique central O6-MeG:T, G:T, O6-MeG:C, or G:C base pair were used. Cell lines included both human glioma cells and mouse embryonic fibroblasts. Loss of function was performed with shRNA-mediated p50 knockdown and targeted p50 knockout. Techniques used include EMSA, NF-κB-dependent luciferase reporter assays, in-vitro kinase assay, indirect immunofluorescence, annexin V binding and colony formation assays. Results: When administered to nuclear extracts, O6-MeG:T substrate inhibits NF-κB DNA binding substantially more than control duplex, and, when used in live cells, inhibition of NF-kB-dependent activity is seen only in response to O6-MeG:T substrate. The inhibition of NF-kB by O6-MeG:T substrate is noted only in p50-proficient cells. O6-MeG:T, but not control substrate, induces Chk1-mediated phosphorylation of p50 at a novel serine residue, a pathway that is shown to be necessary for inhibition of NF-kB DNA binding. O6-MeG:T substrate, used at a concentration sufficient to induce MMR- and p50-mediated signaling, does not increase apoptosis or decrease clonogenic survival relative to control duplexes. However, O6-MeG:T, but not control duplex, sensitizes p50-proficient, but not p50-deficent, cells to non-cytotoxic doses of ionizing radiation. O6-MeG:T-induced sensitization to cytotoxicity occurs without changing the level of IR-induced DSB and is only seen when duplex substrate is given prior to, but not after, IR. Conclusion: While an O6-MeG-induced signaling pathway has been previously described, the role of such a pathway to the damage response is disputed. The above findings suggest that O6-MeG:T-induced, p50-dependent signaling sensitizes cells to cytotoxicity that is ultimately induced by DNA DSBs. Such a model is temporally consistent with the response to O6-MeG in that MMR-induced signaling is induced after the first S-phase following O6-MeG formation while DSBs are formed after the second S-phase. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 262. doi:1538-7445.AM2012-262

SN1-methylating agents form O6-methylguanine (O6-MeG) lesions that induce apoptosis following mis-pairing with thymine (T) and activation of the mismatch repair (MMR) system. Previous work has shown that O6-MeG inhibits the activity of the transcription factor, nuclear factor-κB (NF-κB), by a mechanism involving MMR-dependent inhibition of NF-κB DNA-binding. In the current study, we set out to determine the mechanism by which methylating agents block NF-κB as a prerequisite to understanding the role of NF-κB in the response to O6-MeG. We hypothesize that a single NF-κB subunit is the target that is essential for mediating both inhibition of NF-κB and cytotoxicity in response to methylation damage. Methods: Temozolomide and methyl-nitrosourea were used as model methylators and both human glioma cells and mouse embryonic fibroblasts were used. Loss of function was performed with siRNA-mediated NF-κB knockdown and targeted NF-κB subunit knockout. Techniques used include EMSA, ChIP assay, NF-κB- and Gal4-dependent luciferase reporter assays, quantitative real time-PCR, single cell gel electrophoresis (comet) assay, flow cytometric analysis of annexin V binding, MTS short term cell killing assay and long-term colony formation assay. Results: The NF-κB subunits affected by SN1-methylators include p65 and p50 suggesting that one or both of these subunits mediates the response to SN1-methylation. Studies demonstrate that while p65 is dispensable for methylation-induced inhibition of NF-κB, p50 is required for inhibition of NF-κB. Furthermore, p50 is necessary for methylation-induced inhibition of endogenous NF-κB-dependent anti-apoptotic gene expression. The specific role of O6-MeG: T mismatches to inhibition of NF-κB was confirmed using oligonucleotide duplexes bearing a central O6-MeG: T, G: T, O6-MeG: C, or G: C base pair and observing that only O6-MeG: T mismatches inhibit NF-κB, in a p50-dependent manner. Because of the importance O6-MeG and MMR to inhibition of NF-κB, the requirement of p50 for methylator-induced cytotoxicity was examined. p50-deficient cells are resistant to methylation-induced apoptosis and also show increased clonal viability following methylator treatment compared to wild-type (wt) cells. The resistance to killing is specific to MMR-mediated cytotoxicity as p50 deficient cells are as sensitive as wt cells to ionizing radiation and doxorubicin. Importantly, there is equivalent damage induction following methylator treatment in p50 deficient cells relative to wt cells as assessed by comet assay. The specificity of p50 to methylation-induced killing was further confirmed by demonstrating that deletion of the p65 subunit increases methylation-induced cytotoxicity. Conclusion: The p50 NF-κB subunit acts downstream of MMR to enable apoptosis in response to SN1-methylation damage. This study sets the groundwork for evaluation of a novel intermediate, p50, in the MMR-directed cytotoxic response. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3659.