Anthony Tc Chan

Epigenetic identification of ADAMTS18 as a novel 16q23.1 tumor suppressor frequently silenced in esophageal, nasopharyngeal and multiple other carcinomas

Tumor suppressor genes (TSGs) often locate at chromosomal regions with frequent deletions in tumors. Loss of 16q23 occurs frequently in multiple tumors, indicating the presence of critical TSGs at this locus, such as the well-studied WWOX. Herein, we found that ADAMTS18, located next to WWOX, was significantly downregulated in multiple carcinoma cell lines. No deletion of ADAMTS18 was detected with multiplex differential DNA-PCR or high-resolution 1-Mb array-based comparative genomic hybridization (CGH) analysis. Instead, methylation of the ADAMTS18 promoter CpG Island was frequently detected with methylation-specific PCR and bisulfite genome sequencing in multiple carcinoma cell lines and primary carcinomas, but not in any nontumor cell line and normal epithelial tissue. Both pharmacological and genetic demethylation dramatically induced the ADAMTS18 expression, indicating that CpG methylation directly contributes to the tumor-specific silencing of ADAMTS18. Ectopic ADAMTS18 expression led to significant inhibition of both anchorage-dependent and -independent growth of carcinoma cells lacking the expression. Thus, through functional epigenetics, we identified ADAMTS18 as a novel functional tumor suppressor, being frequently inactivated epigenetically in multiple carcinomas.

Prognostic values of EORTC QLQ-C30 and QLQ-HCC18 index-scores in patients with hepatocellular carcinoma – clinical application of health-related quality-of-life data

BackgroundHealth-related quality-of-life (HRQOL) assessment with EORTC QLQ-C30 was prognostic for overall survival (OS) in patients with advance-stage hepatocellular carcinoma (HCC), but no data existed for early-stage patients. The HCC-specific QLQ-HCC18 has not been evaluated for prognostic value in HCC patients. Utilization of raw HRQOL data in clinical setting has been impractical and non-meaningful. Therefore we developed index scores of QLQ-C30 and QLQ-HCC18 in an attempt to enable clinical utilization of these HRQOL measurements. This study investigates the prognostic significance of QLQ-C30, QLQ-HCC18 and C30/HCC18 index-scores in patients with newly diagnosed HCC which encompasses all stages.MethodsFrom 2007–2011, 517 patients were prospectively recruited. HRQOL was assessed at diagnosis using QLQ-C30 and QLQ-HCC18; C30 and HCC18 index-scores were calculated from raw HRQOL data. Cox regression was performed using continuous, dichotomized QLQ-C30 and QLQ-HCC18 variables, or index-scores, together with clinical factors to identify independent factors for OS. Various multivariate models were validated with c-index and bootstrapping for 1000 replications.ResultsFour hundred and seventy two patients had complete HRQOL data. Their median OS was 8.6 months. In multivariate analysis, independent prognostic HRQOL variables for OS were QLQ-C30 pain (HR 1.346 [1.092–1.661], pu2009=u20090.0055), QLQ-C30 physical functioning (HR 0.652 [0.495–0.860], pu2009=u20090.0024); QLQ-HCC18 pain (HR 1.382 [1.089–1.754], pu2009=u20090.0077) and QLQ-HCC18 fatigue (HR 1.441 [1.132–1.833], pu2009=u20090.0030). C30 index-score (HR 2.143 [1.616–2.841], pu2009<u20090.0001) and HCC18 index-score (HR 1.957 [1.411–2.715], pu2009<u20090.0001) were highly significant factors for OS. The median OS of patients with C30 index-score of 0–20, 21–40, 41–60, 61–100 were 16.4, 7.3, 3.1, 1.8 months respectively (pu2009<u20090.0001); while for HCC18 index-score: 16.4, 6.0, 2.8, 1.8 months respectively (pu2009<u20090.0001). All the multivariate models were validated, with mean optimism <0.01. The bootstrap validated c-index was 0.78.ConclusionsQLQ-C30 and QLQ-HCC18 were prognostic for OS in patients with newly diagnosed HCC irrespective of stage. Both C30 and HCC18 index-scores were highly significant prognostic factors for OS in newly diagnosed HCC patients. Index-scoring provides an effective way to summarize, analyze and interpret raw HRQOL data, and renders QLQ-C30 and QLQ-HCC18 meaningful and communicable in clinical practice. Index-scores could potentially serve as a standardized tool for future HRQOL research.

Prospective evaluation of plasma Epstein–Barr virus DNA clearance and fluorodeoxyglucose positron emission scan in assessing early response to chemotherapy in patients with advanced or recurrent nasopharyngeal carcinoma

BackgroundPlasma Epstein–Barr virus (pEBV) DNA and fluorodeoxyglucose positron emission (PET) reflect tumour burden in advanced NPC. This study hypothesised that a dual endpoint based on assessing pEBV DNA clearance and PET response could predict early drug response.MethodsEligible patients underwent a computed tomography (CT) scan and dual PET-CT at baseline, a PET-CT at 4 weeks, and then a CT scan at 10 weeks after starting palliative or induction chemotherapy. Plasma EBV DNA clearance was determined.ResultsFifty-eight out of 70 enrolled patients completed all imaging and 50/58 had falling pEBV DNA level, which allowed calculation of the clearance. At a median follow-up of 29.1 months, the dual endpoint (pEBV DNA clearance ≤u200910 days and >u200950% drop in sum of SUVmax of target lesions) was an independent indicator of overall survival (hazard ratio (HR)u2009=u20090.135, 95% CIu2009=u20090.039 to 0.466, pu2009=u20090.0015) and progression-free survival (HRu2009=u20090.136, 95% CIu2009=u20090.048 to 0.385, pu2009=u20090002). This dual endpoint could predict subsequent response by Response Evaluation Criteria In Solid Tumours (RECIST) criteria at 10 weeks after chemotherapy.ConclusionsEarly PET-CT response and pEBV DNA clearance could predict survival and subsequent response. This dual endpoint is an innovative tool for assessing early drug response.

Corrigendum: Epigenetic inactivation of the CpG demethylase TET1 as a DNA methylation feedback loop in human cancers.

Scientific Reports 6: Article number: 26591; published online: 26 May 2016; updated: 06 October 2016. This Article contains errors in Figure 2D where the Hodgkin lymphoma ‘TET1-MSP’ methylated and unmethylated MSP bands are incorrect. The correct Figure 2D appears below as Figure 1.

Abstract 5594: Progression of paraproteinemia in HIV-positive versus HIV-negative patients

BACKGROUND: Paraproteinemias occur in 1 to 3% of people over the age of 50 and progress to hematological malignancies (HM) at the rate of about 1% per year. In HIV+ patients a higher incidence of paraproteinemia has been reported however the rate of progression to HM remains unclear. We studied a large database comparing HIV+ and HIV- patients with paraproteinemia for incidence of HM. METHODS: Patients tested for HIV who also had a serum protein electrophoresis test (SPEP) performed between January 1 st 2001 and December 31 st 2011 were identified using a medical database at a large tertiary care center. SPEP+ patients were stratified into distinct (D-SPEP) or faint/multiple/oligoclonal (F-SPEP) bands by an independent laboratory technician. Demographics, coinfections and biopsy data were reviewed. RESULTS: 181,851 patients underwent a HIV test and 10,293 were HIV+. Significantly greater number of HIV+ patients (1381 of 10,293) compared to HIV- (6512 of 171,588) were tested for paraprotein (13.4% vs 3.8%, p HIV- SPEP+ patients were more likely to have a D-SPEP and IgA and IgM subtype paraproteins than HIV+ patients. HIV- patients also had a higher incidence of HM which persisted when adjusted for year of SPEP and duration of follow up (p CONCLUSIONS: While a higher prevalence of paraproteinemia was noted in the HIV+, HM incidence was lower in the HIV+ compared to HIV-, suggesting that nonmalignant virus-dependent proliferation may lead to paraproteinemia in some HIV+ cases. Identification of HIV+SPEP+ cases with higher risk of HM will be clinically relevant. Citation Format: Erin Jou, Oleg Gligich, Alvita CY Chan, Diwakar Mohan, Uriel R. Felsen, Sabarish Ayyappan, Henny H. Billett, Edwin P. Hui, Anthony TC Chan, Radha Raghupathy. Progression of paraproteinemia in HIV-positive versus HIV-negative patients. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5594. doi:10.1158/1538-7445.AM2015-5594

Abstract B273: Multicenter Phase II study of MK-2206 in previously treated patients (pts) with recurrent and metastatic nasopharyngeal carcinoma (NPC): Mayo Clinic Phase II Consortium (Protocol: MC1079).

Background: NPC is endemic to Asia and over 40% of cases harbor PIK3CA amplification. MK2206 is an allosteric AKT inhibitor with activity in NPC in vitro. Methods: Pts who had progressed after palliative chemotherapy (chemo) for metastatic or recurrent NPC, received oral MK-2206 at 200 mg on Days 1, 8, 15 & 22 of each 28-day cycle until disease progression. Plasma samples were collected at serial time points during cycle 1 for EBV DNA analysis, archived tumor samples were collected where feasible. The primary dual endpoints (2-stage design) consisted of RECIST-defined tumor response rate (RR) and 6-month (m) progression-free survival (PFS) rate. Secondary endpoints were overall survival (OS), PFS and adverse events (AEs). Results: Of the 21 pts enrolled, the median age was 47 years (range: 32-67), 91% were male, 81% had prior radiotherapy and 81% had > 1 prior line of palliative chemo. At the time of analysis, 20 out of 21 pts have ended treatment. The best responses were: 1 partial response (PR, 5%) lasting 4 ms; 10 stable disease (SD, 50%), 9 progressive disease (PD, 45%). The 6-m PFS rate was 38.9% (95% CI: 18.1-59.3%) and median PFS was 2.7 ms (95% CI: 0.9-7.2 ms). The 6-m OS rate was 67.9% (95% CI: 41.8-84.1%) and median survival has not been reached. In 7 pts who had SD more than or equal to 6 ms, the duration of treatment ranged from 6.4-13.9 ms. Of the 21 pts evaluable for AEs, 12 pts (57%) had at least one grade 3 AE [[Unable to Display Character: –]] macular rash (6 pts - 29%), dysphagia (2 pts - 10%), hyperglycemia (2 pts - 10%) (see Table 1). The tumor samples of 7 pts were analyzed by FISH; 3 showed PIK3CA amplification, including 1 pt with chromosome 3 polysomy. Amongst these pts, 1 had SD more than 6ms, 1 had SD more than 12 ms, and 1 is still on treatment. Pts who had SD less than 6 m or PD did not have PIK3CA amplification. Conclusions: MK2206 is well tolerated and has signs of activity in unselected pts with NPC. Preliminary results suggest that PIK3CA amplification may be related to prolonged disease stabilization from MK2206, and analysis for other PIK3CA gene alterations in more samples will be undertaken. Result of the plasma EBV DNA result will be presented. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B273. Citation Format: Brigette B. Ma, Boon Cher Goh, Wan Teck Lim, Eng Huat Tan, Gilberto de Lima Lopes, Edwin P. Hui, Ann D. King, Kwok Wai Lo, Herbert Loong, Leung Li, Nathan Foster, Michael Kam, Sing Fai Leung, Charles Erlichman, Anthony TC Chan. Multicenter Phase II study of MK-2206 in previously treated patients (pts) with recurrent and metastatic nasopharyngeal carcinoma (NPC): Mayo Clinic Phase II Consortium (Protocol: MC1079). [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B273.

SU‐E‐J‐119: Geometric Accuracy Verification for Gated RapidArc Using Gated CBCT Reconstructed From Continuously Triggered KV Images

Purpose: To develop a method using continuously triggered kV images acquired during gated RapidArc to reconstruct a gated CBCT for geometric accuracy verification of a moving target. Methods: A gated RapidArc treatment was planned to be delivered to a commercial breathing simulation phantom embedded with metallic markers using a Varian TrueBeam™ linear accelerator. The phantom was setup to the treatment position using 2D/2D match followed by marker match IGRT procedure. Continuously triggered on‐board‐imager kV images were taken immediately before each MV beam on cycle at various gantry angles during the gated RapidArc delivery. The kV images obtained were imported into an in‐house developed software to reconstruct a gated CBCT corresponding to the beam on triggering phase. The gated CBCT was then imported into a commercial treatment planning system. The geometric displacement of the target in the gated CBCT from its counterpart in the planning CT was determined through image registration based on marker alignment. The entire process was repeated 10 times using a variety of target movement magnitudes in the range of 1cm to 3cm and periods in the range of 4s to 8s. Results: The magnitude of the translational shifts of the target at the beam on triggering phase was 0.18+/−0.11mm in left/right direction, 0.38+/−0.15mm in anterior/posterior direction and 0.56+/−0.19mm in the superior/inferior direction. The composite 3D translational shift was 0.74+/−0.12mm. Conclusion: Gated CBCT reconstruction could be a practical and efficient way of utilizing continuously triggered kV images acquired during gated RapidArc treatments to verify geometric accuracy of a moving target.

SU‐E‐T‐94: Surface Dose Characteristics of Flattened and Flattening Filter Free Megavoltage Photon Beam

PURPOSEnTo evaluate the surface dose characteristics of the flattened and flattening filter free (FFF) megavoltage photon beam with radiochromic film and compare the Result: with that from ion chamber.nnnMETHODSnA Varian TrueBeam linear accelerator capable to produce both flattened and FFF photon at 6 MV and 10 MV was used in this study. Surface dose measurement was performed with both Gafchromic EBT3 radiochromic film and PTW23342 parallel plate chamber. Build-up dose was measured by adding different thickness of solid water slabs on the top of the measuring devices, at 100 cm SSD with field size of 2×2, 5×5, 10×10 and 20×20 cm2 . The measurement data were normalized to PDD at 5 cm depth which was obtained from commissioning data. Percentage surface dose was calculated by extrapolating the PDD from 2 mm build-up to the surface.nnnRESULTSnSurface doses of the FFF photon were 5 - 10% higher than that of the flattened photon at field size smaller than 10×10 cm2 . In film measurement, the surface doses for 6X flattened and FFF photon increased from 12.0% to 30.6% and 20.5% to 36.1% respectively, when field size increased from 2×2 to 20×20 cm2 ; for 10X flattened and FFF photon, they were increased from 6.1% to 24.2% and 11.2% to 23.5% respectively. Surface dose obtained in chamber measurement showed 2 - 6% higher than the corresponding measurement with film, but with a similar trend with that in the film measurement.nnnCONCLUSIONnFFF photon has a higher surface dose than flattened photon at field size smaller than 10×10 cm2 . Surface dose measured from chamber is found to be higher than that from film, which is probably due to the chamber design. Nonetheless, the trend of surface dose increases with field size is consistent between the two measuring devices.

SU-C-137-03: Inter-Machine Comparison of Volumetric Intensity Modulated Arc Therapy (VIMAT) Delivery Based On Trajectory Log Analysis

PURPOSEnTo compare the machine performance including the MU delivery, Gantry Angle trajectory and Multi-Leaf Collimator (MLC) leaf motion of RapidArc delivery based on trajectory log analysis.nnnMETHODnFive RapidArc cases were selected for the study. Each case was delivered at Varian Unique, iX23 and TrueBeam Linear Accelerator (LINAC) system. The system log files were obtained after their corresponding field measurements. During measurements, an independent inclinometer was mounted on the machine to verify the gantry rotation dynamically. In-house software was developed to extract and reconstruct the data into trajectory plots for comparison. Another in-house software was used to compare the Integrated Transient Fluence Map (ITFM) to check the accuracy of MLC leaf position and dose index.nnnRESULTnFor all selected cases delivered in the Unique, iX23 and TrueBeam system, the typical deviations of gantry angle and MU were found to be (0.6+/-0.1°, 0.0+/-0.2 MU), (0.4+/-0.1°, 0.0+/-0.1 MU) and (0.0+/-0.1°, 0.0+/-0.0 MU) respectively. Their angular trajectories of the independent inclinometer agreed well with the digital readout of gantry angle. The trajectory plots of dose index against gantry angle were in a good agreement with their plans. The reconstructed ITFM showed no observable difference when compared with the planned one, and their typical correlation coefficients were very close to unity. This indicated accurate MU delivery and MLC leaf position during the delivery. The higher accuracy of RapidArc delivery was achieved by the digital control system (TrueBeam).nnnCONCLUSIONnThe analysis of trajectory log is presented in the form of trajectory plot and ITFM, which are the powerful tools to check the machine performance of RapidArc delivery. For the inter-machine comparison, the integrated and digital control LINAC (TrueBeam) delivers the RapidArc treatment more precisely compared to its counterparts (iX23 and Unique).

Abstract 4602: Preclinical evaluation of the AKT inhibitor MK2206 in nasopharyngeal carcinoma cell lines

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, ILnnMK2206 is an allosteric inhibitor of AKT with potent activity in cancer cell lines that exhibit genetic aberrations in the PI3K-AKT-PTEN pathway. AKT is frequently activated in nasopharyngeal carcinoma (NPC), while PIK3CA amplification is found in 40-70% of NPC tissues. The preclinical activity of MK2206 was evaluated in NPC cell lines: HONE-1-EBV, HONE-1, CNE-2, HNE-1, and 2 cell lines with PIK3CA amplifications, HK-1 and C666-1. All 6 cell lines showed increased basal level of activated (p-)AKT(ser473), p-GSK3β, p-mTOR, pi-p70S6K and p-4EBP1, except in C666-1 cells where p-70S6K and p-4EBP1 were weakly expressed. Basal expression of p-MAPK was most pronounced in HK-1, CNE-2 and HONE-1-EBV, and weakly expressed in C666-1 and HONE-1. The effect on cell growth was evaluated by exposing cells to increasing concentrations (conc) of MK2206 (100pM, 2nM, 20nM, 0.2µM, 2µM, 30µM) for up to 72 hrs followed by MTT assay. Over 95% of growth inhibition was achieved in all cell lines with respective IC50 values of: CNE-2=0.39µM, HK-1 = 0.48µM, HONE-1= 1.51µM, C666-1= 1.64µM, HNE-1= 1.92µM, HONE1-EBV= 2.36µM. CNE-2, HONE-1-EBV and C666-1 were selected for assessing the effect on AKT signaling, apoptosis, cell cycle and synergism with chemotherapy. Treatment of these cells with MK2206 at IC50 conc for 15 and 24 hours, resulted in G1 arrest in CNE-2 and HONE-1-EBV, and G2 arrest in C666-1 cells. Apoptosis (increased cleaved PARP) was detected in CNE-2 cells only. MK2206 reduced the expression of p-AKT, p-mTOR, p-BAD, p-FKHD and p-GSK3β in CNE-2, HONE-1-EBV and C666-1 cells, while the level of p-4EBP1 level was significantly reduced in C666-1 and CNE-2 cells only. The effect on p-70S6K expression in all 3 cell lines was minimal. MK2206 increased expression of p-MAPK in HONE1-EBV-1 and C666-1 cells, but not CNE-2 cells. A supra-additive effect on cell growth was observed when cisplatin was added to MK2206, while the effect of adding paclitaxel to MK2206 was minimal in all 3 cell lines. Our result suggests that MK2206 has activity in NPC in vitro. The increased expression of p-MAPK observed in some cell lines suggests the presence of compensatory MAPK activation as described with mTOR inhibitors in other cancers. MK-2206 is currently under clinical investigation in recurrent NPC.nnCitation 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 4602. doi:1538-7445.AM2012-4602