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new diagnostics<br />
1173P A HIGHLY SENSITIVE IMMUNOHISTOCHEMICAL ASSAY TO<br />
DETECT BRAF V600E MUTATIONS IN PATIENTS WITH<br />
COLORECTAL CANCER<br />
J. Desai 1 ,F.Day 2 , A. Muranyi 3 , S. Singh 3 , K. Shanmugam 3 , T. Grogan 3 ,<br />
P. Gibbs 4 , D. Williams 2 , O. Sieber 2 , P. Waring 5<br />
1 Medical Oncology, Ludwig Institute for Cancer Research, Royal Melbourne<br />
Hospital, Peter MacCallum Cancer Centre, Parkville, AUSTRALIA, 2 LCCI, Ludwig<br />
Institute for Cancer Research, Parkville, AUSTRALIA, 3 Ventana, Ventana Medical<br />
Systems, Tucson, AZ, UNITED STATES OF AMERICA, 4 LCCI, Ludwig Institute<br />
for Cancer Research, Royal Melbourne Hospital, Parkville, VIC, AUSTRALIA,<br />
5 Pathology, University of Melbourne, Parkville, AUSTRALIA<br />
Background: The BRAF V600E mutation is a well-validated negative prognostic<br />
biomarker in metastatic colorectal cancer (mCRC), and is a highly attractive drug<br />
target. Barriers to <strong>the</strong> development of agents targeting BRAF V600E in mCRC are<br />
<strong>the</strong> low rate of mutations (approximately 10%) and reliance on to sequencing-based<br />
technologies, which are not routinely available outside of large cancer centres. A<br />
simple immunohistochemistry (IHC) test, more suited to routine pathology practice,<br />
would provide much broader access to patient (pt) identification, and would also<br />
enable studies of tumor heterogeneity. Aims: To validate an IHC-based method of<br />
detecting <strong>the</strong> BRAF V600E mutation in a large cohort of community-based CRC<br />
patients.<br />
Methods: Tissue microarrays, comprising matched normal and tumor paraffin<br />
embedded tissue samples obtained from colectomy specimens from a community<br />
cohort of 505 pts with stage I–IV CRC, were tested with 2 antibodies (Ab): pBR for<br />
total BRAF and VE1 for BRAF V600E, using <strong>the</strong> Ventana UltraView and OptiView<br />
kits, respectively. IHC was assessed independently by 2 blinded pathologists, and<br />
results compared to BRAF V600E status determined by Sanger sequencing (SS). pBR<br />
negative samples were considered non - evaluable. Nine discordant cases were<br />
re-tested with a BRAF V600E SNaPshot assay.<br />
Results: Demographic features were evenly matched. SS was evaluable in 504/505;<br />
IHC in 477/505; with both evaluable in 476/505 pts. 56/476 (11.8%) pts had V600E<br />
mutations detected by SS, 65/476 (13.7%) by IHC. The positive predictive value was<br />
84.6% (55/65). 1 pt was negative by IHC and positive on SS and SNaPshot; resulting<br />
in a negative predictive value of 99.8% (410/411 cases). There was 100% concordance<br />
between SS and SNaPshot. Fur<strong>the</strong>r validation is ongoing, and outcome data will be<br />
available at <strong>the</strong> time of presentation.<br />
Conclusions: We have conducted a comprehensive analytical and clinical validation<br />
and feasibility analysis of an IHC-based method to detect <strong>the</strong> BRAF V600E mutation<br />
in a large community-based population of pts with CRC. Shown to be highly<br />
sensitive, we are planning to adopt this approach as our initial screening step in an<br />
upcoming prospective combination trial targeting BRAF V600E in pts with mCRC.<br />
Disclosure: J. Desai: Research Support: Roche, Ventana Medical Systems,<br />
A. Muranyi: Employee: Ventana Medical Systems, K. Shanmugam: Employee and<br />
Shareholder, Ventana Medical Systems, T. Grogan: Shareholder and Chief Scientific<br />
Officer, Ventana Medical Systems, P. Gibbs: Research Support, Ventana Medical<br />
Systems, P. Waring: Research Support: Ventana Medical Systems, All o<strong>the</strong>r authors<br />
have declared no conflicts of interest.<br />
1174P DIAGNOSTIC AND PROGNOSTIC SIGNIFICANCE OF THE<br />
ALTERNATIVELY SPLICED ACTN4 VARIANT IN HIGH-GRADE<br />
NEUROENDOCRINE PULMONARY TUMOURS<br />
A. Miyanaga 1 , K. Honda 1 , K. Tsuta 1 , M. Masuda 1 , H. Tsuda 2 , H. Asamura 3 ,<br />
A. Gemma 4 , T. Yamada 1<br />
1 Division of Chemo<strong>the</strong>rapy and Clinical Research, National Cancer Center<br />
Research Institute, Tokyo, JAPAN, 2 Pathology and Clinical Laboratory Division,<br />
National Cancer Center Hospital, Tokyo, JAPAN, 3 Division of Thoracic Surgery,<br />
National Cancer Center Hospital, Tokyo, JAPAN, 4 Internal Medicine, Nippon<br />
Medical School, Tokyo, JAPAN<br />
Background: High-grade neuroendocrine tumours (HGNTs) of <strong>the</strong> lung manifest a<br />
wide spectrum of clinical behaviour, but no method of predicting <strong>the</strong>ir outcome has<br />
been established.<br />
Materials and methods: We newly established a monoclonal antibody specifically<br />
recognizing <strong>the</strong> product of <strong>the</strong> alternatively spliced ACTN4 transcript (namely,<br />
variant actinin-4), and used it to examine <strong>the</strong> expression of variant actinin-4<br />
Annals of Oncology 23 (Supplement 9): ix383–ix384, <strong>2012</strong><br />
doi:10.1093/annonc/mds406<br />
immunohistochemically in a total of 609 surgical specimens of various histological<br />
subtypes of lung cancer.<br />
Results: Variant actinin-4 was expressed in 55% (96/176) of HGNTs, but in only<br />
0.8% (3/378) of non-neuroendocrine lung cancers. Expression of variant actinin-4<br />
was significantly associated with unfavorable overall survival in HGNT patients<br />
(P = 0.00021, log-rank test). Multivariate analysis using <strong>the</strong> Cox proportional hazards<br />
model showed that expression of variant actinin-4 was <strong>the</strong> most significant<br />
independent negative predictor of survival in HGNT patients (hazard ratio, 2.18;<br />
P = 0.000714) after <strong>the</strong> presence of lymph node metastasis (hazard ratio, 2.30;<br />
P = 0.00012).<br />
Conclusions: Expression of variant actinin-4 is an independent prognostic factor for<br />
patients with HGNTs. This protein has high affinity for filamentous actin polymers<br />
and likely promotes aggressive behaviour of cancer cells. The present clinical findings<br />
clearly support this notion.<br />
Disclosure: All authors have declared no conflicts of interest.<br />
1175P CLINICAL FEASIBILITY STUDY OF A NOVEL<br />
CYTOMETRY-BASED SYSTEM FOR THE DETECTION OF<br />
CIRCULATING TUMOR CELLS IN PATIENTS WITH LUNG<br />
CANCER<br />
Y. Koh 1 , M. Watanabe 1 , T. Sawada 2 , Y. Uehara 2 , Y. Fujimura 3 , T. Tamura 4 ,<br />
F. Koizumi 2<br />
1 Division of Drug Discovery and Development, Shizuoka Cancer Center,<br />
Sunto-gun, JAPAN, 2 Shien-Lab, National Cancer Center Hospital, Tokyo,<br />
JAPAN, 3 R&D, On-Chip Biotechnologies Co., Ltd, Koganei, JAPAN, 4 Division of<br />
Thoracic Oncology, National Cancer Center Hospital, Tokyo, JAPAN<br />
Background: The presence and number of circulating tumor cells (CTCs) in <strong>the</strong><br />
peripheral blood of solid tumor patients are predictive of clinical outcome. To date<br />
<strong>the</strong> CellSearch system has been <strong>the</strong> only FDA-cleared CTCs enumeration system for<br />
advanced breast, prostate and colon cancers. However, low prevalence of CTCs and<br />
lack of capability as an application platform for molecular analysis have limited <strong>the</strong><br />
use of CTCs in <strong>the</strong> clinic. To overcome <strong>the</strong>se shortcomings, innovative and emerging<br />
technologies with easier access to fur<strong>the</strong>r molecular analysis are under development<br />
worldwide.<br />
Methods: We have developed a flow cytometry-based CTCs detection system<br />
independent of EpCAM expression level of tumor cells with cytokeratin and<br />
vimentin-staining after <strong>the</strong> depletion of CD45-expressing cells. In a preclinical study,<br />
various cancer cell lines were spiked into blood from healthy donors and <strong>the</strong><br />
sensitivity in detection was evaluated at two different sites (Shizuoka Cancer Center<br />
and National Cancer Center Tokyo). Then clinical feasibility study was conducted in<br />
patients with lung cancer.<br />
Results: Enumeration of <strong>the</strong> spiked cancer cells (10 to 1000 cells in 4 ml of blood)<br />
was linear, with a recovery rate of over 90%. A significantly higher recovery rate was<br />
observed with our system (90 to 102%) than that with CellSearch system (0%)<br />
particularly when EpCAM-negative PC-14 non-small lung cancer cells were spiked<br />
in, suggesting a superior sensitivity of our system in capturing EpCAM-negative<br />
tumor cells. In 22 blood samples from lung cancer patients, CTCs were detected with<br />
numbers ranging from 0 to 16 CTCs (median, 6.5) per 4 ml of blood with our<br />
system and in 72.7% (17/23) of <strong>the</strong> patients, 4 CTCs or more per 4 ml of blood were<br />
detected. On <strong>the</strong> o<strong>the</strong>r hand with CellSearch system, 2 CTCs or more per 7.5 ml of<br />
blood were detected in only 27% of <strong>the</strong> patients.<br />
Conclusions: The preclinical study and <strong>the</strong> results of <strong>the</strong> clinical feasibility study<br />
suggested superior sensitivity of our flow cytometry-based detection method than<br />
CellSearch system. Cell sorting device under development will be combined with this<br />
system for isolation and collection of CTCs for molecular analysis with<br />
next-generation sequencing.<br />
Disclosure: All authors have declared no conflicts of interest.<br />
1176P EBUS-TBNA GIVES ADEQUATE TISSUE INFORMATION ON<br />
CELL TYPE IN LUNG CANCER<br />
M.K. Wong, M.S. Ip, D.C. Lam, J.C.M. Ho<br />
Medicine, Queen Mary Hospital, Hong Kong, HONG KONG<br />
Introduction: In formulating systemic treatment in patients with advanced stage<br />
lung cancer, it is now considered imperative to know <strong>the</strong> cell type such as squamous<br />
carcinoma, adenocarcinoma and large cell carcinoma as chemo<strong>the</strong>rapeutic agents<br />
would be tailored to treat different cell type.<br />
© European Society for Medical Oncology <strong>2012</strong>. Published by <strong>Oxford</strong> University Press on behalf of <strong>the</strong> European Society for Medical Oncology.<br />
All rights reserved. For permissions, please email: journals.permissions@oup.com<br />
abstracts