Journal Thoracic Oncology

Abstracts Journal of Thoracic Oncology • Volume 12 Issue S1 January 2017
the intra-tumor heterogeneity of ALK RNA-ISH by counting 100 tumor
cells in 10 different loci (total, 1000 tumor cells) in each tumor. Secondly,
we analyzed the diagnostic accuracy of ALK RNA-ISH in tissue microarrays
(TMAs) containing 294 lung adenocarcinoma cores (by counting 100 tumor
cells in each core) with no information about ALK gene rearrangements
and compared these results with those of conventional IHC and FISH
tests. Results: ALK mRNA expression was observed in all 11 resected lung
adenocarcinomas by the ALK RNA-ISH assay and the median of positive tumor
cells was 67.7%, whereas ALK mRNA expression was not observed in normal
lung cells in the background. Next, 5 ALK positive cases were found by IHC
and/or FISH in the 294 cases of lung adenocarcinoma. The median of positive
cells by ALK RNA-ISH in these 5 cases was 75.6% (range: 40-94%), whereas
the median of positive cells by ALK RNA-ISH in the remaining 289 cases was
0.3% (range: 0-15%). When the cutoff value was set as 15% based on the
first test, the ALK RNA-ISH–positive and ALK RNA-ISH–negative cases were
readily distinguishable with 100% sensitivity and specificity compared with
the results of IHC and/or FISH. Conclusion: Our findings suggest that the ALK
RNA-ISH assay is useful for detecting ALK positive lung adenocarcinomas with
high sensitivity and specificity compared with the conventional IHC and FISH
test. Thus, this study provides important and timely insight into the clinical
testing of ALK in lung cancer because the RNA-ISH assay detects the target
mRNA easily and rapidly.
Keywords: ALK, lung adenocarcinoma, RNA in situ hybridization
POSTER SESSION 1 - P1.02: BIOLOGY/PATHOLOGY
DRIVER GENES IN NSCLC, RESISTANCE, AND OTHER –
MONDAY, DECEMBER 5, 2016
P1.02-010 FREQUENCY OF UNCOMMON EGFR MUTATIONS IN NSCLC
IN AN ARGENTINEAN UNIVERSITY INSTITUTION
Carolina Gabay 1 , Martin Krasnapolski 2 , Maria Nazareth Rusjan 2 , Liliana
Gimenez 2 , Erica Rojas Bilbao 2 , Luis Thompson 1 , Monica Castro 1
1 Thoracic Oncology and Translational Research Unit, Instituto de Oncología Angel
H.Roffo, University of Buenos Aires, Buenos Aires/Argentina, 2 Molecular Pathology
Department, Instituto de Oncología Angel H.Roffo, University of Buenos Aires,
Caba/Argentina
Background: EGFR mutations are present in approximately 15% of NSCLC
Caucasian patients, with a similar frequency described in Argentina.Exon
19 deletions and exon 21 L858R are consider common mutations (>90 %)
that predict better progression free survival with EGFR-TKIs than with
chemotherapy treatment. Most relevant uncommon mutations had a
frequency ranged from 1.9% to 7.9% between different populations and their
outcome, in general, is less favorable. Methods: We analyzed, retrospectively,
our dataset of EGFR mutational status in the last two years with the objective
to describe the frequency and characteristics of the patients with uncommon
EGFR mutations in our population of NSCLC patients. The mutational analysis
was performed on formalin fixed paraffin-embedded tissue blocks. EGFR
exons 18 through 21 were amplified by PCR- based technology. Results: A
total of 113 patients underwent EGFR testing since January 2014 until June
2016. Among them, 29 cases (25.7 %) harbored EGFR mutations. The exon
19 deletions (n=9; 8%) and L858R point mutation (n=6; 5.3%) accounted for
the 51.7 % of EGFR mutated cases (13.3% of the population explored) while
48.3 % were uncommon mutations (12,4%). In the last group, mutations sites
were: G719X in exon 18 (n=9; 8%), L861Q in exon 21 (n=2; 1.8%), INS20 in exon
20 (n=2; 1.8%) and S768I in exon 20 (n=1; 0.9%). All the 14 patients carrying
EGFR uncommon mutations had adenocarcinoma histology. In addition, they
were more frequently observed in men than in women (79% versus 21%) and
in smokers than in nonsmokers (65% versus 45%). The mean age was 62.5
years. Most of the patients (n=11; 75.6%) had advanced disease (stage IIIB-IV)
at diagnosis. No one had Asian ethnicity. Seven patients (50%) received
EGFR-TKIs for first or second line treatment (4 erlotinib, 2 afatinib and 1
gefitinib). None of them showed sustained clinical benefit. At present, 7 out
of 12 patients had died. Conclusion: Although the clinical characteristics of
our cohort are similar to the data published, we noted a higher and unusual
frequency of EGFR uncommon mutations especially exon 18 G719X.All cases
treated with EGFR-TKIs showed poor sensitivity to therapy. Time to treatment
and accessibility to appropriate therapy in this subgroup are important issues
to explore in future reports from public institutions of our region.
Keywords: EGFR mutation, TKI, NSCLC
POSTER SESSION 1 - P1.02: BIOLOGY/PATHOLOGY
DRIVER GENES IN NSCLC, RESISTANCE, AND OTHER –
MONDAY, DECEMBER 5, 2016
P1.02-011 COMPARISON OF EGFR AND KRAS MUTATIONS IN
ARCHIVAL TISSUE AND CIRCULATING TUMOR DNA: THE IMPACT OF
TUMOR HETEROGENEITY
Ying Wang 1 , Cheryl Ho 1 , Kevin Bushell 2 , Solomon Vandt 1 , Ian Bosdet 2 , Lucas
Swanson 2 , Janessa Laskin 1 , Sophie Sun 1 , Barbara Melosky 1 , Nevin Murray 1 ,
Ryan Morin 2 , Aly Karsan 2 , Hagen Kennecke 1
1 Medical Oncology, BC Cancer Agency, Vancouver/BC/Canada, 2 Genome Sciences
Centre, BC Cancer Agency, Vancouver/BC/Canada
Background: In non-small cell lung cancer (NSCLC), circulating tumour DNA
(ctDNA) has gained acceptance as a potential alternative to tissue biopsies
to identify targetable mutations. Individual ctDNA platforms have varying
abilities to detect specific mutations. A prospective, multicenter study was
conducted to determine concordance, sensitivity, and specificity of ctDNA
genotyping, with archival tissue DNA (atDNA) as the reference standard.
Methods: Patients with incurable advanced NSCLC at the BC Cancer Agency
were enrolled over 14 months. Next-Generation Sequencing (NGS) and highthroughput
multiplex amplification of a 27-gene panel (Raindance) was used
for atDNA analysis. Four mL of plasma was collected in Streck (Cell Free DNA
BCT) tubes for ctDNA genotyping using the Boreal Genomic OnTarget. Analysis
of concordance, sensitivity, and specificity was conducted with atDNA used
as the standard. Results: Seventy-six patients were enrolled, median age 66,
33 (44%) male, 69 (91%) metastatic disease, 47 (62%) with primary disease insitu.
Twenty-six EGFR mutations in 22 atDNA samples, and 12 mutations in 11
ctDNA samples were detected, with a concordance of 78%, sensitivity of 39%,
and specificity 98%. One EGFR T790M mutation was positive by ctDNA alone.
Twenty-one KRAS mutations in 21 atDNA samples were detected. Within
this subgroup, 10 ctDNA samples had KRAS mutations with a concordance of
76%, sensitivity of 50%, and specificity of 80%. Fourteen KRAS mutations
were detected by ctDNA only. The interval between archival tissue and
ctDNA collection, and time between treatment and ctDNA collection, did not
significantly impact the rate of concordance (p> 0.05). Conclusion: Although
the sensitivity is limited, the Boreal Genomic OnTarget ctDNA analysis is
specific in identifying clinically relevant EGFR mutations and has acceptable
concordance rates between ctDNA and atDNA testing. Targetable EGFR and
KRAS mutations were detected in ctDNA but not atDNA, which may reflect
site of biopsy, tumor heterogeneity, or technical limitations of assays used.
Given the high specificity and non-invasive nature of this test, positive results
in EGFR mutations can be used to direct therapeutic decisions, especially
accounting for clonal evolution overtime in detection of resistance mutations.
Keywords: NSCLC, ctDNA, EGFR, KRAS
POSTER SESSION 1 - P1.02: BIOLOGY/PATHOLOGY
DRIVER GENES IN NSCLC, RESISTANCE, AND OTHER –
MONDAY, DECEMBER 5, 2016
P1.02-012 FREQUENCIES OF ACTIONABLE MUTATIONS AND
SURVIVAL IN VARIANTS OF INVASIVE ADENOCARCINOMA OF THE
LUNG
Zhengbo Song 1 , Xinmin Yu 2 , Yiping Zhang 2
1 Medical Oncology, Zhejiang Cancer Hospital, Hangzhou/China, 2 Zhejiang Cancer
Hospital, Hangzhou/China
Background: 2015 new WHO classification lists four rare variants of invasive
adenocarcinoma of the lung (VIA): invasive mucinous adenocarcinoma,
colloid adenocarcinoma, fetal adenocarcinoma and enteric adenocarcinoma.
Very little information is known regarding the molecular alterations and
prognostic values for rarity of VIA. The aim of present study was to investigate
the common actionable mutations and survival in VIA. Methods: Patients who
with pathologic confirmed as VIA with completely resected stage I-IIIA were
enrolled from 2010 to 2013. For comparison, we evaluated the gene status and
survival from 380 non-VIA lung adenocarcinoma patients in 2012. RT-PCR was
utilized for detecting the mutations of EGFR, KRAS, NRAS, PIK3CA, BRAF,
HER2 and the fusion of ALK, ROS1 and RET. Survival curves were plotted
with Kaplan-Meier method. Results: Thirty one patients were recruited from
1120 lung adenocarcinoma,including invasive mucinous adenocarcinoma
(n=15), enteric adenocarcinoma(n=9), colloid adenocarcinoma (n=4) and fetal
adenocarcinoma(n=3) . The overall frequency of gene abnormality in VIA was
48.4% (15/31). The genes abnormality was as follows: KRAS mutation (n=5),
ALK rearrangement (n=4),PIK3CA (n=2), EGFR mutation (n=2), HER2 mutation
(n=1) and ROS1 rearrangement (n=1). No mutations of NRAS, BRAF or RET were
observed . The frequency of gene abnormality was lower in VIA than non-VIA
patients (48.4% vs.74.7%,P=0.0015). No recurrence free survival difference
existed in the VIA and non-VIA patients (38.0 vs.47.0 months,P=0.524) .
A trend of worse overall survival in VIA than those with non-VIA patients
was found(48.0vs.57.0 months, P=0.052). Conclusion: VIA is rare in lung
adenocarcinoma with lower frequency of common gene abnormality. Invasive
mucinous adenocarcinoma was the most frequent subtype and KRAS was a
predominant actionable mutation in VIA patients. A trend of worse survival
existed in VIA than non-VIA patients.
S254 Journal of Thoracic Oncology • Volume 12 Issue S1 January 2017