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Intratumoral Heterogeneity of ALK-Rearranged and ALK/EGFR Coaltered Lung Adenocarcinoma.

ABSTRACT: PURPOSE:Genetic intratumoral heterogeneity has a profound influence on the selection of clinical treatment strategies and on addressing resistance to targeted therapy. The purpose of this study was to explore the potential effect of intratumoral heterogeneity on both genetic and pathologic characteristics of ALK-rearranged lung adenocarcinoma (LADC). METHODS:We tested ALK fusions and EGFR mutations in 629 patients with LADC by using laser-capture microdissection to capture spatially separated tumor cell subpopulations in various adenocarcinoma subtypes and to test for ALK fusions and EGFR mutations in ALK-rearranged, EGFR-mutated, and ALK/EGFR coaltered LADCs to compare the oncogenic driver status between different tumor cell subpopulations in the same primary tumor. RESULTS:Among the 629 patients, 30 (4.8%) had ALK fusions, 364 (57.9%) had EGFR mutations, and two had ALK fusions that coexisted with EGFR mutations. Intratumoral heterogeneity of ALK fusions were identified in nine patients by reverse-transcriptase polymerase chain reaction. In the two patients with an ALK/EGFR coaltered status, genetic intratumoral heterogeneity was observed both between different growth patterns and within the same growth pattern. The relative abundance of ALK and EGFR alterations was different in the same captured area. ALK fusions were positively associated with a micropapillary pattern (P = .002) and were negatively associated with a lepidic pattern (P = .008) in an expanded statistical analysis of 900 individual adenocarcinoma components, although they appeared to be more common in acinar-predominant LADCs in the analysis of 629 patients. CONCLUSION:Intratumoral genetic heterogeneity was demonstrated to coexist with histologic heterogeneity in both single-driver and ALK/EGFR coaltered LADCs. Altered oncogenic drivers in spatially separated subclones of the same tumor may be different.

SUBMITTER: Cai W

PROVIDER: S-EPMC4770798 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature

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Intratumoral Heterogeneity of ALK-Rearranged and ALK/EGFR Coaltered Lung Adenocarcinoma.

Cai Weijing W Lin Dongmei D Wu Chunyan C Li Xuefei X Zhao Chao C Zheng Limou L Chuai Shannon S Fei Ke K Zhou Caicun C Hirsch Fred R FR

Journal of clinical oncology : official journal of the American Society of Clinical Oncology 20150928 32

<h4>Purpose</h4>Genetic intratumoral heterogeneity has a profound influence on the selection of clinical treatment strategies and on addressing resistance to targeted therapy. The purpose of this study was to explore the potential effect of intratumoral heterogeneity on both genetic and pathologic characteristics of ALK-rearranged lung adenocarcinoma (LADC).<h4>Methods</h4>We tested ALK fusions and EGFR mutations in 629 patients with LADC by using laser-capture microdissection to capture spatial ...[more]

PMID: 26416997

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Project description:IntroductionThe advent of immune checkpoint blockade (ICB) has led to significantly improved disease outcome in lung adenocarcinoma (ADC), but response of ALK/EGFR-positive tumors to immune therapy is limited. The underlying immune biology is incompletely understood.MethodsWe performed comparative mRNA expression profiling of 31 ALK-positive, 40 EGFR-positive and 43 ALK/EGFR-negative lung ADC focused on immune gene expression. The presence and levels of tumor infiltration lymphocytes (TILs) as well as fourteen specific immune cell populations were estimated from the gene expression profiles.ResultsWhile total TILs were not lower in ALK-positive and EGFR-positive tumors compared to ALK/EGFR-negative tumors, specific immunosuppressive characteristics were detected in both subgroups: In ALK-positive tumors, regulatory T cells were significantly higher compared to EGFR-positive (fold change: FC = 1.9, p = 0.0013) and ALK/EGFR-negative tumors (FC = 2.1, p = 0.00047). In EGFR-positive tumors, cytotoxic cells were significantly lower compared to ALK-positive (FC = - 1.7, p = 0.016) and to ALK/EGFR-negative tumors (FC = - 2.1, p = 2.0E-05). A total number of 289 genes, 40 part of cytokine-cytokine receptor signaling, were differentially expressed between the three subgroups. Among the latter, five genes were differently expressed in both ALK-positive and EGFR-positive tumors, while twelve genes showed differential expression solely in ALK-positive tumors and eleven genes solely in EGFR-positive tumors.ConclusionTargeted gene expression profiling is a promising tool to read out tumor microenvironment characteristics from routine diagnostic lung cancer biopsies. Significant immune reactivity including specific immunosuppressive characteristics in ALK- and EGFR-positive lung ADC, but not a total absence of immune infiltration supports further clinical evaluation of immune-modulators as partners of ICB in such tumors.

Dataset Information

Intratumoral Heterogeneity of ALK-Rearranged and ALK/EGFR Coaltered Lung Adenocarcinoma.

Publications

Intratumoral Heterogeneity of ALK-Rearranged and ALK/EGFR Coaltered Lung Adenocarcinoma.

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