SummaryBackground Poly(ADP-ribose) polymerase (PARP) inhibitors have activity in ovarian carcinomas with homologous recombination defi ciency. Along with BRCA1 and BRCA2 (BRCA) mutations genomic loss of heterozygosity (LOH) might also represent homologous recombination defi ciency. In ARIEL2, we assessed the ability of tumour genomic LOH, quantifi ed with a next-generation sequencing assay, to predict response to rucaparib, an oral PARP inhibitor.

A key resistance mechanism to platinum-based chemotherapies and PARP inhibitors in BRCA-mutant cancers is the acquisition of BRCA reversion mutations that restore protein function. To estimate the prevalence of BRCA reversion mutations in high-grade ovarian carcinoma (HGOC), we performed targeted next-generation sequencing of circulating cell-free DNA (cfDNA) extracted from pretreatment and postprogression plasma in patients with deleterious germline or somatic BRCA mutations treated with the PARP inhibitor rucaparib. BRCA reversion mutations were identifi ed in pretreatment cfDNA from 18% (2/11) of platinum-refractory and 13% (5/38) of platinum-resistant cancers, compared with 2% (1/48) of platinum-sensitive cancers (P = 0.049). Patients without BRCA reversion mutations detected in pretreatment cfDNA had signifi cantly longer rucaparib progression-free survival than those with reversion mutations (median, 9.0 vs. 1.8 months; HR, 0.12; P < 0.0001). To study acquired resistance, we sequenced 78 postprogression cfDNA, identifying eight additional patients with BRCA reversion mutations not found in pretreatment cfDNA. SIGNIFICANCE: BRCA reversion mutations are detected in cfDNA from platinum-resistant or platinumrefractory HGOC and are associated with decreased clinical benefi t from rucaparib treatment. Sequencing of cfDNA can detect multiple BRCA reversion mutations, highlighting the ability to capture multiclonal heterogeneity.

DNA derived from NSCLC tumors can be detected with high sensitivity in urine and plasma, enabling diagnostic detection and monitoring of therapeutic response from these noninvasive "liquid biopsy" samples.

Purpose: The evaluation of plasma testing for the EGFR resistance mutation T790M in NSCLC patients has not been broadly explored. We investigated the detection of EGFR activating and T790M mutations in matched tumor tissue and plasma, mostly from patients with acquired resistance to first-generation EGFR inhibitors.Experimental Design: Samples were obtained from two studies, an observational study and a phase I trial of rociletinib, a mutant-selective inhibitor of EGFR that targets both activating mutations and T790M. Plasma testing was performed with the cobas EGFR plasma test and BEAMing.Results: The positive percent agreement (PPA) between cobas plasma and tumor results was 73% (55/75) for activating mutations and 64% (21/33) for T790M. The PPA between BEAMing plasma and tumor results was 82% (49/60) for activating mutations and 73% (33/45) for T790M. Presence of extrathoracic (M1b) versus intrathoracic (M1a/M0) disease was found to be strongly associated with ability to identify EGFR mutations in plasma (P < 0.001). Rociletinib objective response rates (ORR) were 52% [95% confidence interval (CI), 31 -74%] for cobas tumor T790M-positive and 44% (95% CI, 25 -63%) for BEAMing plasma T790M-positive patients. A drop in plasma-mutant EGFR levels to 10 molecules/mL was seen by day 21 of treatment in 7 of 8 patients with documented partial response.Conclusions: These findings suggest the cobas and BEAMing plasma tests can be useful tools for noninvasive assessment and monitoring of the T790M resistance mutation in NSCLC, and could complement tumor testing by identifying T790M mutations missed because of tumor heterogeneity or biopsy inadequacy. Clin Cancer Res; 22(10); 2386-95. Ó2016 AACR.

The mammalian bombesin-like peptides gastrin-releasing peptide (GRP) and neuromedin B regulate numerous and varied cell physiologic processes in various cell types and have also been implicated as autocrine growth factors influencing the pathogenesis and progression of human small cell lung carcinomas. We report here the molecular characterization of the bombesin/GRP receptor. Structural analysis of cDNA clones isolated from Swiss 3T3 murine embryonal fibroblasts shows that the GRP receptor is a member of the guanine nucleotide binding protein-coupled receptor superfamily with seven predicted hydrophobic transmembrane domains. In vitro transcripts from cloned cDNA templates encompassing the predicted protein coding domain, when injected into Xenopus oocytes, resulted in expression of functional GRP receptors. The predicted amino acid sequence of the open reading frame in cDNA clones matches the aminoterminal sequence as well as the sequence of four tryptic fragments isolated from the purified protein. Expression of the GRP receptor cDNA in model systems potentially provides a powerful assay for the development of subtype-specific receptor antagonists that may prove to be of therapeutic importance in human small cell lung carcinoma.The mammalian bombesin-like peptides gastrin-releasing peptide (GRP) and neuromedin B (NMB) are regulatory peptides of importance in a wide variety of cell physiologic processes including secretion, smooth muscle contraction, and modulation of neuron firing rate (for review, see refs. 1 and 2). In addition, bombesin-like peptides can function as growth factors in Swiss 3T3 murine embryonal fibroblasts (3) and have been implicated as autocrine growth factors in the pathogenesis of some human small cell lung carcinomas (4). The bioactivities associated with the mammalian bombesinlike peptides are mediated by high-afflinity binding to cell surface receptors present on many target cells (for review, see ref. 1). The properties of high-affinity bombesin/GRP receptors found in relatively high numbers (=100,000 receptors per cell) on Swiss 3T3 fibroblasts have been extensively studied (5), with subsequent purification of the protein to near homogeneity (6). Molecular cloning ofthe gene encoding the Swiss 3T3 bombesin/GRP receptor is the next step to understanding the diversity and function of mammalian bombesin-like peptides and their receptors in physiologic and pathologic processes. In this paper, we report the isolation and characterization of cDNA clones § encoding the Swiss 3T3 bombesin/GRP receptor, defining the structure of the receptor polypeptide. The clones obtained should provide a basis for further molecular analysis ofthe structure, function, and expression of receptors in Swiss 3T3 cells. In addition, these clones provide a means for a similar analysis of this receptor and other related bombesin peptide receptors expressed in the various cell types known to respond to this family of peptides. MATERIALS AND METHODSReceptor Protein Purification and Peptide Sequencing. The ...