Dataset Information

High level of chromosomal instability in circulating tumor cells of ROS1-rearranged non-small-cell lung cancer.

ABSTRACT:

Background

Genetic aberrations affecting the c-ros oncogene 1 (ROS1) tyrosine kinase gene have been reported in a small subset of patients with non-small-cell lung cancer (NSCLC). We evaluated whether ROS1-chromosomal rearrangements could be detected in circulating tumor cells (CTCs) and examined tumor heterogeneity of CTCs and tumor biopsies in ROS1-rearranged NSCLC patients.

Patients and methods

Using isolation by size of epithelial tumor cells (ISET) filtration and filter-adapted-fluorescence in situ hybridization (FA-FISH), ROS1 rearrangement was examined in CTCs from four ROS1-rearranged patients treated with the ROS1-inhibitor, crizotinib, and four ROS1-negative patients. ROS1-gene alterations observed in CTCs at baseline from ROS1-rearranged patients were compared with those present in tumor biopsies and in CTCs during crizotinib treatment. Numerical chromosomal instability (CIN) of CTCs was assessed by DNA content quantification and chromosome enumeration.

Results

ROS1 rearrangement was detected in the CTCs of all four patients with ROS1 rearrangement previously confirmed by tumor biopsy. In ROS1-rearranged patients, median number of ROS1-rearranged CTCs at baseline was 34.5 per 3 ml blood (range, 24-55). In ROS1-negative patients, median background hybridization of ROS1-rearranged CTCs was 7.5 per 3 ml blood (range, 7-11). Tumor heterogeneity, assessed by ROS1 copy number, was significantly higher in baseline CTCs compared with paired tumor biopsies in the three patients experiencing PR or SD (P < 0.0001). Copy number in ROS1-rearranged CTCs increased significantly in two patients who progressed during crizotinib treatment (P < 0.02). CTCs from ROS1-rearranged patients had a high DNA content and gain of chromosomes, indicating high levels of aneuploidy and numerical CIN.

Conclusion

We provide the first proof-of-concept that CTCs can be used for noninvasive and sensitive detection of ROS1 rearrangement in NSCLC patients. CTCs from ROS1-rearranged patients show considerable heterogeneity of ROS1-gene abnormalities and elevated numerical CIN, a potential mechanism to escape ROS1-inhibitor therapy in ROS1-rearranged NSCLC tumors.

SUBMITTER: Pailler E

PROVIDER: S-EPMC4478971 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:ObjectivesFood and Drug Administration (FDA) approved crizotinib for advanced ROS1-rearranged (ROS1+) non-small-cell lung cancer (NSCLC) patients due to a single-arm study PROFILE 1001. However, there is no direct comparison between crizotinib and platinum-pemetrexed chemotherapy.Materials and methodsClinical data of advanced ROS1+NSCLC patients treated with first-line crizotinib or platinum-pemetrexed chemotherapy between August 2010 and December 2017 were analyzed.ResultsSeventy-seven patients were eligible, including 30 (39.0%) in the crizotinib group and 47 (61.0%) in the platinum-pemetrexed chemotherapy group. The median follow-up was 28.1 months (95% confidence interval [CI]: 19.2-39.0). The objective response rate (ORR) of crizotinib (86.7%, 95% CI: 73.3-96.7) was higher than that of platinum-pemetrexed chemotherapy (44.7%, 95% CI: 29.8-57.4, P < .001). The disease control rate (DCR) was 96.7% (95% CI: 90.0-100) in the crizotinib group and 85.1% (95% CI: 74.5-95.7) in the chemotherapy group (P = .140). Significantly longer progression-free survival (PFS) was observed in the patients treated with crizotinib (18.4 months, 95% CI: 6.4-30.3) versus platinum-pemetrexed chemotherapy (8.6 months, 95% CI: 6.9-10.3, P < .001). Overall survival (OS) was also compared between the two groups and no significant difference was seen (Not reach vs 28.4 months [95% CI: 20.7-36.0], P = .176). Notably, a total of 37 patients have treatment crossover after the failure of first-line treatment. Among those patients, difference in OS was not statistically significant between seven patients who have given first-line crizotinib (38.6 months, 95% CI: 0-81.0) and 30 patients who have given platinum-pemetrexed chemotherapy initially (32.8 months, 95% CI: 11.9-53.8, P = .805).ConclusionsOur results suggested that first-line crizotinib had higher ORR and longer PFS than platinum-pemetrexed chemotherapy in patients with advanced ROS1+NSCLC, but the differences were not observed for OS.