Abstract
Background
Past studies have shown that circulating tumor cells (CTCs) play an important role in the clinical staging, efficacy monitoring and prognosis evaluation of lung cancer.
Methods
In this study we investigated the expression of CK18 and Vimentin on the surface of CTC and the aneuploidy of chromosome 8 in peripheral blood of 24 patients with metastatic primary lung cancer which were detected by subtraction enrichment and immunofluorescence in situ hybridization (SE-iFISH), and their correlation with clinicopathological features, curative effect and prognosis was analyzed.
Results
The positive rate of CTC was 95.83% (23/24). There was a certain correlation between the positive rate of CTC and smoking and a correlation between the number of CTC and the histopathological type of patients. The number of monoploid, diploid, triploid and polyploid CTC had no statistical correlation with progression-free survival (PFS) or overall survival (OS). However, a tetraploid CTC count of two or more was an unfavorable predictor of response and a tetraploid CTC count ≥ 1 is an unfavorable prognostic predictor of poor OS. The positive rate of CK18 + CTC in all 24 patients was 4.35% (1/23). Meanwhile, 7 out of these 24 patients were also tested for Vimentin, and the positive rate of Vimentin + CTC was 85.71% (6/7). Small-cell (≤ 5µm) CTC was found in 6 of these 7 patients and it accounted for 11.83% (11/93) of the total CTC. The tumor marker phenotype of small-cell CTC was CK18 - Vimentin +. In addition, circulating tumor microthrombi (CTM) were found in 2 of these 7 patients (28.57%).
Conclusion
SE-iFISH has a high detection rate of CTC in peripheral blood of patients with metastatic primary lung cancer, and it can identify small-cell CTC. Tetraploid CTC count ≥ 2 can predict poor PFS in patients with advanced lung cancer. Tetraploid CTC count ≥ 1 may predict poor OS in patients with advanced lung cancer. CTM can predict poor prognosis in patients with lung cancer.
Simultaneous in situ detection of protein expression of multiple tumor markers of circulating tumor cells and heteroploid of chromosome 8 in primary lung cancer
