Circulating tumor cell associated white blood cell cluster as a biomarker for metastasis and recurrence in hepatocellular carcinoma

BACKGROUND: Recently, an in vivo study demonstrated that circulating tumor cell-associated white blood cell (CTC-WBC) cluster possess much greater potential than single CTCs. We aim to explore the correlation between the CTC-WBC cluster and the clinicopathological characteristics of hepatocellular carcinoma (HCC) patients to seek novel biomarkers for HCC metastasis and recurrence. METHODS: We retrospectively analyzed 136 HCC patients from October 2014 to March 2020 who received CTC tests using the CanPatrol CTC enrichment technique. The correlation between the clinical features and total CTCs, EMT-CTCs, and CTC-WBC cluster were analyzed by a chi-square test. The ROC curves were simulated for evaluating the diagnostic performance of CTC parameters in HCC metastasis. Patients were followed up from February 2015 to November 2021, and the relapse-free survival (RFS) was analyzed using the Kaplan–Meier curve. RESULTS: A total of 93.4% (127/136) and 31.6% (43/136) of HCC patients had detectable CTCs and CTC-WBC clusters. Baseline CTC-WBC cluster was closely correlated with microvascular invasion, portal vein tumor thrombus, and extrahepatic metastasis in pre-treatment HCC patients (P <0.05). The simulated ROC curves presented an AUC of 0.821 for the CTC-WBC cluster (sensitivity of 90.0% and specificity of 93.7%) in discriminating metastasis from non-metastatic HCC, which was higher than that for total CTCs (0.718) and EMT-CTCs (0.716). Further follow-up analysis showed that compared to the CTC-WBC cluster negative group (<1/5 ml), patients in the CTC-WBC cluster positive group (≥1/5 ml) presented an increased relapse ratio (60.0% versus 17.9%) and shorter RFS (22.9 versus 53.8 months). Dynamic analysis of CTCs parameters showed that total CTC level, EMT-CTCs proportion, and CTC-WBC cluster were decreased after microwave ablation treatment, while CTC-WBC cluster increased on average 10 months in advance of imaging (MRI) diagnosed recurrence. CONCLUSION: The CTC-WBC cluster is a promising biomarker for the metastasis diagnosis and prognosis of HCC metastasis. Dynamic monitoring of the CTC-WBC cluster is an effective method for early detection and intervention of HCC recurrence and metastasis.