Katsuhiro Murakami

Circulating tumor cells as a prognostic factor in patients with small cell lung cancer

The detection of circulating tumor cells (CTCs) in peripheral blood is currently an important field of study. Detection of CTCs by the OBP-401 assay (TelomeScan®) has previously been reported to be useful in the diagnosis, prognosis and evaluation of therapeutic efficacy in breast and gastric cancer. The aim of the present study was to evaluate the OBP-401 assay as a novel method of detecting CTCs of small cell lung cancer (SCLC) patients and to evaluate whether CTC count is associated with prognosis. Prospectively, 30 consecutively diagnosed SCLC patients who had commenced chemotherapy or chemoradiotherapy were enrolled as subjects of the current study. Peripheral blood specimens were collected from the SCLC patients prior to and following the initiation of treatment and the viable CTCs were detected in the specimens following incubation with a telomerase-specific, replication-selective, oncolytic adenoviral agent, which was carrying the green fluorescent protein gene. CTCs were detected in 29 patients (96%). The group of 21 patients with a CTC count of <2 cells/7.5 ml prior to treatment (baseline) had a significantly longer median survival time than the group of eight patients with a CTC count of ≥2 cells/7.5 ml prior to treatment (14.8 and 3.9 months, respectively; P=0.007). The results of a multivariate analysis showed that the baseline CTC count was an independent prognostic factor for survival time (hazard ratio, 3.91; P=0.026). Among the patients that achieved a partial response to treatment, patients who had a CTC count of <2 cells/7.5 ml following two cycles of chemotherapy tended to have a longer median progression-free survival compared with patients who had a CTC count of ≥2 cell/7.5 ml (8.3 and 3.8 months, respectively; P=0.07). Therefore, CTCs may be detected via OBP-401 assay in SCLC patients and the CTC count prior to treatment appears to be a strong prognostic factor.

Prognostic impact of detecting viable circulating tumour cells in gastric cancer patients using a telomerase-specific viral agent: a prospective study

BackgroundThe identification of circulating tumour cells (CTCs) in peripheral blood is a useful approach to estimate prognosis, monitor disease progression, and measure treatment effects in various malignancies. However, clinical relevance of CTCs is controversial. We attempted to detect viable CTCs in the peripheral blood of gastric cancer patients using a telomerase-specific viral agent.MethodsWe took a 7.5-ml blood sample from 65 treatment-negative gastric cancer patients before surgery and 10 healthy volunteers. We detected viable CTCs in the blood samples after incubating them with a telomerase-specific, replication-selective, oncolytic adenoviral agent carrying the green fluorescent protein (GFP) gene (OBP-401). GFP-positive CTCs were defined as having a diameter of at least 7.735 μm; this threshold was determined by receiver operating characteristic curve analysis. GFP-positive cells were counted under a fluorescence microscope.ResultsThere was a significant difference in overall survival among the patients with 0–4 and those with ≥5 GFP-positive CTCs in the stage I–IV disease group and stage II–IV advanced disease group. The number of GFP-positive CTCs was not related to cancer stage. Among the pathological findings, the number of GFP-positive CTCs was only significantly related to venous invasion, although there were trends towards more GFP-positive CTCs with disease progression (tumour depth, lymph node metastasis, distant metastasis, lymphatic invasion, and histological type).ConclusionsThere was a significant relationship between the number of GFP-positive CTCs and overall survival in the patients with gastric cancer. The detection of CTCs using OBP-401 may be useful for prognostic evaluation.Trial registrationUniversity Hospital Medical Information Network in Japan, UMIN000002018.

Detection and preliminary evaluation of circulating tumor cells in the peripheral blood of patients with eight types of cancer using a telomerase-specific adenovirus

We developed a detection method for circulating tumor cells (CTCs) using the telomerase-specific adenovirus OBP-401. This recombinant virus has a telomerase promoter at the 5′-end of the viral genome and GFP at the 3′-end. To date, CTC enumeration using OBP-401 has shown prognostic impact for gastric and small cell lung cancer patients. In the present study, peripheral blood samples from patients with eight types of cancer, including some cancers previously untested with OBP-401 (i.e., esophagus, pancreas, and prostate cancers) were subjected to this method in order to evaluate its versatility. It was recently discovered that some white blood cells (WBCs) false-positively react with OBP-401. Although anti-CD45 antibodies can absorb these adverse cells from peripheral blood, the simplicity of the OBP-401 method would be diminished by the introduction of antibody treatment. Therefore, we evaluated another approach to minimize the false positivity of WBCs. Seven anti-CD antibodies were employed to stain the species of WBCs that false-positively reacted with OBP-401. We revealed that the false-positively reacted WBCs were monocytes in the peripheral blood of both healthy subjects and cancer patients. Based on a size distribution analysis of the GFP-positive monocytes, the size criterion for CTCs using OBP-401 was defined to be a cellular diameter >8.4 μm. In total, 43% of 86 cancer patients examined in the present study were CTC-positive using this definition. CTCs were enumerated from peripheral blood samples collected from patients with each of the eight types of cancer; the detectability of CTCs for esophagus, pancreas and prostate cancers by the OBP-401 method was confirmed for the first time in the present study. However, no clear correlation between CTC positivity and the clinical characteristics of patients with any type of cancer was observed because of the small number of patients with each type of cancer. An additional clinical study will be conducted to confirm the clinical meaning of CTCs enumerated by OBP-401.

Long-term prognostic impact of circulating tumour cells in gastric cancer patients

AIM To analyse the long-term prognostic impact of circulating tumour cells (CTCs) in gastric cancer patients who underwent surgery. METHODS A 7.5-mL peripheral vein blood sample was obtained from each patient with treatment-negative gastric adenocarcinoma before surgery. OBP-401, a telomerase-specific, replication-selective, oncolytic adenoviral agent carrying the green fluorescent protein gene, was used to label CTCs. Correlations between the number of CTCs and clinical end points were evaluated. RESULTS The median follow-up period of the surviving patients with gastric cancer was 60 mo. The CTC number tended to increase concomitantly with disease progression. The overall survival of patients with more than five CTCs in 7.5-mL of peripheral blood was lower than that of patients with five or less CTCs, although the difference was not significant (P = 0.183). A significant difference in relapse-free survival was found between patients with more than five and those with five or less CTCs (P = 0.034). CONCLUSION A lower number of CTCs was correlated with higher relapse-free survival rates in patients. Detection of CTCs using OBP-401 may be useful for predicting prognosis in gastric cancer.

TCT-329 Impaired HDL uptake capacity which measure HDL functionality may associate with target lesion revascularization through provoking neoatherosclerosis formation after stent implantation

The importance of HDL functionality on coronary artery disease has been repeatedly demonstrated in recent studies. However, the association between HDL functionality and stent failure has yet to be clarified. Recently, we established a cell-free assay system to evaluate the capacity of HDL to accept