Clinical significance of cytokeratin positive cells in bone marrow of gastric cancer patients

[Micrometastasis in Gastric Cancer]

Although the incidence and mortality rate of gastric cancer have been steadily declining, gastric cancer is still the fourth most common cancer in the world and more than 50% of cases occur in Eastern Asia. In Korea, gastric cancer is the second most common cancer and third cause of cancer related death. The standard surgical procedure for resectable advanced gastric cancer is D2 lymphadenectomy with radical gastrectomy. Even though R0 resection was completed, recurrence is relatively common, and contributes to the limited survival of the patients in gastric cancer. As a clinically relevant factor for detection of the recurrence, the presence of isolating tumor cells has been introduced and it is so called as 'micrometastasis'. Numerous immunohistochemistry and molecular studies have shown that micrometastasis can be demonstrated not only in lymph nodes but also in such body compartments as the bone marrow, peritoneal cavity and blood. Herein, we review the current knowledge and evidence of the prognostic significance of micrometastasis in peritoneal, lymph node, bone marrow. Also, we discuss the current state of research on the circulating tumor cell in peripheral blood.

miR-615-3p expression level in bone marrow is associated with tumor recurrence in hepatocellular carcinoma

The significance of disseminated tumor cells (DTCs) in bone marrow (BM) on tumor recurrence has not been investigated in patients with hepatocellular carcinoma (HCC). The aim of te present study was to clarify the molecular characteristics of DTCs that affect postoperative recurrence based on microRNA (miRNA) expression profiles in clinical HCC patients undergoing curative resection. DTCs were prospectively collected from the BM of preoperative HCC patients using immunomagnetic beads and subjected to miRNA microarray analysis. Microarray analysis of nine HCC patients (n=5 patients with postoperative HCC recurrence, n=4 patients without HCC recurrence) demonstrated that miR-615-3p is significantly upregulated in the DTCs of patients with recurrence compared to the DTCs from patients without recurrence. In vitro experiments demonstrated that the miR-615-3p expression level is significantly correlated with malignant characteristics in HCC cells. These data suggest that miR-615-3p in DTCs may play an important role in postoperative HCC recurrence, which suggests that miR-615-3p is a potential target molecule for regulating postoperative HCC recurrence.

Disseminated tumor cells in bone marrow of gastric cancer patients: correlation with tumor hypoxia and clinical relevance

Aim. The evaluation of the clinical relevance of disseminated tumor cells (DTCs) in bone marrow (BM) of patients with gastric cancer (GC) and their association with primary tumor hypoxia. Patients and Methods. 89 resected specimens were used. DTCs were detected using immunocytochemistry, the level of tumor hypoxia using NMR spectroscopy, CD68, CD34, VEGF, and VEGFR-1 (Flt-1) expression using immunohistochemistry, and MMP-2 and MMP-9 activity using zymography. Results. DTCs were detected in 51.4% of GC patients with M₀. There was significant correlation between frequency of DTCs in BM and level of tumor hypoxia (P < 0.024). DTCs presence was accompanied with Flt-1 positivity of BM. The correlation between DTCs and tumor VEGF expression in patients with M₀ was shown (P < 0.0248). Activity of MMP-2 and MMP-9 in BM was linked with DTCs in patients with M₀ (P < 0.05). Overall survival (OS) of patients with M₀ and DTCs was shorter than that of patients without DTCs (patients in both groups were operated only) (P = 0.0497). Conclusion. Appearance of DTCs correlates with hypoxia level in primary tumors. Detection of DTCs in GC patients may be relevant indicator for adjuvant chemotherapy using.

Disseminated and circulating tumor cells in gastrointestinal oncology

Circulating (CTCs) and disseminated tumor cells (DTCs) are two different steps in the metastatic process. Several recent techniques have allowed detection of these cells in patients, and have generated many results using different isolation techniques in small cohorts. Herein, we review the detection results and their clinical consequence in esophageal, gastric, pancreatic, colorectal, and liver carcinomas, and discuss their possible applications as new biomarkers.

Aberrant gene methylation in the lymph nodes provides a possible marker for diagnosing micrometastasis in gastric cancer

BACKGROUND

This study was designed to determine whether gene methylation is a novel diagnostic marker for micrometastasis to the lymph nodes (LNs) in gastric cancer.

METHODS

The gene methylation of CHFR, p16, RUNX3, E-cadherin, MGMT, hMLH1, and ABCG2 genes were analyzed in 49 primary gastric cancer tissues, corresponding to noncancerous tissues and matched LNs by quantitative methylation-specific PCR (q-MSP).

RESULTS

CHFR, RUNX3, MGMT, and hMLH1 were more frequently methylated in primary cancer compared with the noncancerous mucosa. Further analyses investigated whether the methylation of the four cancer-specific genes was preserved in LN tissues using the 29 control cases, in which LN metastasis had been histologically confirmed. The methylation of both lesions (M/M pattern) in at least one gene, which was judged to be positive for cancer cells in LNs, was observed in 25 of 29 cases (86%). Quantitative RT-PCR (qRT-PCR) of CEA, CK19, and CK20 mRNA was conducted using the same samples. The mRNA expression of at least one of the three genes was observed in 100% of the specimens. The results of the control analysis were used to attempt to predict micrometastasis by q-MSP and qRT-PCR in the 20 test cases without histological LN metastasis. Six cases (30%) showed the M/M pattern in at least one of the four genes. Three of 20 cases (15%) exhibited both the M/M pattern and positive mRNA.

CONCLUSIONS

The methylation analysis revealed the clinical feasibility of detecting occult neoplastic cells in the regional LNs.