The prognostic role of detection of circulating melanoma cells in the blood

A Comparison of 3 Tumor Markers (MIA, TA90IC, S100B) in Stage III Melanoma Patients

PURPOSE

There is no consensus regarding the optimal tumor markers for melanoma. We compared 3 tumor markers, TA90-immune complex (TA90IC), melanoma-inhibiting activity (MIA) protein, and S100B protein in Stage III melanoma patients undergoing adjuvant vaccine immunotherapy.

EXPERIMENTAL DESIGN

The serum of 75 patients representing 3 prognostic cohorts was assayed for the tumor markers prior to initiating immunotherapy and at 6 follow-up time points. Upper limits of normal for TA90IC, MIA and S100B were set at OD 0.41, 8.5 ng/ml, and 2.5 microg/l, respectively.

RESULTS

At least 1 marker became elevated prior to 41 (80 percent) of 51 recurrences. TA90IC was the earliest elevated marker in 29 (57 percent), MIA in 11 (22 percent), and S100B in 4 (8 percent). Multivariate regression analysis revealed that TA90IC was an independent predictor of survival when elevation occurred between 2 weeks and 3 months, whereas MIA was an independent predictor at 4-6 months. In the poor prognostic cohort, mean values for MIA and S100B increased progressively, whereas TA90IC exhibited a parabolic curve.

CONCLUSION

In this patient population, TA90IC and MIA were complementary; elevation of the immune complex preceded elevation of the tumor antigen in patients who developed recurrence. Additional studies in populations not receiving vaccine will further clarify the clinical utility of these assays.

Molecular markers of circulating melanoma cells

Of all skin cancers, cutaneous malignant melanoma (CMM) is the most aggressive and the life expectancy of patients with lymphatic or systemic metastases is dramatically reduced. Understandably therefore, scientists and clinicians have focused on improving diagnostic and prognostic techniques. Of these, perhaps the most promising are multimarker real-time RT-PCR and microarray for detection of circulating CMM cells in peripheral blood. While the optimal set of markers is still to be identified that can accurately assess disease severity and progression at all clinical stages of the disease, recent progress has been dramatic. Here we provide an exhaustive review of recent studies in which a variety of markers are assessed. Moreover, the efficacy of the markers relative to clinical stage is discussed in light of experimental findings. From these studies, it is apparent that researchers are now much closer to defining a set of markers of circulating cells that can be utilized in routine diagnostic tests.

Serial detection of circulating tumour cells by reverse transcriptase-polymerase chain reaction assays is a marker for poor outcome in patients with malignant melanoma

Background

Detection of circulating malignant cells (CMCs) through a reverse transcriptase-polymerase chain reaction (RT-PCR) assay seems to be a demonstration of systemic disease. We here evaluated the prognostic role of RT-PCR assays in serially-taken peripheral blood samples from patients with malignant melanoma (MM).

Methods

One hundred forty-nine melanoma patients with disease stage ranging from I to III were consecutively collected in 1997. A multi-marker RT-PCR assay was used on peripheral blood samples obtained at time of diagnosis and every 6 months during the first two years of follow-up (total: 5 samples). Univariate and multivariate analyses were performed after 83 months of median follow-up.

Results

Detection of at least one circulating mRNA marker was considered a signal of the presence of CMC (referred to as PCR-positive assay). A significant correlation was found between the rate of recurrences and the increasing number of PCR-positive assays (P = 0.007). Presence of CMC in a high number (≥2) of analysed blood samples was significantly correlated with a poor clinical outcome (disease-free survival: P = 0.019; overall survival: P = 0.034). Multivariate analysis revealed that presence of a PCR-positive status does play a role as independent prognostic factors for overall survival in melanoma patients, adding precision to the predictive power of the disease stage.

Conclusion

Our findings indicated that serial RT-PCR assay may identify a high risk subset of melanoma patients with occult cancer cells constantly detected in blood circulation. Prolonged presence of CMCs seems to act as a surrogate marker of disease progression or a sign of more aggressive disease.

Flavonoids inhibit melanoma lung metastasis by impairing tumor cells endothelium interactions

Flavonoids comprise a class of low molecular weight compounds displaying a variety of biological activities including inhibition of tumor growth and metastasis. To gain insight into the mechanisms underlying metastasis inhibition, we have employed the B16-BL6 murine melanoma metastasis model. B57BL/6N mice were injected i.v. with tumor cells and Apigenin, Quercetin, or Tamoxifen, each at 50 mg/kg given i.p., and lung tumor cell colonies counted 14-6 days thereafter. Three different injection schedules were used for each drug: (a) daily injection, starting 24 h before injection of the tumor cells; (b) single dose, 24 h preceding tumor challenge; (c) daily injection, starting 24 h after the injection of the tumor cells. All three compounds significantly reduced tumor lung deposits (Apigenin = Quercetin > Tamoxifen). However, when treatment was delayed by 24 h after tumor cells (schedule c), multiple daily doses of Apigenin or Quercetin were less effective that a single dose of the same compound given 24 h before tumor challenge (schedule b). Apigenin and Quercetin, but not Tamoxifen, were found to inhibit VCAM-1 expression in a dose-dependent manner in HUVEC and in murine pulmonary endothelial cells. In ex vivo experiments, the number of tumor cells adhering to lung vessels was significantly diminished in animals treated with a single dose of Apigenin and Quercetin. These findings indicate that the inhibition of tumor cell metastasis by Apigenin or Quercetin may significantly depend on the ability of these compounds to alter the host's microenvironment, further substantiating the role of the intravascular processes in the metastatic cascade.

Molecular Staging in Stage II and III Melanoma Patients and Its Effect on Long-Term Survival

Purpose

To assess the prognostic value of serial reverse transcriptase polymerase chain reaction (RT-PCR) -based measurements of tyrosinase mRNA in peripheral blood of stage II and III melanoma patients.

Patients and Methods

During routine follow-up of American Joint Committee on Cancer stage II and III melanoma patients, serial testing for tyrosinase transcripts in peripheral blood was performed by RT-PCR. The PCR results were compared with the clinical data collected during the follow-up.

Results

Over a period of 3 years, 111 patients (78 stage II and 33 stage III patients) were enrolled, and tyrosinase determinations were carried out. The 6-year disease-specific survival probability was 97% for patients always showing negative RT-PCR results and 67% for patients who tested positive at least once. In a Cox proportional hazards model, the prognostic value of sex, age, site of primary tumor, histologic subtype, stage, Breslow's tumor thickness, Clark level, and the time-dependent variable PCR result was assessed. Patients with a positive RT-PCR test had a distinctly higher risk of dying from melanoma, with a hazard ratio of 12.6 (95% CI, 3.4 to 46.3; P < .001).

Conclusion

Our study shows a strong association between PCR and disease-specific survival time. Detection of tyrosinase mRNA in peripheral blood may be of similar importance for the clinical course of melanoma as the detection of micrometastatic disease in the sentinel lymph node. Whether a combination of these two factors leads to a better definition of the prognosis of melanoma patients is under investigation in current studies.

Preclinical studies on detection of circulating melanoma cells in patients: telomerase as a recognition marker of malignancy

Preclinical studies based on a "simulation design", were performed with cultured melanoma cells prelabeled with 51Cr, added to normal blood and subjected to separation and recognition steps. Mononuclear cells (MNC) were isolated on ficollhypaque gradient, and melanoma cells were separated from lymphocytes using anti-CD45 immunomagnetic beads. Malignant cells were then recognized by measuring telomerase activity (TRAP and TRAP-ELISA assays). It was found that: (a)recovery of prelabeled cells present in MNC did not exceed 75%; (b) further recovery of prelabeled cells after separation from lymphocytes did not exceed 68%. Therefore, the overall recovery of prelabeled cells did not exceed 48%; (c) the entire procedure was able to reliably detect as few as 30 malignant cells added to normal blood, providing a telomerase signal significantly higher than that found in absence of melanoma cells. These results furnish the technical bases for developing a tumor detection assay in the blood of melanoma patients.