Association of Circulating Tumor Cells with Serum Tumor-Related Methylated DNA in Peripheral Blood of Melanoma Patients

Abstract

Although previous studies have separately shown the utility of circulating tumor cells (CTC) or cell-free tumor-related DNA in blood of cancer patients, there has been no investigation of their association and/or the prognostic value of combining these assessments. To date, the true source of tumor-related DNA in serum remains unknown. We hypothesized that CTC is a possible origin of serum tumor-related methylated DNA and their combination can predict disease outcome. To test this hypothesis, we obtained matched pairs of peripheral blood lymphocytes and serum specimens simultaneously from 50 American Joint Committee on Cancer stage IV melanoma patients before administration of biochemotherapy. Peripheral blood leukocytes were analyzed for three mRNA markers of CTC: MART-1, GalNAc-T, and MAGE-A3. Sera were analyzed for two methylated DNA markers: RASSF1A and RAR-b2. CTC were detected in 13 of 15 (86%) patients with serum tumorrelated methylated DNA and only in 13 of 35 (37%) patients without methylated DNA (P = 0.001). The number of CTC markers detected significantly correlated with methylated DNA (P = 0.008). CTC and methylated DNA were significantly correlated with biochemotherapy-treated patients' outcome. Patients with both CTC and methylated DNA showed significantly poorer response to biochemotherapy (P = 0.02) and worse time to progression and overall survival (P = 0.009 and 0.02, respectively). The correlation between CTC and serum tumor-related methylated DNA and the significant effect of this correlation on disease outcome indicate that a composite molecular assessment in blood may be a useful determinant of disease status and efficacy of systemic therapy for melanoma. (Cancer Res 2006; 66(12): 6111-7)

RASSF1A hypermethylation in pretreatment serum DNA of neuroblastoma patients: a prognostic marker

“…In patients with malignancies, aberrant methylation of serum DNA has been reported (Müller et al, 2003;Ibanez de Caceres et al, 2004;Fiegl et al, 2005;Mori et al, 2005;Koyanagi et al, 2006). We have detected cell-free tumour DNA in serum of neuroblastoma patients (Gotoh et al, 2005).…”

“…Recently, one study showed that the detection of circulating tumour cells was correlated with tumour-related methylated DNA in patients with melanoma (Koyanagi et al, 2006), suggesting that circulating tumour cells are a potential source of circulating methylated DNA. Our study suggests that methylated RASSF1A DNA in serum is a surrogate marker for circulating neuroblastoma cells.…”

“…Methylation-specific PCR assay is a sensitive and specific assay for tumour-related DNA methylation in serum. Several studies have investigated the prospect of using DNA methylation as a surrogate marker for circulating tumour cells in serum samples from breast cancer or melanoma patients (Fiegl et al, 2005;Koyanagi et al, 2006). However, no studies of neuroblastoma have assayed serum samples for aberrant DNA methylation.…”

Detection of mutated BRAFV600E variant in circulating DNA of stage III–IV melanoma patients

“…[20][21][22] Recent studies indicate that these markers may show a predictive value of the response to biochemotherapy in stage IV patients. 23,24 Here, we report the results of a pilot study aimed at evaluating the BRAFV600E mutation as a molecular marker in circulating DNA from cutaneous melanoma patients. Both plasma and serum samples were analyzed and different disease stages were considered.…”

Liquid biopsy

“…8,12,13 In 2006, Hoon and colleagues published data in Cancer Research that melanoma patients with detectable levels of both circulating tumor cells and methylated cell-free DNA had a poorer response to therapy than patients who had detectable levels of only one of the markers. 14 Getting real "We are now moving our liquid biopsy into a real-world hospital setting, " Brenton told SciBX. "We initially plan to use it early in the diagnostic pathway, to diagnose low-bulk ovarian tumors prior to a pelvic scan.…”