Circulating tumor DNA (ctDNA) detection is associated with shorter progression-free survival in advanced melanoma patients

Abstract

BRAF, NRAS and TERT mutations occur in more than 2/3 of melanomas. Its detection in patient’s blood, as circulating tumor DNA (ctDNA), represents a possibility for identification and monitoring of metastatic disease. We proposed to standardize a liquid biopsy platform to identify hotspot mutations in BRAF, NRAS and TERT in plasma samples from advanced melanoma patients and investigate whether it was associated to clinical outcome. Firstly, we performed digital polymerase chain reaction using tumor cell lines for validation and determination of limit of detection (LOD) of each assay and screened plasma samples from healthy individuals to determine the limit of blank (LOB). Then, we selected 19 stage III and IV patients and determined the somatic mutations status in tumor tissue and track them in patients’ plasma. We established a specific and sensitive methodology with a LOD ranging from 0.13 to 0.37%, and LOB ranging from of 0 to 5.201 copies/reaction. Somatic mutations occurred in 17/19 (89%) patients, of whom seven (41%) had ctDNA detectable their paired plasma. ctDNA detection was associated with shorter progression free survival (p = 0.01). In conclusion, our data support the use of ctDNA as prognosis biomarker, suggesting that patients with detectable levels have an unfavorable outcome.

Intermittent BRAF inhibition in advanced BRAF mutated melanoma results of a phase II randomized trial

“…Twenty-one (62%) patients had detectable BRAFV600 mutation in pretreatment cfDNA (preBRAF+). As expected [6][7][8][9] , preBRAF+ patients had a significantly worse outcome compared with patients with baseline BRAF mutation undetectable in cfDNA (preBRAF−). Median PFS was 8.2 months for preBRAF+ (95%CI = 5.2−13.6) vs. non-reached (NR) for preBRAF− (95% CI = 2.8−NR) (p = 0.017) (Supplementary Fig.…”

Molecular Profile of Skin Cancer

“…The predominance of either GLI1 or GLI2 in relation to the development of BCC is still unclear; however, there seems to be a positive feedback loop in which GLI2 directly activates the expression of GLI1. Moreover, there is a small number of sporadic BCCs where SMO mutations are found, also resulting in the up-regulation of this pathway [42,[56][57][58][59][60][61].…”

Impact of Circulating and Tissue Biomarkers in Adjuvant and Neoadjuvant Therapy for High-Risk Melanoma: Ready for Prime Time?

“…Digital polymerase chain reaction (dPCR) methodology is one of the most convenient methods in this setting, given its limited costs, high specificity, and accuracy. However, the dPCR approach lacks sensitivity since it covers BRAF, NRAS, and TERT mutations, which together occur in more than 80% of cutaneous melanomas [ 47 ]. Other methods of ctDNA detection, such as next-generation sequencing (NGS), can detect genome-wide DNA variation with the aid of multiple targeted gene panels, with lower costs compared with whole genome sequencing (WGS) and whole exome sequencing (WES).…”