TY - JOUR
T1 - Clonal heterogeneity of melanoma in a paradigmatic case study
T2 - Future prospects for circulating melanoma cells
AU - Scaini, Maria Chiara
AU - Pigozzo, Jacopo
AU - Pizzi, Marco
AU - Manicone, Mariangela
AU - Chiarion-Sileni, Vanna
AU - Zambenedetti, Pamela
AU - Rugge, Massimo
AU - Zanovello, Paola
AU - Rossi, Elisabetta
AU - Zamarchi, Rita
AU - Facchinetti, Antonella
PY - 2019/2/1
Y1 - 2019/2/1
N2 - The management of metastatic melanoma is a difficult matter. Nevertheless, the advent of target therapy has significantly improved patient outcome, provided that tumor molecular characteristics become available: the detection of drug-resistant clones can contribute to understanding the reasons for resistance onset, influencing the choice of subsequent therapy. This work aimed to provide a possible explanation for the early resistance to vemurafenib developed by a patient with melanoma, and concurrently to assess the extent, and role, of the tumor clonal heterogeneity. We analyzed tissue samples from different sites and time points: first/second primary, three lymph node metastases, and circulating melanoma cells (CMCs). We first investigated these samples by the routine Sanger sequencing for BRAF, NRAS, and KIT, and then, we focused on specific hotspots by droplet digital PCR. We detected a BRAF V600E mutation by Sanger sequencing in the second primary and distant lymph node metastases, but not in the first primary or sentinel lymph node. Interestingly, by droplet digital PCR, the V600E mutation was also detected in the first primary, and the V600K in the second primary and metastases. Moreover, we identified a rare KIT V569G mutation, appearing to be CMC exclusive. This finding confirms the potential of CMCs as a source of tumor material for genetic analysis, reflecting real-time systemic disease evolution and, most likely, the most aggressive, treatment-resistant clones. In summary, this work underlines the importance of CMCs in the early identification of tumor clones putatively responsible for therapy resistance.
AB - The management of metastatic melanoma is a difficult matter. Nevertheless, the advent of target therapy has significantly improved patient outcome, provided that tumor molecular characteristics become available: the detection of drug-resistant clones can contribute to understanding the reasons for resistance onset, influencing the choice of subsequent therapy. This work aimed to provide a possible explanation for the early resistance to vemurafenib developed by a patient with melanoma, and concurrently to assess the extent, and role, of the tumor clonal heterogeneity. We analyzed tissue samples from different sites and time points: first/second primary, three lymph node metastases, and circulating melanoma cells (CMCs). We first investigated these samples by the routine Sanger sequencing for BRAF, NRAS, and KIT, and then, we focused on specific hotspots by droplet digital PCR. We detected a BRAF V600E mutation by Sanger sequencing in the second primary and distant lymph node metastases, but not in the first primary or sentinel lymph node. Interestingly, by droplet digital PCR, the V600E mutation was also detected in the first primary, and the V600K in the second primary and metastases. Moreover, we identified a rare KIT V569G mutation, appearing to be CMC exclusive. This finding confirms the potential of CMCs as a source of tumor material for genetic analysis, reflecting real-time systemic disease evolution and, most likely, the most aggressive, treatment-resistant clones. In summary, this work underlines the importance of CMCs in the early identification of tumor clones putatively responsible for therapy resistance.
KW - circulating melanoma cells
KW - droplet digital PCR
KW - laser capture microdissection
KW - melanoma clonal heterogeneity
KW - Sanger sequencing
KW - target therapy
UR - http://www.scopus.com/inward/record.url?scp=85058760483&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85058760483&partnerID=8YFLogxK
U2 - 10.1097/CMR.0000000000000510
DO - 10.1097/CMR.0000000000000510
M3 - Article
C2 - 30222690
AN - SCOPUS:85058760483
VL - 29
SP - 89
EP - 94
JO - Melanoma Research
JF - Melanoma Research
SN - 0960-8931
IS - 1
ER -