Immunotherapy with PD-1 antibodies has greatly increased prognosis of patients with advanced melanoma.,Identifying biomarkers that predict overall survival (OS) and response to immunotherapy is important.,OS and best overall response according to RECIST version 1.1 were analysed, and S100B and lactate dehydrogenase (LDH) serum levels were assessed retrospectively in 152 patients treated with anti-PD-1, and in 86 patients treated with anti-PD-1 plus anti-CTLA-4 antibodies at University Hospital Tuebingen, Germany.,In the pembrolizumab group, patients with elevated baseline S100B or LDH exhibited significantly impaired OS compared with patients with normal S100B (1-year OS: 51.1% vs 83.1%, log-rank P < .0001) and normal LDH (1-year OS: 44.4% vs 80.8%, P = .00022), respectively.,LDH increases of >25% and S100B increases of >145% compared to baseline were significantly associated with impaired OS (both P < .0001).,In patients treated with ipilimumab and nivolumab, baseline S100B and increasing S100B levels of >145% as well as baseline LDH were associated with impaired OS (P < .0001, P = .00060, and P = .0050, respectively), whereas increasing LDH of >25% was not (P = .64).,S100B could serve as a strong baseline marker for OS in melanoma patients receiving anti-PD-1 therapy.,Rising S100B levels during the first weeks of therapy could help guide treatment decisions.
Blocking oncogenic signaling induced by the BRAFV600E mutation is a promising approach for melanoma treatment.,We tested the anti-tumor effects of a specific inhibitor of Raf protein kinases, PLX4032/RG7204, in melanoma cell lines.,PLX4032 decreased signaling through the MAPK pathway only in cell lines with the BRAFV600E mutation.,Seven out of 10 BRAFV600E mutant cell lines displayed sensitivity based on cell viability assays and three were resistant at concentrations up to 10 μM.,Among the sensitive cell lines, four were highly sensitive with IC50 values below 1 μM, and three were moderately sensitive with IC50 values between 1 and 10 μM.,There was evidence of MAPK pathway inhibition and cell cycle arrest in both sensitive and resistant cell lines.,Genomic analysis by sequencing, genotyping of close to 400 oncogeninc mutations by mass spectrometry, and SNP arrays demonstrated no major differences in BRAF locus amplification or in other oncogenic events between sensitive and resistant cell lines.,However, metabolic tracer uptake studies demonstrated that sensitive cell lines had a more profound inhibition of FDG uptake upon exposure to PLX4032 than resistant cell lines.,In conclusion, BRAFV600E mutant melanoma cell lines displayed a range of sensitivities to PLX4032 and metabolic imaging using PET probes can be used to assess sensitivity.