Whole-exome sequencing of a chronic lymphocytic leukemia (CLL) developed during vemurafenib treatment of a patient with malignant melanoma. Peripheral blood mononuclear cells were separated by Ficoll gradient centrifugation. DNA was extracted from highly purified (>97%) CD19+CD5+ cells obtained from the patient while being under BRAF inhibition versus CD14+ germline control cells (>90% purity). No alterations that could be linked to aberrant RAS activity or paradoxical RAF/MEK/ERK ... (Show More)

Whole-exome sequencing of a chronic lymphocytic leukemia (CLL) developed during vemurafenib treatment of a patient with malignant melanoma. Peripheral blood mononuclear cells were separated by Ficoll gradient centrifugation. DNA was extracted from highly purified (>97%) CD19+CD5+ cells obtained from the patient while being under BRAF inhibition versus CD14+ germline control cells (>90% purity). No alterations that could be linked to aberrant RAS activity or paradoxical RAF/MEK/ERK signaling could be identified in the CLL, which shows characteristic copy number alterations.

Mutations that activate the RAF-MEK-ERK signaling pathway, in particular BRAFV600E, occur in many cancers, and mutant BRAF-selective inhibitors have clinical activity in these diseases. Activating BRAF alleles are usually considered to be mutually exclusive with mutant RAS, whereas inactivating mutations in the D594F595G596 motif of the BRAF activation segment can coexist with oncogenic RAS and cooperate via paradoxical MEK/ERK activation. We determined the functional consequences of a largely ... (Show More)

Mutations that activate the RAF-MEK-ERK signaling pathway, in particular BRAFV600E, occur in many cancers, and mutant BRAF-selective inhibitors have clinical activity in these diseases. Activating BRAF alleles are usually considered to be mutually exclusive with mutant RAS, whereas inactivating mutations in the D594F595G596 motif of the BRAF activation segment can coexist with oncogenic RAS and cooperate via paradoxical MEK/ERK activation. We determined the functional consequences of a largely uncharacterized BRAF mutation, F595L, which was detected along with an HRASQ61R allele by clinical exome sequencing in a patient with histiocytic sarcoma and also occurs in epithelial cancers, melanoma, and neuroblastoma, and investigated its interact... (Read more)