Novel BRAFI599Ins Mutation Identified in a Follicular Variant of a Papillary Thyroid Carcinoma: A Molecular Modeling Approach

Dabrafenib for Pilocytic Astrocytoma With BRAF V599ins

This report highlights the first pediatric case of pilocytic astrocytoma with BRAF V599ins mutation, successfully treated with dabrafenib.

Identification of a Novel Non-V600E BRAF Mutation in Papillary Thyroid Cancer

Papillary thyroid cancer (PTC) is a common endocrine malignancy, and its incidence is reported to be constantly increasing. BRAF mutation is detected in approximately 44% of PTCs, and the most common BRAF mutation is thymine (T) to adenine (A) missense mutation in nucleotide 1796 (T1796A, V600E). Although BRAFV600E represents 95% of all BRAF mutations, uncommon BRAF mutations have been reported in thyroid carcinomas and represent an alternative mechanism of BRAF activation with unclear clinical significance. We report a novel non-V600E mutation (c.1799_1812delinsAT, p.V600_W604delinsD), identified preoperatively with next-generation sequencing (NGS) on the material obtained with fine-needle aspiration cytology (FNAC) performed on a thyroid nodule cytologically suspicious for malignancy in a 35-year-old male patient. The presence of this new variant of BRAF mutation was subsequently confirmed in the postoperative phase by direct Sanger sequencing. In conclusion, we report a new non-V600E variant previously undetected in papillary thyroid cancer. In addition, this case report shows that the NGS technique on cytological tissue allows to detect the presence of rare mutations, thus increasing the diagnostic specificity of molecular analysis.

Genomic Landscape, Clinical Features and Outcomes of Non-Small Cell Lung Cancer Patients Harboring BRAF Alterations of Distinct Functional Classes

BACKGROUND

In non-small cell lung cancer (NSCLC), BRAF class 1 alterations are effectively targeted by BRAF inhibitors. Conversely, targeted therapies have very low or absent activity in patients carrying class 2 and 3 alterations. The spectrum of BRAF alterations in NSCLC patients, and their accompanying clinical features, genomic landscape and treatment outcomes have been poorly reported.

PATIENTS AND METHODS

We identified BRAF alterations of defined functional class across different tumors through a systematic review. Then, we selected NSCLC patients carrying BRAF alterations, according to the systematic review, in the cBioPortal (cBioPortal cohort) to collect and analyze clinical, biomolecular and survival data. Finally, we identified NSCLC patients carrying BRAF non-V600 mutations enrolled in POPLAR and OAK trials (POPLAR/OAK cohort), extracting clinical and survival data for survival analyses.

RESULTS

100 different BRAF non-V600 alterations were identified through the systematic review. In the cBioPortal cohort (n = 139), patients harboring class 2 and 3 alterations were more frequently smokers and had higher tumor mutational burden compared to those carrying class 1 alterations. The spectrum of most frequently co-altered genes was significantly different between BRAF alterations classes, including SETD2, STK11, POM121L12, MUC16, KEAP1, TERT, TP53 and other genes. In the POPLAR/OAK cohort, patients carrying non-V600 BRAF alterations were characterized by poor prognosis compared to BRAF wild-type patients.

CONCLUSIONS

Different classes of BRAF alterations confer distinctive clinical features, biomolecular signature and disease behavior to NSCLC patients. Non-V600 alterations are characterized by poor prognosis, but key gene co-alterations involved in cancer cell survival and immune pathways may suggest their potential sensitivity to tailored treatments.