Somatic mutational profiling and clinical impact of driver genes in Latin-Iberian medulloblastomas: Towards precision medicine.

Medulloblastoma (MB) is the most prevalent malignant brain tumor in children, known for its heterogeneity and treatment-associated toxicity, and there is a critical need for new therapeutic targets. We analyzed the somatic mutation profile of 15 driver genes in 69 Latin-Iberian molecularly characterized medulloblastomas using the Illumina TruSight Tumor 15 panel. We classified the variants based on their clinical impact and oncogenicity. Among the patients, 66.7% were MBSHH, 13.0% MBWNT, 7.3% MBGrp3, and 13.0% MBGrp4. Among the 63 variants found, 54% were classified as Tier I/II and 31.7% as oncogenic/likely oncogenic. We observed 33.3% of cases harboring at least one mutation. TP53 (23.2%, 16/69) was the most mutated gene, followed by PIK3CA (5.8%, 4/69), KIT (4.3%, 3/69), PDGFRA (2.9%, 2/69), EGFR (1.4%, 1/69), ERBB2 (1.4%, 1/69), and NRAS (1.4%, 1/69). Approximately 41% of MBSHH tumors exhibited mutations, TP53 (32.6%) being the most frequently mutated gene. Tier I/II and oncogenic/likely oncogenic TP53 variants were associated with relapse, progression, and lower survival rates. Potentially actionable variants in the PIK3CA and KIT genes were identified. Latin-Iberian medulloblastomas, particularly the MBSHH, exhibit higher mutation frequencies than other populations. We corroborate the TP53 mutation status as an important prognostic factor, while PIK3CA and KIT are potential therapeutic targets.

Detection of NTRK fusions by RNA-based nCounter is a feasible diagnostic methodology in a real-world scenario for non-small cell lung cancer assessment.

NTRK1, 2, and 3 fusions are important therapeutic targets for NSCLC patients, but their prevalence in South American admixed populations needs to be better explored. NTRK fusion detection in small biopsies is a challenge, and distinct methodologies are used, such as RNA-based next-generation sequencing (NGS), immunohistochemistry, and RNA-based nCounter. This study aimed to evaluate the frequency and concordance of positive samples for NTRK fusions using a custom nCounter assay in a real-world scenario of a single institution in Brazil. Out of 147 NSCLC patients, 12 (8.2%) cases depicted pan-NTRK positivity by IHC. Due to the absence of biological material, RNA-based NGS and/or nCounter could be performed in six of the 12 IHC-positive cases (50%). We found one case exhibiting an NTRK1 fusion and another an NTRK3 gene fusion by both RNA-based NGS and nCounter techniques. Both NTRK fusions were detected in patients diagnosed with lung adenocarcinoma, with no history of tobacco consumption. Moreover, no concomitant EGFR, KRAS, and ALK gene alterations were detected in NTRK-positive patients. The concordance rate between IHC and RNA-based NGS was 33.4%, and between immunohistochemistry and nCounter was 40%. Our findings indicate that NTRK fusions in Brazilian NSCLC patients are relatively rare (1.3%), and RNA-based nCounter methodology is a suitable approach for NRTK fusion identification in small biopsies.

ERBB2 exon 20 insertions are rare in Brazilian non-small cell lung cancer.

ERBB2 exon 20 insertions may impact the clinical management of lung cancer patients. However, the frequency of ERBB2 exon 20 insertions in lung cancer patients in Brazil is scarce. Here, we analyzed 722 Brazilian non-small cell lung cancer (NSCLC) patients from Barretos Cancer Hospital that were indicated to require routine lung cancer molecular testing. ERBB2 exon 20 insertions were evaluated by a targeted panel using next-generation sequencing (NGS). Clinicopathological and molecular data were collected from patient medical records. Among the 722 NSCLC patients, 85.2% had lung adenocarcinomas, 53.9% were male, 66.8% were quitter or current smokers, and 63.2% were diagnosed at an advanced stage of the disease. We identified 0.8% (6/722) of patients who harbored the insertion p.(Tyr772_Ala775dup) at exon 20 of the ERBB2 gene. All ERBB2 mutated patients were diagnosed with lung adenocarcinoma, were never smokers, and wild-type for EGFR, KRAS, and ALK hotspot alterations. Less than 1% of Brazilian NSCLC patients harbor ERBB2 exon 20 insertions, yet they could benefit in future from the new drugs in development.

EGFR Mutations and PD-L1 Expression in Early-Stage Non-Small Cell Lung Cancer: A Real-World Data From a Single Center in Brazil.

BACKGROUND: Targeted and immunotherapies are currently moving toward early-stage settings for patients with non-small cell lung cancer (NSCLC). Predictive biomarkers data are scarce in this scenario. We aimed to describe the frequency of EGFR mutations and PD-L1 expression levels in early-stage non-squamous patients with NSCLC from a large, single Brazilian oncology center. METHODS: We retrospectively evaluated patients with NSCLC diagnosed at an early-stage (IB to IIIA-AJCC seventh edition) at Barretos Cancer Hospital (n = 302). EGFR mutational status was assessed in FFPE tumor tissues using distinct methodologies (NGS, Cobas, or Sanger sequencing). PD-L1 expression was evaluated by immunohistochemistry (clone 22C3) and reported as Tumor Proportion Score (TPS), categorized as <1%, 1-49%, and ≥50%. We evaluated the association between EGFR mutational status and PD-L1 expression with sociodemographic and clinicopathological parameters by Fisher's test, qui-square test, and logistic regression. Survival analysis was assessed by the Kaplan-Meier method and Cox regression model. RESULTS: EGFR mutations were detected in 17.3% (n = 48) of cases and were associated with female sex, never smokers, and longer overall and event-free survival. PD-L1 positivity was observed in 36.7% (n = 69) of cases [TPS 1-49% n = 44(23.4%); TPS ≥50% n = 25(13.3%)]. PD-L1 positivity was associated with smoking, weight loss, and higher disease stages (IIB/IIIA). CONCLUSION: The frequencies of EGFR mutations and PD-L1 positivity were described for early-stage non-squamous patients with NSCLC. These results will be essential for guiding treatment strategies with the recent approvals of osimertinib and immunotherapy in the adjuvant setting.

A PCR-Based Approach for Driver Mutation Analysis of EGFR, KRAS, and BRAF Genes in Lung Cancer Tissue Sections.

Driver mutations in non-small cell lung cancer (NSCLC) have a relevant significance for clinical management. EGFR mutations are the most important predictive biomarkers for NSCLC, although KRAS and BRAF mutations can also be prognostic and predictive biomarkers, respectively. PCR-based approaches followed by sequencing are useful for EGFR, KRAS, and BRAF mutational analysis. Herein, all steps for a PCR-based technique, from DNA isolation from tumor tissue sections to DNA sequencing for genetic analysis of EGFR, KRAS, and BRAF hotspot regions are described.