Unique SLC12A2-ROS1 fusion is associated with marked response to crizotinib in lung adenocarcinoma.

Chromosomal rearrangements involving the c-ros oncogene 1 (ROS1) gene define a subset of non-small cell lung cancers highly sensitive to small-molecule tyrosine kinase inhibitors. However, little is known about the impact of different fusion partners on tyrosine kinase inhibitor efficacy. We herein describe a case of a 26-year-old never-smoker patient from southern Africa with metastatic lung adenocarcinoma driven by SLC12A2-ROS1 fusion, who had a pronounced and durable response to crizotinib. The present case underscores the importance of pursuing actionable alterations in patients with similar clinical and epidemiological characteristics. In addition, provides the second report of crizotinib activity against lung malignancies harboring the unique SLC12A2-ROS1 fusion and highlights the importance of a deeper understanding of molecular alterations in underrepresented subgroups of patients to tailor the decision-making in daily practice.

Impressive response to dabrafenib, trametinib, and osimertinib in a metastatic EGFR-mutant/BRAF V600E lung adenocarcinoma patient.

The survival outcomes of the FLAURA trial support osimertinib as the new standard of care for untreated patients harboring activating mutations in the epidermal growth factor receptor (EGFR). Despite the initial response, disease progression invariably occurs. Although uncommon, BRAF V600E mutation arises as a unique mechanism of resistance, and thus far, no prospective studies are available to support concurrent EGFR/BRAF blockade. We report a case of impressive radiological and ctDNA response under dabrafenib, trametinib, and osimertinib in an advanced EGFR-mutant lung adenocarcinoma patient who developed BRAF V600E as one of the acquired resistance mechanisms to second-line osimertinib. Moreover, the patient experienced remarkable clinical improvement and good tolerance to combination therapy. The present case suggests the importance of prospective studies evaluating both efficacy and safety of the combination in later line settings and points towards the potential of ctDNA to monitor resistance mechanisms and treatment benefit in clinical practice.

Sequential liquid biopsies reveal dynamic alterations of EGFR driver mutations and indicate EGFR amplification as a new mechanism of resistance to osimertinib in NSCLC.

Osimertinib is an EGFR-T790M-specific TKI, which has demonstrated impressive response rates in NSCLC, after failure to first-line anti-EGFR TKIs. However, acquired resistance to osimertinib is also observed and the molecular mechanisms of resistance are not yet fully understood. Monitoring and managing NSCLC patients who progressed on osimertinib is, therefore, emerging as an important clinical challenge. Sequential liquid biopsies were used to monitor a patient with EGFR-exon19del positive NSCLC, who received erlotinib and progressed through the acquisition of the EGFR-T790M mutation. Erlotinib was discontinued and osimertinib was initiated. Blood samples were collected at erlotinib progression and during osimertinib treatment for the detection of the activating (EGFR-exon19del) and resistance mutations (EGFR-T790M, EGFR-C797S, BRAF-V600E, METamp and ERBB2amp) in the plasma DNA using digital droplet PCR. Plasma levels of the activating EGFR-exon19del accurately paralleled the clinical and radiological progression of disease and allowed early detection of AR to osimertinib. Resistance to osimertinib coincided with the emergence of a small tumor cell subpopulation carrying the known EGFR-C797S resistance mutation and an additional subpopulation carrying amplified copies of EGFR-exon19del. Given the existence of multiple AR mechanisms, quantification of the original EGFR activation mutation, instead of the resistance mutations, can be efficiently used to monitor response to osimertinib, allowing early detection of AR. Absolute quantification of both activation and resistance mutations can provide important information on tumor clonal evolution upon progression to osimertinib. Selective amplification of the EGFR-exon19del allele may represent a novel resistance mechanism to osimertinib.

Neoadjuvant endocrine therapy in breast cancer: current role and future perspectives.

Luminal breast cancer, as defined by oestrogen and/or progesterone expression by immunohistochemistry, accounts for up to 75% of all breast cancers. In this population, endocrine therapy is likely to account for most of the gains obtained with the administration of adjuvant systemic treatment. The role of adjuvant chemotherapy in these patients remains debatable since it is known that only a small fraction of patients will derive meaningful benefit from this treatment whilst the majority will be exposed to significant and unnecessary chemotherapy-related toxicities, in particular the elderly and frail. Therefore, neoadjuvant endocrine therapy (NET) becomes an attractive option for selected patients with hormonal-receptor positive locally advanced breast cancer. In this review, we discuss the current role of NET and future perspectives in the field.