High-throughput somatic mutation profiling in pulmonary sarcomatoid carcinomas using the LungCarta™ Panel: exploring therapeutic targets.

BACKGROUND: Pulmonary sarcomatoid carcinomas (SC) are tumors characterized by poor prognosis and resistance to conventional platinum-based chemotherapy. This study sought to describe the mutational profile of SC using high-throughput genotyping technology. PATIENTS AND METHODS: We used mass spectrometry to test 114 surgical biopsies from 81 patients with SC for 214 mutations affecting 26 oncogenes and tumor suppressor genes. RESULTS: In total, 75 (92.6%) patients were smokers. Within the total 81 tumors, 67 distinct somatic alterations were identified, with 56 tumors (69.1%) harboring at least one mutation. The most frequent mutations were KRAS (27.2%), EGFR (22.2%), TP53 (22.2%), STK11 (7.4%), NOTCH1 (4.9%), NRAS (4.9%), and PI3KCA (4.9%). The EGFR mutations were almost always rare mutations (89%). In 32 tumors (39.5%), two or more mutations co-existed, with up to four mutations in a single case. In six different cases, comparative genetic analysis of different histological areas from the same tumor (giant, spindle, or epithelial component) revealed a 61% concordance rate for all the mutations with a 10% detection threshold, compared with 91.7% with a 20% detection threshold. CONCLUSION: Our results demonstrated a high mutation rate and frequent co-mutations. Despite SC tumors exhibiting a high histological heterogeneity, some intratumoral molecular homogeneity was found. Now with newly developed targeted therapies, SC patients may be eligible for new target mutations, and can now therefore be screened for clinical trials.

Clinical and molecular features in patients with advanced non-small-cell lung carcinoma refractory to first-line platinum-based chemotherapy.

Most of the cases of non-small-cell lung cancer (NSCLC) are diagnosed at an advanced stage and are treated with platinum-doublet chemotherapy. However, some patients are refractory to this treatment. The aim of this study was to identify the clinical and molecular characteristics of patients with refractory disease. All consecutive patients between 2003 and 2006, who received a platinum-doublet chemotherapy as first-line treatment for stage IIIb-IV NSCLC, were included. Refractory patients were defined as early progressive disease (PD) at the first evaluation of chemotherapy according to WHO criteria. The clinical, histo-pathological, and molecular characteristics (EGFR: exon 19, 20, 21 and KRAS: exon 2 by PCR sequencing; ALK by immunohistochemistry) and survival of refractory patients with initial PD (r-patients) and controlled disease (c-patients) were compared by univariate analyses. Factors that differed between the two groups (p-value <0.25 in univariate analyses) were entered into multivariate analysis. In this study, 178 patients were included. The first tumor assessment was carried out after a median of three cycles (range 1-4). Forty-six (25.8%) patients were refractory. Clinical presentation was similar between r- and c-patients. The sarcomatoid histological subtype was more common in r-patients than c-patients (10.9% vs. 1.5%, respectively; p=0.057). The proportion of EGFR (5.2% vs. 9.6%, p=0.224) and KRAS mutations (11.1% vs. 5.7%, p=0.357), and the expression of ALK (6.3% vs. 2.5%, p=0.327) did not differ significantly between the two groups. In multivariate analysis, sarcomatoid histological subtype was the only factor associated with early PD (OR=7.50; 95%CI: 1.02-55.45; p=0.048). r-Patients had significantly shorter survival than c-patients (median 5 months (IQR 3.2-9.9) vs. 15.4 months (IQR 9.9-22.5), respectively; p<0.0001). In conclusion, patients with early PD under platinum-doublet chemotherapy had shorter survival than c-patients. Sarcomatoid histological subtype was the only independent factor associated with early PD.

[A simple view on lung cancer biology: The EGFR pathway]. / Un regard simple sur la biologie du cancer bronchique : EGFR.

Epidermal growth factor receptor (EGFR) is a cell membrane tyrosine kinase receptor. Activating mutations at exon 19 and 21 of the EGFR gene are associated with the occurrence and development of lung adenocarcinoma. These gain of function mutations predict responsiveness to EGFR tyrosine kinase inhibitors (TKis), erlotinib or gefitinib and are also a favorable prognostic factor in lung cancer. Sequencing is the recommended technique to detect the mutations, but other more sensitive technics are under evaluation. Treatment as first line therapy by gefitinib is limited to lung cancer patients harboring an EGFR mutation. Erlotinib can be given regardless of the EGFR status as second or third line therapy, as well as maintenance therapy in patients with a stable disease after platinum based chemotherapy. In EGFR mutated tumors, most patients present a recurrence of the disease, despite an initial response on EGFR TKis. Two mechanisms of secondary resistance have been identified, the selection of the T790M mutation in EGFR exon 20 and the MET amplification. Other molecular anomalies as the ras mutations or the EMLA-ALK protein fusion are mutually exclusive with the EGFR mutations and are associated with primary resistance to EGFR TKis.