Purpose: To analyze the impact of TP53 mutations on response to first-line tyrosine kinase inhibitors (TKI) in patients with EGFR-mutated non–small cell lung cancer (NSCLC). Experimental Design: 136 EGFR-mutated NSCLC patients receiving first-line TKIs were analyzed. TP53 mutations were evaluated in 123 patients in relation to disease control rate (DCR), objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). Results: TP53 mutations were observed in 37 (30.1%), 10 (27.0%), 6 (16.2%), 9 (24.3%), and 12 (32.4%) patients in exons 5, 6, 7, and 8, respectively. DCR was 70% in TP53-mutated patients compared with 88% in TP53-wild type (wt) patients [relative risk, RR, of disease progression: 3.17 (95% CI, 1.21–8.48), P = 0.019]. In particular, a 42% DCR was observed in patients with TP53 exon 8 mutation versus 87% in exon 8 wt patients [RR of disease progression 9.6 (2.71–36.63), P < 0.001]. Shorter median PFS and OS were observed in patients with TP53 exon 8 mutations compared with others (4.2 vs. 12.5, P = 0.058, and 16.2 vs. 32.3, P = 0.114, respectively); these differences became significant in the subgroup with EGFR exon 19 deletion (4.2 vs. 16.8, P < 0.001, and 7.6 vs. not reached, P = 0.006, respectively), HR 6.99 (95% CI, 2.34–20.87, P < 0.001) and HR 4.75 (95% CI, 1.38–16.29, P = 0.013), respectively. Conclusions: TP53 mutations, especially exon 8 mutations, reduce responsiveness to TKIs and worsen prognosis in EGFR-mutated NSCLC patients, mainly those carrying exon 19 deletions. Clin Cancer Res; 23(9); 2195–202. ©2016 AACR.

Background: Non-small cell lung cancer (NSCLC) is the primary cause of cancer-related deaths worldwide. Epidermal Growth Factor Receptor (EGFR)-mutated patients usually benefit from TKIs treatment, but a significant portion show unresponsiveness due to primary resistance mechanisms. We investigated the role of TP53 mutations in predicting survival and response to EGFR-TKIs in EGFR-mutated NSCLC patients, to confirm, on an independent case series, our previous results. Methods: An independent retrospective cohort study was conducted, on a case series of 136 EGFR-mutated NSCLC patients receiving first or second generation TKIs as a first line therapy, and a smaller fraction of patients who acquired the T790M resistance mutation and were treated with third generation TKIs in the second or further line of treatment. TP53 mutations were evaluated in relation to disease control rate (DCR), objective response rate (ORR), progression-free survival (PFS) and overall survival (OS) of the patients. Results: Forty-two patients (30.9%) showed a TP53 mutation. Considered together, TP53 mutations had no significant impact on time-to-event endpoints. Considering the different TP53 mutations separately, exon 8 mutations confirmed their negative effect on PFS (HR 3.16, 95% 1.59–6.28, p = 0.001). In patients who developed the T790M resistance mutation, treated with third generation TKIs, the TP53 exon 8 mutations predicted worse PFS (even though not statistically significant), and OS (HR 4.86, 95% CI: 1.25–18.90, p = 0.023). Conclusions: TP53 exon 8 mutations confirmed their negative prognostic impact in patients treated with first and second generation TKIs and demonstrated a role in affecting clinical outcome in patients treated with third generation TKIs.

Background: KRASmutations negatively affect outcome after treatment with cetuximab in metastatic colorectal cancer (mCRC) patients. As only 20% ofKRASwild type (WT) patients respond to cetuximab it is possible that other mutations, constitutively activating the EGFR pathway, are present in the non-respondingKRASWT patients. We retrospectively analyzed objective tumor response rate, (ORR) progression-free (PFS) and overall survival (OS) with respect to the mutational status ofKRAS,BRAF,PIK3CAand PTEN expression in mCRC patients treated with a cetuximab-based regimen.Methods: 67 mCRC patients were enrolled onto the study. DNA was extracted from paraffin-embedded sections derived from primary or metastatic lesions. Exon 2 ofKRASand exon 15 ofBRAFwere analyzed by direct sequencing,PIK3CAwas evaluated by pyrosequencing and PTEN expression by immunohistochemistry.Results: BRAFandPIK3CAmutations were independently associated with worse PFS (p = 0.006 andp = 0.028, respectively) and OS (p = 0.008 andp = 0.029, respectively). No differences in clinical outcome were found between patients who were positive or negative for PTEN expression. Conversely, patients negative forKRAS,BRAFandPIK3CAmutations were characterized by significantly better ORR, PFS and OS than patients with at least one of these mutations.Conclusions: BRAFandPIK3CAmutations would seem to be independent predictors of anti-EGFR therapy effectiveness and could be taken into consideration during treatment decision making.

Sorafenib is a multi-targeted kinase inhibitor with a demonstrated activity in renal cell carcinoma (RCC) and hepatocellular carcinoma (HCC), and it is currently used for the treatment of these pathologies. Ongoing clinical trials are studying its activity in other malignancies, such as non-small-cell lung cancer (NSCLC). However, no biological marker is known to define either the sensitivity or resistance to the drug. Here we report a case of a patient with two synchronous tumors, HCC and NSCLC, with metastases in the contralateral lung and bone. The patient was treated with gemcitabine as first line, with a resulting progressive disease after two months, and then with sorafenib at standard dosage in the second line setting. After 6 months of treatment CT scan showed a partial response in the primary lesion of the lung, complete response of the metastasis in the contralateral lung, and stability of HCC. The patient had progression in the lung, liver and bone after 13 months of therapy. A molecular characterization of NSCLC and HCC lesions was performed, revealing a BRAF exon 11 mutation (G469V) only in NSCLC. We hypothesize that the response observed in NSCLC lesions could be due to the presence of BRAF mutation, and that this alteration could be responsible in determining sorafenib sensitivity. Results observed in this case encourage further research on the activity of sorafenib in both HCC and NSCLC, based on the presence of BRAF mutation. This could lead to a selection of HCC patients to be treated with this drug, and could help identify a novel treatment strategy for BRAF-mutated NSCLC patients.